Letter and Word Perception: Orthographic Structure and Visual Processing in Reading
Transcript of Letter and Word Perception: Orthographic Structure and Visual Processing in Reading
LETTER AND WORD PERCEPTION
ADVANCES IN
PSYCHOLOGY 4
Editors
G. E. STELMACH
P. A. VROON
NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM * NEW YORK * OXFORD
LETTER AND WORD PERCEPTION
Orthographic Structure and Visual Processing in Reading
Dominic W. MASSARO Glen A. TAYLOR
Richard L. VENEZKY James E. JASTRZEMBSKI
Peter A. LUCAS and
Wisconsin Research and Development Center for Individualized Schooling
University of Wisconsin
1980
NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM * NEW YORK * OXFORD
Copyright 1980 -The Board of Regentsof the University of Wisconsin System
Copyright is claimed until 1990. Thereafter all portionsof this work covered by this copyright will be in the public domain. Thiswork was developed under agrant from the National Institute of Education, Department of Health, Education, and Welfare. However, the content does not necessarily reflect the position or policy of that Agency, and no official endorsement of these
materials should be inferred.
ISBN: 0 444 85493 2
Publishers:
NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAMoNEW YORK. OXFORD
Sole distributors for the U.S.A. and Canada:
5 2 VANDERBILT AVENUE, NEW YORK, N.Y. 10017
ELSEVIER NORTH-HOLLAND, INC.
Library of Congress Cataloging in Publieation Data
Main entry under title:
Letter and vord perception.
(Advances in psychology ; 4) Includes bibliopaphical references and indexes. 1. Reading. 2. Word recognition. 3. English
langupee--Alphabet. 4. Reading, Psychology of. I. M688az.0, Dominic W. 11. Series: Advauces in psychology (Amsterdam) 4. LBlO#O.L47 428.4 80-14350
PRINTED IN THE NETHERLANDS
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... t o c o m p l e t e l y a n a l y z e what w e d o when w e r e a d would a l m o s t b e t h e acme o f a p s y c h o l o g i s t ' s a c h i e v e m e n t s , f o r i t would b e t o d e s c r i b e v e r y many o f t h e most i n t r i c a t e w o r k i n g s o f t h e human mind , a s w e l l a s t o u n r a v e l t h e t a n g l e d s t o r y o f t h e mos t r e m a r k a b l e s p e c i f i c p e r f o r m a n c e t h a t c i v i l i z a t i o n h a s l e a r n e d i n a l l i t s h i s t o r y .
T h e s e words a r e no l e s s a p p r o p r i a t e t o d a y t h a n t h e y were when Edmund Burke Huey c o n f r o n t e d t h e c h a l l e n g e of u n d e r s t a n d i n g r e a d i n g i n 1908 . And a l t h o u g h m o s t l i t e r a t e s o c i e t i e s d e v o t e v a l u a b l e f i n a n c i a l and human r e s o u r c e s t o u n d e r s t a n d i n g r e a d i n g , i t o f t e n seems a s i f w e a r e no n e a r e r t o a c h i e v i n g t h i s g o a l . However, some p r o g r e s s i s a p p a r e n t . I t is g e n e r a l l y a g r e e d t h a t r e a d i n g i n v o l v e s t h e u t i l i z a t i o n of a v a s t r a n g e o f p e r f o r m a n c e s k i l l s a l o n g w i t h t h e a c t i v e a p p l i c a t i o n o f t h e knowledge r e s o u r c e s o f t h e r e a d e r . The g o a l f o r t h e r e s e a r c h e r , i s t o d e s c r i b e e a c h o f t h e s k i l l s and t o e v a l u a t e how knowledge c o n t r i b u t e s t o t h e s k i l l e d p e r f o r m a n c e .
Our r e s e a r c h i n v e s t i g a t e s how knowledge o f t h e o r t h o g r a p h y ( r u l e s o f s p e l l i n g ) is a c t i v e l y engaged i n l e t t e r and word p e r c e p t i o n o f s k i l l e d r e a d e r s . As m i g h t b e e x p e c t e d , o u r r e s e a r c h e n t e r p r i s e had i t s s h a r e o f b o t h s u b s t a n t i v e a d v a n c e s i n o u r u n d e r s t a n d i n g o f b a s i c p s y c h o l o g i c a l p r o c e s s e s and d i s t r a c t i n g g l a n c e s a t some o f t h e m i n d ' s b e w i l d e r i n g i n c o n s i s t e n c i e s . Our g o a l i n t h i s monograph is t o communica te b o t h t h e p r o g r e s s and some o f t h e d i s t r a c t i o n t h a t we
vi i
Preface
v i i i PREFACE
e x p e r i e n c e d . Because o f t h e d e t a i l e d p r e s e n t a t i o n s o f v a r i o u s d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , t h e ex tended s e r i e s o f e x p e r i m e n t a l s t u d i e s , and t h e f i n e - g r a i n e d a n a l y s e s o f t h e c o n t r i b u t i o n of many d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , piecemeal p u b l i c a t i o n s o f t h i s r e s e a r c h e f f o r t would have been i n a p p r o p r i a t e . T h i s monograph p r o v i d e s t h e c h a l l e n g e of n o t o n l y communicating a p r o t r a c t e d r e s e a r c h e n t e r p r i s e b u t a l s o a n i l l u m i n a t i n g and i n t e r n a l l y - c o n s i s t e n t a c c o u n t o f how r e a d e r s u t i l i z e knowledge o f o r t h o g r a p h i c s t r u c t u r e i n l e t t e r and word p e r c e p t i o n . The s u c c e s s o f t h i s work w i l l be e v a l u a t e d by t h e r e s e a r c h e r , and m u s t s t a n d t h e t e s t o f i t s a p p l i c a b i l i t y t o reading i n s t r u c t ion.
Given t h e r e l a t i v e l y l a r g e number of new e x p e r i m e n t a l s t u d i e s t o be r e p o r t e d , w e d e c i d e d t o o m i t t h e unimpor tan t d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s i n t h e a c t u a l d i s c u s s i o n o f t h e e x p e r i m e n t s i n Chapter 4 . However, s i n c e t h i s i n f o r m a t i o n is s t i l l of i n t e r e s t t o many p o t e n t i a l r e a d e r s and r e s e a r c h e r s , i t h a s been p laced i n a p p e n d i c e s a t t h e end of Chapter 4 . Each e x p e r i m e n t a l s t u d y i s numbered i n Chapter 4 and i t s appendix is g i v e n t h e same number. By p l a c i n g unnecessary d e t a i l s i n a p p e n d i c e s , i t is e a s i e r t o m a i n t a i n t h e l o g i c a l c o n t i n u i t y i n t h e p r e s e n t a t i o n of t h e e x p e r i m e n t a l s t u d i e s . When n e c e s s a r y , t h e r e a d e r can a lways t u r n d i r e c t l y t o t h e r e l e v a n t appendix f o r a d d i t i o n a l i n f o r m a t i o n .
I n a d d i t i o n , Appendix 5.1 g i v e s t h r e e performance measures f o r each o f o u r 200 s t i m u l u s i t e m s so t h a t t h e i n t e r e s t e d i n v e s t i g a t o r c a n t e s t a d d i t i o n a l d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e w i t h t h e s e d a t a . S i n c e s u b l e x i c a l p o s i t i o n - s e n s i t i v e s i n g l e - l e t t e r and bigram c o u n t s a r e i m p o r t a n t components o f o r t h o g r a p h i c s t r u c t u r e , Appendix 5 . 2 and 5.3 p r e s e n t n o r m a t i v e c o u n t s based on a sample o f roughly o n e m i l l i o n words o f p r i n t e d t e x t . The o n l y c o u n t s c u r r e n t l y a v a i l a b l e i n p r i n t a r e based on a sample o n l y 2 % a s l a r g e . These c o u n t s s h o u l d be v a l u a b l e t o r e s e a r c h e r s and e d u c a t o r s i n t e r e s t e d i n t h e normat ive s t r u c t u r e of Eng 1 i s h o r t h o g r a p h y .
The pr imary o b j e c t i v e of t h i s monograph is t h e p r e s e n t - a t i o n o f our new e m p i r i c a l and t h e o r e t i c a l r e s e a r c h . Because of s p a c e l i m i t a t i o n s , we were unable t o rev iew much o f t h e o t h e r r e l e v a n t r e s e a r c h i n l e t t e r and word p e r c e p t i o n . For rev iews o f t h i s r e s e a r c h , t h e r e a d e r is r e f e r r e d t o A l l p o r t ( 1 9 7 9 ) , Baron ( 1 9 7 8 ) , E s t e s (1977, 1 9 7 8 ) , Gibson and Levin ( 1 9 7 5 ) , Henderson ( 1 9 7 7 ) , Johnson (19771, Krueger ( 1 9 7 5 ) ,
PREFACE ix
Massa ro ( 1 9 7 5 , 1 9 7 8 , 1 9 7 9 b , i n p r e s s ) , and P o l l a t s e k and Carr ( 1 9 7 9 ) .
T h i s r e s e a r c h i s t h e ou tcome o f c o n t r i b u t i o n s o f f i v e r e l a t i v e l y d i s p a r a t e r e s e a r c h e r s . I n time, t h e need t o u n d e r s t a n d l e t t e r and word p e r c e p t i o n became t h e d r i v i n g , f o r c e and o u r o r i g i n a l b i a s e s and b e l i e f s were e v e n t u a l l y m o d i f i e d by a c t u a l e x p e r i m e n t a t i o n and t h e o r t i c a l tests. I f t h i s c o n t r i b u t i o n b e n e f i t s r e a d i n g r e s e a r c h h a l f a s much a s i t b e n e f i t e d e a c h o f t h e p a r t i c i p a n t s f rom t h e c o l l a b o r a t i v e e f f o r t s , t h e n t h e p r o j e c t c a n b e c o n s i d e r e d t o b e a s u c c e s s .
T h i s r e s e a r c h e f f o r t h a s b e e n s u p p o r t e d by f u n d s from t h e N a t i o n a l I n s t i t u t e o f E d u c a t i o n t o t h e W i s c o n s i n R e s e a r c h and Development C e n t e r f o r I n d i v i d u a l i z e d S c h o o l i n g , U n i v e r s i t y o f W i s c o n s i n , Mad i son , W i s c o n s i n 53706 U . S . A . J a c k Wende and Rod McCoy c o n t r i b u t e d t o t h e d e v e l o p m e n t o f t h e c o m p u t e r - c o n t r o l l e d r e s e a r c h f a c i l i t i e s . David K l i t z k e was r e s p o n s i b l e f o r some o f t h e compute r programming, S u s a n C h i c o n e t e s t e d some o f t h e s u b j e c t s . J e n n i f e r A r g e l a n d e r e d i t e d and D o r i s King t y p e d t h e m a n u s c r i p t u s i n g a n o t a l w a y s s t r a i g h t f o r w a r d c o m p u t e r - e d i t i n g s y s t e m . Bob Cavey d r e w t h e many g r a p h s . Don Ander son c o n t r i b u t e d t h e ABC p r i n t .
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PREFACE vi i
1. READING AND INFORMATION PROCESSING . . . . . . . . . . 1
An Information Processing Model of Reading 2
2. VISUAL INFORMATION . . . . . . . . . . . . . . . . . . 1 1
Early Work 11 Feature Analysis 13 Letter Features 14
3. Orthographic Structure . . . . . . . . . . . . . . . . 23
Statistical Redundancy 24 Phonologically Based Descriptions 29 Rule-Governed Regularity 30
Phonological Constraints 30 Scribal Constraints 31 Morphemic Featukes 3 2 Psychological Assumptions 34 Dichotomy Issue 34
An Initial Algorithm for Rule-Governed Regularity 35
4. EXPERIMENTAL STUDIES . 0 . . . . . . m 37
xi
Contents
xii CONTENTS
M a s s a r o e t a l . 1979 S t u d i e s 38 S t u d y 1: I n i t i a l R e p l i c a t i o n s 47
P r o c e d u r e 47 O r t h o g r a p h i c S t r u c t u r e 49 S i m i l a r i t y E f f e c t s 5 1 T a r g e t - C a t c h D i f f e r e n c e s 55
I n f o r m a t i o n P r o c e s s i n g Model 55 S t u d y 2: P r e c u e V e r s u s P o s t c u e 6 1
O r t h o g r a p h i c S t r u c t u r e 6 3 S i m i l a r i t y E f f e c t s 64 T a r g e t V e r s u s C a t c h T r i a l s 6 5 I n f o r m a t i o n P r o c e s s i n g Model 6 6
O r t h o g r a p h i c S t r u c t u r e 69 S i m i l a r i t y E f f e c t s 70
S t u d y 4 : L i m i t e d Viewing Time 7 1 O r t h o g r a p h i c S t r u c t u r e 7 1 S i m i l a r i t y E f f e c t s 7 2 T a r g e t V e r s u s C a t c h T r i a l s 7 3 D i s c u s s i o n 7 3
S t u d y 3: Mixed-Case 67
S t u d y 5 : Speeded RT T a s k w i t h Good V i s u a l I n f o r m a t i o n 7 3
P r o c e d u r e 7 6 O r t h o g r a p h i c S t r u c t u r e 77
S t u d y 6: Speeded RT Task w i t h Poor V i s u a l I n f o r m a t i o n 7 7
P r o c e d u r e 78 O r t h o g r a p h i c S t r u c t u r e 78
S t u d y 7 : H igh-Accuracy RT Task w i t h P o o r V i s u a l I n f o r m a t i o n 7 9
P r o c e d u r e 79 O r t h o g r a p h i c S t r u c t u r e 79
Summary o f A c c u r a c y and R e a c t i o n
O v e r t J u d g m e n t s 8 1 S t u d y 8 : T y p i c a l i t y R a t i n g s 8 2 S t u d y 9 : P o s i t i o n a l - F r e q u e n c y R a t i n g s 8 5 S t u d y 1 0 : R e g u l a r i t y V e r s u s
Summary of O v e r t J u d g m e n t E x p e r i m e n t s 90
Time E x p e r i m e n t s 8 0
P o s i t i o n a l - F r e q u e n c y J u d g m e n t s 8 7
CONTENTS xiii
A p p e n d i x 4 . 1 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 1: I n i t i a l R e p l i c a t i o n 9 1
Method 9 1 R e s u l t s 9 4
A p p e n d i x 4.1A R u l e s f o r t h e S e l e c t i o n o f O r t h o g r a p h i c a l l y R e g u l a r a n d I r r e g u l a r S t r i n g s 9 6
A p p e n d i x 4 . 1 8 T h e 200 S t i m u l u s Items Used i n S t u d i e s 1-10 9 7
A p p e n d i x 4 . 2 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 2: P r e c u e V e r s u s P o s t c u e 9 9
Method 9 9 R e s u l t s 1 0 0
A p p e n d i x 4 . 3 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 3: M i x e d - C a s e 1 0 1
Method 0 1 R e s u l t s 1 0 1
A p p e n d i x 4 . 4 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 4: L i m i t e d V i e w i n g T i m e 1 0 3
Method 1 0 3 R e s u l t s 1 0 3
A p p e n d i x 4 . 5 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 5 : S p e e d e d RT T a s k w i t h Good V i s u a l I n f o r m a t i o n 1 0 5
Method 1 0 5 R e s u l t s 1 0 6
A p p e n d i x 4 . 6 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 6 : S p e e d e d RT T a s k w i t h P o o r V i s u a l I n f o r m a t i o n 1 0 8
Method 1 0 8 R e s u l t s 1 0 8
A p p e n d i x 4 . 7 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 7: H i g h - A c c u r a c y RT T a s k w i t h P o o r V i s u a l I n f o r m a t i o n 111
Method 111 R e s u l t s 111
A p p e n d i x 4 . 8 D e t a i l s o f M e t h o d , P r o c e d u r e , a n d R e s u l t s o f S t u d y 8 : T y p i c a l i t y R a t i n g s 113
Method 1 1 3 R e s u l t s 1 1 4
A p p e n d i x 4.8A T h e P s e u d o w o r d s Used i n S t u d y 8 1 1 5
xiv CONTENTS
Appendix 4.88 Directions for Typicality Ratings Without Words and for Typicality Ratings with
Pseudowords 116 Appendix 4.8C Directions for Typicality Ratings with
Appendix 4.9 Details of Method, Procedure, and Words 117
Results of Study 9: Positi,onal-Frequency Ratings 118 Method 118 Results 118
Appendix 4.9A Directions for Positional-Frequency
Appendix 4.10 Details of Method, Procedure, and Ratings 119
Results of Study 10: Regularity Versus Positional-Frequency Paired-Judgments 120
Method 120 Results 121
Appendix 4.10A Regularity Instructions for
Appendix 4.108 Positional-Frequency Instructions Paired-Judgments 122
for Paired-Judgments 123
5. STRUCTURAL DESCRIPTIONS . . . . . . . Descriptive Measures 125 Type Versus Token Counts 128 Scale of Frequency 130 Position-Sensitive Versus Position
The Most Effective Frequency Measure Frequency Versus Regularity 138 Within Class Analysis 140 Word Frequency 141 Multiple Regression 141 Summary 142
Insensitive Counts 132
. . . . . . . 125
133
Appendix 5.1 Stimulus Items and Results 143 Appendix 5.2 Single-Letter Positional Frequencies 149
Three-letter Words 150 Four-letter Words 152 Five-letter Words 154 Six-letter Words 156 Seven-letter Words 158
CONTENTS xv
Appendix 5.3 Bigrarn Positional Frequencies 160 Three-letter Words 161 Four-letter Words 172 Five-letter Words 188 Six-letter Words 205 Seven-letter Words 224
6. SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . . 245
REFERENCES 249 GLOSSARY 263 AUTHOR INDEX 269 SUBJECT INDEX 275
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1 Reading and Information Processing
The p r o c e s s e s by which words a r e r e c o g n i z e d d u r i n g r e a d i n g h a v e c o n c e r n e d p s y c h o l o g i s t s and e d u c a t o r s f o r almost a c e n t u r y . The b a s i c a s s u m p t i o n is t h a t a t h o r o u g h u n d e r s t a n d i n g o f t h e p r o c e s s e s i n v o l v e d i n word r e c o g n i t i o n w i l l a f f o r d a m a j o r a d v a n c e i n t h e u n d e r s t a n d i n g o f how p e o p l e r e a d . E v e r y m a j o r t r e a t i s e on r e a d i n g from Huey (1908 /1968) t o G i b s o n and L e v i n ( 1 9 7 5 ) h a s d i s c u s s e d t h i s i s sue a t l e n g t h , b u t g e n e r a l l y h a s c o n c l u d e d , a s d i d Huey ( 1 9 0 8 / 1 9 6 8 , p. 1 0 2 ) , t h a t " i t is v e r y d i f f i c u l t t o d raw f i n a l c o n c l u s i o n s c o n c e r n i n g v i s u a l p e r c e p t i o n i n r e a d i n g . . . ."
R e c e n t l y two d i f f e r e n t p a n e l s wh ich recommended f u n d i n g p r i o r i t i e s i n b a s i c s k i l l s r e s e a r c h t o t h e N a t i o n a l I n s t i t u t e o f E d u c a t i o n a s s i g n e d h i g h p r i o r i t i e s t o s t u d i e s on word r e c o g n i t i o n . C o n s e q u e n t l y , a h i g h p r i o r i t y c u r r e n t l y i s b e i n g g i v e n t o o b t a i n i n g a b e t t e r u n d e r s t a n d i n g o f word r e c o g n i t i o n w i t h s t r e s s on t h e b a s i c s t a g e s of v i s u a l i n f o r m a t i o n p r o c e s s i n g . I n f o r m a t i o n p r o c e s s i n g d u r i n g r e a d i n g is c u r r e n t l y t h e p r i m a r y c o n c e r n o f many e x p e r i m e n t a l p s y c h o l o g i s t s , and t h e r e f o r e , a n e x p a n d i n g body o f e x p e r i m e n t a l d a t a is b e i n g b r o u g h t t o b e a r on t h e s e q u e s t i o n s . S i n c e word r e c o g n i t i o n f o r m s a b r i d g e be tween v i s u a l i n f o r m a t i o n p r o c e s s i n g s k i l l s and c o m p r e h e n s i o n , i t is i m p o r t a n t f o r u n d e r s t a n d i n g how t h e two r e l a t e t o e a c h o t h e r .
R e s e a r c h on word r e c o g n i t i o n p r o c e s s e s is s e e n a s h a v i n g a h i g h p o t e n t i a l f o r improv ing r e a d i n g i n s t r u c t i o n . Good and poor r e a d e r s h a v e been shown t o d i f f e r i n p e r f o r m a n c e o n a v a r i e t y o f g e n e r a l t a s k s b u t u n t i l r e c e n t l y , l i t t l e a t t e m p t h a s been made t o e x p l o r e how c h i l d r e n w i t h d i f f e r e n t l e v e l s o f r e a d i n g a b i l i t y m i g h t d i f f e r i n b a s i c word r e c o g n i t i o n p r o c e s s e s . We b e l i e v e t h a t b a s i c word r e c o g n i t i o n p r o c e s s e s ,
2 CHAPTER 1
once d e f i n e d f o r competent a d u l t r e a d e r s , c a n be used t o a s s e s s word r e c o g n i t i o n a b i l i t i e s of good and poor r e a d e r s i n t h e e l e m e n t a r y g r a d e s . ~f good and poor r e a d e r s u t i l i z e t h e same p r o c e s s e s , b u t d i f f e r i n speed or a c c u r a c y , t h e n r e m e d i a t i o n methods based on common approaches t o r e a d i n g i n s t r u c t i o n would be w a r r a n t e d . However, i f fundamental d i f f e r e n c e s i n v i s u a l r e c o g n i t i o n p r o c e s s e s a r e found, t h e n t o t a l l y d i f f e r e n t remedia l methods would be r e q u i r e d .
The o v e r a l l o b j e c t i v e of t h i s r e s e a r c h p r o j e c t i s t o a s s e s s how t h e r e a d e r ' s h i g h e r - o r d e r knowledge of t h e l a n g u a g e i n t e r a c t s w i t h l o w e r - l e v e l p e r c e p t u a l a n a l y s e s d u r i n g r e a d i n g . The s p e c i f i c q u e s t i o n t h a t is a d d r e s s e d is how t h e r e a d e r ' s a b s t r a c t knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e is combined wi th t h e i n f o r m a t i o n d e r i v e d from v i s u a l f e a t u r a l a n a l y s i s i n word r e c o g n i t i o n . O r t h o g r a p h i c s t r u c t u r e r e f e r s t o t h e s p e l l i n g c o n s t r a i n t s i n a w r i t t e n l a n g u a g e . There is a c o n s i d e r a b l e amount of p r e d i c t a b i l i t y i n E n g l i s h w r i t i n g , f o r example, and t h e r e a d e r may a c t i v e l y u t i l i z e t h i s i n f o r m a t i o n i n word r e c o g n i t i o n . V i s u a l f e a t u r a l a n a l y s i s r e f e r s t o t h e e v a l u a t i o n of component p r o p e r t i e s of l e t t e r s i n t h e c o u r s e of l e t t e r and word r e c o g n i t i o n . Given e v i d e n c e t h a t bo th of t h e s e s o u r c e s o f i n f o r m a t i o n c o n t r i b u t e t o word r e c o g n i t i o n , t h e g o a l i s t o d e f i n e what i n f o r m a t i o n t h e r e a d e r a c t u a l l y u t i l i z e s (what i n f o r m a t i o n i s p s y c h o l o g i c a l l y r e a l ) and t o d e f i n e how t h e s e s o u r c e s of i n f o r m a t i o n a r e i n t e g r a t e d t o g e t h e r i n r e a d i n g . T h i s r e q u i r e s examinat ion of t h e p s y c h o l o g i c a l r e a l i t y of v a r i o u s d e s c r i p t i o n s of v i s u a l f e a t u r e s , of o r t h o g r a p h i c s t r u c t u r e , and of q u a n t i t a t i v e models t h a t d e s c r i b e how v i s u a l f e a t u r e s and o r t h o g r a p h i c s t r u c t u r e a r e i n t e g r a t e d d u r i n g word p e r c e p t i o n and r e c o g n i t i o n .
AN INFORMATION PROCESSING MODEL OF R E A D I N G
E v a l u a t i o n of t h e c o n t r i b u t i o n s of v i s u a l f e a t u r e s and o r t h o g r a p h i c s t r u c t u r e t o word r e c o g n i t i o n r e q u i r e s t h a t we d e s c r i b e i n some d e t a i l t h e p r o c e s s e s involved i n r e a d i n g . The model f o r d e s c r i b i n g t h e s e p r o c e s s e s is p a r t of a more g e n e r a l language p r o c e s s i n g model which has been developed and t e s t e d over t h e p a s t few y e a r s (Massaro, 1975, 1978, 1 9 7 9 a ) . F i g u r e 1.1 p r e s e n t s a s c h e m a t i c r e p r e s e n t a t i o n of t h e s t a g e s of p r o c e s s i n g i n r e a d i n g . A t each s t a g e of p r o c e s s i n g , memory and p r o c e s s components a r e r e p r e s e n t e d . Each memory component ( i n d i c a t e d by a r e c t a n g l e ) c o r r e s p o n d s t o t h e i n f o r m a t i o n a v a i l a b l e a t a p a r t i c u l a r s t a g e of p r o c e s s i n g . Each p r o c e s s
R E A D I N G AND INFORMATION PROCESSING 3
component ( i n d i c a t e d by a c i r c l e ) c o r r e s p o n d s t o t h e o p e r a t i o n s a p p l i e d t o t h e i n f o r m a t i o n h e l d by t h e memory component. The memory components a r e temporary s t o r a g e s e x c e p t f o r long-term memory which is r e l a t i v e l y permanent a n d , i n a d d i t i o n , supplements t h e i n f o r m a t i o n a t some of t h e p r o c e s s i n g s t a g e s . T h i s model p r o v i d e s a framework from which h y p o t h e s e s a b o u t word r e c o g n i t i o n can be d e r i v e d and t e s t e d .
The t y p i c a l t e x t i n r e a d i n g i s a sequence of l e t t e r s and s p a c e s which conform t o o r t h o g r a p h i c , s y n t a c t i c , and s e m a n t i c c o n s t r a i n t s of t h e w r i t t e n language . The a v e r a g e E n g l i s h r e a d e r b e g i n s a t t h e t o p l e f t - h a n d c o r n e r of t h e page and r e a d s each l i n e from l e f t t o r i g h t . The r e a d e r ' s eye movements a c r o s s a l i n e a r e n o t c o n t i n u o u s b u t occur i n a s e r i e s of s h o r t jumps c a l l e d s a c c a d e s . The f i x a t i o n time between s a c c a d e s is r o u g h l y t e n times l o n g e r t h a n t h e s a c c a d e . The t y p i c a l s a c c a d e of 1 t o 2 d e g r e e s r e q u i r e s 2 0 t o 30 msec, whereas f i x a t i o n t ime a v e r a g e s 250 msec ( S h e b i l s k e , 1975; Woodworth, 1 9 3 8 ) . I n i t i a l p r o c e s s i n g of t h e v i s u a l s t i m u l u s m u s t O C C U K d u r i n g t h e f i x a t i o n time because t h e s t i m u l u s p a t t e r n is b l u r r e d d u r i n g a s a c c a d e and i t s d u r a t i o n is t o o s h o r t f o r s u f f i c i e n t p r o c e s s i n g t o o c c u r . During an eye f i x a t i o n , t h e l i g h t p a t t e r n r e f l e c t e d from l e t t e r s i s t r a n s d u c e d by t h e v i s u a l r e c e p t o r s and a p r o c e s s d e t e c t s and t r a n s m i t s v i s u a l f e a t u r e s t o p r e p e r c e p t u a l v i s u a l s t o r a g e ( s e e F i g u r e 1.1). I n our model, w e c a l l t h i s i n i t i a l p r o c e s s f e a t u r e d e t e c t i o n . The f e a t u r e s a r e d e s c r i b e d a s v i s u a l because i t is assumed t h a t t h e r e i s a d i r e c t r e l a t i o n s h i p between t h e s t i m u l u s p r o p e r t i e s of t h e l e t t e r s and
LONG TERM MEMORY
t T
MEMORY MEMORY
F i g u r e 1.1 A s t a g e model of r e a d i n g p r i n t e d t e x t .
CHAPTER 1
t h e i n f o r m a t i o n i n p r e p e r c e p t u a l v i s u a l s t o r a g e . The p a s s i v e t r a n s d u c t i o n of f e a t u r e d e t e c t i o n c o n t r a s t s w i t h t h e a c t i v e c o n s t r u c t i o n of t h e s u b s e q u e n t p r o c e s s i n g s t a g e s . There is no e x a c t one-to-one r e l a t i o n s h i p between t h e i n p u t and o u t p u t of t h e f o l l o w i n g p r o c e s s i n g s t a g e s s i n c e t h e s e l a t e r s t a g e s a c t i v e l y u t i l i z e i n f o r m a t i o n s t o r e d i n long-term memory.
Given t h e se t of v i s u a l f e a t u r e s i n p r e p e r c e p t u a l v i s u a l s t o r a g e , t h e p r i m a r y r e c o g n i t i o n p r o c e s s a t t e m p t s t o t r a n s f o r m t h e s e i s o l a t e d f e a t u r e s i n t o a sequence of l e t t e r s and s p a c e s i n s y n t h e s i z e d v i s u a l memory. To d o t h i s , t h e p r i m a r y r e c o g n i t i o n p r o c e s s can u t i l i z e i n f o r m a t i o n h e l d i n long-term memory which f o r t h e accomplished r e a d e r i n c l u d e s a l i s t of f e a t u r e s f o r each l e t t e r of t h e a l p h a b e t a l o n g w i t h i n f o r m a t i o n a b o u t t h e o r t h o g r a p h i c s t r u c t u r e of t h e l a n g u a g e . The p r i m a r y r e c o g n i t i o n p r o c e s s u t i l i z e s both t h e v i s u a l f e a t u r e s i n p r e p e r c e p t u a l s t o r a g e and knowledge of o r t h o g r a p h i c s t r u c t u r e i n i t s s y n t h e s i s of t h e l e t t e r s t r i n g s . The t ime-honored b e l i e f t h a t r e c o g n i t i o n of l e t t e r s t r i n g s becomes p r o g r e s s i v e l y e a s i e r a s t h e s t r i n g s more c l o s e l y approximate words i m p l i e s t h a t r e a d e r s c a p i t a l i z e on t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e . Recogni t ion u s u a l l y means t h e p r o c e s s of d i s - c r i m i n a t i n g , i d e n t i f y i n g , and c o r r e c t l y o r d e r i n g t h e l e t t e r s of a l e t t e r s t r i n g (Smi th , 1 9 7 1 ) . Given t h i s i n t e r p r e t a t i o n of r e c o g n i t i o n , t h e f a c i l i t a t i n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e on l e t t e r - s t r i n g r e c o g n i t i o n m u s t a l m o s t be t r u e by d e f i n i t i o n . Recogni t ion i n v o l v e s a c c e s s i n g knowledge b u i l t up through e x p e r i e n c e . I t is o n l y n a t u r a l t h a t a r e a d e r ' s e x p e r i e n c e w i t h words w i l l g e n e r a l i z e more t o w o r d l i k e t h a n nonwordl ike s t r i n g s . Our g o a l s i n t h i s r e s e a r c h endeavor a r e t o p r o v i d e a b e t t e r u n d e r s t a n d i n g of t h e r e c o g n i t i o n p r o c e s s and t o e v a l u a t e which a s p e c t s of o r t h o g r a p h i c s t r u c t u r e t h e r e a d e r knows and u t i l i z e s .
The c e n t r a l assumpt ion a d d r e s s e d h e r e i s t h a t o r t h o g r a p h i c s t r u c t u r e i n f l u e n c e s p e r c e p t u a l r e c o g n i t i o n ( p r i m a r y r e c o g n i t i o n i n our m o d e l ) , i n a d d i t i o n t o o t h e r i n f l u e n c e s a t l a t e r s t a g e s of p r o c e s s i n g . We b e l i e v e t h a t o r t h o g r a p h i c s t r u c t u r e a l s o f a c i l i t a t e s p r o c e s s i n g from a p e r c e p t u a l t o a c o n c e p t u a l l e v e l ( s e c o n d a r y r e c o g n i t i o n i n our m o d e l ) . By f o c u s i n g on t h e f a c i l i t a t i n g e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on v i s u a l p e r c e p t i o n , w e have a l i g n e d o u r s e l v e s w i t h a t r a d i t i o n over 100 y e a r s o l d concerned w i t h how knowledge i n f l u e n c e s p e r c e p t i o n . James (1890/1950, p. 4 4 4 ) c a p t u r e d t h e s p i r i t of t h e work begun by Wundt w i t h t h e o f t e n quoted s t a t e m e n t , " . . . t h e o n l y t h i n g s which w e commonly s e n a r e t h o s e which w e p r e p e r c e i v e . "
R E A D I N G AND INFORMATION PROCESSING 5
In our model , t h e p r imary r e c o g n i t i o n p r o c e s s e v a l u a t e s t h e f e a t u r e s i n p r e p e r c e p t u a l v i s u a l s t o r a g e and compares o r matches t h e s e f e a t u r e s t o d e s c r i p t i o n s of p e r c e p t u a l u n i t s i n long-term memory. A p e r c e p t u a l u n i t o r p r o t o t y p e r e p r e s e n t s each of t h e l e t t e r s i n long- te rm memory a s i t would be i d e a l l y r e p r e s e n t e d i n p r e p e r c e p t u a l v i s u a l s t o r a g e . The p r i m a r y r e c o g n i t i o n p r o c e s s s e e k s f o r each l e t t e r p o s i t i o n t h e p e r c e p t u a l p r o t o t y p e t h a t p r o v i d e s t h e b e s t match t o t h e f e a t u r a l i n f o r m a t i o n . I t is a t p r imary r e c o g n i t i o n t h a t o r t h o g r a p h i c s t r u c t u r e r e d u c e s u n c e r t a i n t y o r c o n t r i b u t e s i n f o r m a t i o n . The outcome of pr imary r e c o g n i t i o n i s , t h e r e f o r e , t h e j o i n t p r o d u c t of f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l v i s u a l s t o r a g e and knowledge of l e t t e r c o n s t r a i n t s i n long- te rm memory.
S i n c e t h e r e a r e a l i m i t e d number of ways t h a t s e q u e n c e s of l e t t e r s and l e t t e r g r o u p s c a n be assembled t o form E n g l i s h words, knowledge of t h e s e s e q u e n c e s can h e l p t h e r e a d e r t o r e s o l v e t h e l e t t e r s i n s t r i n g s t h a t conform t o t h e l a n g u a g e ( c f . Massaro, 1975, Chapter 7 ) . I t a l s o h a s been h y p o t h e s i z e d t h a t t h i s knowledge c a n a s s i s t t h e r e a d e r i n d e t e r m i n i n g t h e r e l a t i v e p o s i t i o n s of l e t t e r s once t h e y a r e r e c o g n i z e d ( E s t e s , 1975a , 1 9 7 5 b ) . For example, g i v e n t h e l e t t e r s &, knowledge of o r t h o g r a p h i c s t r u c t u r e d o e s n o t a l l o w t h e s e l e t t e r s t o be read i n t h e o p p o s i t e o r d e r . However, G e o f f r i o n (1976) found t h a t t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is n o t dependent on d e t e r m i n i n g t h e r e l a t i v e p o s i t i o n s of l e t t e r s . I n a d d i t i o n , r e c e n t r e s e a r c h by MaSSaKO (1979a) found a l a r g e e f f e c t of o r t h o g r a p h i c s t r u c t u r e on l e t t e r r e c o g n i t i o n b u t no e f f e c t on t h e d e t e r m i n a t i o n of r e l a t i v e s p a t i a l p o s i t i o n . I n t h e p r e s e n t r e s e a r c h , t h e e x p e r i m e n t s a r e d e s i g n e d such t h a t any f a c i l i t a t i n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e a t p r i m a r y r e c o g n i t i o n m u s t be due t o l e t t e r r e c o g n i t i o n and n o t p o s i t i o n u n c e r t a i n t y .
The p r i m a r y r e c o g n i t i o n p r o c e s s o p e r a t e s on a number of l e t t e r s s i m u l t a n e o u s l y ( i n p a r a l l e l ) . The v i s u a l f e a t u r e s d e t e c t e d a t each s p a t i a l l o c a t i o n d e f i n e a s e t of p o s s i b l e l e t t e r s f o r t h a t p o s i t i o n . The pr imary r e c o g n i t i o n p r o c e s s chooses from t h i s s e t of c a n d i d a t e s t h e l e t t e r a l t e r n a t i v e which h a s t h e b e s t cor respondence i n t e r m s of v i s u a l f e a t u r e s . However, t h e s e l e c t i o n of a b e s t c o r r e s p o n d e n c e can be f a c i l i t a t e d by knowledge of o r t h o g r a p h i c s t r u c t u r e . The pr imary r e c o g n i t i o n p r o c e s s , t h e r e f o r e , a t t e m p t s t o u t i l i z e bo th t h e f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l s t o r a g e and knowledge a b o u t t h e s t r u c t u r e of l e g a l l a t t e r s t r i n g s . A
c r i t i c a l concern is w i t h t h e i n t e r a c t i o n of t h e s e two s o u r c e s
CHAPTER 1
of i n f o r m a t i o n ; i n our model , i t is assumed t h a t t h e two s o u r c e s of i n f o r m a t i o n make independent c o n t r i b u t i o n s t o pr imary r e c o g n i t i o n (Massaro, 1973, 1975, 1978, 1979b; Thompson & Massaro, 1 9 7 3 ) .
The p r e s e n t a n a l y s i s of t h e f a c i l i t a t i o n of o r t h o g r a p h i c s t r u c t u r e i n l e t t e r r e c o g n i t i o n is i d e n t i c a l i n s p i r i t t o t h e o r i g i n a l a n a l y s i s provided by M i l l e r , Bruner , and Postman ( 1 9 5 4 ) . They observed t h a t t h e number of l e t t e r s c o r r e c t l y r e p o r t e d from a t a c h i s t o s c o p i c e x p o s u r e i n c r e a s e d w i t h i n c r e a s e s i n f a m i l i a r i t y of t h e l e t t e r p a t t e r n . The f a m i l i a r i t y of t h e l e t t e r sequences was v a r i e d by t h e d e g r e e t o which t h e sequence approximated p r i n t e d E n g l i s h (Shannon, 1 9 4 8 ) . U t i l i z i n g t h e t h e o r y of i n f o r m a t i o n developed by Shannon ( 1 9 4 8 ) , however, t h e y observed t h a t t h e number of l e t t e r s r e p o r t e d i s n o t a d i r e c t index of t h e amount of s t i m u l u s i n f o r m a t i o n d e r i v e d from t h e e x p o s u r e i t s e l f s i n c e t h e redundancy of c o n t e x t u a l l y c o n s t r a i n e d s e q u e n c e s is n o t t a k e n i n t o a c c o u n t .
M i l l e r e t a l . (1954) c a l c u l a t e d t h e redundancy o f t h e i r sequences a t e a c h o r d e r of approximat ion t o E n g l i s h u s i n g t h e c o u n t s g i v e n by Shannon (1951) and c o u n t s of t h e i r own. When performance was c o r r e c t e d f o r redundancy, t h e r e was no e f f e c t of f a m i l i a r i t y (see a l s o T u l v i n g , 1 9 6 3 ) . T h i s r e s u l t was i n t e r p r e t e d t o mean t h a t t h e amount o f s t i m u l u s i n f o r m a t i o n r e c e i v e d from t h e e x p o s u r e d i d n o t depend on t h e f a m i l i a r i t y of t h e l e t t e r p a t t e r n . I n te rms of our a n a l y s i s , over two d e c a d e s l a t e r , t h e r e s u l t s c a n be i n t e r p r e t e d t o mean t h a t o r t h o g r a p h i c s t r u c t u r e and v i s u a l i n f o r m a t i o n c o n t r i b u t e independent s o u r c e s of i n f o r m a t i o n i n r e a d i n g .
The c u r r e n t view was d e v e l o p e d , i n p a r t , on t h e b a s i s o f e x p e r i m e n t s c a r r i e d o u t u s i n g t h e Reicher-Wheeler paradigm i n word r e c o g n i t i o n ( R e i c h e r , 1969; Wheeler , 1970; Thompson &
Massaro, 1 9 7 3 ) . I n t h i s paradigm, s u b j e c t s a r e p r e s e n t e d w i t h e i t h e r a t e s t word o r a s i n g l e t e s t l e t t e r f o r a s h o r t d u r a t i o n fo l lowed immediately by a masking s t i m u l u s and two r e s p o n s e a l t e r n a t i v e s . The r e s p o n s e a l t e r n a t i v e s both s p e l l words i n t h e t e s t word c o n d i t i o n ; f o r example, g i v e n t h e t e s t s t i m u l u s WORD, t h e r e s p o n s e a l t e r n a t i v e s ---g and ---E would be p r e s e n t e d . I n t h e c o r r e s p o n d i n g s i n g l e t e s t l e t t e r c o n d i t i o n , - D is p r e s e n t e d and f o l l o w e d by t h e r e s p o n s e a l t e r n a t i v e s g and - K . I n t h e s e s t u d i e s , r e c o g n i t i o n of t h e t e s t word i s a b o u t 1 0 % b e t t e r t h a n r e c o g n i t i o n of t h e t e s t l e t t e r .
Given t h e t w o - a l t e r n a t i v e f o r c e d - c h o i c e c o n t r o l , i t is assumed t h a t t h e r e a d e r u t i l i z e s o r t h o g r a p h i c s t r u c t u r e t o e l i m i n a t e p o s s i b l e a l t e r n a t i v e s d u r i n g t h e p e r c e p t i o n of t h e
R E A D I N G AND INFORMATION PROCESSING
t e s t d i s p l a y (Thompson & Massaro, 1 9 7 3 ) . A s a n example, p r e s e n t e d w i t h t h e t e s t s t i m u l u s WORD and g i v e n r e c o g n i t i o n of t e s t l e t t e r s WOR and a c u r v i l i n e a r segment of t h e f i n a l l e t t e r , t h e r e a d e r c o u l d narrow down t h e a l t e r n a t i v e s f o r t h e f i n a l l e t t e r t o D , 0 , and Q. I f 0 and Q a r e c o n s i d e r e d t o be o r t h o g r a p h i c a l l y i l l e g a l i n t h e c o n t e x t m, t h e n D r e p r e s e n t s an unambiguous c h o i c e . The r e a d e r w i l l t h e r e f o r e p e r c e i v e t h e word WORD g i v e n j u s t p a r t i a l i n f o r m a t i o n a b o u t t h e f i n a l l e t t e r . I f t h e r e a d e r r e c o g n i z e s t h e same c u r v i l i n e a r segment i n t h e c o r r e s p o n d i n g s i n g l e t e s t l e t t e r c o n d i t i o n , however , any of t h e t h r e e l e t t e r s ( D , 0 , and Q ) a r e p o s s i b l e and t h e p e r c e p t u a l s y n t h e s i s w i l l r e s u l t i n D o n l y one o u t of t h r e e times. What is c r i t i c a l i n t h i s a n a l y s i s i s t h a t t h e b e t t e r per formance on words compared t o s i n g l e l e t t e r s i s o b t a i n e d even though t h e v i s u a l f e a t u r a l i n f o r m a t i o n a v a i l a b l e t o t h e p r i m a r y r e c o g n i t i o n p r o c e s s i s e q u i v a l e n t i n t h e word and l e t t e r c o n d i t i o n s . The o r t h o g r a p h i c s t r u c t u r e of t h e word s imply p r o v i d e s an a d d i t i o n a l b u t independent s o u r c e of i n f o r m a t i o n . The f e a t u r a l i n f o r m a t i o n a v a i l a b l e t o t h e r e c o g n i t i o n p r o c e s s d o e s n o t change w i t h changes i n o r t h o g r a p h i c s t r u c t u r e . I n t h i s v iew, a l t h o u g h o r t h o g r a p h i c s t r u c t u r e f a c i l i t a t e s word p e r c e p t i o n , i t d o e s n o t modify t h e f e a t u r e a n a l y s i s of t h e p r i n t e d p a t t e r n (Krueger & S h a p i r o , 1979; Massaro, 1 9 7 9 a ) .
As ure have d i s c u s s e d , one r o l e of o r t h o g r a p h i c s t r u c t u r e is c o n c e n t r a t e d i n t h e p r i m a r y r e c o g n i t i o n p r o c e s s and s e r v e s t o f a c i l i t a t e t h e r e c o g n i t i o n of i n d i v i d u a l l e t t e r s . I n a d d i t i o n , o r t h o g r a p h i c s t r u c t u r e is f u n c t i o n a l a t l a t e r s t a g e s of p r o c e s s i n g , such a s i t s f a c i l i t a t i n g e f f e c t i n s h o r t - t e r m memory (Massaro , i n p r e s s ) . Baddeley ( 1 9 6 4 ) , f o r example, showed t h a t a w e l l - s t r u c t u r e d s t r i n g of l e t t e r s is e a s i e r t o remember and r e c a l l t h a n a random s t r i n g . Whether o r t h o g r a p h i c s t r u c t u r e f a c i l i t a t e s p e r c e p t u a l r e c o g n i t i o n i s a more c o n t r o v e r s i a l i s s u e . We assume t h a t i t is u t i l i z e d i n t h e f o l l o w i n g manner. Upon p r e s e n t a t i o n of a l e t t e r s t r i n g , t h e pr imary r e c o g n i t i o n p r o c e s s b e g i n s i n t e g r a t i n g and s y n t h e s i z i n g f e a t u r a l i n f o r m a t i o n passed on by f e a t u r e d e t e c t i o n t o p r e p e r c e p t u a l v i s u a l s t o r a g e . F e a t u r a l i n f o r m a t i o n i s r e s o l v e d a t d i f f e r e n t r a t e s and t h e r e is some e v i d e n c e t h a t g r o s s f e a t u r e s a r e a v a i l a b l e b e f o r e t h e more d e t a i l e d f e a t u r e s (Massaro & S c h m u l l e r , 1 9 7 5 ) . The p r i m a r y r e c o g n i t i o n p r o c e s s i s f a c e d w i t h a s u c c e s s i o n of p a r t i a l i n f o r m a t i o n s t a t e s . These p a r t i a l v i s u a l i n f o r m a t i o n s t a t e s a r e supplemented w i t h knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e . A s s u m e , f o r example, a n i n i t i a l g h a s been p e r c e i v e d i n a
8 CHAPTER 1
l e t t e r s t r i n g , and t h e f e a t u r e s a v a i l a b l e f o r t h e n e x t l e t t e r e l i m i n a t e a l l a l t e r n a t i v e s e x c e p t c o r g . The p r i m a r y r e c o g n i t i o n p r o c e s s m i g h t s y n t h e s i z e 5 w i t h o u t w a i t i n g f o r f u r t h e r v i s u a l i n f o r m a t i o n , s i n c e i n i t i a l the is n o t a c c e p t a b l e w h i l e i n i t i a l the is.
The p r i m a r y r e c o g n i t i o n p r o c e s s t r a n s m i t s a s e q u e n c e o f r e c o g n i z e d l e t t e r s t o s y n t h e s i z e d v i s u a l memory. F i g u r e 1.1 shows h o r t h e s e c o n d a r y r e c o g n i t i o n p r o c e s s t r a n s f o r m s t h i s s y n t h e s i z e d v i s u a l p e r c e p t i n t o m e a n i n g f u l form i n g e n e r a t e d a b s t r a c t memory. We assume s e c o n d a r y r e c o g n i t i o n a t t e m p t s t o c l o s e o f f t h e l e t t e r s t r i n g i n t o a word. The s e c o n d a r y r e c o g n i t i o n p r o c e s s makes t h i s t r a n s f o r m a t i o n by f i n d i n g t h e b e s t ma tch be tween t h e l e t t e r s t r i n g and a word i n t h e l e x i c o n i n l o n g - t e r m memory. Knowledge o f o r t h o g r a p h i c s t r u c t u r e c a n a l s o c o n t r i b u t e t o s e c o n d a r y r e c o g n i t i o n ; word r e c o g n i t i o n c a n o c c u r w i t h o u t c o m p l e t e r e c o g n i t i o n o f a l l o f t h e component l e t t e r s . G i v e n t h e l e t t e r s & and t h e v i a b l e a l t e r n a t i v e s 1. and t i n f i n a l p o s i t i o n , o n l y J makes a word , and t h e r e f o r e word i d e n t i f i c a t i o n ( l e x i c a l a c c e s s ) c a n b e . a c h i e v e d ( M a s s a r o , 1 9 7 7 ) . Each word i n t h e l e x i c o n c o n t a i n s b o t h p e r c e p t u a l and c o n c e p t u a l c o d e s . The word which is r e c o g n i z e d i s t h e o n e whose p e r c e p t u a l code g i v e s t h e b e s t ma tch and whose c o n c e p t u a l c o d e is mos t a p p r o p r i a t e i n t h a t p a r t i c u l a r c o n t e x t .
G e n e r a t e d a b s t r a c t memory c o r r e s p o n d s t o t h e s h o r t - t e r m o r working memory o f mos t i n f o r m a t i o n p r o c e s s i n g mode l s . I n o u r m o d e l , t h i s memory i s common t o b o t h s p e e c h p e r c e p t i o n and r e a d i n g . Recoding and r e h e a r s a l p r o c e s s e s b u i l d and m a i n t a i n s e m a n t i c and s y n t a c t i c s t r u c t u r e s a t t h e l e v e l o f g e n e r a t e d a b s t r a c t memory. I t i s a l s o p o s s i b l e t o g o from meaning t o a v i s u a l o r a u d i t o r y p e r c e p t i n o u r mode l . The r e c o d i n g o p e r a t i o n c a n t r a n s f o r m t h e meaning o f a c o n c e p t i n t o i ts s u r f a c e s t r u c t u r e i n a n a u d i t o r y o r v i s u a l fo rm.
Two i s sues c o n c e r n i n g l e t t e r and word r e c o g n i t i o n i n r e a d i n g w i l l b e a d d r e s s e d i n t h e p r e s e n t r e s e a r c h . F i r s t , wha t a r e t h e v i s u a l f e a t u r e s o f l e t t e r s u t i l i z e d by t h e p r i m a r y r e c o g n i t i o n p r o c e s s ? Second , how is knowledge o f o r t h o g r a p h i c s t r u c t u r e p s y c h o l o g i c a l l y r e p r e s e n t e d ? To a d d r e s s t h e s e i s s u e s , a n y s t u d y m u s t b e c o n c e r n e d w i t h how t h e s e s o u r c e s o f i n f o r m a t i o n a r e e v a l u a t e d , i n t e g r a t e d , and combined i n p e r c e p t u a l r e c o g n i t i o n ( M a s s a r o , 1 9 7 9 b ) . The d i s c u s s i o n o f v i s u a l f e a t u r e s i s p r e s e n t e d i n C h a p t e r 2 and t h e d i s c u s s i o n o f o r t h o g r a p h i c s t r u c t u r e is p r e s e n t e d i n C h a p t e r 3 . The f o u r t h c h a p t e r f o c u s e s on how t h e r e a d e r u t i l i z e s b o t h s o u r c e s o f i n f o r m a t i o n i n a v a r i e t y o f p e r c e p t u a l r e c o g n i t i o n and o v e r t
R E A D I N G AND INFORMATION PROCESSING 9
j udgmen t t asks . T o s u s t a i n t h e l o g i c a l c o n t i n u i t y of t h e p r e s e n t a t i o n o f t h e e x p e r i m e n t s , d e t a i l s o f t h e m e t h o d , p r o c e d u r e , and r e s u l t s a r e p l a c e d i n a p p e n d i c e s a t t h e end of t h e c h a p t e r . The f i f t h c h a p t e r p r e s e n t s a d e t a i l e d e v a l u a t i o n Of t h e p s y c h o l o g i c a l r e a l i t y o f many d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e . The d a t a b a s e d e r i v e d from t h e p r e s e n t e x p e r i m e n t s is a l s o p r e s e n t e d t o a l l o w a d d i t i o n a l tests o f o t h e r d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e . I n a d d i t i o n , n o r m a t i v e c o u n t s o f l e t t e r and l e t t e r c l u s t e r o c c u r r e n c e s i n t e x t a r e p r e s e n t e d . T h e s e c o u n t s m a k e p o s s i b l e t h e measu remen t o f a v a r i e t y of s t i m u l u s and t e s t i t ems a c c o r d i n g t o a number o f f o r m a l d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e . The l a s t c h a p t e r s u m m a r i z e s t h e c o n t r i b u t i o n s of t h e p r e s e n t r e s e a r c h . The c e n t r a l c o n c e r n o f t h e e m p i r i c a l and t h e o r e t i c a l work p r e s e n t e d h e r e is t o e v a l u a t e t h e n a t u r e of t h e p r o c e s s e s i n v o l v e d i n l e t t e r and word r e c o g n i t i o n and t o d i s c o v e r how knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e is r e p r e s e n t e d and u t i l i z e d .
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2 Visual Information
Most of t h e t r a d i t i o n a l r e s e a r c h r e l e v a n t t o v i s u a l i n f o r m a t i o n i n r e a d i n g h a s been concerned w i t h t h e l e g i b i l i t y of v a r i o u s t y p e f o n t s and t e x t f o r m a t s . Spencer (1969) summarizes t h i s work i n an a d e q u a t e and i n t e r e s t i n g manner and w e w i l l n o t a t t e m p t t o d u p l i c a t e a d e t a i l e d c o v e r a g e h e r e . A f t e r ment ioning a few g e n e r a l p r i n c i p l e s of t h e l e g i b i l i t y of p r i n t e d t e x t , we w i l l p r o v i d e some d i s c u s s i o n of t h e r o l e of f e a t u r e t h e o r i e s i n d e s c r i b i n g how l e t t e r s a r e r e c o g n i z e d . F i n a l l y , we w i l l e v a l u a t e t h e f u n c t i o n a l p r o p e r t i e s of t h e t y p e f o n t s used i n our e x p e r i m e n t s s i n c e t h i s i n f o r m a t i o n w i l l be n e c e s s a r y i n our s t u d i e s of how v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e t o p e r c e p t u a l r e c o g n i t i o n .
EARLY WORK
Much of t h e e a r l y work r e v e a l e d t h a t l e t t e r s a r e n o t e q u a l l y l e g i b l e . Table 2 . 1 p r e s e n t s t h e rank o r d e r of t h e l e g i b i l i t y of t h e l o w e r c a s e l e t t e r s i n an exper iment by C a t t e l l i n 1885 ( c i t e d i n Anderson & Dearborn , 1952) and an e x p e r i m e n t i n our l a b o r a t o r y some 90 y e a r s l a t e r . Except f o r a few of t h e l e t t e r s s u c h a s 9, 5 , and 1, t h e r e is an i m p r e s s i v e agreement between t h e two s t u d i e s . Both s t u d i e s found t h a t some of t h e most f r e q u e n t l e t t e r s a r e t h e l e a s t l e g i b l e . The h i g h l y f r e q u e n t x-he ight l e t t e r s a , c , e , 0 , and 2 were p o o r l y recognized i n both s t u d i e s . The s i m i l a r s i z e and o v e r a l l shape of t h e s e l e t t e r s c a u s e them t o be c o n f u s a b l e and , t h e r e f o r e , p o o r l y l e g i b l e . C a t t e l l ' s r e s e a r c h ( 1 8 8 5 ) , as w e l l a s more
1 2 CHAPTER 2
Table 2 . 1 Rank o r d e r of d i s t i n c t i v e n e s s of lowercase l e t t e r s a c c o r d i n g t o C a t t e l l (1885) and i n t h e p r e s e n t s t u d y .
L e t t e r a b
d e f 9 h i
k 1 m
C
1
C a t t e l l 19
6 25 1
2 2 1 7 2 4
5 23 11
2 1 0
3
P r e s e n t S tudy
2 2 1
19 9
23 1 8
4 6
26 20
7 1 5 11
L e t t e r n
P 4 r S
t
0
U
V
W
X
Y z
Ca t t e l l 18 1 6
I 4
1 5 2 6 1 2
9 1 3
8 2 0 2 1 1 4
P r e s e n t
1 7 2 4
2 8
1 2 2 5 2 1 1 4 1 6 1 0
3 5
1 3
Study
r e c e n t s t u d i e s by Bouma (1971) and o u r s e l v e s , found t h a t t h e s l i m l e t t e r s g, &, 1, I, r , and t were s i m i l a r l y confused f o r one a n o t h e r l e a d i n g t o r e l a t i v e l y poor r e c o g n i t i o n . F i n a l l y , C a t t e l l observed t h a t l e g i b i l i t y i s h i g h l y c o r r e l a t e d w i t h o v e r a l l l e t t e r s i z e ; contemporary s t u d i e s a l s o s u p p o r t t h i s o b s e r v a t i o n .
Tinker (1965) a l s o noted agreement among s t u d i e s of l e t t e r l e g i b i l i t y . H e r e p o r t e d c o r r e l a t i o n s between .48 and .88 a c r o s s s t u d i e s u s i n g , q v a r i e t y of measurement t e c h n i q u e s and t y p e f a c e s . For i n s t a n c e , t h e l e t t e r s 4, m, 2 , g , and w were c o n s i s t e n t l y found t o be h i g h l y l e g i b l e whereas c , e , I, 1, and - n were p o o r l y l e g i b l e . T inker concluded t h a t o v e r a l l s i z e , s i m p l i c i t y of o u t l i n e , and t h e amount of w h i t e s p a c e e n c l o s e d by a l e t t e r a r e i m p o r t a n t d e t e r m i n a n t s of l e g i b i l i t y . We w i l l p r o v i d e a more d e t a i l e d a n a l y s i s of l e t t e r l e g i b i l i t y and l e t t e r c o n f u s i o n s l a t e r i n t h i s c h a p t e r .
Another common o b s e r v a t i o n i n e a r l y r e s e a r c h was t h a t t e x t p r i n t e d i n uppercase l e t t e r s is inore d i f f i c u l t t o read t h a n i ts lowercase e q u i v a l e n t . Lowercase p r i n t may be more f a m i l i a r t h a n uppercase because of d i f f e r e n c e s i n f r e q u e n c y of o c c u r r e n c e . However, a s Spencer (1969) p o i n t s o u t , p r o p o r t i o n a t e l y - s p a c e d p r i n t e d t e x t i n c a p i t a l s o c c u p i e s a b o u t 5 0 % more s p a c e than it d o e s i n l o w e r c a s e . (Uppercase and
VISUAL INFORMATION I N R E A D I N G 1 3
l o w e r c a s e o c c u p y t h e same amount o f s p a c e i n t y p e w r i t t e n t e x t , a s i n t h e p r e s e n t m o n o g r a p h ) . The r e a d e r m u s t m a i n t a i n a l a r g e r s p a n o f a p p r e h e n s i o n i n t e r m s o f v i s u a l a n g l e i n o r d e r t o r e a d u p p e r c a s e t e x t a t t h e same r a t e a s l o w e r c a s e . G i v e n t h a t a c u i t y f a l l s o f f d r a m a t i c a l l y w i t h e x t e n t i n t o t h e p e r i p h e r a l v i s i o n , i t i s n o t s u r p r i s i n g t h a t l o w e r c a s e t e x t w i l l show a n a d v a n t a g e . I t would b e i n t e r e s t i n g t o compare upper- and l o w e r c a s e t e x t when t h e s i z e o f t h e l e t t e r s is a d j u s t e d t o e q u a t e f o r v i s u a l a n g l e . However, p e r f o r m a n c e may s t i l l be a t a d i s a d v a n t a g e w i t h u p p e r c a s e s i n c e on t h e a v e r a g e , t h e l a r g e r l e t t e r s w i l l b e c l o s e r t o g e t h e r and a l l o w f o r more l a t e r a l i n t e r f e r e n c e ( t h e m u t u a l d e g r a d a t i o n o f t h e p e r c e p t i b i l i t y o f a d j a c e n t l e t t e r s b e c a u s e o f t h e p r o x i m i t y o f t h e i r c o n t o u r s ) . The s i m p l e s t e x p l a n a t i o n is t h a t l o w e r c a s e l e t t e r s may b e s i m p l y more p e r c e p t i b l e t h a n u p p e r c a s e .
J a v a 1 ( c i t e d i n S p e n c e r , 1 9 6 9 ) showed t h a t r e a d i n g is much e a s i e r when t h e t o p h a l f , r a t h e r t h a n t h e b o t t o m h a l f , o f a l i n e o f words is e x p o s e d . I t is n o t c l e a r where t h e v e r t i c a l c e n t e r was d e f i n e d , b u t w e m i g h t assume t h a t i t was i n t h e m i d d l e o f a n x - h e i g h t l e t t e r . I t would b e v a l u a b l e t o d e f i n e t h e p e r c e p t u a l m i d d l e , i . e . , t h e p o i n t a t wh ich r e a d i n g t h e t o p and bo t tom p o r t i o n s o f a l i n e o f p r i n t is e q u a l l y e a s y . C o n s i s t e n t w i t h J a v a l ' s f i n d i n g s , Messmer ( c i t e d i n Huey, 1908 /1968) c o n c l u d e d t h a t a s c e n d i n g l e t t e r s ( e . g . , b, h) a r e " d o m i n a n t " and c o n t r i b u t e more t o word r e c o g n i t i o n t h a n x - h e i g h t ( e . g . , a , 5 ) or d e s c e n d i n g ( e . g . , g, E) l e t t e r s . Z e i t l e r ( c i t e d i n Woodworth, 1 9 3 8 ) a l s o found t h a t i n s h o r t p r e s e n t a t i o n s , a s c e n d i n g and d e s c e n d i n g l e t t e r s were more l i k e l y t o b e p e r c e i v e d ( a l s o see Huey, 1908 /1968 , pp . 7 9 - 8 7 ) . J a v a l ' s i d e a was t h a t a s c e n d i n g l e t t e r s a r e more e a s i l y p e r c e i v e d b e c a u s e t h e e y e t e n d s t o f i x a t e above t h e m i d d l e of t h e l i n e of p r i n t . Huey (1908 /1968 p . 99) r e j e c t e d t h i s p r o p o s a l by c i t i . i g some s t a t i s t i c s showing t h a t a s c e n d i n g l e t t e r s a r e much more f r e q u e n t t h a n d e s c e n d i n g l e t t e r s , and t h e r e f o r e , a word i s s i m p l y l i k e l y t o h a v e more i n f o r m a t i o n above t h a n be low t h e m i d d l e of a l i n e o f p r i n t .
FEATURE ANALYSIS
C o n s i s t e n t w i t h t h e t r a d i t i o n o f p s y c h o p h y s i c s , p s y c h o l o g i s t s h a v e been c o n c e r n e d w i t h t h e v i s u a l c h a r a c t e r i s t i c s o f t h e s t i m u l u s t h a t a r e f u n c t i o n a l i n l e t t e r and word p e r c e p t i o n . The g o a l o f t h i s work i s t o r e l a t e t h e p h y s i c a l f e a t u r e s o f l e t t e r s and words t o t h e i r p e r c e p t u a l
CHAPTER 2
r e c o g n i t i o n . The e a r l y workers i n t h i s a r e a i m p l i c i t l y assumed t h a t l e t t e r s were t h e s m a l l e s t u n i t s of v i s i b l e a n a l y s i s . I n t h i s view, l e t t e r s a r e i n d i v i s i b l e u n i t s t h a t can n o t be ana lyzed f u r t h e r t o p r o v i d e a d e s c r i p t i o n of t h e r e l a t i o n s h i p among d i f f e r e n t l e t t e r s . I n t o d a y ' s t e r m i n o l o g y , t h i s view would c o r r e s p o n d t o a t e m p l a t e v i e w of l e t t e r r e c o g n i t i o n . I d e a l l y , t h e r e a d e r would have a t e m p l a t e c o r r e s p o n d i n g t o e a c h of t h e l e t t e r s i n t h e language and p e r c e p t u a l r e c o g n i t i o n would i n v o l v e f i n d i n g t h e b e s t match between t h e v i s u a l i n f o r m a t i o n i n t h e l e t t e r and t h e t e m p l a t e i n memory.
Opposing t h e view of l e t t e r s a s i n d i v i s i b l e u n i t s is t h e i d e a of l e t t e r s having a number of d i s t i n c t i v e f e a t u r e s . T h i s i d e a was g e n e r a t e d by work on t h e l i n g u i s t i c d e s c r i p t i o n of speech sounds a b o u t 30 y e a r s ago (Jakobson, F a n t , & H a l l e , 1 9 6 1 ) . Many s t r u c t u r a l l i n g u i s t s a t t h a t t i m e t r e a t e d phonemes a s t h e s m a l l e s t u n i t s of speech . I f phoneme u n i t s a r e i n d i v i s i b l e , t h e n t h e p h y s i c a l o r p e r c e p t u a l r e l a t i o n s h i p between two phonemes is n o t of c e n t r a l i n t e r e s t . Jakobson e t a l . c h a l l e n g e d t h i s p o i n t of view by t r e a t i n g phonemes a s c o n s i s t i n g of a bundle of d i s t i n c t i v e f e a t u r e s . A r e l a t i v e l y s m a l l number of d i s t i n c t i v e f e a t u r e s c h a r a c t e r i z e d each phoneme of t h e language . As an example, Jakobson e t a l . (1961) were a b l e t o u s e j u s t n i n e f e a t u r e s t o d i s t i n g u i s h 28 phonemes i n E n g l i s h . The i d e a of d i s t i n c t i v e f e a t u r e a n a l y s i s a l s o proved p r o d u c t i v e i n d e v e l o p i n g p a t t e r n r e c o g n i t i o n by machine. S e l f r i d g e and N e i s s e r (1960) reviewed t e m p l a t e matching schemes and f e a t u r e a n a l y s i s schemes f o r t h e r e c o g n i t i o n of l e t t e r s . These developments i n l i n g u i s t i c s and a r t i f i c i a l i n t e l l i g e n c e i n f l u e n c e d t h e development of f e a t u r e models of t h e v i s i b l e c h a r a c t e r i s t i c s of l e t t e r s .
LETTER FEATURES
A v a l u a b l e t e c h n i q u e f o r t h e s t u d y of t h e v i s u a l f e a t u r e s of l e t t e r s i n v o l v e s t h e g e n e r a t i o n of c o n f u s i o n m a t r i c e s . A c o n f u s i o n m a t r i x i n d i c a t e s what l e t t e r s w i l l be seen a s o t h e r l e t t e r s when e r r o r s a r e made. To induce e r r o r s , e i t h e r t h e v i s u a l i n p u t from t h e l e t t e r m u s t be degraded o r t h e p r o c e s s i n g time a v a i l a b l e f o r r e c o g n i t i o n of t h a t l e t t e r m u s t be l i m i t e d . To d e g r a d e l e t t e r s , t h e y have been p r e s e n t e d a t r e l a t i v e l y l a r g e d i s t a n c e s o r i n p e r i p h e r a l v i s i o n . P r o c e s s i n g time is n o t l i m i t e d b u t f e a t u r a l i n f o r m a t i o n i s degraded . To l i m i t p r o c e s s i n g t i m e , l e t t e r s have been p r e s e n t e d f o r a s h o r t d u r a t i o n a t a good f igure-ground c o n t r a s t b u t c l o s e l y f o l l o w e d
VISUAL INFORMATION I N R E A D I N G 1 5
by a masking s t i m u l u s t h a t s e r v e s t o h a l t p r o c e s s i n g . The assumpt ion i n l i m i t i n g p r o c e s s i n g t i m e is t h a t t h e r e a d e r m a k e s an e r r o r because of i n s u f f i c i e n t time t o p r o c e s s c o m p l e t e l y t h e f e a t u r a l i n f o r m a t i o n . Of c o u r s e , i t is i m p o r t a n t t o a n a l y z e c o n f u s i o n m a t r i c i e s g e n e r a t e d from both t h e s e methods and t o d e t e r m i n e whether t h e y g i v e s i m i l a r r e s u l t s .
P r i o r t o Bouma's (1971) s t u d y , most contemporary e x p e r i m e n t s s t u d i e d t h e c o n f u s i o n s of uppercase l e t t e r s ( e . g . , Gibson , O s s e r , S c h i f f , & Smith , 1963; Townsend, 1 9 7 1 ) . Bouma u t i l i z e d l o w e r c a s e l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e shown i n F i g u r e 2 . 1 . Bouma p r e s e n t e d t h e l e t t e r s a t a r e l a t i v e l y l a r g e r e a d i n g d i s t a n c e i n one s t u d y and i n p e r i p h e r a l v i s i o n i n a n o t h e r . The c o n f u s i o n s were v e r y s y s t e m a t i c and a l lowed Bouma t o a s s i g n t h e l e t t e r s t o g r o u p s of l e t t e r s t h a t were c o n f u s a b l e w i t h i n a g r o u p b u t n o t among g r o u p s . The c o n f u s i o n s among l e t t e r s were p r i m a r i l y dependent upon o v e r a l l l e t t e r shape and s i z e . Many of t h e r e c o g n i t i o n c o n f u s i o n s c o u l d be d e s c r i b e d by j u s t t h r e e c l a s s e s of l e t t e r s : s h o r t o r x - h e i g h t l e t t e r s , a s c e n d i n g l e t t e r s ( a s c e n d e r s ) , and d e s c e n d i n g l e t t e r s ( d e s c e n d e r s ) . Given an x - h e i g h t l e t t e r , a r e c o g n i t i o n con- f u s i o n u s u a l l y r e s u l t e d from a n o t h e r x-he ight l e t t e r and s o on. The x - h e i g h t l e t t e r s and a s c e n d e r s c a n a l s o be broken down i n t o s m a l l e r g r o u p s a s i n d i c a t e d i n Table 2 . 2 . Bouma a r g u e s t h a t o v e r a l l l e t t e r shape is a n i m p o r t a n t d e t e r m i n a n t of r e c o g n i t i o n c o n f u s i o n s and i n t r o d u c e s t h e c o n c e p t of e n v e l o p e . The envelope of a l e t t e r i s t h e s m a l l e s t polygon s u r r o u n d i n g a l e t t e r w i t h o u t i n d e n t a t i o n . For example, t h e e n v e l o p e f o r c would be c i r c u l a r , whereas would be e n c l o s e d by a n i n v e r t e d
a c e m n
o r s u
v w x z
b d f h
i k l t
F i g u r e 2 . 1 Lowercase l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e used by Bouma ( 1 9 7 1 ) .
16 CHAPTER 2
Table 2 . 2 The seven g r o u p s of c o n f u s a b l e l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e ( a f t e r Bouma, 1 9 7 1 ) .
1. a s z x 2 . e o c 3. n m u 4 . r v u 5. d h k b 6 . t i l f 7 . g p j y q
t r i a n g l e . These e n v e l o p e s of l e t t e r s a c c o u n t f o r some of t h e c o n f u s i o n e r r o r s . A s an example, t h e g r o u p of c o n f u s a b l e l e t t e r s (a, 2 , z, z) have roughly r e c t a n g u l a r e n v e l o p e s w i t h inner p a r t s .
I n o r d e r t o p r o v i d e an independent a s s e s s m e n t of t h e f e a t u r a l i n f o r m a t i o n t h a t i s f u n c t i o n a l i n t h e r e c o g n i t i o n of lowercase l e t t e r s , we c a r r i e d o u t a l e t t e r r e c o g n i t i o n exper iment . F i g u r e 2 . 2 p r e s e n t s a photograph of t h e l e t t e r s a s t h e y appeared i n t h e e x p e r i m e n t . A s i n g l e l e t t e r was p r e s e n t e d on each t r i a l a t a r e l a t i v e l y dim i n t e n s i t y t o keep o v e r a l l
0123456789 : ; ?
ABCDEFGHIJKLMNO PQRSTUVWXYZ abcdefghijklmno
pqrstuvwxyz F i g u r e 2 . 2 The s e t of c h a r a c t e r s c u r r e n t l y be ing used i n our
l a b o r a t o r y . The c h a r a c t e r s a r e p l o t t e d a s p o i n t s on an o s c i l l o s c o p e and t h e a v e r a g e c h a r a c t e r is composed of approximate ly 35 p o i n t s .
VISUAL INFORMATION I N READING 17
a c c u r a c y a t a b o u t 5 0 % . The t e s t l e t t e r was p r e s e n t e d a t t h e f i x a t i o n p o i n t f o r a s h o r t d u r a t i o n and no masking s t i m u l u s was p r e s e n t e d . Three s u b j e c t s c o n t r i b u t e d a t o t a l of 296 o b s e r v a t i o n s f o r e a c h of t h e 26 l e t t e r s of t h e a l p h a b e t . T a b l e 2.3 p r e s e n t s t h e o v e r a l l a c c u r a c y f o r each o f t h e 26 l e t t e r s , t h e f a l s e a l a r m r a t e s , t h e d' v a l u e s , and c o n f u s i o n r e s p o n s e s t h a t o c c u r r e d more t h a n 5% of t h e t i m e t o a g i v e n tes t l e t t e r .
One p o s s i b l e l i m i t a t i o n w i t h t h e s e d a t a and o t h e r s t u d i e s o f t h i s n a t u r e i s t h a t t h e l e t t e r s d i f f e r i n o v e r a l l a c c u r a c y , and t h e r e f o r e , t h e r e is n o t an e q u a l o p p o r t u n i t y f o r c o n f u s i o n s f o r each of t h e l e t t e r s . On t h e o t h e r hand, i t might be a r g u e d t h a t t h e o v e r a l l a c c u r a c y of a g i v e n a l t e r n a t i v e may r e f l e c t how e a s i l y i t is confused w i t h o t h e r l e t t e r s . That is t o s a y , a l e t t e r c o m p l e t e l y d i s s i m i l a r from t h e o t h e r l e t t e r s would g i v e good per formance s i n c e i t w i l l n o t be confused f o r any of t h e a l t e r n a t i v e s . R e g a r d l e s s of which i n t e r p r e t a t i o n is more r e a s o n a b l e , i t might be wor thwhi le t o r e p e a t t h e e x p e r i m e n t w h i l e a d j u s t i n g t h e i n t e n s i t y i n d i v i d u a l l y f o r each l e t t e r t o keep i t s per formance a t 50% c o r r e c t .
The p e r c e n t a g e c o r r e c t i d e n t i f i c a t i o n f o r each of t h e 26 l e t t e r s of t h e a l p h a b e t i n T a b l e 2.3 shows t h a t r e c o g n i t i o n a c c u r a c y ranged w i d e l y . T h i s r e s u l t may r e p r e s e n t a v i s u a l e f f e c t O K a d e c i s i o n e f f e c t . Some l e t t e r s may p r o v i d e more v i s u a l f e a t u r a l i n f o r m a t i o n t h a n o t h e r l e t t e r s under t h e same s t i m u l u s c o n d i t i o n s . A l t e r n a t i v e l y , o b s e r v e r s may d e r i v e e q u i v a l e n t amounts of f e a t u r a l i n f o r m a t i o n from a l l l e t t e r s b u t may have d e c i s i o n b i a s e s i n t h e i n t e r p r e t a t i o n of t h e f e a t u r a l i n f o r m a t i o n . A s a n example, o b s e r v e r s might be b i a s e d t o i n t e r p r e t t h e f e a t u r a l i n f o r m a t i o n i n te rms of l e t t e r s t h a t occur more f r e q u e n t l y i n t h e language . The d e c i s i o n i n t e r p r e t a t i o n , however, a p p e a r s t o be i n c o n s i s t e n t w i t h t h e r e s u l t s . For example, t h e i n f r e q u e n t l e t t e r s 5 , y , and z averaged a b o u t 65% c o r r e c t , whereas t h e f r e q u e n t l e t t e r s e , g, - 0, and 2 averaged a b o u t 35% c o r r e c t . I n c o n t r a s t t o what would be e x p e c t e d from a f r e q u e n c y b i a s , t h e s e l e a s t f r e q u e n t l e t t e r s a r e r e c o g n i z e d much b e t t e r t h a n t h e more f r e q u e n t l e t t e r s . T h i s a n a l y s i s p r o v i d e s s u p p o r t f o r t h e i d e a t h a t d i f f e r e n c e s i n a c c u r a c y a r e due t o d i f f e r e n c e s i n t h e f e a t u r a l i n f o r m a t i o n of t h e l e t t e r s . A more d i r e c t measure of v i s u a l r e s o l u t i o n i s t o take a 4' measure a s proposed by t h e t h e o r y of s i g n a l d e t e c t a b i l i t y (Green & Swets , 1966; Massaro &
Schmuller , . 1 9 7 5 ) . Table 2.3 shows t h a t t h e s e d' v a l u e s c o r r e l a t e r a t h e r h i g h l y w i t h t h e p e r c e n t a g e c o r r e c t v a l u e s . Given t h e assumpt ion t h a t t h e d' v a l u e s a r e n o t i n f l u e n c e d by any d i f f e r e n c e s i n d e c i s i o n b i a s e s , t h e r e s u l t s
1 8 CHAPTER 2
T a b l e 2 .3 P r o p o r t i o n o f times a l e t t e r was r e c o g n i z e d c o r r e c t l y ( H i t ) a n d was g i v e n as a n i n c o r r e c t r e s p o n s e t o o t h e r l e t t e r s ( F a l s e A l a r m ) ; t h e d'
a l u e ; a n d t h e c o n f u s i o n r e s p o n s e s g r e a t e r t h a n 5 % ( f r o m p r e s e n t s t u d y ) .
L e t t e r H i t F a l s e Ala rm A ' C o n f u s i o n s Greater t h a n 5%
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. 0 1 4
. 0 1 6 , 0 1 0 . 0 2 3 .010 .0 20 . 0 1 0 . 0 1 5 . 0 1 0 . 0 1 0 . 0 1 5 . 0 1 0
1 . 8 5 2 . 7 2 2 .05 2 .64 1 . 7 9 1 . 9 4 2 . 5 6 2 .46 1 . 4 2 1 . 9 2 2 . 6 1 2 .10 2 .66 2 .24 1 . 7 8 2 .78 2 . 7 1 2 .24 1 . 8 7 1 . 7 6 2 .46 2 .16 2 .66 2 .94 2 .67 2 . 5 1
l o c a t e t h e d i f f e r e n c e s i n l e t t e r r e c o g n i t i o n a t a v i s u a l s t a g e o f p r o c e s s i n g .
T a b l e 2 .3 a l s o p r o v i d e s a n i n d e x o f t h e l e t t e r s w h i c h a re c o n f u s e d w i t h o t h e r l e t t e r s i n t h e t a s k . F o r e a c h l e t t e r , a l l c o n f u s i o n s g i v e n f o r t h a t l e t t e r g r e a t e r t h a n 5% o f t h e t i m e a r e p r e s e n t e d . As a n e x a m p l e , g i v e n t h e s t i m u l u s a, s u b j e c t s r e s p o n d e d 1 4 % o f t h e time w i t h t h e a l t e r n a t i v e g a n d 7 % o f t h e time w i t h a l t e r n a t i v e g. T h i s means t h a t t h e l e t t e r a is o f t e n
VISUAL INFORMATION I N R E A D I N G 1 9
i n t e r p r e t e d a s e . The c o n f u s i o n s a p p e a r t o b e r e l a t i v e l y s y s t e m a t i c and t h e r e f o r e s u g g e s t wh ich f e a t u r e s a r e f u n c t i o n a l i n l e t t e r r e c o g n i t i o n . T a b l e 2 . 4 p r o v i d e s a n a l o g o u s d a t a f rom t h e p e r i p h e r a l - v i e w i n g e x p e r i m e n t c a r r i e d o u t by Bouma on t h e I B M C o u r i e r 1 0 t y p e f a c e . The c o n f u s i o n s w i l l b e u t i l i z e d i n o u r l a t e r work when t h e r e l a t i v e s i m i l a r i t y b e t w e e n l e t t e r s becomes a n i m p o r t a n t q u e s t i o n i n o u r e x p e r i m e n t s .
The l e t t e r c o n f u s i o n s s u g g e s t t h a t o v e r a l l l e t t e r s h a p e i n f o r m a t i o n may b e o b t a i n e d b e f o r e c o m p l e t e l e t t e r p e r c e p t i o n ( r e s o l u t i o n ) . For example , 48% o f t h e e r r o r r e s p o n s e s t o t h e s t i m u l u s 2 were e and 0; t h i s i n d i c a t e s t h a t s u b j e c t s s aw a c i r c u l a r s h a p e on many o f t h e t r i a l s b u t d i d n o t know w h e t h e r t h e l e t t e r was 2 , e , o r 0. T h i s r e s u l t m i g h t b e i n t e r p r e t e d t o mean t h a t t h e o v e r a l l e n v e l o p e o f a l e t t e r is r e s o l v e d b e f o r e d e t a i l s o f i t s component f e a t u r e s . I n d e p e n d e n t l y o f w h e t h e r t h e whole is g r e a t e r t h a n t h e sum o f i t s p a r t s , a g e n e r a l i m p r e s s i o n o f t h e who le ( a l t h o u g h ambiguous ) i s s e e n b e f o r e a l l o f t h e p a r t s . T h a t a l e t t e r ' s e n v e l o p e ( n o pun i n t e n d e d ) becomes a v a i l a b l e b e f o r e i t s d e t a i l s i s a l s o c o n s i s t e n t w i t h f o u r i e r - a n a l y s i s s t u d i e s . T h e r e is e v i d e n c e t h a t i n f o r m a t i o n g i v e n by l o w s p a t i a l f r e q u e n c i e s i s p r o c e s s e d f a s t e r t h a n h i g h s p a t i a l f r e q u e n c y i n f o r m a t i o n ( B r e i t m e y e r & Ganz , 1976 ; B r o a d b e n t , 1 9 7 7 ) . A c c o r d i n g l y , l ow s p a t i a l f r e q u e n c i e s p r o v i d e i n f o r m a t i o n a b o u t o v e r a l l s h a p e w h e r e a s h i g h f r e q u e n c y i n f o r m a t i o n r e d u c e s u n c e r t a i n t y a b o u t l e t t e r d e t a i l . E i t h e r l i m i t e d p r o c e s s i n g time o r a r e d u c e d f i g u r e - g r o u n d c o n t r a s t c o u l d a l l o w e n v e l o p e r e s o l u t i o n w i t h o u t c o r r e s p o n d i n g r e s o l u t i o n o f l e t t e r d e t a i l . I n terms o f t h e p r e s e n t a n a l y s i s , t h e r e a d e r w i l l have t o d e c i d e wh ich l e t t e r b e s t f i t s t h e p e r c e i v e d b u t f u z z y e n v e l o p e . For e x a m p l e , r e c o g n i t i o n o f a c i r c u l a r e n v e l o p e w i t h o u t f u r t h e r d e t a i l would b e s u f f i c i e n t t o l i m i t t h e a l t e r n a t i v e s t o t h e t h r e e l e t t e r s 2 , g , a n d 0.
G i v e n t h a t o u r p r i m a r y m o t i v a t i o n is t o s t u d y t h e i n t e r a c t i o n o f l o w e r - l e v e l v i s u a l i n f o r m a t i o n w i t h h i g h e r - o r d e r knowledge i n l e t t e r r e c o g n i t i o n , we a r e n o t d i r e c t l y c o n c e r n e d w i t h which l e t t e r f e a t u r e s a r e u t i l i z e d i n p e r c e p t u a l r e c o g n i t i o n . T h e r e a r e now s u f f i c i e n t d a t a c o n s i s t e n t w i t h t h e i d e a t h a t l e t t e r r e c o g n i t i o n is m e d i a t e d by f e a t u r e s ( M a s s a r o &
S c h m u l l e r , 1 9 7 5 ) . F e a t u r e s a r e n o t l i m i t e d t o s m a l l component p r o p e r t i e s b u t c a n b e r e l a t i v e l y complex r e l a t i o n a l p r o p e r t i e s s u c h a s t h e o v e r a l l c i r c u l a r e n v e l o p e o f t h e l e t t e r s 5, g , a n d - 0. A d d i t i o n a l l y , i n c o n t r a s t t o t h e common a s s u m p t i o n t h a t f e a t u r e s a r e d e t e c t e d i n a n a l l - o r - n o n e m a n n e r , w e p r e f e r t o v i e w t h e f e a t u r e d e t e c t i o n p r o c e s s a s c o n t i n u o u s . V i s i b l e f e a t u r e s may b e f u z z y s o t h a t r e c o g n i t i o n c o n s i s t s o f
20 CHAPTER 2
T a b l e 2 .4 P r o p o r t i o n of times a l e t t e r was r e c o g n i z e d c o r r e c t l y ( H i t ) a n d was g i v e n a s an i n c o r r e c t r e s p o n s e t o o t h e r l e t t e r s ( F a l s e Alarm) ; t h e c o r r e s p o n d i n g d' v a l u e ; a n d t h e c o n f u s i o n r e s p o n s e s g r e a t e r t h a n 5% ( f r o m Bouma, 1 9 7 1 ) .
Let ter H i t F a l s e Alarm d' C o n f u s i o n s Greater t h a n 5%
a b
d e f g h i j k 1 m n
P 9 r
t
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U
V
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X
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. 6 2 0 . 0 5 3
. 6 2 0 . 0 2 4
. 1 9 0 . 0 0 6
. 8 3 0 . 0 1 9
. 3 4 0 . 0 4 5
. 8 1 0 . 0 1 3
. 3 1 0 . 0 1 8
. 8 0 0 . 0 2 8
. 6 9 0 . 0 3 5
. 8 2 0 .008
. 5 1 0 . 0 0 8
. 2 6 0 .007
. 7 9 0 . 0 2 8
. 5 6 0 . 0 2 6
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. 8 4 0 . 0 1 7
. 7 4 0 . 0 1 9
. 5 5 0 . 0 1 5
. 1 0 0 . 0 0 9
. 5 9 0 . 0 1 3 . 5 6 0 .018 . 7 2 0 .016 . 7 0 0 . 0 1 4 . 3 2 0 . 0 0 3 . 5 7 0 . 0 0 3 . 1 2 0 .004
1 . 9 3 2 . 2 9 1 . 6 2 3 . 0 3 1 . 2 9 3 . 1 1 1 . 6 0 2 . 7 6 2 . 3 1 3 . 3 3 2 . 4 6 1 . 8 1 2 .72 2 . 1 0 2 . 3 0 3 . 1 2 2 . 7 1 2 . 3 1 1 . 0 8 2 .46 2 . 2 6 2 . 7 3 2 . 7 3 2 . 2 5 2 . 9 5 1 . 4 6
VISUAL INFORMATION I N READING 2 1
a s c e r t a i n i n g t h e d e g r e e t o which t h a t f e a t u r e is p r e s e n t o r a b s e n t i n t h e s t i m u l u s . Oden and Massaro (1978) have developed a model of speech p e r c e p t i o n based on t h e i d e a of c o n t i n u o u s a c o u s t i c f e a t u r e s . A s i m i l a r a n a l y s i s would seem t o be a v a l u a b l e c o n t r i b u t i o n i n l e t t e r r e c o g n i t i o n , a l t h o u g h beyond t h e scope of t h e p r e s e n t r e s e a r c h . For i n t e r e s t e d r e a d e r s , Oden (1979) i n i t i a t e d a n e m p i r i c a l and t h e o r e t i c a l s t u d y of f u z z y f e a t u r a l i n f o r m a t i o n i n l e t t e r s , and Massaro (1979a) q u a n t i f i e d a model t o a c c o u n t f o r how c o n t i n u o u s f e a t u r a l i n f o r m a t i o n of a l e t t e r is i n t e g r a t e d w i t h o r t h o g r a p h i c c o n t e x t i n l e t t e r r e c o g n i t i o n .
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3 Orthographic Structure
I n t h i s c h a p t e r we d e s c r i b e t h e fundamenta l p r o p e r t i e s of o r t h o g r a p h i c s t r u c t u r e and s p e c u l a t e on how t h e s e p r o p e r t i e s might f a c i l i t a t e l e t t e r and word r e c o g n i t i o n . The g o a l of t h i s d i s c u s s i o n is t o d e r i v e d i f f e r e n t m e t r i c s f o r s c a l i n g t h e o r t h o g r a p h i c s t r u c t u r e of l e t t e r s t r i n g s based upon d i f f e r e n t assumpt ions a b o u t how o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s t o r e c o g n i t i o n p r o c e s s e s . The e x p e r i m e n t s p r e s e n t e d i n Chapter 4 a t t e m p t t o e v a l u a t e t h e p s y c h o l o g i c a l r e a l i t y of s e v e r a l of t h e s e measures .
C e n t r a l t o t h e d i s c u s s i o n of t h i s c h a p t e r i s t h e assumpt ion t h a t s k i l l e d r e a d e r s d e r i v e i n f o r m a t i o n a b o u t l e g a l o c c u r r e n c e s of l e t t e r s o r l e t t e r s e q u e n c e s from r e p e a t e d e x p o s u r e s t o p r i n t e d words and t h a t t h e y employ t h i s i n f o r m a t i o n t o f a c i l i t a t e word r e c o g n i t i o n i n normal r e a d i n g t a s k s . Our concern h e r e is w i t h both t h e d e s c r i p t i o n of t h e a b s t r a c t e d i n f o r m a t i o n and i ts u t i l i z a t i o n i n t h e r e c o g n i t i o n p r o c e s s . I n t h e d i s c u s s i o n which f o l l o w s w e c o n c e n t r a t e on two broad c a t e g o r i e s of o r t h o g r a p h i c s t r u c t u r e : s t a t i s t i c a l redundancy and ru le -governed r e g u l a r i t y . S t a t i s t i c a l redundancy a p p l i e s t o t h o s e measures which can be d e r i v e d s o l e l y from t h e f r e q u e n c y w i t h which l e t t e r s , l e t t e r s e q u e n c e s , and words occur i n n a t u r a l t e x t s . Such measures might be based upon t y p e o r t o k e n c o u n t s . The measures might a p p l y t o l e t t e r s , l e t t e r s e q u e n c e s , o r t o any c l a s s i f i c a t i o n of t h e s e e n t i t i e s ( e . g . , vowel, c o n s o n a n t ) . Rule-governed r e g u l a r i t y a p p l i e s t o t h o s e p r o p e r t i e s o f l e t t e r s and l e t t e r s e q u e n c e s which can be g e n e r a l i z e d from e i t h e r t h e p h o n o l o g i c a l c o n s t r a i n t s of E n g l i s h words o r t h e s c r i b a l c o n v e n t i o n s . The l a t t e r c o n t r o l t h e s e l e c t i o n of l e t t e r s f o r e i t h e r r e p r e s e n t i n g sounds o r marking graphemic , g r a p h o t a c t i c , o r morphologica l
24 CHAPTER 3
func t io : i s . Rule-governed r e g u l a r i t y u s u a l l y s p e c i f i e s a l e t t e r s t r i n g a s r e g u l a r o r i r r e g u l a r . I n a d d i t i o n , th rough t h e s p e c i f i c a t i o n of r u l e s f o r g e n e r a t i n g l e g a l ( i . e . , E n g l i s h - l i k e ) l e t t e r s t r i n g s , l e v e l s of r e g u l a r i t y c a n be d e f i n e d .
STATISTICAL REDUNDANCY
Ordered a p p r o x i m a t i o n s t o E n g l i s h , based on a l g o r i t h m s proposed by Shannon ( 1 9 4 8 ) , were t h e f i r s t d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e u t i l i z e d by p s y c h o l o g i s t s . Shannon (1948) c r e a t e d a zero-order approximat ion t o E n g l i s h by drawing l e t t e r s w i t h rep lacement from a p o o l of 27 unweighted symbols--the 26 l e t t e r s of t h e a l p h a b e t p l u s a s p a c e . ( I n t h i s a s i n most o t h e r s e q u e n t i a l g e n e r a t i o n t e c h n i q u e s , a n i n i t i a l s p a c e symbol is assumed.) I f t h i s same p r o c e d u r e is employed w i t h symbols t h a t a r e weighted a c c o r d i n g t o t h e i r f r e q u e n c i e s of o c c u r r e n c e i n t e x t s , f i r s t - o r d e r a p p r o x i m a t i o n s r e s u l t .
An n-g o r d e r approximat ion is produced by f i r s t s e l e c t i n g a l e t t e r s t r i n g of l e n g t h n-1. T h i s forms t h e beginning p a r t of t h e new s t r i n g . The t e x t is t h e n scanned f o r t h e f i r s t o c c u r r e n c e of t h i s i n i t i a l s t r i n g . When found, t h e n e x t l e t t e r a f t e r t h e l e t t e r s t r i n g sequence is added t o t h e s t r i n g b e i n g g e n e r a t e d , and a n e w s e a r c h s t r i n g i s c o n s t r u c t e d by d r o p p i n g t h e f i r s t l e t t e r of t h e l a s t s e a r c h s t r i n g and adding t h e l e t t e r j u s t l o c a t e d . T h i s p r o c e d u r e is t h e n r e p e a t e d u n t i l a space o c c u r s o r a d e s i r e d l e n g t h reached . M i l l e r , B r u n e r , and Postman (1954) used t h i s t e c h n i q u e t o g e n e r a t e e i g h t - l e t t e r pseudowords f o r a f u l l - r e p o r t t a s k . T h e i r f o u r t h - o r d e r approximat ions i n c l u d e d items l i k e m o s s i a n t , o n e t i c u l , p r e v e r a l , and f a v o r i a l , a l l q u i t e E n g l i s h - l i k e . Wallach ( 1 9 6 3 ) , on t h e o t h e r hand, t r u n c a t e d two l e t t e r s from each s t r i n g used by Miller e t a l . t h u s o c c a s i o n a l l y p r o d u c i n g a non-English s p e l l i n g ( e . g . , moss ia , l o r i a i ) . Although M i l l e r e t a l . (1954) were p r i m a r i l y concerned w i t h i n f o r m a t i o n t h e o r y , l a t e r e x p e r i m e n t e r s ( e . g . , L e f t o n , S p r a g i n s , & Byrnes, 1973; Mewhort & B e a l , 1977) have advoca ted o r d e r e d a p p r o x i m a t i o n s a s p s y c h o l o g i c a l l y r e l e v a n t d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e .
A major shor tcoming of o r d e r e d a p p r o x i m a t i o n d e s c r i p t i o n s i s t h e i r i n a b i l i t y t o c o n t r o l s t r u c t u r a l v a r i a t i o n s w i t h i n approximat ion l e v e l s . Although any l a r g e g r o u p of s t i m u l i g e n e r a t e d by t h i s t e c h n i q u e w i l l approximate t h e f r e q u e n c i e s of o c c u r r e n c e of E n g l i s h l e t t e r s e q u e n c e s , t h e r e is no m e t r i c
ORTHOGRAPHIC STRUCTURE 25
i n c o r p o r a t e d i n t o t h e method f o r a s s e s s i n g t h e r e l a t i v e d e g r e e o f o r t h o g r a p h i c s t r u c t u r e o f s t r i n g s w i t h i n o r d e r c l a s s e s . I n G i l m o r e and E g e t h ( 1 9 7 6 ) , f o r e x a m p l e , z e r o - o r d e r a p p r o x i m a t i o n s t o E n g l i s h w e r e used t o g e n e r a t e wha t t h e a u t h o r s i n t e n d e d t o b e nonwords , wh ich t h e y c o n t r a s t e d w i t h r e a l E n g l i s h words . I f n o o t h e r c r i t e r i a were used t o e v a l u a t e t h e 30 s t r i n g s g e n e r a t e d f o r u s e i n t h e i r e x p e r i m e n t s , t h e r e was a 1 8 % c h a n c e t h a t a t l e a s t o n e r e a l word o c c u r r e d ( b a s e d on t h e a s s u m p t i o n o f 1 , 5 0 0 common f o u r - l e t t e r words i n E n g l i s h ) ; t h e p r o b a b i l i t y t h a t p seudowords o c c u r r e d was c o n s i d e r a b l y h i g h e r .
A s e c o n d s h o r t c o m i n g o f a s t r i c t p s y c h o l o g i c a l a p p l i c a t i o n of t h i s a p p r o a c h i s i t s s t r i c t r e l i a n c e on l e f t - t o - r i g h t g e n e r a t i o n o f l e t t e r s d u r i n g word r e c o g n i t i o n . For e x a m p l e , g i v e n th- and th-ugh a s p a r t i a l l y p e r c e i v e d s i x - l e t t e r s t r i n g s , t h e p r o b a b i l i t i e s o f i d e n t i f y i n g t h e t h i r d l e t t e r i n e a c h would b e t h e same i n t h a t o n l y i n f o r m a t i o n t o t h e l e f t b u t n o t t o t h e r i g h t o f a n y l e t t e r p o s i t i o n i s r e l e v a n t .
To overcome t h e s e d i f f i c u l t i e s , summed b i g r a m and t r i g r a m c o u n t s h a v e been p r o p o s e d a s metr ics . Underwood and S c h u l z ( 1 9 6 8 ) t a b u l a t e d t h e b i g r a m s and t r i g r a m s i n 2 ,090 w o r d s sampled f rom T h o r n d i k e and L o r g e ( 1 9 4 4 ) . S i n c e e a c h s a m p l e word was w e i g h t e d by i t s f r e q u e n c y o f o c c u r r e n c e i n t e x t s , t o k e n - b a s e d b i g r a m and t r i g r a m c o u n t s r e s u l t e d . By summing t h e f r e q u e n c i e s o f a l l t h e b i g r a m s o r t r i g r a m s w i t h i n a l e t t e r s t r i n g , a f a m i l i a r i t y i n d e x c a n b e d e r i v e d . Such a p r o c e d u r e was used by A n i s f e l d ( 1 9 6 4 ) , f o r e x a m p l e , i n r e a n a l y z i n g t h e G i b s o n , P i c k , Osser, and Hammond ( 1 9 6 2 ) s t u d y o f a f u l l r e p o r t o f v i s u a l l y - p r e s e n t e d l e t t e r s t r i n g s v a r y i n g i n p r o n o u n c e a b i l i t y . A c c o r d i n g t o A n i s f e l d ( 1 9 6 4 ) , t h e G i b s o n e t a l . r e s u l t s c o u l d b e a c c o u n t e d f o r a s e a s i l y by d i f f e r e n c e s i n summed b i g r a m c o u n t s a s t h e y c o u l d by t h e s p e l l i n g - t o - s o u n d u n i t s a d v o c a t e d by G i b s o n e t a l . G i b s o n ( 1 9 6 4 ) , i n a r e p l y t o A n i s f e l d ( 1 9 6 4 1 , however , showed t h a t c o r r e l a t i o n s o f summed b i g r a m and summed t r i g r a m c o u n t s w i t h s u b j e c t r e s p o n s e s were low and n o n s i g n i f i c a n t . I n a d d i t i o n , G i b s o n , S h u r c l i f f , and Yonas ( 1 9 7 0 ) found n e i t h e r summed b i g r a m n o r summed t r i g r a m c o u n t s t o b e a n a d e q u a t e p r e d i c t o r o f r e c o g n i t i o n s c o r e s f o r u n p r o n o u n c e a b l e and p r o n o u n c e a b l e l e t t e r s t r i n g s .
G i b s o n e t a l . ( 1 9 7 0 ) d i d n o t p r o v i d e a f a i r t e s t o f t h e f r e q u e n c y m e a s u r e s , however , b e c a u s e t h e c o u n t s were n o t a d j u s t e d f o r word l e n g t h i n a n y r e a s o n a b l e manner . Word l e n g t h a l o n e a c c o u n t e d f o r a b o u t 70% of t h e v a r i a n c e i n t h e r e c a l l s c o r e s ; t h e number o f e r r o r s n a t u r a l l y i n c r e a s e d w i t h i n c r e a s e s i n t h e l e n g t h o f t h e l e t t e r s t r i n g . The s i g n i f i c a n t
26 CHAPTER 3
c o r r e l a t i o n of p r o n o u n c e a b i l i t y could be due t o t h e s i m p l e f a c t t h a t s h o r t e r words a r e more pronounceable t h a n l o n g e r words. Suppor t ing t h i s i n t e r p r e t a t i o n , Spreen and S c h u l z (1966) found a n e g a t i v e c o r r e l a t i o n of . 8 3 between word l e n g t h and p r o n o u n c e a b i l i t y f o r 329 common nouns. T h e r e f o r e , t h e r e s u l t s of Gibson e t a l . (1962, 1970) r e a l l y d o n o t speak t o t h e issue of p r o n o u n c e a b i l i t y v e r s u s o r t h o g r a p h i c s t r u c t u r e of l e t t e r s t r i n g s when s t r i n g l e n g t h is h e l d c o n s t a n t .
The Underwood and Schulz (1960) t a b l e s p r o v i d e a means f o r d i f f e r e n t i a t i n g f a m i l i a r and u n f a m i l i a r s t r i n g s w i t h i n approximat ion c l a s s e s , b u t s u f f e r from l a c k of a t t e n t i o n t o word l e n g t h o r p o s i t i o n of l e t t e r s w i t h i n a word. A common s u f f i x l i k e -& would h e a v i l y weight a t r i g r a m c o u n t f o r a pseudoword whether i n i n i t i a l o r f i n a l p o s i t i o n a c c o r d i n g t o t h e s e t a b l e s , y e t i n E n g l i s h words t h i s sequence never o c c u r s i n i t i a l l y . I f l e t t e r p o s i t i o n w i t h i n a word i s a p s y c h o l o g i c a l l y r e l e v a n t v a r i a b l e , t h e Underwood and S c h u l z (1960) t a b l e s could n o t be used f o r e x p l o r i n g t h i s f a c t o r .
T h i s shor tcoming h a s been overcome, however, i n t h e Mayzner and T r e s s e l t (1965) and Mayzner, T r e s s e l t , and Wolin (1965a, 1965b) t a b l e s , which g i v e b igram, t r i g r a m , and t e t r a g r a m c o u n t s by word p o s i t i o n and by word l e n g t h f o r words from t h r e e t o seven c h a r a c t e r s i n l e n g t h . Mayzner and T r e s s e l t (1965) a l s o g i v e s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c i e s , which have been used by Mason (1975) t o e x p l o r e d i f f e r e n c e s between good and poor r e a d e r s i n a r e c o g n i t i o n t a s k . Although Mason (1975) confounds ru le -governed o r t h o g r a p h i c s t r u c t u r e w i t h p o s i t i o n a l f r e q u e n c y , a s m a l l b u t s i g n i f i c a n t p o s i t i o n a l - f requency e f f e c t remains when t h e s e v a r i a b l e s a r e s e p a r a t e d (Massaro, Venezky, & T a y l o r , 1 9 7 9 ) .
The r e l a t i o n s h i p s among s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y , bigram p o s i t i o n a l f r e q u e n c y , and t r i g r a m p o s i t i o n a l f requency have o n l y begun t o be e x p l o r e d . McClelland and J o h n s t o n (1977) observed t h a t a c c u r a c y of r e p o r t of f o u r - l e t t e r i t e m s was s i g n i f i c a n t l y c o r r e l a t e d w i t h summed s i n g l e - l e t t e r p o s i t i o n a l f requency b u t n o t w i t h bigram p o s i t i o n a l f r e q u e n c y . Bouwhuis (1979) found t h a t s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y made a s i g n i f i c a n t c o n t r i b u t i o n t o l e x i c a l d e c i s i o n s a b o u t t h r e e - l e t t e r items. R e a c t i o n times t o words d e c r e a s e d w i t h i n c r e a s e s i n f r e q u e n c y whereas r e a c t i o n times t o pseudowords i n c r e a s e d . S i m i l a r l y , h i g h s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y i n c r e a s e d t h e number of "word" r e s p o n s e s t o both words and pseudowords. These s i g n i f i c a n t c o r r e l a t i o n s were c o n s i d e r a b l y d i m i n i s h e d when bigram p o s i t i o n a l f r e q u e n c y was used a s t h e p r e d i c t o r v a r i a b l e . These r e s u l t s imply t h a t t h e power of t h e
ORTHOGRAPHIC STRUCTURE 27
b i g r a m f r e q u e n c y m e a s u r e ( s e e C h a p t e r 5 ) w i t h o u r s i x - l e t t e r i t ems may n o t g e n e r a l i z e c o m p l e t e l y t o s m a l l e r l e t t e r - s t r i n g l e n g t h s .
I t is p o s s i b l e t o g e n e r a t e l e t t e r s t r i n g s w h i l e i n d e p e n d e n t l y v a r y i n g summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y and summed b i g r a m p o s i t i o n a l - f r e q u e n c y c o u n t s . Wi th some s t r a i n i n g , t h e same c a n b e d o n e f o r summed b i g r a m and summed t r i g r a m c o u n t s . F o r e x a m p l e , nach im h a s ( a c c o r d i n g t o Mayzne r , e t a l . 1 9 6 5 b ) l e g a l b i g r a m s b u t no l e g a l t r i g r a m s . N a t h e r , o n t h e o t h e r h a n d , h a s l e g a l b i g r a m s and l e g a l t r i g r a m s . A l e g a l b ig ram o r a l e g a l t r i g r a m means t h a t t h e s p e l l i n g p a t t e r n o c c u r s w i t h f r e q u e n c i e s a b o v e z e r o i n t h e Mayzner e t a l . t a b l e s . The Mayzner e t a l . t a b l e s m i g h t b e b a s e d o n t o o s m a l l a s a m p l e f o r r e l i a b l e c o u n t s . C o n s e q u e n t l y , we h a v e d e v i s e d t a b l e s f rom t h e Kuce ra and F r a n c i s ( 1 9 6 7 ) m i l l i o n - w o r d l i s t and h a v e u t i l i z e d them i n t h e p r e s e n t p r o j e c t . The d e s c r i p t i o n o f t h e a n a l y s i s and t h e s i n g l e - l e t t e r and b i g r a m t a b l e s a r e g i v e n i n Appendix 5 .2 a n d 5 .3 .
A f u r t h e r i s s u e t h a t n e e d s t o b e c l a r i f i e d is t h e r e l a t i v e i m p o r t a n c e o f t o k e n m e a s u r e s and t y p e m e a s u r e s . Token c o u n t s r e p r e s e n t a summed o c c u r r e n c e f o r some l e t t e r s e q u e n c e , r e g a r d l e s s o f t h e number o f u n i q u e w o r d s wh ich c o n t r i b u t e t o t h i s sum. Type c o u n t s , o n t h e o t h e r h a n d , r e p r e s e n t a sum o f t h e u n i q u e w o r d s i n wh ich a l e t t e r s e q u e n c e o c c u r s , r e g a r d l e s s o f t h e f r e q u e n c i e s o f o c c u r r e n c e o f t h e w o r d s . I n a l l o f t h e e x p e r i m e n t a l work r e p o r t e d s o f a r t h a t used s e q u e n t i a l r e d u n d a n c y m e a s u r e s , t o k e n c o u n t s h a v e b e e n employed . S o l s o and h i s c o l l e a g u e s ( S o l s o , 1 9 7 9 ; S o l s o & K i n g , 1976 ; S o l s o , B a r b u t o , & J u e l , 1979 ; S o l s o , T o p p e r , & Macey, 1 9 7 3 ; T o p p e r , Macey, & S o l s o , 1 9 7 3 ) r e p o r t some t y p e - b a s e d t a b u l a t i o n s b a s e d on t h e Kuce ra and F r a n c i s ( 1 9 6 7 ) word l i s t s b u t no e x p e r i m e n t a l d a t a . However, t h e r e is no a p r i o r i r e a s o n f o r a s s u m i n g t h a t word t o k e n s h a v e g r e a t e r p s y c h o l o g i c a l r e a l i t y t h a n word t y p e s n o r a r e t h e r e e m p i r i c a l d a t a r e l e v a n t t o t h i s q u e s t i o n . We a d d r e s s t h i s i s s u e i n C h a p t e r 5 .
Type-based m e a s u r e s c o u l d b e d e r i v e d from a r e p r e s e n t a t i o n o f a n i n t e r n a l l e x i c o n , b u t t o k e n m e a s u r e s a l s o r e q u i r e t h e e x i s t e n c e o f d i s t r i b u t i o n a l i n f o r m a t i o n i n memory. W h i l e i t is r e a s o n a b l e t o a s sume t h a t some f o r m s o f b o t h t o k e n and t y p e i n f o r m a t i o n m i g h t h a v e p s y c h o l o g i c a l r e a l i t y , how t h e r e a d e r m i g h t a p p l y raw t o k e n m e a s u r e s i n word r e c o g n i t i o n is n o t c o i n p l e t e l y o b v i o u s ( c f . S a v i n , 1 9 6 3 ) . However , some i n t e r e s t i n g a p p r o a c h e s t o u s i n g t o k e n m e a s u r e s embedded w i t h i n t y p e m e a s u r e s h a v e b e e n p r o p o s e d b y Solomon and Pos tman ( 1 9 5 2 ) , S a v i n ( 1 9 6 3 ) , and more r e c e n t l y b y L a n d a u e r and S t r e e t e r
28 CHAPTER 3
( 1 9 7 3 ) . As a n e x a m p l e , t h e v i a b , l e a l t e r n a t i v e s c o u l d b e na r rowed down t o a l l words c o n s i s t e n t w i t h t h e f e a t u r a l i n f o r m a t i o n and t h e r e a d e r m i g h t c h o o s e t h e m o s t f r e q u e n t word from t h i s s e t .
But w h a t e v e r a p p l i c a t i o n m i g h t b e shown f o r f r e q u e n c y i n f o r m a t i o n i n word r e c o g n i t i o n , t h e s p e c i f i c r o l e o f t h e s e m e a s u r e s h a s y e t t o b e d e t e r m i n e d . I f summed f r e q u e n c y ( t o k e n o r t y p e ) i s p s y c h o l o g i c a l l y r e l e v a n t , t h e n t h e u t i l i z a t i o n o f a measu re l i k e b ig ram f r e q u e n c y would r e q u i r e a max imiz ing p r o c e s s . C o n s i d e r t h e t a s k o f p e r c e i v i n g a f i v e - l e t t e r s t r i n g where t h e v i s u a l i n f o r m a t i o n a l l o w s a n a c c e p t a b l e r e s o l u t i o n o f a l l l e t t e r s e x c e p t o n e , e . g . , L l L 2 - L 4 L 5 . Assume t h a t no v i s u a l i n f o r m a t i o n is a v a i l a b l e f o r L 3 . The u s e o f b i g r a m i n f o r m a t i o n r e q u i r e s t h a t L 3 b e s e l e c t e d t o maximize t h e sum o f t h e b ig ram f r e q u e n c i e s o f L 2 L 3 and L 3 L 4 , s e l e c t i n g L 3 f rom a p o o l o f a l l 26 l e t t e r s . I f some v i s u a l i n f o r m a t i o n i s a v a i l a b l e f o r L 3 , t h e n t h e p o o l O E a v a i l a b l e l e t t e r s m i g h t b e r e s t r i c t e d t o t h o s e t h a t were c o m p a t i b l e w i t h t h e a v a i l a b l e i n f o r m a t i o n b u t o t h e r w i s e t h e s t r a t e g y would b e t h e same. For a t r i g r a m s t r a t e g y , a s i m i l a r p r o c e s s c o u l d b e used b u t w i t h t h e max imiz ing o f t h e combined f r e q u e n c i e s f o r L l L 2 L 3 + L 2 L 3 L 4 + L 3 L 4 L 5 . The c o m p l e x i t y o f t h i s s t r a t e g y d o e s n o t n e c e s s a r i l y make i t s p s y c h o l g i c a l r e l e v a n c e s u s p e c t .
A p o t e n t i a l drawback t o summed s i n g l e - l e t t e r , b i g r a m , and t r i g r a m p o s i t i o n a l c o u n t s , p a r t i c u l a r l y where t o k e n c o u n t s a r e u t i l i z e d , i s t h e d o m i n a t i n g r o l e p l a y e d by a s m a l l g r o u p o f h i g h - f r e q u e n c y words . For t h e f o u r - l e t t e r w o r d s , a s a n example , t h e 37 most f r e q u e n t words o f t h i s l e n g t h a c c o u n t f o r a p p r o x i m a t e l y o n e - h a l f o f a l l t o k e n s o f f o u r - l e t t e r words. T h i s g u a r a n t e e s , o n t h e a v e r a g e , a h i g h , p o s i t i v e c o r r e l a t i o n be tween d i f f e r e n t s t a t i s t i c a l m e a s u r e s . However, low summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y s t r i n g s w i l l u s u a l l y b e low i n summed p o s i t i o n a l b i g r a m and t r i g r a m f r e q u e n c y , b u t s t r i n g s h i g h i n summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y a r e n o t n e c e s s a r i l y h i g h i n t h e o t h e r two m e a s u r e s .
F u r t h e r m o r e , s i n c e t h e e x t r e m e l y h i g h f r e q u e n c y w o r d s i n E n g l i s h a r e m o s t l y t h r e e , f o u r , and ( t o a l e s s e r d e g r e e ) f i v e l e t t e r s i n l e n g t h , t h e i n f l u e n c e o f t h e h i g h e s t f r e q u e n c y w o r d s n e c e s s a r i l y d e c r e a s e s w i t h i n c r e a s i n g word l e n g t h . T h u s , we would e x p e c t a l o w e r c o r r e l a t i o n be tween b i g r a m and t r i g r a m c o u n t s i n s e v e n - l e t t e r s t r i n g s t h a n i n f o u r - l e t t e r s t r i n g s .
The c e n t r a l l i m i t a t i o n i n f r e q u e n c y - b a s e d s c h e m e s , e v e n when p o s i t i o n and word l e n g t h s a r e o b s e r v e d , i s t h a t t h e y c a n g e n e r a t e pseudowords wh ich v i o l a t e E n g l i s h p h o n o l o g i c a l and s p e l l i n g c o n v e n t i o n s . For e x a m p l e , t h r s m , s t h s e , and w h r s t a r e
ORTHOGRAPHIC STRUCTURE 29
unpronounceable b u t have r e l a t i v e l y h i g h summed bigram p o s i t i o n a l c o u n t s . These can be c o n t r a s t e d w i t h b i p o n , s l e v y , and d u f i p , which have r e l a t i v e l y low summed bigram p o s i t i o n a l c o u n t s , b u t a r e l e g a l from a ru le -governed s t a n d p o i n t . V i o l a t i o n s can be a v o i d e d , f o r t h e most p a r t , by u s i n g p o s i t i o n - s e n s i t i v e f o u r t h - o r d e r a p p r o x i m a t i o n s which a r e a l s o h i g h i n summed t r i g r a m p o s i t i o n a l c o u n t s .
PHONOLOGICALLY-BASED DESCRIPTIONS
An a l t e r n a t i v e t o s t a t i s t i c a l redundancy h a s been t o u s e t h e r e l a t i o n s h i p between s p e l l i n g and sound ( i . e . , p r o n o u n c e a b i l i t y ) as a d e f i n i n g m e t r i c . Gibson e t a l . (1962) found t h a t l e t t e r s of pronounceable pseudowords were more e a s i l y r e c a l l e d i n a f u l l r e p o r t t h a n were l e t t e r s of unpronounceable nonwords ( e . g . , dink v s . G). The a u t h o r s h y p o t h e s i z e d t h a t t h e o p e r a t i v e u n i t i n word p e r c e p t i o n was n o t t h e l e t t e r ( o r t h e whole w o r d ) , b u t a sequence of l e t t e r s which had an i n v a r i a n t s p e l l i n g - t o - s o u n d r e l a t i o n s h i p . However, Gibson e t a l . (1970) o b t a i n e d t h e same r e s u l t s w i t h c o n g e n i t a l l y d e a f s u b j e c t s , t h e r e b y d e m o n s t r a t i n g t h a t t h e s p e l l i n g - t o - s o u n d r e l a t i o n s h i p c o u l d n o t a l o n e a c c o u n t f o r t h e r e s p o n s e d i f f e r e n c e s . I t is l i k e l y t h a t o r t h o g r a p h i c s t r u c t u r e d i f f e r e n c e s (whether f requency-based o r ru le -governed) were c r i t i c a l .
L e t t e r - s o u n d c o r r e s p o n d e n c e s have a l s o been u t i l i z e d i n word r e c o g n i t i o n models by R u b e n s t e i n , Lewis , and Rubens te in (1971) and by Smith and Spoehr ( 1 9 7 4 ) . However, bo th t h e paradigm employed and t h e assumed u s e of l e t t e r - s o u n d r e l a t i o n s h i p s i n t h e l a t t e r two s t u d i e s d i f f e r e d from t h a t i n Gibson e t a l . ( 1 9 6 2 ) . Both Rubens te in e t a l . (1971) and Smith and Spoehr (1974) assumed t h a t l e t t e r r e c o g n i t i o n o c c u r s on t h e b a s i s of l e t t e r f e a t u r e s ; t h e n sounds a r e a t t a c h e d t o l e t t e r s o r l e t t e r sequenLes and l e x i c a l a c c e s s made on t h e b a s i s o f a p h o n o l o g i c a l u n i t . Gibson e t a l . (1962) assumed t h a t word r e c o g n i t i o n o c c u r r e d on t h e b a s i s of h i g h e r - o r d e r v i s u a l u n i t s which t h e r e a d e r formed through e x p e r i e n c e w i t h l e t t e r - s o u n d t r a n s l a t i o n . The r e l i a b i l i t y o f any o f t h e s e h y p o t h e s e s , when viewed i n r e l a t i o n t o t h e c o m p l e x i t i e s of l e t t e r - s o u n d c o r r e s p o n d e n c e s i s q u e s t i o n a b l e ( c f . Venezky, 1 9 7 0 ) .
Fur thermore , some e m p i r i c a l e v i d e n c e i n d i c a t e s t h a t p h o n o l o g i c a l encoding is n o t n e c e s s a r y f o r l e x i c a l a c c e s s (Kleiman, 1975; Levy, 1978; Massaro, 1978; 1979b; Tzeng, Hung, & Wang, 1 9 7 7 ) . However, even i f p h o n o l o g i c a l t r a n s l a t i o n were shown t o p l a y a r o l e i n word r e c o g n i t i o n , p r o n o u n c e a b i l i t y
30 CHAPTER 3
a l o n e would s t i l l be i n a d e q u a t e f o r d e s c r i b i n g o r t h o g r a p h i c s t r u c t u r e . E n g l i s h s p e l l i n g i s c o n s t r a i n e d by p h o n o l o g i c a l c o n v e n t i o n s f i r s t , b u t a l s o by s c r i b a l c o n v e n t i o n s , which out law c e r t a i n p o s s i b l e b u t pronounceable s p e l l i n g s i n s e l e c t e d c o n t e x t s .
RULE-GOVERNED REGULARITY
Rule-governed r e g u l a r i t y d e s c r i b e s t h e p r e d i c t a b l e s t r u c t u r e of t h e o r t h o g r a p h y i n t e r m s of p h o n o l o g i c a l and s c r i b a l c o n s t r a i n t s . However, a c r i t i c a l f e a t u r e of t h i s d e s c r i p t i o n is t h a t t h e p r e d i c t a b l e s t r u c t u r e of l e t t e r o c c u r r e n c e s is u t i l i z e d w i t h o u t any m e d i a t i o n of t h e spoken language . I n c o n t r a s t t o t h e s p e l l i n g - t o - s o u n d d e s c r i p t i o n of Gibson e t a l . (1962) , Rubens te in e t a l . ( 1 9 7 1 ) , and Smith and Spoehr (1974) , u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n is assumed t o occur b e f o r e t h e p r i n t e d p a t t e r n is t r a n s l a t e d t o sound. Although much o f t h e s t r u c t u r e of a w r i t t e n a l p h a b e t i c language n e c e s s a r i l y f o l l o w s i ts phonology, a c c e s s t o t h e phonology i s n o t n e c e s s a r y f o r u t i l i z a t i o n of t h e o r t h o g r a p h i c s t r u c t u r e . D i r e c t e v i d e n c e f o r t h i s assumpt ion comes from t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e by d e a f r e a d e r s (Gibson e t a l . , 1 9 7 0 ) . I n a d d i t i o n , S inger ( i n p r e s s ) found t h a t a p h o n o l o g i c a l r e n d e r i n g of words p r e s e n t e d i n an a r t i f i c i a l a l p h a b e t was n o t n e c e s s a r y f o r l e a r n i n g and u t i l i z i n g o r t h o g r a p h i c s t r u c t u r e . I n t h e s e c t i o n s which f o l l o w , both t h e p h o n o l o g i c a l and t h e s c r i b a l c o n s t r a i n t s of E n g l i s h s p e l l i n g s a r e o u t l i n e d .
P h o n o l o g i c a l C o n s t r a i n t s
The pr imary c o n s t r a i n t s on E n g l i s h o r t h o g r a p h y d e r i v e from t h e a l l o w a b l e sequences of sounds i n E n g l i s h words. Thus, / s k / i s an a l l o w a b l e i n i t i a l consonant c l u s t e r and t h e r e f o r e s p e l l i n g s f o r i t e x i s t ( e . g . , e, E, e); on t h e o t h e r hand , /tl/ and / d l / d o n o t occur and never d i d occur i n i t i a l l y i n E n g l i s h words, and t h e r e f o r e no s p e l l i n g f o r t h e s e s e q u e n c e s occur i n E n g l i s h words ( b u t t h e y d o i n T l i n g i t and s e v e r a l o t h e r languages i n which i n i t i a l /tl/ and / d l / a r e l e g a l ) . Compl ica t ing t h i s r e l a t i o n s h i p between sound and s p e l l i n g , however, a r e s e v e r a l f a c t o r s , i n c l u d i n g s c r i b a l p e d a n t r y , which l e a v e u s w i t h s p e l l i n g s f o r (1) sound s e q u e n c e s which once o c c u r r e d , b u t have s i n c e been dropped from t h e language ( e . g . , - W L - , &-, F-), o r f o r ( 2 ) sound sequences t h a t were presumed
ORTHOGRAPHIC STRUCTURE 31
t o have o c c u r r e d i n t h e language from which a word was borrowed ( e . g . , psychology, p t a r m i g a n , debt). For psychology, t h i s assumpt ion is s u p p o r t a b l e ; f o r p t a r m i g a n i t is c l e a r l y based on m i s t a k e n etymology; and f o r debt (and v a r i o u s o t h e r s ) , i t is o n l y p a r t i a l l y t r u e , i n t h a t /b/ and /t/ o c c u r r e d i n t h e L a t i n a n c e s t o r of debt ( d e b i t u m ) , b u t n o t a s a f i n a l c l u s t e r .
A f u r t h e r c o m p l i c a t i o n is t h e d e v i a t i o n i n s e r i a l o r d e r of s e v e r a l s p e l l i n g s from t h e o r d e r of sounds which t h e y r e p r e s e n t . Chief among t h e s e i s %, a s p e l l i n g which a t l e a s t some E n g l i s h s p e a k e r s have r e t a i n e d a s /hw/, and -& a s i n b o t t l e , e t c . , which s p e l l s ( i n d e l i b e r a t e s p e e c h ) /al/ (&- and -1e - a r e s c r i b a l r e v e r s a l s of e a r l i e r k- and -e).
B u t even w i t h t h e s e d e v i a t i o n s from e x p e c t e d p r a c t i c e , most E n g l i s h sounds a r e r e p r e s e n t e d i n a m o d e r a t e l y r a t i o n a l f a s h i o n i n t h e o r t h o g r a p h y (Venezky, 1 9 7 0 ) . However, s i n c e E n g l i s h p o s s e s s e s more t h a n one p o t e n t i a l s p e l l i n g f o r a l m o s t e v e r y sound, a second s e t of c o n s t r a i n t s , h e r e c a l l e d s c r i b a l c o n s t r a i n t s , e n t e r i n t o ru le -governed o r t h o g r a p h i c s t r u c t u r e .
S c r i b a l C o n s t r a i n t s
To e x p l a i n t h e rudiments of t h e s e c o n s t r a i n t s , some new te rminology is h e l p f u l .
Vowel s p e l l i n g s a r e c l a s s e d a s p r i m a r y ( 2 , g, i f 0 , g, y ) o r s e c o n d a r y (&, 3, ", ", e t c . ) .
Consonant s p e l l i n g s a r e e i t h e r f u n c t i o n a l l y s i m p l e (b, c, - c h , d, e t c . ) o r f u n c t i o n a l l y compound (11, =, 3, *, and 3).
Graphemic c o n s t r a i n t s r e g u l a t e p r i m a r i l y t h e d i s t r i b u t i o n of (1) geminated ( d o u b l e ) l e t t e r s , ( 2 ) u-v-w, and ( 3 ) y-1. F i r s t , u n l i k e S p a n i s h , E n g l i s h r e s i s t s doubled l e t t e r s i n w o r d - i n i t i a l p o s i t i o n , e s p e c i a l l y c o n s o n a n t s . Only a h a n d f u l of e x c e p t i o n s t o t h i s e x i s t s , p r i m a r i l y i n v o l v i n g t h e form 00 ( e . g . , o o d l e s , o o z e ) . I n o t h e r p o s i t i o n s o n l y 1 5 l e t t e r s c a n d o u b l e : t h o s e t h a t d o n ' t ( o r r a r e l y do) a r e 2 , h, A , i, &, g , 2 , y, w, 5 , y. But t h e r e a r e f u r t h e r r e s t r i c t i o n s . With few e x c e p t i o n s , doubled c o n s o n a n t s do n o t occur a f t e r secondary vowels , and i n f i n a l p o s i t i o n o n l y ff, 11, and a r e common. F i n a l l y , t h e d i g r a p h u n i t s a r e n o t a l lowed t o double . For one , - c h , a pseudogeminate (3) was adopted i n e a r l y modern E n g l i s h , a t a b o u t t h e same t i m e t h a t 3 was adopted t o r e p r e s e n t doubled 9 when i t r e p r e s e n t e d / j / . S i m i l a r l y , & was i n v e n t e d f o r d o u b l e k which now o c c u r s o n l y i n i n f l e c t e d forms of trek ( e . g . , t r e k k i n g ) .
A second s e t of graphemic c o n s t r a i n t s r e g u l a t e t h e d i s t r i b u t i o n of 2-y-w and 4-y. From t h e Middle E n g l i s h p e r i o d
3 2 CHAPTER 3
up t o a b o u t t h e middle of t h e 1 7 t h c e n t u r y , y and v were used i n d i s c r i m i n a t e l y t o r e p r e s e n t / u / and / v / , a l t h o u g h v tended t o be used i n i t i a l l y and 3 e l s e w h e r e . (Accord ing t o P y l e s ( 1 9 6 4 ) , - v was a l s o p r e f e r r e d i n t h e v i c i n i t y of m and n). Digraphs l i k e OJ, when w r i t t e n b e f o r e a vowel might be m i s t a k e n f o r 3; t h e r e f o r e ; was d o u b l e d , and e v e n t u a l l y w r i t t e n y. I n time, 2 i n f i n a l p o s i t i o n as t h e second p a r t of a secondary vowel s p e l l i n g was r e p l a c e d by y, g i v i n g t h e p r e s e n t - d a y a l t e r n a t i o n s -- au/aw, eu/ew, and ou/ow. I n g e n e r a l , t h e w v a r i a n t o c c u r s b e f o r e vowels and i n f i n a l p o s i t i o n ; t h e 3 v a r i a n t o c c u r s e l s e w h e r e . Where 2 would occur a s a p r i m a r y vowel s p e l l i n g i n f i n a l p o s i t i o n , a f i n a l e is added ( e . g . , blue).
For r e a s o n s n o t a l t o g e t h e r c l e a r , b u t r e l a t e d t o t h e ambigui ty of 3-v s p e l l i n g s , y was a l s o e x o r c i s e d from f i n a l p o s i t i o n . But s ince no s i m p l e rep lacement was a v a i l a b l e as was f o r 2 , a n e was added a f t e r t h e l e t t e r , t h u s g i v i n g p r e s e n t - d a y s p e l l i n g s l i k e dove, l o v e , and have, where t h e f i n a l e d o e s n o t mark a f r e e ( l o n g ) vowel p r o n u n c i a t i o n .
S i m i l a r l y , I-y now a l t e r n a t e e x a c t l y a s y and )1! d o , as second e l e m e n t s of a d i g r a p h vowel , t h u s , maid/may, o i l / b o y , and either/-.
Three a d d i t i o n a l f e a t u r e s of E n g l i s h s p e l l i n g which have l i m i t e d u t i l i t y i n s o u n d - t o - s p e l l i n g r u l e s , b u t which a r e i m p o r t a n t f o r t h e r e c o g n i t i o n of r e a l words, a r e d i s c u s s e d b r i e f l y i n t h e f o l l o w i n g s e c t i o n .
Morphemic F e a t u r e s
Morpheme I d e n t i t y . The r e t e n t i o n of morphemic i d e n t i t y a s i n p a i r s l i k e cone /conic i s a n a t u r a l consequence of c o n d i t i o n e d sound change unaccompanied by a c o r r e s p o n d i n g s p e l l i n g change and n o t t h e r e s u l t o f o v e r t s c r i b a l i n t e n t i o n . For t h e most p a r t , however, r e t e n t i o n of morphemic i d e n t i t y is l i m i t e d t o vowels and t h o s e consonant l e t t e r s which a r e s i l e n t i n one form b u t pronounced i n a r e l a t e d one. I n t h e f i r s t c a t e g o r y a r e a l t e r n a t i o n s of t h e form s a n e / s a n i t y and t e l e g r a p h / t e l e g r a p h y ; i n t h e l a t t e r a r e p a i r s a k i n t o s i g n / s i g n a l , bomb/bombard, and hymn/hymnal. Where no s i n g l e s p e l l i n g can s t a n d f o r a p a i r of sounds , c o n s i s t e n t s p e l l i n g of a l lomorphs which d i f f e r by t h o s e sounds is n o t p o s s i b l e . Thus, c o l l i d e / c o l l i s i o n m u s t u t i l i z e d i f f e r e n t s p e l l i n g s f o r /d/ and
I n bound morphemes, s i m i l a r p r o c e s s e s c a n be s e e n a s e x e m p l i f i e d by t h e noun p l u r a l (and t h i r d - p e r s o n s i n g u l a r ) -2 and t h e p a s t t e n s e marker , -3.
/:/.
ORTHOGRAPHIC STRUCTURE 33
S e p a r a t i o n of homophones. P a r t l y by a c c i d e n t and p a r t l y by o v e r t a t t e n t i o n , E n g l i s h s p e l l i n g h a s t e n d e d t o d i f f e r e n t i a t e homophones w h e r e v e r o r t h o g r a p h i c l i c e n s e would a l l o w . P a i r s l i k e s e a / s e e , b l u e / b l e w , and r i g h t / w r i t e b e l o n g t o t h e a c c i d e n t c a t e g o r y , b u t f o u l / f o w l , p l a i n / p l a n e , and -- s u n / s o n r e s u l t f rom o v e r t s c r i b a l p r a c t i c e (Vachek , 1 9 5 9 , 1 9 7 3 ; on t h e o r t h o g r a p h i c d i s t i n c t i v e n e s s o f homophones, see O l s o n &
K a u s l e r , 1 9 7 1 ) . The two-let ter word ban . S i n c e a t l e a s t t h e time o f Noah
Webs te r and p r o b a b l y b e f o r e , E n g l i s h l e x i c o g r a p h e r s h a v e a v o i d e d e x t e n d i n g t h e r e p e r t o i r e o f t w o - l e t t e r words beyond a small g r o u p o f f u n c t i o n words ( e . g . , &, of, on, if). Two mechanisms were a d o p t e d f o r l e n g t h e n i n g two- le t te r w o r d s wh ich d i d n ' t q u a l i f y f o r i n c l u s i o n i n t h i s g r o u p : d o u b l i n g t h e f i n a l c o n s o n a n t , as i n ebb, add, odd, a n d a, o r a d d i n g a f i n a l - e , ( e . g . , doe, hoe, &, and * ) . The f o r m e r mechanism h a s c r e a t e d u n i q u e f i n a l c o n s o n a n t c l u s t e r s i n t h a t b, fi, 9, and 1 d o n o t d o u b l e i n f i n a l p o s i t i o n i n a n y o t h e r E n g l i s h words .
T h e s e g r a p h e m i c c o n s t r a i n t s h a v e e v o l v e d i n d e p e n d e n t l y o f s o u n d , f o r u n l i k e t h e o r t h o g r a p h i e s o f o t h e r m a j o r l a n g u a g e s , modern E n g l i s h s p e l l i n g p r e s e r v e s c l e a r e v i d e n c e o f n e a r l y 1 , 3 0 0 y e a r s o f sound c h a n g e , s c r i b a l t a m p e r i n g , p a r t i a l r e f o r m s , and f o r e i g n i n t r u s i o n s . T h e r e is a n u n d e r l y i n g p a t t e r n t o t h i s o r t h o g r a p h y , a s d e s c r i b e d i n Venezky ( 1 9 7 0 ) , b u t t h e r e is a l s o a s u b s t a n t i a l m a r g i n a l mess which c a n o n l y i n p a r t be o r g a n i z e d i n t o s u b p a t t e r n s o r j u s t i f i e d by a p p e a l t o s u c h p r i n c i p l e s as t h e o r t h o g r a p h i c s e p a r a t i o n o f homophones ( e . g . , b e l l / b e l l e ) . N e v e r t h e l e s s , p e r m e a t i n g t h e e n t i r e s p e l l i n g s y s t e m f rom o r g a n i z e d c o r e t o t h e most d i s j o i n t o u t e r f r i n g e s is a n i n t e r a c t i o n be tween p h o n o l o g i c a l and v i s u a l f o r c e s wh ich r a n g e s f rom p r o d u c t i v e c o u n t e r p o i n t a s i n s u c h s p e l l i n g s a s c o n e / c o n i c t o t h e d i s s o n a n c e o f s u c h mots n o i r s a s women.
S i n c e no E n g l i s h l a n g u a g e academy e v e r imposed a g r a n d d e s i g n on E n g l i s h s p e l l i n g , wha t g e n e r a l p r i n c i p l e s t h e r e a r e r e s u l t e d from t h e c o n f l u e n c e o f v a r i o u s s c r i b a l t r a d i t i o n s w i t h t h e p e r i o d i c r a v a g e s o f sound c h a n g e unaccompanied b y s p e l l i n g c h a n g e . Y e t a p r i n c i p l e o f s o r t s d o e s emerge from t h e c u r r e n t s y s t e m , v i z . , "Accede t o a l l v i s u a l i n t e r e s t s up t o , b u t n o t beyond , t h e p o i n t where p a s s a g e from s p e l l i n g t o sound is i m p a i r e d . "
34 CHAPTER 3
P s y c h o l o g i c a l Assumptions
Rule-governed d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e d i f f e r from o t h e r d e f i n i t i o n s o f o r t h o g r a p h i c s t r u c t u r e i n two a s p e c t s : F i r s t , i n t h e u t i l i z a t i o n of word t y p e s r a t h e r t h a n word t o k e n s , and s e c o n d , i n c l a s s i f y i n g a s r e g u l a r c e r t a i n s p e l l i n g s which d o n o t occur ( y e t ) i n E n g l i s h words and c l a s s i f y i n g a s i r r e g u l a r some t h a t do. The f i r s t d i f f e r e n c e is n o t e s s e n t i a l t o t h e d e f i n i t i o n of o r t h o g r a p h i c s t r u c t u r e , b u t i t is p r o b a b l y more a r e f l e c t i o n of t h e d i f f e r i n g e p i s t e m o l o g i e s of l i n g u i s t s and p s y c h o l o g i s t s . The second d i f f e r e n c e , however, is c e n t r a l t o t h e c o n c e p t of o r t h o g r a p h i c s t r u c t u r e and r e q u i r e s f u r t h e r e x p l i c a t i o n .
The p r i m a r y assumpt ion behind t h e o r t h o g r a p h i c r u l e s p r e s e n t e d h e r e i s t h a t r e a d e r s a b s t r a c t from t h e i r e x p e r i e n c e s w i t h p r i n t e d words t h o s e s p e l l i n g s t h a t a r e p r o d u c t i v e i n present -day E n g l i s h and u s e t h e s e t o f a c i l i t a t e r e c o g n i t i o n . For example, s i l e n t i n i t i a l l e t t e r s , r e g a r d l e s s o f t h e f requency of o c c u r r e n c e o f t h e words i n which t h e y o c c u r , a r e c l a s s i f i e d as i r r e g u l a r s i n c e i t is u n l i k e l y t h a t new words brought i n t o t h e E n g l i s h language would e v e r be s p e l l e d w i t h them. ( S p e l l i n g a n a l o g i e s might p r e s e n t an e x c e p t i o n t o t h i s assumpt ion and c a n n o t be i g n o r e d . However, i t is u n l i k e l y t h a t s i l e n t i n i t i a l s p e l l i n g s would e v e r be w i d e l y e x t e n d e d . )
On t h e o t h e r hand, t h e i n i t i a l s e q u e n c e s E- and e- and t h e f i n a l sequences -eng, -&, and -ofe d o n o t occur i n t h e f i r s t 2 0 , 0 0 0 words i n t h e Thorndike and Lorge ( 1 9 4 4 ) l i s t , y e t t h e y a r e c l a s s i f i e d as o r t h o g r a p h i c a l l y r e g u l a r s i n c e t h e y d o n o t v i o l a t e any p h o n o l o g i c a l o r s c r i b a l p a t t e r n . Thus pseudowords l i k e 9, woach, t r e n g , d e r l , and s t r o f e a r e pronounceable and s t r u c t u r a l l y r e g u l a r , even though t h e y c o n t a i n t r i g r a m s t h a t d o n o t occur i n E n g l i s h words. The p e r c e p t u a l r e c o g n i t i o n of such s t r i n g s r e l a t i v e t o s i m i l a r pseudowords w i t h h i g h e r summed t r i g r a m c o u n t s is an i s sue t h a t remains t o be i n v e s t i g a t e d .
Dichotomy Issue
Another issue which m e r i t s e m p i r i c a l i n v e s t i g a t i o n c o n c e r n s t h e assumed dichotomous d e t e r m i n a n t s of o r t h o g r a p h i c r e g u l a r i t y . Given t h e two d i f f e r e n t c o n s t r a i n t s on o r t h o g r a p h i c s t r u c t u r e d i s c u s s e d above , w e s h o u l d q u e s t i o n whether o r n o t t h e s c r i b a l and p h o n o l o g i c a l e l e m e n t s a r e s e p a r a t e d p s y c h o l o g i c a l l y . Are, f o r example, i r r e g u l a r s t r i n g s l i k e and c k l i b p r o c e s s e d d i f f e r e n t l y from a n i l l e g a l
ORTHOGRAPHIC STRUCTURE 35
s t r i n g l i k e t p r i f ? A l l a r e i l l e g a l and non-occurr ing , y e t t h e y d i f f e r i n t y p e o f i l l e g a l i t y . T p r i f c o n t a i n s a n i n i t i a l consonant c l u s t e r t h a t is p h o n o l o g i c a l l y i l l e g a l and t h e r e f o r e s c r i b a l l y non-occurr ing . and c k l i b a r e b o t h p h o n o l o g i c a l l y a c c e p t a b l e , b u t c o n t a i n s c r i b a l l y out lawed f e a t u r e s , v i z . , f i n a l i n and i n i t i a l & i n c k l i b . For example, d o e s t h e p r o b a b i l i t y of c o r r e c t l y i d e n t i f y i n g a t a r g e t l e t t e r depend upon whether i t is i n a p h o n o l o g i c a l l y - i l l e g a l or a s c r i b a l l y - i l l e g a l t e s t s t r i n g ?
AN I N I T I A L ALGORITHM FOR RULE-GOVERNED REGULARITY
The approach t h a t we p r o p o s e , b u t have n o t y e t f u l l y d e v e l o p e d , for r e p r e s e n t i n g t h e d i s p a r a t e p a t t e r n s j u s t d e s c r i b e d is t o c o n s t r u c t a s e t o f g e n e r a t i v e r u l e s which b e g i n by s e l e c t i n g a consonant-vowel-consonant s t r u c t u r e f o r a p h o n o l o g i c a l word. Replacement r u l e s a r e a p p l i e d t o expand l e f t t o r i g h t of e a c h vowel and each c o n s o n a n t u n i t u n t i l a p h o n o l o g i c a l l y l e g a l s t r i n g r e s u l t s . A second s e t of r u l e s t h e n a p p l i e s s o u n d - t o - s p e l l i n g r u l e s t o g e n e r a t e a l e g a l pseudoword (or word) . By r e l a x i n g r u l e s a t v a r i o u s l e v e l s of g e n e r a t i o n , w e c a n t h e n g e n e r a t e l e t t e r s t r i n g s w i t h c o n t r o l l e d i r r e g u l a r i t i e s . For example, by removing t h e p l a c e r e s t r i c t i o n on f i n a l c l u s t e r s of t h e form NASAL + STOP, w e g e n e r a t e unpronounceable f i n a l c l u s t e r s l i k e -9 and -g. On t h e o t h e r hand, a l l o w i n g f i n a l /v/ t o be r e p r e s e n t e d by 1 r a t h e r t h a n a l l o w s s c r i b a l l y i l l e g a l forms l i k e mov and s l a i v . So f a r , a p r e l i m i n a r y s e t of r u l e s f o r g e n e r a t i n g l e g a l m o n o s y l l a b l e s h a s been d e v e l o p e d , drawing on a v a r i e t y o f s o u r c e s ( e . g . , Whorf, 1956; K u r a t h , 1964; Chomsky & Halle, 1968; Venezky, 1 9 7 0 ) . A sample d e r i v a t i o n of a l e g a l pseudoword from t h e s e r u l e s is shown i n Table 3 . 1 .
I n summary, w e have p r e s e n t e d two g e n e r a l a p p r o a c h e s t o d e s c r i b i n g o r t h o g r a p h i c s t r u c t u r e : s t a t i s t i c a l redundancy and ru le -governed r e g u l a r i t y . For t h e f o r m e r , c l a s s m e t r i c s a r e d e r i v e d from f u n c t i o n s on t h e f r e q u e n c i e s w i t h which v a r i o u s s i z e u n i t s occur ( e . g . , summed bigram c o u n t s ) . For t h e l a t t e r c l a s s we have s u g g e s t e d t h a t a comparable metric might be deve loped through a s e t of g e n e r a t i v e r u l e s which c o u l d be v i o l a t e d a t v a r i o u s l e v e l s t o produce nonwords w i t h c o n t r o l l e d d e v i a t i o n s from ru le-governed r e g u l a r i t y .
36 CHAPTER 3
Table 3.1 Derivation of a legal pseudoword (a).
A. Apply Base Generation Rules
Step
1 2 3 4 5 6 7 8 9 10 11 12 13
Rule - Initialize w -----> cvc C/# ------- CC/# -------
> cc > SCL
SCL ------ > s+NASAL NASAL -----> 11. V/else -----> Vf Vf/else ----> vfr Vfr -----> 4 C/-# ----- > cs CS/Vf-# ---- > STOPg STOPg ----- > STOPVg STOPvg ----- > b
Result
#W# # c+v+c # #CC+V+C# # SCL+V+C# #g+NASAL+V+C# #s+"+V+C # #S+"+Vf+C#
tg+n+i+c # #s+E+i+CS#
#s+E+vfr+C#
#s+g+i+STOPg # #s+g+i-+STOPvg# #S+"+i+b#
B. Apply Base-to-Spelling Rules
Step. Rule Result
14 - s/else ----> <s> #<El>*#
15 - n ----> <n> # < sn>i&# 16 - i/-Cs# ---- > <e...e#> #<sne>b<e>#
b ---- > <b> # < snebe># 17 -
------------- (a)Terminal phonological symbols are underlined; terminal spelling symbols occur in wedges, e.g., <a>. A rule of the form x/# ------- > Y is read "Rewrite X as Y when X occurs after juncture ( I ) .'I
4 Experimental Studies
The r e s e a r c h r e p o r t e d i n t h i s book evolved from a commonality o f i n t e r e s t s among t h e a u t h o r s . These i n t e r e s t s p r i m a r i l y c e n t e r e d around f u r t h e r i n g t h e u n d e r s t a n d i n g o f t h e p e r c e p t u a l p r o c e s s e s involved i n word r e c o g n i t i o n and e s p e c i a l l y d e l i n e a t i n g t h e r o l e t h a t o r t h o g r a p h i c s t r u c t u r e p l a y s i n t h e s e p r o c e s s e s . An e x t e n s i o n of an i n t e r e s t i n g s t u d y by Mason (1975) appeared t o be a p r o d u c t i v e way t o a t t a c k t h e problems of o r t h o g r a p h i c s t r u c t u r e and p e r c e p t u a l r e c o g n i t i o n of words. Mason e v a l u a t e d t h e c o n t r i b u t i o n of summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y i n a t a r g e t s e a r c h t a s k . Good and poor r e a d e r s i n d i c a t e d whether or n o t a s i x - l e t t e r s t r i n g c o n t a i n e d a prede termined t a r g e t l e t t e r . Good r e a d e r s averaged 6 3 msec f a s t e r f o r s t r i n g s h i g h t h a n f o r s t r i n g s low i n p o s i t i o n a l f requency . We were concerned w i t h two p r i m a r y issues w i t h r e s p e c t t o Mason's r e s u l t s . F i r s t , w e q u e s t i o n e d whether a f r e q u e n c y measure of o r t h o g r a p h i c s t r u c t u r e was s u f f i c i e n t t o d e s c r i b e t h e f a c i l i t a t i n g e f f e c t s of s t r u c t u r e on p e r c e p t u a l r e c o g n i t i o n . A s d i s c u s s e d i n Chapter 3 , a ru le -governed d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e may b e a more a p p r o p r i a t e r e p r e s e n t a t i o n of t h e r e a d e r ' s knowledge.
Second, Mason's r e s u l t s appeared t o be h i g h l y v a r i a b l e and w e q u e s t i o n e d whether t h e t a r g e t s e a r c h t a s k u s i n g r e a c t i o n time a s a dependent measure r e v e a l s l a r g e e f f e c t s of o r t h o g r a p h i c s t r u c t u r e . There were a number of r e a s o n s t o s u s p e c t t h e r o b u s t n e s s of t h e e f f e c t i n Mason's s t u d y . S u b j e c t s had o n l y 5 p r a c t i c e t r i a l s and j u s t 7 2 e x p e r i m e n t a l t r i a l s . Each s u b j e c t was t e s t e d on 2 4 words, 24 s t r i n g s h i g h i n p o s i t i o n a l f r e q u e n c y , and 2 4 s t r i n g s low i n p o s i t i o n a l f r e q u e n c y . Given 1 2 good r e a d e r s , t h e r e were 288 o b s e r v a t i o n s minus e r r o r s c o n t r i b u t i n g t o e a c h e x p e r i m e n t a l
38 CHAPTER 4
c o n d i t i o n . Mason found t h a t 100 p r a c t i c e t r i a l s i n a f o l l o w u p exper iment reduced t h e a d v a n t a g e of per formance on s t r i n g s h i g h i n summed p o s i t i o n a l f r e q u e n c y t o a n a v e r a g e of a b o u t 2 2 msec. S i n c e p r a c t i c e t r i a l s reduced t h e a d v a n t a g e by a b o u t t w o - t h i r d s we f e l t t h a t a r e p l i c a t i o n of Mason's s t u d y w i t h improved methodology was n e c e s s a r y t o d e t e r m i n e t h e r e l i a b i l i t y of h e r r e s u l t s .
MASSARO ET AL. 1979 STUDIES
Massaro, Venezky, and Taylor (1979) r e p l i c a t e d Mason's exper iment u s i n g t h e t a r g e t s e a r c h t a s k w i t h s i x t h - g r a d e s u b j e c t s . To o b t a i n g r e a t e r r e l i a b i l i t y , b o t h t h e number of o b s e r v a t i o n s and t h e number of t e s t s t i m u l i were i n c r e a s e d . Fur thermore , t h e l e t t e r s t r i n g s were n o t o n l y h i g h and low i n p o s i t i o n a l f r e q u e n c y b u t a l s o were c o n t r a s t e d a l o n g a n o t h e r dimension which we c a l l e d o r t h o g r a p h i c r e g u l a r i t y . We had n o t y e t deve loped a s y s t e m a t i c ru le -based d e s c r i p t i o n of E n g l i s h o r t h o g r a p h y , b u t we were a b l e t o choose s t r i n g s t h a t appeared t o be r e g u l a r o r i r r e g u l a r . T h e r e f o r e , a l t h o u g h we had no s y s t e m a t i c d e s c r i p t i o n of r e g u l a r i t y , w e f e l t t h a t t h e d e c i s i o n s we made t o choose s t r i n g s t h a t were r e g u l a r and i r r e g u l a r would p r o v i d e a tes t of whether t h e f a c i l i t a t i n g e f f e c t s of o r t h o g r a p h i c s t r u c t u r e c o u l d be c o m p l e t e l y accounted f o r by t h e p o s i t i o n a l f r e q u e n c y h y p o t h e s i s proposed by Mason.
To c r e a t e t h e t e s t s t i m u l i , Massaro e t a l . (1979) s e l e c t e d f o u r anagrams from each o f 40 s i x - l e t t e r words such t h a t t h e anagrams were e i t h e r h i g h or low i n s i n g l e - l e t t e r p o s i t i o n a l f requency and e i t h e r r e g u l a r or i r r e g u l a r . The r e s u l t i n g 2 x 2 f a c t o r i a l d e s i g n p r o v i d e s a d i r e c t a s s e s s m e n t of t h e c o n t r i b u t i o n s of f r e q u e n c y and r e g u l a r i t y on l e t t e r - s t r i n g p e r c e p t i o n . Each of t h e s i x t h g r a d e r s began by t a k i n g a w r i t t e n comprehension t e s t . The t a r g e t s e a r c h t a s k was t h e n i n t r o d u c e d by showing t h e s u b j e c t s t h e v i s u a l d i s p l a y and t h e r e s p o n s e p a n e l . To a c q u a i n t t h e s u b j e c t s w i t h t h e r e s p o n s e p r o c e d u r e , t h e y were f i r s t 'given 50 t r i a l s o f responding "yes" and "no" t o t h e words YES and NO p r e s e n t e d on t h e v i s u a l d i s p l a y . Each s u b j e c t pushed t h e " y e s " b u t t o n w i t h h i s or h e r p r e f e r r e d hand. Next , t h e s u b j e c t s r e c e i v e d 50 p r a c t i c e t r i a l s w i t h random l e t t e r s t r i n g s . The s u b j e c t s were asked t o i n d i c a t e whether o r n o t a t a r g e t l e t t e r was p r e s e n t i n t h e six-letter s t r i n g . Each t r i a l began w i t h t h e p r e s e n t a t i o n of t h e t a r g e t l e t t e r f o l l o w e d 800 msec l a t e r by t h e t e s t l e t t e r s t r i n g . The t e s t l e t t e r s t r i n g remained on u n t i l t h e s u b j e c t
EXPERIMENTS ON LETTER AND WORD PERCEPTION 39
responded. S u b j e c t s were i n s t r u c t e d t o respond " y e s " i f t h e t a r g e t l e t t e r appeared a t l e a s t once i n t h e l e t t e r s t r i n g and "no" i f i t d i d n o t a p p e a r . The t a r g e t l e t t e r appeared i n t h e l e t t e r s t r i n g on h a l f of t h e t r i a l s ( t a r g e t t r i a l s ) and d i d n o t appear on t h e o t h e r h a l f ( c a t c h t r i a l s ) . They were t o l d t o respond as a c c u r a t e l y a s p o s s i b l e . The s u b j e c t s were t e s t e d on each of t h e unique 1 6 0 s t i m u l i , once on t a r g e t t r i a l s and once on c a t c h t r i a l s , g i v i n g roughly 8 0 o b s e r v a t i o n s p e r s u b j e c t a t each o f t h e f o u r e x p e r i m e n t a l c o n d i t i o n s ( l e s s e r r o r t r i a l s ) .
F i g u r e 4 . 1 g i v e s t h e r e s u l t s from t h i s i n i t i a l e x p e r i m e n t . Although t h e r e a c t i o n times were a b o u t 1 2 msec f a s t e r f o r
R-L I-H
F i g u r e 4 . 1 R e a c t i o n t i m e and p e r c e n t a g e c o r r e c t f o r s i x t h g r a d e r s a s a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f rom Massaro e t a l . , 1 9 7 9 ) (key: p = o r t h o g r a p h i c a l l y r e g u l a r : I = o r t h o g r a p h i c a l l y i r r e g u l a r ; ; = h i g h summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y ; & = low summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y ) .
CHAPTER 4
r e g u l a r t h a n f o r i r r e g u l a r s t r i n g s and a b o u t 1 2 msec f a s t e r f o r h i g h t h a n f o r low p o s i t i o n a l f r e q u e n c y , n e i t h e r r e s u l t was s t a t i s t i c a l l y s i g n i f i c a n t . These r e s u l t s imply t h a t n e i t h e r p o s i t i o n a l f r e q u e n c y nor r e g u l a r i t y c o n t r i b u t e s i g n i f i c a n t l y t o p e r c e p t u a l r e c o g n i t i o n i n t h e t a r g e t s e a r c h t a sk . One r e a s o n could be t h a t our m a n i p u l a t i o n of p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y d i d n o t c a p t u r e t h e knowledge t h a t s u b j e c t s u t i l i z e i n p e r c e p t u a l r e c o g n i t i o n . A second p o s s i b i l i t y i s t h a t our m a n i p u l a t i o n of o r t h o g r a p h i c s t r u c t u r e d i d m i r r o r d i f f e r e n c e s i n t h e p s y c h o l o g i c a l r e a l i t y of t h e s e s t r u c t u r e s b u t t h a t t h e t a r g e t s e a r c h t a s k u s i n g r e a c t i o n times is i n s e n s i t i v e t o u t i l i z a t i o n of s t r u c t u r e .
We s u s p e c t e d t h a t t h e s m a l l e f f e c t s i n t h e f i r s t exper iment were p r i m a r i l y due t o t h e t a r g e t s e a r c h t a s k r a t h e r t h a n t o t h e s t r i n g s u t i l i z e d i n t h e e x p e r i m e n t s . T h e r e f o r e , we c a r r i e d o u t two more e x p e r i m e n t s t o c o n t r a s t t h e t a r g e t s e a r c h t a s k u t i l i z i n g r e a c t i o n time (RT) a s a d e p e n d e n t measure w i t h a t a r g e t s e a r c h t a s k u s i n g a c c u r a c y as a d e p e n d e n t measure. We employed c o l l e g e s t u d e n t s r a t h e r t h a n s i x t h g r a d e r s as s u b j e c t s s i n c e t h e y were more r e a d i l y a v a i l a b l e f o r t e s t i n g . One exper iment was a r e p l i c a t i o n of our RT e x p e r i m e n t . The o t h e r , a n a c c u r a c y e x p e r i m e n t , involved a s l i g h t m o d i f i c a t i o n of a more common paradigm used t o s t u d y t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e . I n v a r i a n t s of a Reicher-Wheeler p o s t c u e t a s k (see Chapter l ) , t h e s u b j e c t i s shown a word o r a nonword f o r a b r i e f d u r a t i o n f o l l o w e d by a masking s t i m u l u s . Two a l t e r n a t i v e l e t t e r s a r e t h e n g i v e n and t h e s u b j e c t c h o o s e s which l e t t e r he or s h e t h i n k s was p r e s e n t e d on t h a t t r i a l . I n o r d e r t o make t h i s a c c u r a c y t a s k comparable t o t h e RT t a s k , we modi f ied i t by p r e s e n t i n g j u s t one a l t e r n a t i v e l e t t e r a f t e r t h e masking s t i m u l u s . I n t h i s case t h e s i x - l e t t e r i tem would be p r e s e n t e d f o l l o w e d by a masking s t i m u l u s and t h e n t h e t a r g e t l e t t e r . The t a r g e t l e t t e r would be p r e s e n t i n t h e t e s t item on h a l f o f t h e t r i a l s and n o t p r e s e n t on t h e o t h e r h a l f . The s u b j e c t s would s imply i n d i c a t e whether o r n o t t h e t a r g e t l e t t e r o c c u r r e d i n t h e t e s t l e t t e r s t r i n g . Per formance , i n t e r m s of r e a c t i o n time iri t h e f i r s t e x p e r i m e n t and o v e r a l l a c c u r a c y i n t h e second e x p e r i m e n t , r e f l e c t s how well t h e t e s t s t r i n g s were p e r c e i v e d .
The r e s u l t s of t h e s e two e x p e r i m e n t s a r e shown i n F i g u r e s 4 . 2 and 4 . 3 . I n t h e r e a c t i o n time t a s k , r e a c t i o n times averaged 1 6 msec f a s t e r f o r h i g h t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . Responses were 9 msec f a s t e r f o r r e g u l a r t h a n f o r i r r e g u l a r s t r i n g s . The a c c u r a c y t a s k showed t h a t r e s p o n s e a c c u r a c y was 5% h i g h e r f o r r e g u l a r t h a n f o r
EXPERIMENTS ON LETTER AND WORD PERCEPTION 41
i r r e g u l a r s t r i n g s and 4 % h i g h e r f o r h i g h t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . A l l of t h e s e r e s u l t s were s t a t i s t i c a l l y s i g n i f i c a n t . T h e r e f o r e , a l t h o u g h t h e magni tude of t h e e f f e c t s on r e a c t i o n time f o r t h e a d u l t s was o f t h e same o r d e r of magni tude a s t h a t f o r t h e s i x t h g r a d e r s , lower v a r i a n c e among t h e a d u l t s made t h e e f f e c t s s t a t i s t i c a l l y s i g n i f i c a n t . One l i m i t a t i o n a t t h i s s t a g e of t h e r e s e a r c h was t o know whether o r n o t s i x t h g r a d e r s would g i v e s t a t i s t i c a l l y s i g n i f i c a n t a c c u r a c y r e s u l t s i n t h e a c c u r a c y t a s k . However, s i n c e t h i s l a t t e r ' i n f o r m a t i o n was n o t a v a i l a b l e , w e were f a c e d w i t h t h e problem of comparing t h e magni tude of t h e r e a c t i o n t ime r e s u l t w i t h t h e magni tude of t h e a c c u r a c y r e s u l t and r e a l i z e d t h a t i t resembled t h a t o f comparing a p p l e s and o l i v e s .
I f i t is a c c e p t e d t h a t t h e r e a c t i o n t i m e r e s u l t is small ,
750
- 700
v) I - Y
5
%
650
F 2 600
550
k
K K 0 90 0 n
y 100
I I I I
Target 0 Catch
nnnn R-H R-L I-H I -L
F i g u r e 4 . 2 R e a c t i o n time and p e r c e n t a g e c o r r e c t f o r c o l l e g e s t u d e n t s a s a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f rom Massaro e t a l . , 1 9 7 9 ) .
4 2 CHAPTER 4
t h e n one e x p l a n a t i o n f o r t h e small e f f e c t c o u l d t a k e t h e f o l l o w i n g form. I n t h e r e a c t i o n . t i m e t a s k t h e s u b j e c t was g i v e n t h e t a r g e t l e t t e r b e f o r e t h e t e s t s t r i n g was p r e s e n t e d . S i n c e t h e s u b j e c t s imply was r e q u i r e d t o i n d i c a t e whether or n o t t h e t a r g e t was c o n t a i n e d i n t h e t e s t s t r i n g , h e or s h e may n o t have had t o r e s o l v e c o m p l e t e l y a l l o f t h e l e t t e r s i n t h e s t r i n g b e f o r e a c o r r e c t d e c i s i o n was made. For example, suppose a s u b j e c t is l o o k i n g f o r t h e t a r g e t l e t t e r i n t h e l e t t e r s t r i n g s c o s e , deom, and 9 r e s p e c t i v e l y . I n a l l cases t h e a p p r o p r i a t e r e s p o n s e is no , b u t t h e s u b j e c t may be a b l e t o d e c i d e on t h i s f a s t e r w i t h some of t h e s t r i n g s t h a n w i t h o t h e r s . Cons ider t h e f o l l o w i n g argument . There i s some e v i d e n c e t h a t o v e r a l l l e t t e r shape c a n be r e s o l v e d and made a v a i l a b l e t o l a t e r s t a g e s o f p r o c e s s i n g b e f o r e t h e l e t t e r is
'oo!7----- 90
c---oCatch -
50 - R H R-L I-H I-L
F i g u r e 4 . 3 P e r c e n t a g e c o r r e c t f o r c o l l e g e s t u d e n t s as a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f rom Massaro e t a l . , 1 9 7 9 ) .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 43
T a b l e 4 . 1 The s i x s e t s of l e t t e r s based on t h e s i m i l a r i t y r e s u l t s of Bouma (1971) used by Massaro e t a l . ( 1 9 7 9 ) .
1.
2 .
3 .
4.
5 .
6 .
it Although Bouma's a n a l y s i s i n d i c a t e d t h a t t h e f i r s t s e t c o u l d be f u r t h e r d i v i d e d i n t o two sets c o n s i s t i n g of m , n , u , and r , v , w , t h e s e two s e t s were combined because of t h e i r r e l a t i v e s i m i l a r i t y and t o p r o v i d e more r e l i a b l e d a t a by i n c r e a s i n g t h e number of o b s e r v a t i o n s w i t h i n a s e t .
c o m p l e t e l y r e c o g n i z e d (Bouma, 1971; Massaro & S c h m u l l e r , 1 9 7 5 ) . A t a r g e t s e a r c h t a s k c a n be used t o s t u d y t h e f e a t u r e s n e c e s s a r y f o r r e c o g n i t i o n . N e i s s e r (1963, 1967) f o r example, showed t h a t s u b j e c t s s e a r c h e d f a s t e r f o r an uppercase 2 i n a l i s t of curved l e t t e r s t h a n i n a l i s t of l i n e a r l e t t e r s . T h i s r e s u l t i n d i c a t e s t h a t t h e s u b j e c t s were a b l e t o r e j ec t t h e curved l e t t e r s a s f o i l s more q u i c k l y t h a n t h e l i n e a r l e t t e r s . Applying t h i s a n a l y s i s t o t h e p r e s e n t example, s l i b j e c t s s h o u l d be a b l e t o respond "no" q u i c k l y t o t h e e x t e n t t h a t none of t h e l e t t e r s i n t h e t e s t s t r i n g h a s t h e same o v e r a l l a s c e n d e r shape a s t h e t a r g e t l e t t e r b. T h e r e f o r e , i t w i l l t a k e t h e s u b j e c t l o n g e r t o r e j e c t t h e s t r i n g deih t h a n t o r e j e c t t h e s t r i n g deom. The s t r i n g s h o u l d be r e j e c t e d f a s t e s t o f a l l . To t h e e x t e n t t h e s u b j e c t is a b l e t o u t i l i z e t h i s f e a t u r e d e t e c t i o n s t r a t e g y l t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e might be a t t e n u a t e d . T h e r e f o r e , i t was of i n t e r e s t t o s e e t h e e x t e n t t o which s u b j e c t s appeared t o be u s i n g t h i s s t r a t e g y i n
4 4 CHAPTER 4
t h e r e a c t i o n time and a c c u r a c y tasks . We h y p o t h e s i z e d t h a t t h i s s t r a t e g y would be u t i l i z e d i n t h e r e a c t i o n time b u t n o t t h e a c c u r a c y t a s k . I n t h e a c c u r a c y t a s k , t h e s u b j e c t w i l l r e s o l v e t h e l e t t e r s t r i n g t o t h e d e e p e s t l e v e l p o s s i b l e . I n t h e r e a c t i o n time t a s k , having t h e t a r g e t s p e c i f i e d i n advance and having t h e t e s t l e t t e r s t r i n g v i s i b l e d u r i n g t h e p r o c e s s i n g i n t e r v a l w i l l a l l o w t h e s u b j e c t t o t e r m i n a t e e a r l y on some c a t c h t r i a l s .
To e v a l u a t e t h i s h y p o t h e s i s , t h e l o w e r c a s e l e t t e r s o f t h e a l p h a b e t were grouped i n t o s i x g r o u p s based on t h e s i m i l a r i t y r e s u l t s of Bouma ( 1 9 7 1 ) . T h i s grouping is g i v e n i n T a b l e 4.1. The r e l a t i o n s h i p between each t a r g e t l e t t e r and t e s t s t r i n g was d e f i n e d i n t e r m s of t h e number of n o n t a r g e t l e t t e r s i n t h e s t r i n g t h a t were members of t h e same s e t as t h e t a r g e t l e t t e r .
P
I I 1 1 2 3 5501 ,!,
NUMBER OF SIMILAR NONTARGETS
F i g u r e 4 . 4 R e a c t i o n time i n t h e t a r g e t s e a r c h t a s k a s a f u n c t i o n o f t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g (from Massaro e t a l . , 1 9 7 9 ) .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 4 5
For example, t h e t e s t s t r i n g l i s v e r would have two l e t t e r s (1 and i-) from t h e same s e t a s t h e l e t t e r t , two (v and LJ from t h e same s e t as u, and none from t h e same set a s 5. F i g u r e s 4.4 and 4.5 g i v e t h i s s i m i l a r i t y a n a l y s i s f o r r e a c t i o n time and a c c u r a c y t a s k s r e s p e c t i v e l y . The r e s u l t s show h i g h l y s i g n i f i c a n t e f f e c t s on c a t c h t r i a l s i n t h e r e a c t i o n time t a s k , s u p p o r t i n g t h e i d e a of a f e a t u r e d e t e c t i o n s t r a t e g y i n t h e r e a c t i o n t i m e t a s k .
The number of l e t t e r s i n t h e t e s t s t r i n g having t h e same o v e r a l l shape a s t h e t a r g e t s h o u l d n o t be i m p o r t a n t on t a r g e t t r i a l s i n t h e r e a c t i o n time t a s k s . The t a r g e t l e t t e r m u s t be c o m p l e t e l y r e s o l v e d b e f o r e a " y e s " r e s p o n s e can be made. I f t h e s u b j e c t s s imply responded " y e s " whenever t h e o v e r a l l shape of t h e t a r g e t was p e r c e i v e d , r e c o g n i t i o n e r r o r s would be h i g h l y
I 1 I 1 2 3
NUMBER OF SIMILAR NONTARGETS
F i g u r e 4 .5 P e r c e n t a g e c o r r e c t i n t h e t a r g e t s e a r c h t a sk a s a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e tes t s t r i n g ( f rom Massaro e t a l . , 1 9 7 9 ) .
4 6 CHAPTER 4
p r o b a b l e . S i n c e a h i g h a c c u r a c y c r i t e r i o n was e n f o r c e d , we would n o t e x p e c t t h e number of s i m i l a r l y shaped l e t t e r s t o be a c r i t i c a l v a r i a b l e on t a r g e t t r i a l s . A s c a n be s e e n i n F i g u r e 4 . 4 , t h e s i m i l a r i t y v a r i a b l e had no s i g n i f i c a n t e f f e c t on t a r g e t t r i a l s i n t h e r e a c t i o n time e x p e r i m e n t .
I n t h e a c c u r a c y t a s k , per formance on c a t c h t r i a l s tended t o d e c r e a s e w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t l e t t e r s . I n c o n t r a s t , per formance improved somewhat on t a r g e t t r i a l s w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t l e t t e r s . Although t h e s e r e s u l t s were n o t s t a t i s t i c a l l y s i g n i f i c a n t , t h e y show t h a t s i m i l a r i t y may a l s o p l a y a r o l e i n t h e a c c u r a c y t a s k .
Although it is d i f f i c u l t t o compare d i r e c t l y t h e magni tude of t h e e f f e c t s of a c c u r a c y w i t h t h o s e of r e a c t i o n time, t h e s i m i l a r i t y a n a l y s i s makes such a comparison more meaningfu l . The r e a c t i o n time s t u d y i n d i c a t e d s m a l l e f f e c t s of o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o t h e e f f e c t s of s i m i l a r i t y . The a c c u r a c y s t u d y r e v e a l e d l a r g e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o s m a l l e f f e c t s of s i m i l a r i t y . C o n t r a s t i n g t h e s e two v a r i a b l e s i n e a c h t a s k might a l l o w a more r e l i a b l e a s s e s s m e n t of t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . From t h i s a n a l y s i s it a p p e a r s t h a t o r t h o g r a p h i c s t r u c t u r e p l a y s a l a r g e r r o l e i n t h e a c c u r a c y s t u d y t h a n it d o e s i n t h e r e a c t i o n time s t u d y . One of t h e p r i m a r y m o t i v a t i o n s of t h e p r e s e n t se t of e x p e r i m e n t s was t o e x p l o r e t h e d i f f e r e n c e s between t h e s e two t a s k s . Of c o u r s e , i t is n o t t h e t a s k s themselves t h a t a r e i n t e r e s t i n g b u t r a t h e r , what t h e y r e v e a l a b o u t t h e p e r c e p t u a l r e c o g n i t i o n of l e t t e r s t r i n g s .
The f o l l o w i n g s e t of e x p e r i m e n t s was a l s o deemed n e c e s s a r y because of t h e l i m i t a t i o n s i n t h e m a n i p u l a t i o n of o r t h o g r a p h i c s t r u c t u r e i n our p r e v i o u s s t u d i e s . Although w e a t t e m p t e d t o choose r e g u l a r and i r r e g u l a r s t r i n g s f o r e a c h l e v e l of h i g h o r low p o s i t i o n a l f r e q u e n c y , we were n o t c o n f i d e n t t h a t w e had been c o m p l e t e l y s u c c e s s f u l . I t was d i f f i c u l t t o s e l ec t regular - low p o s i t i o n a l - f r e q u e n c y items and i r r e g u l a r - h i g h p o s i t i o n a l - f r e q u e n c y items. T h i s fo l lowed from t h e f a c t t h a t p o s i t i o n a l f requency and our i n t u i t i v e i m p r e s s i o n of o r t h o g r a p h i c r e g u l a r i t y might have been h i g h l y c o r r e l a t e d . T h e r e f o r e , we may have i n a d v e r t e n t l y confounded r e g u l a r i t y w i t h p o s i t i o n a l f r e q u e n c y i n t h a t t h e h i g h p o s i t i o n a l - f r e q u e n c y items were more r e g u l a r t h a n t h e low p o s i t i o n a l - f r e q u e n c y items. I t remained a p o s s i b i l i t y t h a t t h e e f f e c t of p o s i t i o n a l f r e q u e n c y would be e l i m i n a t e d i f w e c o u l d f i n d items t h a t were e q u a l l y r e g u l a r f o r h i g h and low p o s i t i o n a l f r e q u e n c i e s . T h e r e f o r e , we r e f i n e d our d e s c r i p t i o n
EXPERIMENTS ON LETTER AND WORD PERCEPTION 47
o f o r t h o g r a p h i c r e g u l a r i t y and c h o s e a new s e t of items on t h e b a s i s o f t h e s e r u l e s f o r t h e p r e s e n t e x p e r i m e n t s . The r u l e s a r e p r e s e n t e d i n Appendix 4 . 1 A .
I n a d d i t i o n t o s e l e c t i n g new items w e a l s o employed word s t i m u l i i n t h e e x p e r i m e n t s . Krueger (1979) s p e c u l a t e d t h a t a much l a r g e r f a c i l i t a t i o n i n t h e t a r g e t s e a r c h t a s k would be found w i t h words t h a n w i t h pseudowords. By i n c l u d i n g w i t h our f o u r c a t e g o r i e s o f m e a n i n g l e s s anagrams t h e words from which t h e y were d e r i v e d , w e c o u l d p r o v i d e a d i r e c t e v a l u a t i o n of t h e f a c i l i t a t i n g e f f e c t s of word s t r u c t u r e r e l a t i v e t o p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y . We a l s o saw t h e p o t e n t i a l f o r t e s t i n g a wider r a n g e of formal d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e i n t h e p r e s e n t e x p e r i m e n t s . A s i n d i c a t e d e a r l i e r , t h e q u a l i t a t i v e t e s t p r o v i d e d by t h e f a c t o r i a l d e s i g n is l i m i t e d . A good d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e must a l s o d e s c r i b e per formance f o r i n d i v i d u a l l e t t e r s t r i n g s . T h e r e f o r e , we planned t o a n a l y z e per formance a s a f u n c t i o n of i n d i v i d u a l l e t t e r s t r i n g s i n t h e p r e s e n t s t u d i e s . These a n a l y s e s would go s i g n i f i c a n t l y beyond t h e q u a l i t a t i v e compar isons between word, pseudoword, and nonword items of p r e v i o u s s t u d i e s . A second m o t i v a t i o n f o r i n c l u d i n g word items was t h a t any d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e must n o t be l i m i t e d t o nonword items b u t m u s t a l s o be f u n c t i o n a l f o r word items. I f i n some manner l e x i c a l ( i . e . , word) i d e n t i t y o v e r r u l e s o r t h o g r a p h i c s t r u c t u r e , t h e n t h e l a t t e r would n o t be p s y c h o l o g i c a l l y r e l e v a n t i n r e a d i n g .
T h e r e f o r e t h e f i r s t two e x p e r i m e n t s of t h e p r e s e n t s e t of e x p e r i m e n t s c a n be c o n s i d e r e d t o be a d i r e c t r e p l i c a t i o n of t h e Massaro e t a l . (1979) e x p e r i m e n t s which have j u s t been d e s c r i b e d . However, t h e p r e s e n t e x p e r i m e n t s i n c l u d e d a new s e t o f items a l o n g w i t h t h e c o r r e s p o n d i n g word s t i m u l i . I n t h i s s e n s e , t h e e x p e r i m e n t s conform t o t h e e x p e r i m e n t a l framework g i v e n by Sidman (1960) i n t h a t we a r e both r e p l i c a t i n g and e x t e n d i n g p r e v i o u s e x p e r i m e n t s . F i g u r e 4.6 i l l u s t r a t e s t h e f i v e t y p e s of i t e m s used i n a l l o f t h e c u r r e n t e x p e r i m e n t s .
STUDY 1: I N I T I A L REPLICATION
Procedure
Two e x p e r i m e n t s were c a r r i e d o u t w i t h 1 4 s u b j e c t s i n e a c h exper iment . F i g u r e 4 . 7 g i v e s a s c h e m a t i c r e p r e s e n t a t i o n of t h e p r o c e d u r e s f o r t h e a c c u r a c y and RT e x p e r i m e n t s . I n t h e a c c u r a c y e x p e r i m e n t t h e t e s t l e t t e r s t r i n g was p r e s e n t e d f o r a
48 CHAPTER 4
wrntei ahcger rdnuet (1421)
s h o r t d u r a t i o n fo l lowed immediately by a masking s t i m u l u s . The d u r a t i o n of t h e t e s t item was a d j u s t e d f o r each s u b j e c t i n o r d e r t o o b t a i n an a v e r a g e of 75% c o r r e c t a c r o s s a l l c o n d i t i o n s i n t h e t a s k . The t a r g e t l e t t e r fo l lowed t h e 208 msec masking s t i m u l u s . The s u b j e c t ' s t a s k was t o i n d i c a t e by p r e s s i n g t h e a p p r o p r i a t e b u t t o n whether or n o t t h e t a r g e t l e t t e r was c o n t a i n e d i n t h e t e s t l e t t e r s t r i n g . I n t h e RT e x p e r i m e n t t h e t a r g e t l e t t e r was p r e s e n t e d f o r 500 msec fo l lowed by a 1 sec blank p e r i o d . The t e s t s t r i n g was t h e n p r e s e n t e d and remained on u n t i l t h e s u b j e c t responded " y e s " o r "no" w i t h r e s p e c t t o whether or n o t t h e t a r g e t l e t t e r o c c u r r e d i n t h e t e s t s t r i n g . A r e a s o n a b l e amount o f p r a c t i c e was g i v e n on both tasks . The t e s t items were s i x - l e t t e r s t r i n g s c o n s i s t i n g of 4 0 words and 160 anagrams c r e a t e d by t h e f a c t o r i a l combina t ion of h i g h or
rntewi hreagc edtrnu (526)
low p o s i t i o n a l - f r e q u e n c y
I winter charge
words I turned I (1293)
Regular
Orthographic Regularity
and r e g u l a r or i r r e g u l a r
Positional Frequency
High Low
triwen trewin chager greach drunet tredun (1438) (540)
I I
F i g u r e 4 . 6 The f i v e t y p e s of i t e m s and examples of e a c h t y p e used i n t h e e x p e r i m e n t s . The number i n e a c h c e l l is t h e a v e r a g e summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t h a t item t y p e (based on t h e Mayzner & T r e s s e l t , 1965, c o u n t s ) .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 49
s t r u c t u r e . On any t r i a l , any of t h e f i v e t y p e s of s t r i n g s c o u l d be p r e s e n t e d a s e i t h e r a c a t c h o r t a r g e t t r i a l . The tes t s t r i n g s a r e p r e s e n t e d i n Appendix 4 . 1 B . The d e t a i l s of t h e method, p r o c e d u r e , and r e s u l t s o f t h e two t a s k s a r e p r e s e n t e d i n Appendix 4 . 1 .
O r t h o g r a p h i c S t r u c t u r e
F i g u r e s 4.8 and 4.9 p r e s e n t t h e r e s u l t s from t h e a c c u r a c y and RT t a s k s as a f u n c t i o n of t h e f i v e classes of items. Performance i n t h e a c c u r a c y t a s k depended g r e a t l y on t h e s t r u c t u r e of t h e t e s t s t r i n g . Words were r e c o g n i z e d 1 2 % more o f t e n t h a n t h e b e s t r e g u l a r h i g h items. The r e g u l a r s t r i n g s were judged 8 % more a c c u r a t e l y t h a n t h e i r r e g u l a r s t r i n g s . Accuracy was 5% h i g h e r f o r h i g h p o s i t i o n a l - f r e q u e n c y
PRECUE RT
Target Test Letter Display
:-+L I- 500 I 1000 I
POSTCUE ACCURACY
Test Mask Target Letter
F i g u r e 4 . 7 Schemat ic r e p r e s e n t a t i o n s of t h e p r e c u e r e a c t i o n time and p o s t c u e a c c u r a c y e x p e r i m e n t s .
50 CHAPTER 4
1 I I I
s t r i n g s t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . A l l of t h e s e r e s u l t s were s t a t i s t i c a l l y s i g n i f i c a n t . The d e t a i l e d r e s u l t s and t h e s t a t i s t i c a l a n a l y s e s are p r e s e n t e d i n Appendix 4 . 1 .
I n t h e RT t a s k , r e a c t i o n times t o words were o n l y 7 msec f a s t e r t h a n r e a c t i o n times t o r e g u l a r - h i g h anagrams. Regular items were judged 2 3 msec f a s t e r t h a n i r r e g u l a r items, whereas h i g h p o s i t i o n a l - f r e q u e n c y items were responded t o o n l y 4 msec f a s t e r t h a n low p o s i t i o n a l - f r e q u e n c y items. Only t h e e f f e c t of r e g u l a r i t y was s t a t i s t i c a l l y s i g n i f i c a n t . The d e t a i l e d r e s u l t s and s t a t i s t i c a l a n a l y s e s a r e p r e s e n t e d i n Appendix 4.1.
The h i g h l y s i g n i f i c a n t e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on r e s p o n s e a c c u r a c y and t h e r e l a t i v e l y minor , and f o r t h e most p a r t , n o n s i g n i f i c a n t e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on r e a c t i o n time p r o v i d e a d i r e c t r e p l i c a t i o n of our p r e v i o u s
50 WORD R-H R-L I-H I-L
F i g u r e 4 . 8 P e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e f o r t a r g e t and c a t c h t r i a l s i n t h e p o s t c u e a c c u r a c y t a s k of S tudy 1.
EXPERIMENTS ON LETTER AND WORD PERCEPTION 5 1
I Y
5
w E 600 I-
P 550-
work. These r e s u l t s u n d e r s c o r e t h e r e l i a b i l i t y of t h e r e g u l a r i t y and p o s i t i o n a l - f r e q u e n c y e f f e c t s on a c c u r a c y by d e m o n s t r a t i n g a g e n e r a l i z a t i o n t o both a new sample o f s u b j e c t s and a new sample of s t i m u l u s items ( C l a r k , 1 9 7 3 ) . N e i t h e r r e g u l a r i t y nor p o s i t i o n a l f r e q u e n c y , however, a p p e a r s t o be s u f f i c i e n t t o a c c o u n t f o r t h e s t r o n g a c c u r a c y a d v a n t a g e found f o r words. The i s sue of whether or n o t o r t h o g r a p h i c s t r u c t u r e r a t h e r t h a n l e x i c a l i d e n t i t y c a n a c c o u n t for t h e word a d v a n t a g e w i l l be d e l a y e d u n t i l a more d e t a i l e d d i s c u s s i o n and e v a l u a t i o n of o r t h o g r a p h i c s t r u c t u r e is p r e s e n t e d .
-
S i m i l a r i t y E f f e c t s
To t e s t f o r t h e e f f e c t s of s i m i l a r i t y between t h e t a r g e t l e t t e r s o u g h t i n a d i s p l a y and t h e l e t t e r s a c t u a l l y o c c u r r i n g
F i g u r e 4 . 9 R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e for t a r g e t and c a t c h t r i a l s i n t h e p r e c u e r e a c t i o n t i m e t a s k o f S tudy 1.
52 CHAPTER 4
Table 4 . 2 For e a c h o f t h e 26 l e t t e r s i s l i s t e d t h e o t h e r l e t t e r s i n t h e a l p h a b e t t h a t were e r r o n e o u s l y i d e n t i f i e d a s t h a t l e t t e r more t h a n 5% of t h e t i m e (from Bouma, 1 9 7 1 ) .
S i m i l a r S i m i l a r T a r g e t N o n t a r g e t L e t t e r s T a r g e t N o n t a r g e t L e t t e r s
a c , e l m , n , 0 , s , x , z n a , e l s , u , x
C 0 P 4
i . 1, t V W
j 1 W V
k t , x X
Y V
i n t h e d i s p l a y , t h e d a t a were pooled a c r o s s a l l f i v e d i s p l a y t y p e s and r e p a r t i t i o n e d . The b a s i s f o r t h i s r e p a r t i t i o n i n g was t h e c l a s s i f i c a t i o n o f each t r i a l ' s t a r g e t l e t t e r a c c o r d i n g t o which l e t t e r s a r e l i k e l y t o be s e e n a s v e r y s i m i l a r t o t h e t a r g e t . The c l a s s i f i c a t i o n was d e r i v e d from t h e l o w e r c a s e s i n g l e - l e t t e r c o n f u s a b i l i t y s t u d y o f Bouma ( 1 9 7 1 ) shown i n t a b l e 2 . 4 . We counted a n o n t a r g e t l e t t e r a s s i m i l a r t o t h e t a r g e t l e t t e r i f t h e n o n t a r g e t l e t t e r was e r r o n e o u s l y i d e n t i f i e d a s t h e t a r g e t more t h a n 5% of t h e t ime i n Bouma's s t u d y . T a b l e 4 .2 p r e s e n t s t h e s i m i l a r i t y c l a s s i f i c a t i o n a c c o r d i n g t o t h i s a n a l y s i s . For example, g i v e n t h e t a r g e t
EXPERIMENTS ON LETTER AND WORD PERCEPTION 53
l e t t e r &, t h e s i m i l a r n o n t a r g e t l e t t e r s a r e k, E, and - u. T h i s means t h a t t h e s t i m u l u s l e t t e r s k t k, p, a n d 2 were i d e n t i f i e d a s b more t h a n 5% o f t h e t i m e i n Bouma's s t u d y . Each u n i q u e t r i a l i n o u r t a r g e t s e a r c h t a s k was t h e n d e s c r i b e d by t h e number o f n o n t a r g e t l e t t e r s i n t h e d i s p l a y t h a t were s i m i l a r t o t h e t a r g e t a c c o r d i n g t o t h i s c las - s i f i c a t i o n . Rough ly 46 , 3 3 , 1 3 , and 7 % o f e a c h s u b j e c t ' s t r i a l s f e l l i n t o t h e c a t e g o r i e s z e r o , o n e , two , a n d t h r e e s i m i l a r l e t t e r s ( o t h e r t h a n t h e t a r g e t l e t t e r i t s e l f ) , r e s p e c t i v e l y .
F i g u r e s 4.10 and 4 .11 p r e s e n t t h e a c c u r a c y and r e a c t i o n t ime r e s u l t s a s a f u n c t i o n o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e d i s p l a y . T a r g e t v e r s u s c a t c h t r i a l s i s t h e c u r v e p a r a m e t e r i n t h e f i g u r e s . I n t h e a c c u r a c y t a s k , a c c u r a c y i n c r e a s e d w i t h i n c r e a s e s i n t h e number o f s i m i l a r n o n t a r g e t
100
90 k Y 8 80
a
0
B 70
I2 k
60
50
I 1 I I
1 I 1 L 0 1 2 3
NUMBER OF SIMILAR NONTARGETS
F i g u r e 4.10 P e r c e n t a g e c o r r e c t a s a f u n c t i o n o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g s i n t h e a c c u r a c y e x p e r i m e n t o f S t u d y 1.
54 CHAPTER 4
l e t t e r s on t a r g e t t r i a l s and d e c r e a s e d on c a t c h t r i a l s . The l a r g e s i m i l a r i t y e f f e c t s i n t h e a c c u r a c y t a s k c o n t r a s t w i t h t h e s m a l l e r e f f e c t s o f Massaro e t a l . shown i n F i g u r e 4 . 5 . The p r e s e n t a n a l y s i s may have provided a more s e n s i t i v e t e s t o f s i m i l a r i t y t h a n t h e Massaro e t a l . a n a l y s i s s i n c e t h e c o n f u s i o n s e t s were computed i n a more p r e c i s e manner. I n p a r t i c u l a r , t h e p r e s e n t a n a l y s i s a l l o w s f o r asymmetr ic c o n f u s i o n s . Although c is c o n s i d e r e d t o b e a s i m i l a r n o n t a r g e t l e t t e r g i v e n t h e t a r g e t l e t t e r d, e , 9, o r 2 , t h e o n l y s i m i l a r n o n t a r g e t l e t t e r f o r t h e t a r g e t l e t t e r i s t h e l e t t e r 0. I n t h e r e a c t i o n t i m e t a s k , r e a c t i o n time i n c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r t a r g e t l e t t e r s on c a t c h t r i a l s b u t d i d not change much on t a r g e t t r i a l s . T h i s r e s u l t p r o v i d e s a d i r e c t r e p l i c a t i o n o f t h e s i m i l a r i t y a n a l y s i s i n t h e Massaro e t a l . s t u d y shown i n F i g u r e 4.4.
650 700r---
+--+Target 500 t r E l 450 h 1 2 3
NUMBER OF SIMILAR NONTARGETS
F i g u r e 4.11 R e a c t i o n time a s a f u n c t i o n of t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g i n t h e r e a c t i o n t i m e exper iment o f S tudy 1.
EXPERIMENTS ON LETTER AND WORD PERCEPTION 55
Targe t -Catch D i f f e r e n c e s
Accuracy was 1 2 % h i g h e r f o r c a t c h t r i a l s t h a n f o r t a r g e t t r i a l s and t h i s e f f e c t i n t e r a c t e d w i t h d i s p l a y t y p e s ( c f . F i g u r e 4 . 8 ) . Reac t ion times were 47 msec s lower f o r c a t c h t r i a l s t h a n f o r t a r g e t t r i a l s ( c f . F i g u r e 4 . 9 ) . The r e s u l t s show t h a t s u b j e c t s i n an a c c u r a c y t a s k tend t o be more a c c u r a t e on c a t c h t r i a l s t h a n on t a r g e t t r i a l s whereas t h e y t e n d t o t a k e l o n g e r on c a t c h t r i a l s i n t h e r e a c t i o n time e x p e r i m e n t . Given t h a t t h e s e r e s u l t s d o n o t come from t h e same e x p e r i m e n t , t h e y c a n n o t be i n t e r p r e t e d i n te rms of a speed a c c u r a c y t r a d e - o f f . However, r e s p o n s e a c c u r a c y i n t h e RT t a s k was a l s o s i g n i f i c a n t l y h i g h e r f o r c a t c h t h a n f o r t a r g e t t r i a l s ( F i g u r e 4.9) and t h i s r e s u l t might a c c o u n t f o r t h e l o n g e r r e a c t i o n times on c a t c h t r i a l s i n t h e r e a c t i o n t i m e t a s k .
A c e n t r a l q u e s t i o n r a i s e d by t h i s s t u d y c o n c e r n s t h e n a t u r e of t h e s i m i l a r i t i e s and t h e d i f f e r e n c e s between a c c u r a c y and r e a c t i o n time paradigms. R e s u l t s from a c c u r a c y and r e a c t i o n time s t u d i e s a r e f r e q u e n t l y r e g a r d e d a s c o n v e r g e n t i n d i c a t i o n s of common p e r c e p t u a l p r o c e s s i n g . S y s t e m a t i c d i f f e r e n c e s between t h e a c c u r a c y and RT e f f e c t s would s u g g e s t t h a t p e r c e p t u a l p r o c e s s e s may n o t be t h e same i n b o t h c a s e s . Thus, two i m p o r t a n t q u e s t i o n s a r e whether o r n o t a c c u r a c y and r e a c t i o n time r e s u l t s can be p r e d i c t e d from a common p r o c e s s i n g model, and i f so , how t h e d i f f e r e n t s t i m u l u s envi ronments of t h e a c c u r a c y and r e a c t i o n time t a s k s c a u s e t h e observed d i f f e r e n c e s i n t h e magnitude of t h e e f f e c t s . The a c c u r a c y and t h e r e a c t i o n time t a s k s w i l l be e v a l u a t e d i n t h e framework of t h e i n f o r m a t i o n p r o c e s s i n g model. I n o r d e r t o b e t t e r unders tand t h e e f f e c t s of t a r g e t and c a t c h t r i a l s and t o b e t t e r e x p l i c a t e our i n t e r p r e t a t i o n of t h e p r o c e s s e s i n t h e a c c u r a c y and r e a c t i o n t i m e t a s k s , we w i l l p r e s e n t an i n f o r m a t i o n p r o c e s s i n g a n a l y s i s of per formance i n t h e a c c u r a c y and r e a c t i o n time t a s k s .
INFORMATION PROCESSING MODEL
With t h e r e g i s t r a t i o n of a l e t t e r s t r i n g a s a n image upon t h e r e t i n a , s e n s o r y t r a n s d u c t i o n b e g i n s . F e a t u r e s a r e e x t r a c t e d s i m u l t a n e o u s l y ( i n p a r a l l e l ) from e a c h l e t t e r p o s i t i o n i n t h e d i s p l a y and a r e e n t e r e d i n t o p r e p e r c e p t u a l v i s u a l s t o r a g e . F e a t u r e e x t r a c t i o n i s a t e m p o r a l l y ex tended p r o c e s s so t h a t t h e c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e
CHAPTER 4
b u i l d up over t ime. Concurren t w i t h t h e e s t a b l i s h m e n t o f t h e new c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e , t h e p r i m a r y r e c o g n i t i o n p r o c e s s t r a n s f o r m s t h e c u r r e n t c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e i n t o s y n t h e s i z e d v i s u a l memory. The c o n t e n t s of s y n t h e s i z e d v i s u a l memory a r e c o n t i n u a l l y monitored by a d e c i s i o n p r o c e s s which, i n t h e case of t h e precue t a r g e t s e a r c h t a s k , endeavors t o match t h e t a r g e t w i t h t h e f r e s h l y r e s o l v e d and c o n t i n u o u s l y updated l e t t e r s t r i n g i n s y n t h e s i z e d v i s u a l memory, a s i n T u r v e y ' s (1973) c o n c u r r e n t - c o n t i n g e n t model.
To d e r i v e s p e c i f i c p r e d i c t i o n s from t h e model, i t is n e c e s s a r y t o make a few assumpt ions a b o u t t h e p r i m a r y r e c o g n i t i o n p r o c e s s and t h e d e c i s i o n p r o c e s s . Exper imenta l s u p p o r t f o r t h e s e assumpt ions p r e v i o u s l y h a s been d e m o n s t r a t e d (Massaro, 1 9 7 9 a ) . The f i r s t assumpt ion is t h a t knowledge of o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s a n independent s o u r c e o f knowledge a b o u t t h e l e t t e r s t r i n g . A c c o r d i n g l y , e x p e r i e n c e d r e a d e r s w i l l be b i a s e d t o i n t e r p r e t t h e l e t t e r s t r i n g as one t h a t is o r t h o g r a p h i c a l l y s t r u c t u r e d . T h e r e f o r e , t o t h e e x t e n t t h a t t h e l e t t e r s be ing r e s o l v e d from p r e p e r c e p t u a l v i s u a l s t o r a g e form w e l l - s t r u c t u r e d l e t t e r s e q u e n c e s , t h e y may be r e s o l v e d w i t h fewer f e a t u r e s or b e f o r e a l l f e a t u r e s have been e x t r a c t e d . I n c o n t r a s t , a p o o r l y - s t r u c t u r e d s t r i n g w i l l r e q u i r e n e a r l y comple te f e a t u r a l i n f o r m a t i o n f o r r e c o g n i t i o n because o r t h o g r a p h i c knowledge w i l l p r o v i d e no a d d i t i o n a l a s s i s t a n c e . Thus, t h e c o n t e n t s o f s y n t h e s i z e d v i s u a l memory a r e e s t a b l i s h e d by p r i m a r y r e c o g n i t i o n more q u i c k l y and a c c u r a t e l y f o r w e l l - s t r u c t u r e d t h a n f o r p o o r l y - s t r u c t u r e d s t r i n g s .
The second assumpt ion is r e l a t e d t o t h e d e c i s i o n a l g o r i t h m i n t h e t a r g e t s e a r c h t a sk . When t h e t a r g e t l e t t e r is known i n advance, t h e d e c i s i o n p r o c e s s m o n i t o r s t h e c o n t i n u o u s l y emerging c o n t e n t s o f s y n t h e s i z e d v i s u a l memory s e e k i n g a match t o t h e t a r g e t . A l l l e t t e r p o s i t i o n s a r e moni tored i n d e p e n d e n t l y and i n p a r a l l e l . The d e c i s i o n p r o c e s s m a i n t a i n s two c r i t e r i a or d e c i s i o n a x e s , ana logous t o t h e model of memory s e a r c h developed by Atk inson and J u o l a ( 1 9 7 4 ) . Whenever a l e t t e r p o s i t i o n e x c e e d s t h e f i r s t c r i t e r i o n i n resemblance t o t h e t a r g e t , a match is assumed t o have been found, p r o c e s s i n g t e r m i n a t e s , and a p o s i t i v e r e s p o n s e is e x e c u t e d . Whenever a l e t t e r p o s i t i o n is s u f f i c i e n t l y d i s s i m i l a r t o t h e t a r g e t t o exceed t h e second c r i t e r i o n , t h e l e t t e r is c l a s s i f i e d as a f o i l . Let ter p o s i t i o n s t h a t have n o t y e t been r e s o l v e d s u f f i c i e n t l y t o be c l a s s i f i e d a s t a r g e t o r f o i l c o n t i n u e t o be r e s o l v e d u n t i l t h e y c a n be c l a s s i f i e d or u n t i l f u r t h e r
EXPERIMENTS ON LETTER AND WORD PERCEPTION 57
r e s o l u t i o n is n o t p o s s i b l e . When a l l l e t t e r p o s i t i o n s have been c l a s s i f i e d a s f o i l s , a n e g a t i v e r e s p o n s e i s e x e c u t e d .
I f t h e v i s u a l s t i m u l u s i s impoverished s o t h a t f u l l r e s o l u t i o n of a l l l e t t e r p o s i t i o n s is n o t p o s s i b l e , a d e c i s i o n i s f o r c e d when no f u r t h e r r e s o l u t i o n is p o s s i b l e . Given t h a t t h e f u l l y r e s o l v e d o r c l e a r l y " s e e n " l e t t e r s have been c l a s s i f i e d as f o i l s , a g u e s s r e s p o n s e m u s t be e x e c u t e d based upon t h e remain ing "unseen" l e t t e r s . The o b s e r v e r ' s p r o b a b i l i t y o f g u e s s i n g t h a t one of t h e unreso lved l e t t e r s is a t a r g e t is a j o i n t f u n c t i o n of a p r i o r i e x p e c t a t i o n s t h a t any g i v e n l e t t e r w i l l be a t a r g e t and t h e number of u n r e s o l v e d l e t t e r s . These e x p e c t a t i o n s a r e d e r i v e d from i n s t r u c t i o n s and p a s t e x p e r i e n c e .
For t h e p r e c u e RT t a s k , t h e f o l l o w i n g p r e d i c t i o n s a l s o f o l l o w d i r e c t l y from t h e model. D e c i s i o n time is a d i r e c t f u n c t i o n of t h e r e s o l u t i o n t ime of t h e s t i m u l u s s t r i n g and t h e r e f o r e is i n f l u e n c e d by t h e o r t h o g r a p h i c r e d u n d a n c i e s t h a t c a n be e x p l o i t e d i n t h e s t i m u l u s . The t i m e t o c o r r e c t l y i d e n t i f y a t a r g e t i n t h e l e t t e r s t r i n g is a f u n c t i o n s o l e l y of t h e time r e q u i r e d t o r e s o l v e t h e t a r g e t and w i l l , on t h e a v e r a g e , be s h o r t e r t h a n t h e time r e q u i r e d t o e x h a u s t i v e l y c l a s s i f y a l l l e t t e r s a s f o i l s on a c a t c h t r i a l . I d e n t i f i c a t i o n time f o r t h e t a r g e t l e t t e r is i n f l u e n c e d by t h e o r t h o g r a p h i c c o n s t r a i n t s among t h e l e t t e r s i n t h e c a t c h s t r i n g . The emphasis on a c c u r a c y i n t h e RT t a s k d i s p o s e s t h e o b s e r v e r t o m a i n t a i n s t r i c t c r i t e r i a which, f o r t h e most p a r t , p r e c l u d e e r r o r s .
I n a p o s t c u e t a s k , r e c o g n i t i o n and d e c i s i o n p r o c e s s e s a n a l o g o u s t o t h o s e f o r t h e p r e c u e t a s k a r e assumed t o o p e r a t e , e x c e p t t h a t t h e c o n t e n t s of s y n t h e s i z e d v i s u a l memory m u s t be m a i n t a i n e d a w a i t i n g t h e a r r i v a l and r e c o g n i t i o n of t h e t a r g e t l e t t e r . The s t i m u l u s l e t t e r s t r i n g is r e s o l v e d a s f u l l y a s t h e combined v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e a l l o w and is r e t a i n e d a w a i t i n g p r e s e n t a t i o n of t h e t a r g e t . Once t h e t a r g e t is i d e n t i f i e d , i t is compared w i t h however much of t h e l e t t e r s t r i n g was r e s o l v e d . I f a match is found, a p o s i t i v e r e s p o n s e is e x e c u t e d . Fol lowing t h e argument of Thompson and Massaro ( 1 9 7 3 ) , i t i s assumed t h a t t h e e x a c t f e a t u r a l s i m i l a r i t y of t h e u n r e s o l v e d l e t t e r s t o t h e t a r g e t l e t t e r is n o t d i r e c t l y a v a i l a b l e t o t h e d e c i s i o n p r o c e s s and d o e s n o t i n f l u e n c e t h e g u e s s p r o b a b i l i t y . O r t h o g r a p h i c s t r u c t u r e i n f l u e n c e s a c c u r a c y f o r bo th t a r g e t and c a t c h t r i a l s because i t i n f l u e n c e s t h e number of l e t t e r s t h a t a r e a c c u r a t e l y p e r c e i v e d .
I t may seem s u r p r i s i n g t h a t t h e Thompson and Massaro (1973) and t h e Massaro e t a l . (1979) s t u d i e s r e v e a l e d no
CHAPTER 4
s i g n i f i c a n t e f f e c t s o f l e t t e r s i m i l a r i t y . Even i f f e a t u r a l i n f o r m a t i o n is n o t t r a n s m i t t e d t o s y n t h e s i z e d v i s u a l memory we would e x p e c t i n c o r r e c t s y n t h e s e s t o be s i m i l a r t o t h e t e s t l e t t e r . For example, g i v e n t h e t e s t l e t t e r 0, we would e x p e c t t h a t r e c o g n i t i o n e r r o r s w i l l be more l i k e l y t o c o n s i s t of c and - e t h a n I and 2. One f a c t o r t h a t may work a g a i n s t o b s e r v a t i o n of t h i s phenomenon may be t h a t t h e t e s t d i s p l a y was f o l l o w e d by a masking s t i m u l u s i n t h e a c c u r a c y t a s k and t h e r e is now some e v i d e n c e t h a t f e a t u r e s of t h e mask c o n t r i b u t e t o p e r c e p t u a l memory of t h e t e s t (Kallman & Massaro, 1979; Smi th , H a v i l a n d , Reder , Brownel l , & Adams, 1 9 7 6 ) . Given t h e c o n t r i b u t i o n of t h e mask, i n c o r r e c t r e s p o n s e s might be more e a s i l y p r e d i c t e d by t h e f e a t u r e s of t h e mask t h a n t h e f e a t u r e s of t h e t e s t . A second r e a s o n f o r o b s e r v i n g s m a l l s i m i l a r i t y e f f e c t s i n t h e a c c u r a c y s t u d i e s is t h a t t h e a c c u r a c y s t u d i e s w i t h l e t t e r s t r i n g s employ a f o r c e d - c h o i c e r e s p o n s e s i t u a t i o n so t h a t t h o s e few t r i a l s t h a t i n v o l v e i n c o r r e c t p e r c e p t u a l s y n t h e s e s a r e u n l i k e l y t o a g r e e w i t h t h e i n c o r r e c t r e s p o n s e a l t e r n a t i v e . The s y s t e m a t i c l e t t e r c o n f u s i o n s u s u a l l y found i n s i n g l e - l e t t e r r e c o g n i t i o n s t u d i e s c o u l d depend on an open-ended s e t of l e t t e r r e s p o n s e a l t e r n a t i v e s . However, i t is a l s o p o s s i b l e t o o b s e r v e s i g n i f i c a n t s i m i l a r i t y e f f e c t s a s i n t h e p r e s e n t a c c u r a c y s t u d y ( c f . F i g u r e 4 . 1 8 ) . The p a t t e r n of t h e s e r e s u l t s is c o n s i s t e n t w i t h t h e i d e a t h a t s i m i l a r l e t t e r s may be m i s t a k e n l y i d e n t i f i e d a s t h e t a r g e t . Hence, a c c u r a c y on t a r g e t t r i a l s i n c r e a s e s w i t h t h e number of s i m i l a r l e t t e r s t o t h e t a r g e t i n t h e t e s t s t r i n g , b u t a c c u r a c y on c a t c h t r i a l s d e c r e a s e s a s t h e number of s i m i l a r l e t t e r s t o t h e t a r g e t is i n c r e a s e d .
I t is p o s s i b l e t o q u a n t i f y t h e p r o c e s s i n g model i n o r d e r t o d e s c r i b e t h e q u a n t i t a t i v e r e s u l t s of t h e t a r g e t s e a r c h t a s k . I n an a c c u r a c y t a s k , i t is assumed t h a t t h e l e t t e r s t r i n g is p e r c e i v e d ( i . e . , r e s o l v e d ) a s f u l l y a s p o s s i b l e . R e s o l u t i o n of t h e d i s p l a y i s a d i r e c t f u n c t i o n of b o t h t h e f e a t u r a l i n f o r m a t i o n a v a i l a b l e and t h e o r t h o g r a p h i c s t r u c t u r e of t h e t e s t s t r i n g . S i n c e each o f t h e f o u r t y p e s of m e a n i n g l e s s l e t t e r s t r i n g s was composed by making anagrams of a s i x - l e t t e r word, t h e same l e t t e r s were p r e s e n t a c r o s s t h e f i v e d i s p l a y . t y p e s . The f i v e d i s p l a y t y p e s were a l s o p r e s e n t e d a t t h e same i n t e n s i t y and d u r a t i o n s . T h e r e f o r e , t h e f e a t u r a l i n f o r m a t i o n may be assumed t o be c o n s t a n t a c r o s s t h e d i s p l a y t y p e s . However, t h e d i s p l a y t y p e s d i f f e r w i t h r e s p e c t t o o r t h o g r a p h i c s t r u c t u r e and t h e s e d i f f e r e n c e s can a c c o u n t f o r t h e performance d i f f e r e n c e s a c r o s s t h e f i v e d i s p l a y t y p e s . T h e r e f o r e , t h e number of l e t t e r s r e s o l v e d , R , w i l l depend on t h e d i s p l a y t y p e .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 59
I t i s n e c e s s a r y t o d e s c r i b e a d e c i s i o n r u l e t h a t a l l o w s t h e s u b j e c t t o s e l e c t a " y e s " o r "no" r e s p o n s e . I t is assumed t h a t i f one of t h e r e s o l v e d l e t t e r s is i d e n t i c a l t o t h e t a r g e t , a " y e s " r e s p o n s e is e x e c u t e d . I f t h e t a r g e t l e t t e r is n o t c o n t a i n e d i n t h e se t of r e s o l v e d l e t t e r s , a " y e s " r e s p o n s e i s a f u n c t i o n of t h e number of u n r e s o l v e d l e t t e r s and t h e r e a d e r ' s e x p e c t a t i o n , E , t h a t some l e t t e r i n t h e s i x - l e t t e r s t r i n g w i l l be i d e n t i c a l t o t h e t a r g e t . S i n c e E i s t h e e x p e c t a t i o n f o r a whole s i x - l e t t e r tes t s t r i n g c o n t a i n i n g t h e t a r g e t , t h e n E/6 is t h e e x p e c t a t i o n t h a t any s i n g l e l e t t e r i n t h e t e s t s t r i n g is i d e n t i c a l t o t h e t a r g e t . The e x p e c t a t i o n v a l u e E would be some f u n c t i o n o f i n s t r u c t i o n s , f e e d b a c k , and how o f t e n t h e t a r g e t l e t t e r is a c t u a l l y s e e n i n t h e t e s t s t r i n g . T h e r e f o r e , t h e p r o b a b i l i t y o f a " y e s " r e s p o n s e t o t h e t a r g e t t r i a l i s g i v e n by Equat ion 1 f o r l e t t e r s t r i n g s of l e n g t h 6.
The l e f t - h a n d term of Equat ion 1 i n d i c a t e s t h a t R - s i x t h s of t h e time one o f t h e r e s o l v e d l e t t e r s w i l l be i d e n t i c a l t o t h e t a r g e t and t h e o b s e r v e r w i l l respond " y e s " w i t h p r o b a b i l i t y one. On t h e remain ing t r i a l s , 1 - R/6, t h e t a r g e t was n o t r e s o l v e d and t h e o b s e r v e r g u e s s e s w i t h p r o b a b i l i t y E /6 weighted by t h e number of u n r e s o l v e d l e t t e r s ( 6 - R ) .
For c a t c h t r i a l s , t h e o b s e r v e r w i l l never f i n d t h e t a r g e t and , t h e r e f o r e , i s i n an i m p e r f e c t knowledge s t a t e u n l e s s h e o r s h e r e s o l v e s a l l of t h e l e t t e r s . T h e r e f o r e , t h e l i k e l i h o o d of a " y e s " r e s p o n s e is s imply t h e o b s e r v e r ' s e x p e c t a t i o n t h a t a g i v e n t e s t l e t t e r is a t a r g e t l e t t e r , E/6, weighted by t h e number of u n r e s o l v e d t a r g e t l e t t e r s , 6 - R:
P(Yes lCatch) = (6 - R ) x (E/6) ( 2 )
Of c o u r s e , t h e l i k e l i h o o d of b e i n g c o r r e c t on c a t c h t r i a l s is t h e complement of Equat ion ( 2 ) :
P(No1Catch) = 1 - [ ( 6 - R ) x ( E / 6 ) ] ( 3 )
The model was a p p l i e d t o t h e r e s u l t s of t h e a c c u r a c y e x p e r i m e n t . The model was f i t t o t h e 1 0 a v e r a g e r e s p o n s e a c c u r a c i e s ( t h e f i v e d i s p l a y t y p e s on t a r g e t p r e s e n t t r i a l s and t h e f i v e d i s p l a y t y p e s on c a t c h o r t a r g e t a b s e n t t r i a l s ) . The f i t was o b t a i n e d u s i n g a l e a s t - s q u a r e s parameter e s t i m a t i o n r o u t i n e ( C h a n d l e r , 1 9 6 9 ) . S i x p a r a m e t e r s were e s t i m a t e d from t h e d a t a : one e x p e c t a t i o n p a r a m e t e r , E , and an e s t i m a t e o f t h e
60 CHAPTER 4
number of l e t t e r s f u l l y r e s o l v e d , R , f o r e a c h o f t h e f i v e d i s p l a y t y p e s . The o b t a i n e d f i t was q u i t e good; t h e r o o t mean squared d e v i a t i o n was o n l y 1.3%. Although i t is d i f f i c u l t t o a p p r e c i a t e t h e q u a n t i t a t i v e g o o d n e s s - o f - f i t f o r such a model e s t i m a t i n g s i x p a r a m e t e r s f o r 1 0 d a t a p o i n t s , t h e o b t a i n e d parameter v a l u e s n o n e t h e l e s s a r e r e v e a l i n g . The s u b j e c t s were c l e a r l y informed of t h e e q u a l number of t a r g e t and c a t c h t r i a l s i n t h e exper iment and t h e r e f o r e , t h e y s h o u l d have adopted a n E-value o f .5 . However, t h e observed g r e a t e r a c c u r a c y f o r c a t c h t r i a l s would a p p e a r t o s u g g e s t a b i a s toward "no" r e s p o n s e s o r an a p p a r e n t E-value r a t h e r c l o s e t o z e r o . I n f a c t , t h e e s t i m a t e d E-value was . 4 6 s u g g e s t i n g t h a t t h e s u b j e c t s possessed a t most a v e r y s l i g h t b i a s . The s t r o n g imbalance between c a t c h a c c u r a c y and t a r g e t a c c u r a c y i s a l o g i c a l consequence of t h e model even when l i t t l e o r no b i a s is p r e s e n t . Although t h e r e a r e no a p r i o r i v a l u e s o f t h e R p a r a m e t e r s t o which t h e e s t i m a t e s may be compared, t h e o b t a i n e d e s t i m a t e s f o r R p r o v i d e a r e a s o n a b l e s c a l i n g f o r t h e f i v e t y p e s o f items. These v a l u e s a r e shown i n T a b l e 4.3 a s P o s t c u e (S tudy 1) .
While t h e s p e c i f i c a t i o n of a q u a n t i t a t i v e model p r e d i c t i n g r e a c t i o n times is c o n s i d e r a b l y more complex, i t n o n e t h e l e s s s tems d i r e c t l y from t h e above i n f o r m a t i o n p r o c e s s i n g a n a l y s i s . The r e a c t i o n t ime on a t a r g e t t r i a l i s t h e s u m of t h e t i m e needed t o r e s o l v e t h e t a r g e t l e t t e r i n t h e l e t t e r s t r i n g p l u s t h e time needed t o i n i t i a t e and e x e c u t e t h e c o r r e c t r e s p o n s e . The r e s o l u t i o n time f o r t h e t a r g e t l e t t e r i s a f u n c t i o n of i t s v i s u a l p r o p e r t i e s and of t h e o r t h o g r a p h i c s t r u c t u r e o f t h e l e t t e r s t r i n g i n which t h e t a r g e t o c c u r s . S i n c e o r t h o g r a p h i c s t r u c t u r e a f f e c t s t h e t i m e needed t o r e s o l v e t h e l e t t e r s t r i n g , o r t h o g r a p h i c s t r u c t u r e is a parameter of t h e d i s t r i b u t i o n o f t h e r e a c t i o n t i m e s . The expec ted v a l u e of t h i s d i s t r i b u t i o n p l u s a c o n s t a n t g i v e s a v e r a g e RT f o r t a r g e t t r i a l s . (Response i n i t i a t i o n and e x e c u t i o n t i m e is assumed t o be c o n s t a n t o r a t l e a s t d i s t r i b u t e d i n d e p e n d e n t l y o f t h e e f f e c t o f p r i m a r y i n t e r e s t . )
For c a t c h t r i a l s , t h e RT i s t h e sum of a c o n s t a n t time f o r response e x e c u t i o n p l u s t h e maximum time needed t o c l a s s i f y a l l l e t t e r s a s f o i l s . C l a s s i f i c a t i o n t ime is based upon t h e j o i n t d i s t r i b u t i o n o f comple t ion t i m e s f o r e a c h o f t h e f o i l s on t h e n o n t a r g e t t r i a l s . These d i s t r i b u t i o n s have a s p a r a m e t e r s t h e s i m i l a r i t y o f t h e f o i l t o t h e t a r g e t , o t h e r v i s u a l p r o p e r t i e s which a f f e c t t h e o v e r a l l e a s e of r e s o l v i n g t h e f o i l , t h e i n f l u e n c e o f o r t h o g r a p h i c s t r u c t u r e , and f i n a l l y t h e s u b j e c t ' s c r i t e r i o n f o r a v o i d i n g f a l s e a l a r m s . Having o u t l i n e d t h e model
EXPERIMENTS ON LETTER AND WORD PERCEPTION 6 1
T a b l e 4.3 E s t i m a t e s o f p e r c e p t u a l r e s o l u t i o n ( R ) and a p r i o r i e x p e c t a t i o n ( E ) o f t h e o c c u r r e n c e o f a t a r g e t t r i a l and t h e r o o t mean s q u a r e d (RMS) d e r i v a t i o n s f o r t h e a c c u r a c y t a s k s i n S t u d i e s 1 and 2.
R E RMS ( i n % )
Task Word R-H R-L I - H I - L
5.20 4.40 3.72 3.40 2.98 .459 1 . 2 7
5.22 4.38 3 .56 3 .26 2 .86 . 5 5 0 1 . 7 0
P o s t c u e
( S t u d y 1)
( S t u d y 2 )
P r e c u e
( S t u d y 2 ) 4.87
Combined Da ta 5.08
P o s t c u e P r e c u e
4.29 3 .84 3.85
4.33 3.68 3 . 5 1
3.42 . 8 8 0 1 .67
3.08 2.54
.514
.823
t o t h i s l e v e l o f d e t a i l , w e w i l l p r o c e e d no f u r t h e r . U n l i k e t h e a c c u r a c y model where t h e f i t o f t h e model was e n l i g h t e n i n g a b o u t presumed s u b j e c t b i a s i n t h e t a s k , t h e q u a l i t a t i v e f e a t u r e s o f t h e RT d a t a f o l l o w r a t h e r d i r e c t l y f rom t h e q u a l i t a t i v e d e s c r i p t i o n o f t h i s model . The c o m p l e t i o n o f t h e q u a n t i f i c a t i o n o f t h i s model m i g h t p r o v e a n i n t e r e s t i n g e x e r c i s e b u t would b e u n l i k e l y t o b e e x t r e m e l y r e v e a l i n g , p a r t i c u l a r l y s i n c e t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were v e r y s m a l l .
STUDY 2: PRECUE VERSUS POSTCUE
Whereas i t is n o t p o s s i b l e t o compare d i r e c t l y t h e m a g n i t u d e o f a c c u r a c y and RT e f f e c t s , t h e d i f f e r e n c e s i n a c c u r a c y b e t w e e n words and i r r e g u l a r - l o w a n a g r a m s i n t h e
62 CHAPTER 4
a c c u r a c y t a s k was 21%. The d i f f e r e n c e be tween t h e s e same c o n d i t i o n s i n t h e RT t a s k was o n l y 34 msec o r 5 .8% o f t h e a v e r a g e RT o f 581 msec. 3 o e s t h i s r e p r e s e n t a r ea l d i f f e r e n c e i n t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e i n t h e two t a s k s ? I f s o , what p r o p e r t i e s o f t h e t a s k s a l l o w more o f a c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e i n o n e t a s k t h a n i n t h e o t h e r ?
The o b s e r v a t i o n o f s i g n i f i c a n t a d v a n t a g e s f o r w o r d s and pseudowords o v e r nonwords and s i n g l e l e t t e r s i n t h e p o s t c u e R e i c h e r t a s k ( B a r o n & T h u r s t o n , 1973; R e i c h e r , 1969; Thompson &
Massa ro , 1973 ; W h e e l e r , 1 9 7 0 ) and t h e a b s e n c e o f t h e s e e f f e c t s i n p r e c u e d e t e c t i o n t a s k s ( B j o r k & Estes, 1973 ; E s t e s , B j o r k , &
S k a a r , 1974; M a s s a r o , 1973; Thompson & M a s s a r o , 1 9 7 3 ) h a s l e d t o t h e s u g g e s t i o n t h a t p r e c u i n g p r e c l u d e s t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e . The s u b j e c t i n a p r e c u e t a s k p r e s u m a b l y m a t c h e s t h e f e a t u r e s of t h e remembered t a r g e t l e t t e r d i r e c t l y t o t h e f e a t u r e s o f t h e incoming v i s u a l d i s p l a y . T h i s s t r a t e g y p r e c l u d e s u s i n g o r t h o g r a p h i c s t r u c t u r e t o a s s i s t i n r e s o l u t i o n o f t h e d i s p l a y . Thus , o n e h y p o t h e s i s is t h a t p r e c u i n g p r o m o t e s s m a l l e r a d v a n t a g e s f o r s t r u c t u r e d d i s p l a y s . S t u d y 2 t e s t s w h e t h e r a p r e c u e , p e r se , a c c o u n t s f o r d i m i n i s h e d e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e . The p o s t c u e a c c u r a c y t a s k o f t h e S t u d y 1 was r e p l i c a t e d i n o n e c o n d i t i o n w h i l e a c o m p a r a b l e p r e c u e a c c u r a c y t a s k was u s e d i n t h e o t h e r c o n d i t i o n . I f p r e c u i n g a l w a y s a l l o w s m a t c h e s t o b e made a t a f e a t u r e d e t e c t i o n l e v e l , t h e n t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e s h o u l d b e s e v e r e l y a t t e n u a t e d i n t h e p r e c u e a c c u r a c y t a s k . On t h e o t h e r h a n d , i f t h e d i s p l a y i n t h e a c c u r a c y t a s k i s r e s o l v e d t o t h e f u l l e s t e x t e n t p o s s i b l e and o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s t o r e s o l u t i o n , t h e n t h e r e s u l t s f o r p r e c u e and p o s t c u e a c c u r a c y s h o u l d b e c o m p a r a b l e e x c e p t , p e r h a p s , f o r d i f f e r e n t i a l memory l o a d s i n t h e two c o n d i t i o n s .
The t e s t s t r i n g s , a p p a r a t u s , and d i s p l a y s e q u e n c e s were i d e n t i c a l t o t h o s e o f t h e a c c u r a c y e x p e r i m e n t i n S t u d y 1. One h a l f o f t h e s u b j e c t s r e c e i v e d t h e p r e c u e t a s k o n t h e f i r s t d a y and t h e p o s t c u e t a s k o n t h e second d a y ; f o r t h e r e m a i n i n g s u b j e c t s t h i s o r d e r was r e v e r s e d . The p r e c u e t a s k i n v o l v e d t h e p r e s e n t a t i o n o f t h e t a r g e t l e t t e r f o r 500 msec f o l l o w e d by t h e l e t t e r s t r i n g 1 sec l a t e r . The l e t t e r s t r i n g was p r e s e n t e d b e f o r e t h e t a r g e t i n t h e p o s t c u e t a s k . I n b o t h t a s k s t h e l e t t e r s t r i n g was e x p o s e d f o r a s h o r t d u r a t i o n and masked t o g i v e a n a v e r a g e p e r f o r m a n c e o f 75% c o r r e c t . E i g h t e e n s u b j e c t s were t e s t e d i n t h e e x p e r i m e n t . The d e t a i l s o f t h e me thod , p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4 .2
EXPERIMENTS ON LETTER AND WORD PERCEPTION
w n 60
6 3
-
Or t h o g r a p h i c S t r u c t u r e
F i g u r e 4.12 p r e s e n t s p e r c e n t a g e c o r r e c t t a r g e t i d e n t i f i c a t i o n s a s a f u n c t i o n o f t h e f i v e l e v e l s o f o r t h o g r a p h i c s t r u c t u r e . The p r e c u e t a s k v e r s u s t h e p o s t c u e t a s k i s t h e c u r v e p a r a m e t e r . A s c a n be s e e n i n t h e f i g u r e , l a r g e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were f o u n d i n b o t h t h e p r e c u e and p o s t c u e t a s k s , a l t h o u g h s l i g h t l y l a r g e r e f f e c t s were found i n t h e p o s t c u e t a s k . The p o s t c u e e x p e r i m e n t r e p l i c a t e s t h e p r e v i o u s s t u d y . The p r e c u e r e s u l t s a r e v e r y s i m i l a r t o t h e p o s t c u e r e s u l t s , a l t h o u g h t h e a t t e n t u a t i o n o f t h e o r t h o g r a p h i c s t r u c t u r e e f f e c t s i n t h e p r e c u e t a s k o v e r t h e p o s t c u e t a s k i s s t a t i s t i c a l l y s i g n i f i c a n t .
The p r i m a r y f o c u s o f t h i s e x p e r i m e n t was t o d e t e r m i n e t h e r e l a t i o n s h i p o f p r e c u e a c c u r a c y p e r f o r m a n c e t o p o s t c u e a c c u r a c y
- Postcue - Precue
50 WORD R-H R-L I-H I-L
I
F i g u r e 4 .12 P e r c e n t a g e c o r r e c t a s a f u n c t i o n o f d i s p l a y t y p e i n t h e p r e c u e and p o s t c u e c o n d i t i o n s o f S t u d y 2.
64 CHAPTER 4
performance. Although t h e i n t e r a c t i o n of t a s k w i t h d i s p l a y c o n d i t i o n s s u g g e s t s a s m a l l e r i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e i n t h e p r e c u e t h a n p o s t c u e t a s k , t h e r e su l t s a r e s u f f i c i e n t t o r e j e c t t h e h y p o t h e s i s t h a t p r e c u i n g promotes a d r a s t i c r e d u c t i o n i n t h e u s e of o r t h o g r a p h i c s t r u c t u r e . The e f f e c t s of s t r u c t u r e were v e r y s t r o n g f o r bo th p r e c u e and p o s t c u e , and t h e d i f f e r e n c e between t h e two tasks was s m a l l by comparison.
The observed i n t e r a c t i o n of t a s k w i t h d i s p l a y c o n d i t i o n s probably r e f l e c t s d i f f e r e n t memory r e q u i r e m e n t s f o r t h e two t a s k s . I t is r e a s o n a b l e t o e x p e c t t h a t per formance might be poorer i n a p o s t c u e t a s k because t h e n e c e s s i t y of r e t a i n i n g t h e d i s p l a y u n t i l t h e t a r g e t l e t t e r is p r o c e s s e d c o u l d l e a d t o memory l o s s . I t might f u r t h e r be e x p e c t e d t h a t f o r g e t t i n g would be g r e a t e r f o r t h e more p o o r l y - s t r u c t u r e d d i s p l a y s (Baddeley , 1964). Any d i f f e r e n c e s i n o v e r a l l a c c u r a c y between t h e p o s t c u e t h a n i n p r e c u e t a sks a r e n o t meaningfu l because t h e a d a p t i v e a l g o r i t h m endeavored t o m a i n t a i n o v e r a l l a c c u r a c y a t 7 5 % . I n f a c t , s u b j e c t s r e q u i r e d s i g n i f i c a n t l y l o n g e r e x p o s u r e s i n t h e p o s t c u e t h a n t h e p r e c u e t a s k . The l o n g e r d u r a t i o n s f o r t h e . p o s t c u e t a s k a r e c o n s i s t e n t w i t h t h e i d e a t h a t f o r g e t t i n g o c c u r r e d t o a g r e a t e r d e g r e e i n t h e p o s t c u e t h a n i n t h e p r e c u e t a s k .
S i m i l a r i t y E f f e c t s
F i g u r e 4.13 g i v e s t h e p e r c e n t a g e of c o r r e c t i d e n t i f i c a t i o n s of t h e t a r g e t l e t t e r a s a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t s i n t h e t e s t d i s p l a y . S i m i l a r r e s u l t s were observed i n both t h e p r e c u e and p o s t c u e t a s k s . The o v e r a l l a c c u r a c y d i f f e r e n c e s on t a r g e t and c a t c h t r i a l s f o r bo th t a s k s a r e d i s c u s s e d i n t h e n e x t s e c t i o n . Accuracy d e c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t s on c a t c h t r i a l s b u t remained r e l a t i v e l y c o n s t a n t on t a r g e t t r i a l s . Al though t h e s i m i l a r i t y e f f e c t s a r e s m a l l e r i n magni tude, t h e c a t c h t r i a l s b u t n o t t h e t a r g e t t r i a l s r e p l i c a t e t h e r e s u l t s of t h e a c c u r a c y t a s k i n S tudy 1. The d e c r e a s e i n a c c u r a c y on c a t c h t r i a l s w i t h i n c r e a s e s i n t h e number of s i m i l a r l e t t e r s a p p e a r s t o be a r e l a t i v e l y r e l i a b l e r e s u l t . I n c o n t r a s t , any e f f e c t of s i m i l a r n o n t a r g e t s on t a r g e t t r i a l s a p p e a r s t o be s m a l l e r i n magni tude and l e s s r e l i a b l e .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 65
T a r g e t V e r s u s Catch T r i a l s
F i g u r e 4 . 1 4 p r e s e n t s t h e p e r c e n t a g e of c o r r e c t t a r g e t i d e n t i f i c a t i o n s f o r t a r g e t and c a t c h t r i a l s i n t h e p r e c u e and p o s t c u e a c c u r a c y t a s k s . R e p l i c a t i n g t h e r e s u l t s o f t h e p r e v i o u s s t u d y , o v e r a l l a c c u r a c y was much g r e a t e r on c a t c h t r i a l s t h a n on t a r g e t t r i a l s i n t h e p o s t c u e t a s k . I n c o n t r a s t , per formance on t a r g e t t r i a l s was more a c c u r a t e t h a n on c a t c h t r i a l s i n t h e p r e c u e a c c u r a c y t a sk . These e f f e c t s c a n be d e s c r i b e d by t h e d e c i s i o n r u l e i n t h e model. For a c c u r a c y t a s k s it is assumed t h a t t h e l e t t e r s t r i n g is r e s o l v e d a s f u l l y as p o s s i b l e w i t h t h e a s s i s t a n c e of o r t h o g r a p h i c s t r u c t u r e . I f none of t h e r e s o l v e d l e t t e r s is t h e t a r g e t , a " y e s " r e s p o n s e is a f u n c t i o n of t h e o b s e r v e r ' s a p r i o r i e x p e c t a t i o n p r o b a b i l i t y t h a t a n u n r e s o l v e d l e t t e r i s a t a r g e t and t h e number of
lJ--- Precue
50 mL 0 1 2 3
NUMBER OF SIMILAR NONTARGETS
F i g u r e 4.13 P e r c e n t a g e c o r r e c t f o r t a r g e t and c a t c h t r i a l s i n ' t h e p r e c u e and p o s t c u e c o n d i t i o n s of S t u d y 2 as a
f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g .
66
100
90-
I- 80- y 7 0 -
8 80-
w CJ 50 g 100
CHAPTER 4
I I I I I
Precue
... '.. 0 --...-- .-_______ p .... 0
'.. ... %.
Obs Pre Catch Target
....._...
Postcue
unreso lved l e t t e r s . I n te rms of t h e p r e s e n t model, t h e e x p e c t a t i o n parameter E/6 must have d i f f e r e d f o r t h e p r e c u e and p o s t c u e t a sks .
60-
I n f o r m a t i o n P r o c e s s i n q Model
1 I I I
The model was t e s t e d by f i t t i n g i t t o t h e d a t a o f t h e p r e s e n t exper iment . S i x p a r a m e t e r s were e s t i m a t e d f o r e a c h set of 10 means: one E-value, and a s e p a r a t e R-value f o r e a c h o f t h e f i v e d i s p l a y c o n d i t i o n s , e . g . , word, r e g u l a r - h i g h , e tc . The parameter estimates and t h e i r a s s o c i a t e d root mean squared d e v i a t i o n s a r e shown i n Table 4.3 a s P o s t c u e (S tudy 2 ) and Precue (S tudy 2 ) . The model p r o v i d e s a good d e s c r i p t i o n of t h e r e s u l t s of bo th t a s k s .
F i g u r e 4.14 Observed (Obs) and p r e d i c t e d ( P r e ) p e r c e n t a g e c o r r e c t f o r t a r g e t and c a t c h t r i a l s f o r t h e p r e c u e and p o s t c u e c o n d i t i o n s o f S tudy 2 a s a f u n c t i o n of d i s p l a y t y p e .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 6 7
Not o n l y d o e s t h e f i t of t h e model p r o v i d e s u p p o r t f o r our c o n c e p t u a l i z a t i o n of t h e d e c i s i o n mechanism, b u t t h e parameter v a l u e s a r e meaningfu l . I t is i n t e r e s t i n g t o n o t e t h a t t h e a p p a r e n t b i a s toward "no" r e s p o n s e s i n t h e p o s t c u e t a s k a c t u a l l y r e f l e c t s an a c c u r a t e and unbiased a s s e s s m e n t of t h e e q u a l p r o b a b i l i t y o f t a r g e t and c a t c h t r i a l s . The s u b j e c t s i n t h e p r e c u e t a s k , however, d o e x h i b i t a marked b i a s toward e x p e c t i n g t h e p r e s e n c e of a t a r g e t . Smith e t a l . ( 1 9 7 6 ) have r e p o r t e d s i m i l a r f i n d i n g s i n a precued t a r g e t r e c o g n i t i o n t a sk and s u g g e s t t h a t o b s e r v e r s i n p r e c u e t a s k s may e r r o n e o u s l y i n c o r p o r a t e mask f e a t u r e s i n making t h e i r judgments and t h u s tend t o see t h e t a r g e t i n t h e mask more o f t e n t h a n might be e x p e c t e d . By m a n i p u l a t i n g t h e n a t u r e of t h e m a s k which f o l l o w s t h e d i s p l a y t h e y found a more pronounced e f f e c t when t h e d i s p l a y and mask s h a r e d f e a t u r e s t h a n when t h e y d i d n o t .
Perhaps even more i n t e r e s t i n g t h a n t h e E-parameters were t h e R-values which c o r r e s p o n d t o t h e number of l e t t e r s a c t u a l l y r e s o l v e d f o r each d i s p l a y t y p e . The parameter v a l u e s f o r R a s a f u n c t i o n of d i s p l a y t y p e change s y s t e m a t i c a l l y w i t h o r t h o g r a p h i c s t r u c t u r e a c r o s s both t h e p r e c u e and t h e p o s t c u e exper iments . The l a r g e r e f f e c t of d i s p l a y t y p e f o r t h e p o s t c u e t h a n f o r t h e p r e c u e t a s k is r e f l e c t e d by t h e l a r g e r s p r e a d of t h e R-values f o r t h e p o s t c u e t a s k .
Although t h e i n t e r a c t i o n of d i s p l a y c o n d i t i o n s w i t h t a s k i n t h e p r e s e n t e x p e r i m e n t i m p l i e s t h a t R-values were somewhat d i f f e r e n t i n t h e p r e c u e and p o s t c u e t a s k s , a l l 2 0 d a t a p o i n t s were a l s o f i t w i t h seven p a r a m e t e r s by assuming t h a t a s i n g l e s e t of f i v e R-values and two E-va lues , one f o r p r e c u e and one f o r t h e p o s t c u e , would be s u f f i c i e n t . These p a r a m e t e r s and t h e i r a s s o c i a t e d r o o t mean s q u a r e d d e v i a t i o n s a r e a l s o g i v e n i n Table 4 . 3 a s Combined Data. The p r e d i c t e d r e s u l t s of t h e seven-parameter model a r e shown a l o n g w i t h t h e observed r e s u l t s i n F i g u r e 4.14. The r e a s o n a b l y good d e s c r i p t i o n of t h e r e s u l t shows t h a t t h e combined f i t of t h e two t a s k s is q u i t e a c c e p t a b l e . I n a d d i t i o n , r e d u c i n g t h e number of p a r a m e t e r s from 1 2 t o 7 i n c r e a s e d t h e t o t a l r o o t mean s q u a r e d d e v i a t i o n by less t h a n one p e r c e n t ( f rom 1 . 6 % t o 2 . 5 % ) .
STUDY 3 : MIXED-CASE
The r e s u l t s of t h e comparison between p r e c u e and p o s t c u e t a s k s i n d i c a t e s t h a t p r e c u i n g a l o n e is n o t a s u f f i c i e n t c o n d i t i o n t o c a u s e a d r a s t i c r e d u c t i o n i n t h e use of
CHAPTER A
o r t h o g r a p h i c s t r u c t u r e , a t l e a s t i n a c c u r a c y tasks . I t s t i l l might be t h e c a s e , however, t h a t p r e c u i n g i n t h e RT t a s k i n which u n l i m i t e d viewing time i n s u r e s t h a t a l l o f t h e f e a t u r e s of t h e d i s p l a y c a n be e x t r a c t e d promotes a f e a t u r e d e t e c t i o n s t r a t e g y . The n e x t exper iment a d d r e s s e s t h e issue of whether o r n o t d i s c o u r a g i n g a f e a t u r e d e t e c t i o n s t r a t e g y w i l l promote t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n t h e r e s o l u t i o n of t h e t e s t s t r i n g .
Much o f t h e i n t u i t i v e a p p e a l of t h e f e a t u r e d e t e c t i o n s t r a t e g y is t h e i d e a t h a t r e c o g n i t i o n of t h e t a r g e t l e t t e r could O C C U K on t h e b a s i s of o n l y a few f e a t u r e s and w i t h o u t t h e n e c e s s i t y of f u l l y r e s o l v i n g a l l f e a t u r e s o f t h e l e t t e r . The e f f e c t i v e n e s s of t h i s s t r a t e g y would be reduced i f t h e s p e c i f i c v i s u a l c o n f i g u r a t i o n of t h e t a r g e t , and t h u s t h e e x a c t form o f t h e c r i t i c a l f e a t u r e s , c o u l d n o t be p r e d i c t e d . One p r o c e d u r e would be t o have t h e l e t t e r s t r i n g appear i n s e v e r a l d i f f e r e n t f o n t s w i t h t h e f o n t of t h e t a r g e t a p p e a r i n g on a g i v e n tes t t r i a l be ing u n p r e d i c t a b l e . The p r e s e n t e x p e r i m e n t approximated t h i s method by p r e s e n t i n g t h e d i s p l a y s p r i n t e d h a l f i n uppercase l e t t e r s and h a l f i n l o w e r c a s e . Thus, t h e l e t t e r c a s e of t h e t a r g e t l e t t e r was n o t c o m p l e t e l y p r e d i c t a b l e . Whereas it might s t i l l be p o s s i b l e t o d e t e c t f e a t u r e s f o r u p p e r c a s e and lowercase l e t t e r s s i m u l t a n e o u s l y , t h e e x t r a e f f o r t s h o u l d reduce t h e e f f e c t i v e n e s s of t h e f e a t u r e d e t e c t i o n s t r a t e g y . T h e r e f o r e , i t is p r e d i c t e d t h a t i f t h e f e a t u r e d e t e c t i o n s t r a t e g y i s t h e cause of t h e small e f f e c t o f o r t h o g r a p h i c s t r u c t u r e i n a p r e c u e RT t a s k , t h e n a s i g n i f i c a n t l y l a r g e r e f f e c t should be observed i n t h e mixed-case c o n d i t i o n , where t h e e f f e c t i v e n e s s of t h e f e a t u r e d e t e c t i o n s t r a t e g y w i l l be d i m i n i s h e d .
T a y l o r , M i l l e r , and J u o l a (1977) have r e p o r t e d t h a t mixing c a s e s d i s r u p t s t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n word p e r c e p t i o n . The amount of d i s r u p t i o n was found t o be a m o n o t o n i c a l l y i n c r e a s i n g f u n c t i o n of t h e number of t r a n s i t i o n s between c a s e s i n t h e s t r i n g t o be p e r c e i v e d . To minimize t h e d i s r u p t i v e i n f l u e n c e of c a s e t r a n s i t i o n s on t h e u t i l i z a t i o n of o r t h o g r a p h i c S t K U C t U K e , o n l y a s i n g l e t r a n s i t i o n between t h e t h i r d and f o u r t h l e t t e r s was used i n t h i s exper iment .
The p r o c e d u r e was t h e same as t h e e a r l i e r r e a c t i o n t i m e exper iment w i t h t h e f o l l o w i n g m o d i f i c a t i o n s . The t a r g e t l e t t e r was p r e s e n t e d a t t h e beginning of each t r i a l i n b o t h i t s uppercase and l o w e r c a s e forms. On each t r i a l , t h e t e s t s t r i n g was p r e s e n t e d s o t h a t e i t h e r t h e f i r s t t h r e e l e t t e r s were i n uppercase and t h e l a s t t h r e e l e t t e r s i n lowercase or t h e
EXPERIMENTS ON LETTER AND WORD PERCEPTION 69
- 0
I 750-
I
w z I- 700-
5 I- 8 650-
o p p o s i t e OCCUKKed. The d e t a i l s of t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4.3.
O r t h o g r a p h i c S t r u c t u r e
F i g u r e 4.15 p r e s e n t s t h e mean r e a c t i o n times i n t h e t a s k a s a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e . There was o n l y a 7 msec advantage of words over r e g u l a r - h i g h pseudowords. The 30 msec advantage of r e g u l a r o v e r i r r e g u l a r s t r i n g s was s i g n i f i c a n t a s was t h e 1 4 msec a d v a n t a g e of s t r i n g s h i g h i n p o s i t i o n a l f r e q u e n c y r e l a t i v e t o s t r i n g s low i n p o s i t i o n a l f r e q u e n c y .
By mixing t h e c a s e s of t h e l e t t e r s i n t h e p r e s e n t s t u d y , t h e o v e r a l l e f f e c t of o r t h o g r a p h i c s t r u c t u r e i n c r e a s e d from 34 msec i n t h e r e a c t i o n t i m e exper iment o f Study 1 t o 5 1 msec i n
800, , I 1 I I
F i g u r e 4.15
0 Catch
I-H I-L
R e a c t i o n time and p e r c e n t a g e c o r r e c t a s of d i s p l a y t y p e i n S tudy 3: Nixed-Case
a f u n c t i o n
70 CHAPTER 4
t h e p r e s e n t mixed-case r e a c t i o n t i m e s t u d y . Mixing t h e c a s e s i n c r e a s e d t h e o v e r a l l r e a c t i o n t i m e by a b o u t 120 msec. I t i s , t h e r e f o r e , n e c e s s a r y t o ask whether t h e 17 msec i n c r e a s e f o r t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e is meaningfu l . I f w e c a n assume t h a t t h e 120 msec i n c r e a s e i n RTs t o mixed-case d i s p l a y s r e p r e s e n t s t h e a d d i t i o n a l v i s u a l p r o c e s s i n g r e q u i r e d , t h e n t h e 17 msec i n c r e a s e i n o r t h o g r a p h i c s t r u c t u r e e f f e c t s may p r o v i d e a meaningfu l e v a l u a t i o n of t h e i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e i n t h e RT t a s k . The i n c r e a s e i n t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o t h e a d d i t i o n a l v i s u a l p r o c e s s i n g r e q u i r e d is 1 4 % . Even 1 4 % , however, may b e a n u n d e r e s t i m a t e of t h e s i z e of t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e s i n c e t h e a d d i t i o n a l 120 msec of p r o c e s s i n g r e q u i r e d by mixed-case s t i m u l i may i n c l u d e a d d i t i o n a l t ime needed f o r t h e comparison p r o c e s s when t h e t a r g e t c a n occur i n e i t h e r uppercase o r l o w e r c a s e .
S i m i l a r i t y E f f e c t s
I f mixing t h e c a s e s a t t e n u a t e d t h e f e a t u r e d e t e c t i o n s t r a t e g y t h e n w e would e x p e c t a d e c r e a s e i n t h e e f f e c t s o f t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e d i s p l a y on c a t c h t r i a l s . The s i m i l a r i t y a n a l y s e s a r e c o m p l i c a t e d by t h e m i x t u r e o f upper- and l o w e r c a s e s i n t h e s t r i n g . Because t h e c o n f u s i o n s e t s were d e r i v e d from c o n f u s i o n s o f lowercase l e t t e r s , a p p l i c a t i o n of these c o n f u s i o n s e t s t o t h e d a t a w i t h o u t r e g a r d t o l e t t e r c a s e s would n o t be a p p r o p r i a t e . T h e r e f o r e , a r e s t r i c t e d s i m i l a r i t y a n a l y s i s was done by examining o n l y t h e lowercase l e t t e r s i n t h e d i s p l a y s t r i n g s . When t h i s was done , t h e r e were o n l y two v i a b l e s i m i l a r i t y c a t e g o r i e s : z e r o and one s i m i l a r l e t t e r s . For t a r g e t t r i a l s t h e means were 658 and 658 msec f o r t h e zero and one c a t e g o r i e s r e s p e c t i v e l y . For c a t c h t r i a l s t h e s e means were 731 and 756 msec. These r e s u l t s r e p l i c a t e t h e RT t a s k i n S tudy 1; RTs f o r c a t c h t r i a l s b u t n o t t a r g e t t r i a l s i n c r e a s e w i t h t h e number of s i m i l a r n o n t a r g e t s i n t h e t e s t s t r i n g . Based on t h e s i m i l a r i t y a n a l y s e s , mixing t h e c a s e s d i d n o t appear t o a t t e n t u a t e t h e f e a t u r e d e t e c t i o n s t r a t e g y . The exper iment p r o v i d e s mixed e v i d e n c e f o r t h e h y p o t h e s i s t h a t a f e a t u r e d e t e c t i o n s t r a t e g y o c c u r s i n precue RT t a s k s . The e f f e c t o f o r t h o g r a p h i c s t r u c t u r e was i n c r e a s e d somewhat by mixing t h e c a s e s and i t might have been concluded t h a t use of a f e a t u r e d e t e c t i o n s t r a t e g y was prec luded and more use made of o r t h o g r a p h i c con tex t . However, t h e f a i l u r e t o a t t e n u a t e s i m i l a r i t y e f f e c t s p r e c l u d e s any f i r m c o n c l u s i o n a b o u t t h e f e a t u r e d e t e c t i o n s t r a t e g y . E i t h e r t h e s u b j e c t s
EXPERIMENTS ON LETTER AND WORD PERCEPTION 7 1
p e r s i s t e d i n t h e now more d i f f i c u l t t a s k of l o o k i n g f o r f e a t u r e matches i n t w o - l e t t e r cases o r f e a t u r e d e t e c t i o n is n o t t h e c o r r e c t e x p l a n a t i o n f o r t h e r e s u l t s of e i t h e r of t h e two e x p e r i m e n t s .
STUDY 4 : LIMITED V I E W I N G TIME
I n a n o t h e r a t t e m p t t o d i s c o u r a g e t h e f e a t u r e d e t e c t i o n s t r a t e g y , s u b j e c t s were not g i v e n u n l i m i t e d viewing t i m e i n t h e r e a c t i o n time t a s k of t h e p r e s e n t e x p e r i m e n t . I n t h e RT t a s k ( S t u d i e s 1 and 3 ) , t h e s u b j e c t s were g i v e n u n l i m i t e d time and hence a l l of t h e v i s u a l i n f o r m a t i o n n e c e s s a r y f o r d e t a i l e d p e r c e p t u a l r e s o l u t i o n o f t h e s t i m u l u s d i s p l a y s . I n t h e a c c u r a c y task ( S t u d i e s 1 and 2 ) , viewing time was s h o r t e n e d so t h a t v i s u a l i n f o r m a t i o n was i n a d e q u a t e t o c l e a r l y r e s o l v e a l l of t h e d i s p l a y . D e c i s i o n s a t a f e a t u r e d e t e c t i o n l e v e l may depend on t h e c e r t a i n t y t h a t a l l t h e v i s u a l i n f o r m a t i o n w i l l be r e s o l v e d . I f so , l i m i t i n g viewing time i n t h e RT t a s k s h o u l d i n c r e a s e t h e s i z e of o r t h o g r a p h i c s t r u c t u r e e f f e c t s . S tudy 4 t e s t e d t h i s h y p o t h e s i s by g i v i n g t h e s u b j e c t s t h e d i s p l a y f o r a l i m i t e d time. However, i t was n o t p o s s i b l e t o l i m i t v iewing time a s s e v e r e l y a s i n t h e p r e v i o u s a c c u r a c y t a s k s and s t i l l m a i n t a i n e r r o r r a t e s low enough t o p e r m i t meaningfu l i n t e r p r e t a t i o n o f RTs . S tudy 4 was a h y b r i d ; v iewing time was s h o r t e n e d and e r r o r r a t e s a l lowed t o r i s e b u t n e i t h e r was t a k e n t o e x t r e m e s .
The s t i m u l i and a p p a r a t u s were t h e same a s i n t h e r e a c t i o n time e x p e r i m e n t o f S tudy 1. Rather t h a n l e a v i n g t h e s t i m u l u s d i s p l a y on u n t i l t h e s u b j e c t responded, t h e d i s p l a y was p r e s e n t e d f o r o n l y 2 0 0 msec and fo l lowed immedia te ly by a masking s t i m u l u s . On t h e b a s i s of t h e p i l o t work, t h i s d u r a t i o n was chosen because i t n o t o n l y l i m i t e d viewing time b u t a l s o gave t h e s u b j e c t s u f f i c i e n t v i s u a l i n f o r m a t i o n t o respond r e a s o n a b l y a c c u r a t e l y . S i x t e e n s u b j e c t s were chosen from t h e same p o p u l a t i o n a s t h e e a r l i e r s t u d i e s . A l l o t h e r d e t a i l s a r e g i v e n i n Appendix 4 . 4 .
Or t h o g r a p h i c S t r u c t u r e
F i g u r e 4.16 p r e s e n t s t h e r e a c t i o n time f o r c o r r e c t r e s p o n s e s as a f u n c t i o n o f o r t h o g r a p h i c s t r u c t u r e . A s can be seen i n t h e f i g u r e , no e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were observed . Although o r t h o g r a p h i c s t r u c t u r e d i d n o t have a s i g n i f i c a n t e f f e c t on r e a c t i o n time, i t d i d a f f e c t
1 2 CHAPTER 4
0 0
a c c u r a c y . The small d i f f e r e n c e s i n a c c u r a c y as a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e were found t o be s t a t i s t i c a l l y s i g n i f i c a n t . By l i m i t i n g t h e d i s p l a y d u r a t i o n , i t a p p e a r s t h a t t h e e x p e r i m e n t b e g i n s t o approximate a n a c c u r a c y e x p e r i m e n t , and t h e s m a l l e r e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e c a n s i m p l y be a t t r i b u t e d t o t h e o v e r a l l h i g h l e v e l of per formance .
S i m i l a r i t y E f f e c t s
Although a c c u r a c y v a r i e d s l i g h t l y w i t h d i f f e r e n c e s i n o r t h o g r a p h i c s t r u c t u r e , t h e r e were no s i g n i f i c a n t changes i n a c c u r a c y as a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t s i n t h e t e s t d i s p l a y . I n c o n t r a s t , t h e RTs c o n t i n u e d t o r e v e a l t h e c o n s i s t e n t f i n d i n g t h a t RTs on c a t c h t r i a l s i n c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t s whereas RTs on t a r g e t t r i a l s showed no e f f e c t . A c c o r d i n g l y , t h e r e s u l t s show
7001 1 I I I
F i g u r e 4 . 1 6 R e a c t i o n t i m e and p e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e i n S tudy 4 : Limi ted Viewing Time.
EXPERIMENTS ON LETTER AND WORD PERCEPTION 7 3
t h a t an o r t h o g r a p h i c s t r u c t u r e e f f e c t i n terms of r e s p o n s e a c c u r a c y c a n c o e x i s t w i t h a s i m i l a r i t y e f f e c t on RT. T h i s r e s u l t r e v e a l s t h a t a f e a t u r a l d e t e c t i o n s t r a t e g y a s indexed by s i g n i f i c a n t s i m i l a r i t y e f f e c t s d o e s n o t p r e c l u d e a s i g n i f i c a n t c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . I t a p p e a r s t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s can be found i n both a c c u r a c y and RT measures , b u t t h a t RT e f f e c t s a r e n o t a s r e l i a b l e o r s e n s i t i v e a s a c c u r a c y e f f e c t s .
T a r g e t V e r s u s Catch T r i a l s
T a r g e t t r i a l s ( 5 6 3 msec) were responded t o more q u i c k l y t h a n c a t c h t r i a l s ( 6 3 5 msec) whereas t h e r e was no s i g n i f i c a n t d i f f e r e n c e between t h e two k i n d s of t r i a l s i n t e r m s o f r e s p o n s e a c c u r a c y .
D i s c u s s i o n
The r e s u l t s d i s c o n f i r m t h e h y p o t h e s i s t h a t l i m i t i n g viewing time might i n c r e a s e t h e i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e on RT. R e a c t i o n times were found t o be uni form o v e r c o n d i t i o n s . However, t h e p a t t e r n of e r r o r r a t e s r e f l e c t e d t h e i n f l u e n c e of s t r u c t u r e . L i m i t i n g v i s u a l i n f o r m a t i o n c l e a r l y h a s a n i n f l u e n c e on a c c u r a c y , and t h i s i n f l u e n c e is modulated by t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e . A s f o r t h e u n u s u a l l y uniform RTs, t h e y might r e f l e c t t h e s u b j e c t s having e s t a b l i s h e d and m a i n t a i n e d a se l f - imposed r e s p o n s e d e a d l i n e . T h e r e f o r e , any e f f e c t o f o r t h o g r a p h i c s t r u c t u r e would be r e f l e c t e d o n l y on per formance a c c u r a c y .
STUDY 5 : SPEEDED RT TASK WITH GOOD VISUAL INFORMATION
Study 5 t e s t s between two h y p o t h e s e s of t h e d i f f e r e n c e s i n t h e s e n s i t i v i t y o f t h e a c c u r a c y and RT t a s k s t o o r t h o g r a p h i c s t r u c t u r e . According t o t h e f i r s t h y p o t h e s i s , t h e d i f f e r e n c e between t h e a c c u r a c y and RT t a s k s c o u l d be due t o a t r a d e - o f f between t h e c o n t r i b u t i o n of s t i m u l u s i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e i n t h e t a s k . There is abundant s t i m u l u s i n f o r m a t i o n i n t h e RT t a s k , and t h e r e f o r e , t h e r e may be v e r y l i t t l e o p p o r t u n i t y f o r knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e t o c o n t r i b u t e t o per formance . I n t h e a c c u r a c y t a s k , on t h e o t h e r hand, t h e s t i m u l u s i n f o r m a t i o n is i n a d e q u a t e and c o n s e q u e n t l y , t h e r e i s c o n s i d e r a b l e o p p o r t u n i t y f o r
74 CHAPTER 4
o r t h o g r a p h i c knowledge t o e x e r t an i n f l u e n c e . T h i s e x p l a n a t i o n i s c l e a r l y d i f f e r e n t from t h e f e a t u r e d e t e c t i o n s t r a t e g y d i s c u s s e d e a r l i e r . I n t h e c a s e of a f e a t u r e d e t e c t i o n s t r a t e g y , t h e r e is a n o p p o r t u n i t y f o r o r t h o g r a p h i c s t r u c t u r e t o e x e r t an i n f l u e n c e b u t a d e c i s i o n a b o u t t h e l e t t e r s t r i n g is made w i t h o u t u t i l i z i n g t h e s t r u c t u r e . By c o n t r a s t , i n t h e c a s e of a t r a d e - o f f between v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e , t h e comple te v i s u a l i n f o r m a t i o n p r e c l u d e s a c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e .
Evidence f o r t h e t r a d e - o f f between t h e c o n t r i b u t i o n s of s t i m u l u s i n f o r m a t i o n and knowledge comes from a number of RT e x p e r i m e n t s t h a t have i n d e p e n d e n t l y v a r i e d s t i m u l u s q u a l i t y and knowledge ( c . f . , Meyer, S c h v a n e v e l d t , & Ruddy, 1 9 7 5 ) . M a S S a K O ,
J o n e s , Lipscomb, and Scholz ( 1 9 7 8 ) , f o r example, had s u b j e c t s name a word a s q u i c k l y a s p o s s i b l e . The word was e i t h e r p r e s e n t e d u p r i g h t or was r o t a t e d 1 8 0 d e g r e e s i n t h e p i c t u r e p l a n e . The word was preceded by a word "b lank" or by a c a t e g o r y pr ime, which was t h e s u p e r o r d i n a t e c a t e g o r y name of t h e t e s t word. Pr iming w i t h t h e c a t e g o r y name i s t h e advance knowledge i n t h e task and it might b e e x p e c t e d t o f a c i l i t a t e p r o c e s s i n g of t h e t e s t word. T h e r e f o r e , RTs s h o u l d be f a s t e r on primed t h a n unprimed t r i a l s . Of c o u r s e , r o t a t i n g t h e t e s t words s h o u l d slow down t h e naming r e s p o n s e s i n c e t h e s t i m u l u s i n f o r m a t i o n is degraded; we a r e n o t used t o s e e i n g and r e a d i n g r o t a t e d t e x t . The r e s u l t s showed t h a t pr iming had a n o n s i g n i f i c a n t 7 msec f a c i l i t a t i o n when t h e words were p r e s e n t e d u p r i g h t b u t a s i g n i f i c a n t 1 2 1 msec e f f e c t when words were r o t a t e d 1 8 0 d e g r e e s . S i m i l a r r e s u l t s were found i n a l e x i c a l d e c i s i o n t a s k . With a good q u a l i t y t e s t d i s p l a y , p r iming had e s s e n t i a l l y no e f f e c t : g i v e n a poor q u a l i t y d i s p l a y , advance knowledge f a c i l i t a t e d per formance . I n t h e p r e s e n t e x p e r i m e n t s , g i v e n a good q u a l i t y d i s p l a y i n t h e RT t a s k , o r t h o g r a p h i c s t r u c t u r e had a small e f f e c t ; w i t h a poor q u a l i t y d i s p l a y i n t h e a c c u r a c y t a s k , o r t h o g r a p h i c s t r u c t u r e had a l a r g e e f f e c t .
The second h y p o t h e s i s is t h a t t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e i s s i m i l a r i n t h e a c c u r a c y and RT t a s k s b u t t h e a c c u r a c y t a s k a l l o w s a more d i r e c t measure of t h e s i z e of t h i s c o n t r i b u t i o n . I n t h e RT t a s k where t h e v i s u a l d i s p l a y i s c l e a r l y v i s i b l e and viewing time u n l i m i t e d , t h e l e t t e r s t r i n g is r e s o l v e d v e r y q u i c k l y and t h e time t o r e s o l v e t h e l e t t e r s may be s m a l l r e l a t i v e t o t h e times f o r t h e remain ing p r o c e s s e s of s e a r c h , compar ison , d e c i s i o n , and r e s p o n s e s e l e c t i o n . Thus, t h e f a c i l i t a t i n g e f f e c t o f o r t h o g r a p h i c s t r u c t u r e might be l a r g e i n terms of t h e time s a v i n g s f o r
EXPERIMENTS ON LETTER AND WORD PERCEPTION 75
v i s u a l r e s o l u t i o n , b u t s m a l l r e l a t i v e t o t h e o v e r a l l RT. For example, a 20 msec e f f e c t of s t r u c t u r e when v i s u a l r e s o l u t i o n t a k e s 100 msec w i t h o u t any c o n t r i b u t i o n of s t r u c t u r e would expand a 500 msec RT by o n l y 4 % . Even though t h i s 20% e f f e c t on v i s u a l r e s o l u t i o n is i m p o r t a n t , i t would appear s m a l l r e l a t i v e t o t h e o v e r a l l RT. By c o n t r a s t , t h e v i s u a l i n f o r m a t i o n i n t h e a c c u r a c y t a s k is l i m i t e d and e r r o r s a r e a d i r e c t consequence of l i m i t a t i o n s i n v i s u a l r e s o l u t i o n . Accord ingly , a f a c i l i t a t i o n of v i s u a l r e s o l u t i o n w i l l be more d i r e c t l y r e f l e c t e d i n a n improvement i n t a s k ac- c u r a c y . According t o t h i s h y p o t h e s i s , even though o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s r o u g h l y t h e same a d d i t i o n a l i n f o r m a t i o n i n both t h e RT and a c c u r a c y t a s k s , t h e s i z e of RT e f f e c t w i l l appear s m a l l r e l a t i v e t o t h e a c c u r a c y e f f e c t .
I n o r d e r t o t e s t between t h e s e two h y p o t h e s e s , a n exper iment was c a r r i e d o u t i n which t h e r e a d e r would have good q u a l i t y v i s u a l i n f o r m a t i o n b u t a c c u r a c y r a t h e r t h a n RT would be t h e p r i m a r y dependent v a r i a b l e . ~f t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is i n v e r s e l y r e l a t e d t o t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n a s p r e d i c t e d by t h e t r a d e - o f f h y p o t h e s i s , t h e n a v e r y s m a l l e f f e c t of s t r u c t u r e s h o u l d be a p p a r e n t on a c c u r a c y . However, i f t h e c o n t r i b u t i o n of s t r u c t u r e is independent of t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n and a c c u r a c y i s s imply a more d i r e c t measure , t h e n t h e t y p i c a l l a r g e e f f e c t s of s t r u c t u r e on a c c u r a c y s h o u l d be o b s e r v e d . Given t h a t a c c u r a c y is now t i e d t o 75% c o r r e c t , i t s h o u l d be a more d i r e c t index of t h e c o n t r i b u t i o n of s t r u c t u r e . T h e r e f o r e , t h e p r e s e n t e x p e r i m e n t p r o v i d e s a t e s t between t h e two h y p o t h e s e s w i t h o u t having t o compare a c c u r a c y e f f e c t s t o RT e f f e c t s . A m o d i f i c a t i o n of a speed-accuracy t r a d e - o f f paradigm which r e q u i r e s a speeded r e a c t i o n i n s y n c h r o n i z a t i o n w i t h a s i g n a l e v e n t (Reed, 1973) was used t o keep a v e r a g e per formance a t 75% c o r r e c t . The s u b j e c t s were g i v e n t h e t a r g e t l e t t e r fo l lowed by t h e d i s p l a y and were r e q u i r e d t o respond a s n e a r l y i n synchrony w i t h t h e o f f s e t of t h e d i s p l a y a s p o s s i b l e . Using a n a d a p t i v e a l g o r i t h m , a d i s p l a y d u r a t i o n was c a l c u l a t e d t o keep t h e s u b j e c t ' s o v e r a l l a c c u r a c y a t 75%. Because t h e d u r a t i o n of t h e d i s p l a y averaged around 500 msec, i t seems S a f e t o assume t h a t t h e s u b j e c t s have good q u a l i t y s t i m u l u s i n f o r m a t i o n . T h e r e f o r e , t h e t r a d e - o f f h y p o t h e s i s p r e d i c t s no e f f e c t of s t r u c t u r e whereas t h e h y p o t h e s i s t h a t a c c u r a c y i s a more d i r e c t measure t h a n RT p r e d i c t s a l a r g e e f f e c t O f
s t ruc ture .
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Eleven s t u d e n t s , s e l e c t e d from t h e same p o p u l a t i o n as t h o s e i n t h e e a r l i e r e x p e r i m e n t s , were t e s t e d on a s i n g l e day. A t a r g e t l e t t e r was p r e s e n t e d f o r 5 0 0 msec and fo l lowed by t h e t e s t d i s p l a y a f t e r an i n t e r v a l of 2 5 0 msec. The t e s t d i s p l a y d u r a t i o n was modi f ied e v e r y 20 t r i a l s t h r o u g h o u t t h e e x p e r i m e n t t o keep o v e r a l l per formance a t 75% c o r r e c t . S u b j e c t s were i n s t r u c t e d t o respond as c l o s e t o t h e s t i m u l u s o f f s e t as p o s s i b l e and t h e y were g i v e n feedback on t h i s t a s k a f t e r e a c h b lock of 2 0 t r i a l s . E s s e n t i a l l y , s u b j e c t s s imply l e a r n e d t o m a i n t a i n a p a r t i c u l a r r e s p o n s e time, n o t t o respond t o t h e o f f s e t of t h e d i s p l a y i t s e l f . None of t h e s u b j e c t s had any d i f f i c u l t y w i t h t h i s t a s k . D e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e g i v e n i n Appendix 4.5.
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F i g u r e 4.17 R e a c t i o n time and p e r c e n t a g e c o r r e c t as a f u n c t i o n o f d i s p l a y t y p e i n S tudy 5: Speeded RT Task w i t h Good V i s u a l I n f o r m a t i o n .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 77
O r t h o g r a p h i c S t r u c t u r e
F i g u r e 4.17 p r e s e n t s t h e c o r r e c t r e a c t i o n times and r e s p o n s e a c c u r a c y a s a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e ; t a r g e t and c a t c h t r i a l s a r e p l o t t e d s e p a r a t e l y . There was a 1 5 msec e f f e c t of o r t h o g r a p h i c s t r u c t u r e on c o r r e c t r e a c t i o n times and a 1 . 9 % e f f e c t on a c c u r a c y . T h e r e f o r e , no s t r o n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e on e i t h e r RT o r a c c u r a c y was p r e s e n t . T h i s r e s u l t is c o n s i s t e n t w i t h t h e t r a d e - o f f h y p o t h e s i s whereby t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is i n v e r s e l y r e l a t e d t o t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n i n t h e t e s t s t r i n g .
STUDY 6: SPEEDED RT TASK WITH POOR VISUAL INFORMATION
The speeded RT t a sk i n S tudy 5 p r o v i d e d e v i d e n c e t h a t t h e a c c u r a c y t a sk may g i v e l a r g e r e f f e c t s t h a n d o e s t h e RT t a s k because of t h e p o o r e r q u a l i t y o f t h e v i s u a l i n f o r m a t i o n i n t h e a c c u r a c y t a s k . A c c o r d i n g l y , g i v i n g good q u a l i t y i n f o r m a t i o n i n t h e speeded RT t a s k shows no e f f e c t of o r t h o g r a p h i c s t r u c t u r e on r e s p o n s e a c c u r a c y . Before a c c e p t i n g t h i s c o n c l u s i o n , i t is i m p o r t a n t t o v e r i f y whether t h e speed-accuracy paradigm t h a t was used is i t s e l f s e n s i t i v e t o o r t h o g r a p h i c s t r u c t u r e . I t could be t h e c a s e t h a t t h e p e r c e p t u a l s t a g e g o e s t o c o m p l e t i o n i n a l l c o n d i t i o n s and t h a t e r r o r s are s imply a f u n c t i o n of l a t e r s t a g e s such a s r e s p o n s e s e l e c t i o n . Any small d i f f e r e n c e s i n c o m p l e t i o n times of t h e p e r c e p t u a l s t a g e as a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e may n o t s i g n i f i c a n t l y i n f l u e n c e t h e a c c u r a c y o f l a t e r s t a g e s of p r o c e s s i n g , and t h e r e f o r e , t h e d i f f e r e n c e s i n t h e p e r c e p t u a l s t a g e would n o t be r e f l e c t e d i n e i t h e r r e s p o n s e a c c u r a c y o r r e a c t i o n t i m e . To t e s t t h e s s n s i t i v i t y o f t h e speeded R T t a s k , i t is n e c e s s a r y t o r e p l i c a t e t h e t a s k w i t h poor q u a l i t y i n f o r m a t i o n . I f t h e t a s k is s e n s i t i v e and t h e e f f e c t of s t r u c t u r e is i n v e r s e l y r e l a t e d t o s t i m u l u s q u a l i t y , t h e n s i g n i f i c a n t e f f e c t s s h o u l d be found. I f t h e t a s k i s i n s e n s i t i v e t o t h e p e r c e p t u a l s t a g e , however, no e f f e c t of o r t h o g r a p h i c s t r u c t u r e should be observed .
A s d i s c u s s e d p r e v i o u s l y , MaSSaL-0 e t a l . (1978) degraded t h e q u a l i t y o f test s t r i n g s by r o t a t i n g them 180 d e g r e e s i n t h e p i c t u r e p l a n e . Fol lowing t h i s approach , t h e speeded RT t a sk was r e p l i c a t e d w i t h t h e test s t r i n g s r o t a t e d i n t h e same manner. Given t h a t r o t a t i o n l o w e r s t h e q u a l i t y of t h e v i s u a l
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i n f o r m a t i o n , a n e f f e c t of o r t h o g r a p h i c s t r u c t u r e s h o u l d be observed i f t h e speeded RT t a s k i s s e n s i t i v e t o p e r c e p t u a l d i f f e r e n c e s due t o t h e o r t h o g r a p h i c s t r u c t u r e . I f t h e t a s k i t s e l f is i n s e n s i t i v e t h e n no e f f e c t s of s t r u c t u r e s h o u l d be observed .
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-
Procedure
The speeded RT t a s k i n S tudy 5 was r e p l i c a t e d e x a c t l y w i t h a new g r o u p of s t u d e n t s e x c e p t t h a t t h e t e s t s t r i n g s were r o t a t e d 18B d e g r e e s i n t h e p i c t u r e p l a n e r a t h e r t h a n p r e s e n t e d u p r i g h t . The t a r g e t l e t t e r was s t i l l p r e s e n t e d u p r i g h t . The d e t a i l s of t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4.6.
Or t h o g r a p h i c S t r u c t u r e
F i g u r e 4.18 p r e s e n t s t h e c o r r e c t r e a c t i o n times and accuracy performance. There was a 7 msec e f f e c t of s t r u c t u r e
700 - Catch
*------*Target
,-” a\.\. -.-./- -m
--
0 Catch
O m 8 WORD R-H R-L I-H I-L
F i g u r e 4.18 Reac t ion time and p e r c e n t a g e c o r r e c t as a f u n c t i o n of d i s p l a y t y p e i n S tudy 6 : Speeded RT Task w i t h Poor V i s u a l I n f o r m a t i o n .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 79
on c o r r e c t r e a c t i o n times and a 1 . 7 % e f f e c t on r e s p o n s e a c c u r a c y . The r e s u l t s o f t h i s e x p e r i m e n t a r e a d i r e c t r e p l i c a t i o n of t h o s e i n t h e p r e v i o u s speeded RT t a s k and t h e r e f o r e p r o v i d e s t r o n g e v i d e n c e f o r t h e i d e a t h a t t h e speeded RT t a s k is i n s e n s i t i v e t o p e r c e p t u a l d i f f e r e n c e s due t o t h e o r t h o g r a p h i c s t r u c t u r e . Before t h i s c o n c l u s i o n is a c c e p t e d , however, i t w i l l be n e c e s s a r y t o v e r i f y t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s d o occur w i t h r o t a t e d t e s t s t r i n g s i n o t h e r t a s k s . I n o r d e r t o have a d i r e c t l y a n a l o g o u s s i t u a t i o n t o t h e speeded RT t a s k s , t h e t a s k m u s t keep t h e t e s t s t r i n g i n view d u r i n g t h e p r o c e s s i n g p e r i o d . T h e r e f o r e , h i g h a c c u r a c y i s t o be e x p e c t e d and RT m u s t be t h e d e p e n d e n t measure.
STUDY 7 : HIGH-ACCURACY RT TASK WITH POOR VISUAL INFORMATION
Procedure
To v e r i f y t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s d o o c c u r w i t h r o t a t e d t e s t s t r i n g s , t h e h igh-accuracy r e a c t i o n t i m e exper iment o f S t u d i e s 1 and 3 was r e p l i c a t e d b u t u s i n g r o t a t e d r a t h e r t h a n u p r i g h t t e s t s t r i n g s . An u p r i g h t t a r g e t l e t t e r was p r e s e n t e d fo l lowed by a r o t a t e d t e s t s t r i n g which remained i n view u n t i l t h e l a s t of up t o f o u r s u b j e c t s responded. S u b j e c t s performed a s q u i c k l y a s p o s s i b l e w h i l e m a i n t a i n i n g h i g h a c c u r a c y . The d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4 . 7 .
O r t h o g r a p h i c S t r u c t u r e
R e a c t i o n t i m e s g e n e r a l l y i n c r e a s e d from words t o t h e i r r e g u l a r - l o w s t r i n g s . F i g u r e 4.19 shows t h a t o v e r a l l e f f e c t was 3 2 msec, which is h i g h l y s i m i l a r t o t h e e f f e c t s of s t r u c t u r e on normal ly p r e s e n t e d s t r i n g s ( c f . F i g u r e 4 . 9 ) . T h i s r e s u l t shows t h a t s t r u c t u r e e f f e c t s d o occur w i t h r o t a t e d s t i m u l i b u t t h a t t h e y a r e n o t l a r g e r t h a n t h e s t r u c t u r e e f f e c t s observed w i t h u p r i g h t s t i m u l i . The i d e a t h a t a t r a d e - o f f e x i s t s between s t i m u l u s q u a l i t y and o r t h o g r a p h i c s t r u c t u r e is n o t s u p p o r t e d by t h e s e r e s u l t s . I t a p p e a r s t h a t bo th a c c u r a c y t a s k s and h igh-accuracy RT t a s k s c a n r e v e a l o r t h o g r a p h i c s t r u c t u r e e f f e c t s b u t t h a t t h e speeded RT t a s k d o e s n o t .
80 CHAPTER 4
SUMMARY OF ACCURACY AND REACTION TIME EXPERIMENTS
These e x p e r i m e n t s t e n d t o s u p p o r t t h e i d e a t h a t p e r c e p t u a l r e s o l u t i o n of a l e t t e r s t r i n g i s f a c i l i t a t e d t o t h e d e g r e e t h e l e t t e r s i n t h e s t r i n g a r e w e l l - s t r u c t u r e d . Both a c c u r a c y t a sks w i t h l i m i t e d s t i m u l u s i n f o r m a t i o n and h i g h a c c u r a c y RT t a s k s w i t h comple te s t i m u l u s i n f o r m a t i o n appear t o be s e n s i t i v e t o t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e . However, t h e magni tude of t h e RT e f f e c t a p p e a r s s m a l l e r because of t h e r e l a t i v e l y l a r g e o v e r a l l RT due t o t h e p r o c e s s i n g time r e q u i r e d f o r o t h e r t h a n v i s u a l p r o c e s s i n g s t a g e s i n t h e RT t a s k . I n c o n t r a s t , a v e r a g e per formance i n t h e a c c u r a c y task i s t i t r a t e d t o remain a t 75% c o r r e c t and t h i s p e r c e n t a g e measure is i n f l u e n c e d a l m o s t c o m p l e t e l y by t h e v i s u a l p r o c e s s i n g s t a g e s . The p o s t hoc e v a l u a t i o n of v a r i o u s measures of o r t h o g r a p h i c s t r u c t u r e i n
H E-I F i g u r e 4.19 R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n
of d i s p l a y t y p e i n S tudy 7 : High-accuracy RT Task w i t h Poor V i s u a l I n f o r m a t i o n .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 8 1
Chapter 5 w i l l a l l o w a more d i r e c t a s s e s s m e n t o f t h e s e n s i t i v i t y of per formance i n t h e RT and a c c u r a c y t a s k s .
A second i m p o r t a n t c o n t r i b u t i o n t o per formance is t h e f e a t u r a l i n f o r m a t i o n c o n t a i n e d i n t h e v i s u a l d i s p l a y . Performance i n b o t h t h e a c c u r a c y and RT t a s k is s e n s i t i v e t o t h e v i s u a l s i m i l a r i t y o f t h e t e s t l e t t e r s t o t h e t a r g e t l e t t e r . Performance on c a t c h t r i a l s is d i s r u p t e d t o t h e e x t e n t t h a t t h e t e s t d i s p l a y c o n t a i n s n o n t a r g e t l e t t e r s t h a t a re s i m i l a r t o t h e t a r g e t l e t t e r . Performance on t a r g e t t r i a l s is n o t s i g n i f i c a n t l y a f f e c t e d s i n c e p r o c e s s i n g i s p r i m a r i l y a f u n c t i o n of t a r g e t l e t t e r p r o c e s s i n g time. However, t h e r e was some h i n t t h a t s i m i l a r n o n t a r g e t s may be i n c o r r e c t l y confused f o r t h e t a r g e t on t a r g e t t r i a l s and, t h e r e f o r e , lead t o a c o r r e c t r e s p o n s e even though t h e t a r g e t i t s e l f was n o t r e c o g n i z e d on t h a t t r i a l .
I n c o n c l u s i o n , b o t h t h e a c c u r a c y and h i g h a c c u r a c y RT t a sks appear t o o f f e r good measures o f t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n v i s u a l p r o c e s s i n g . The speeded RT t a s k d o e s n o t r e v e a l e f f e c t s of o r t h o g r a p h i c s t r u c t u r e . B e f o r e e v a l u a t i n g s p e c i f i c d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , some r a t i n g e x p e r i m e n t s were c a r r i e d o u t t o a s s e s s t o what e x t e n t knowledge of o r t h o g r a p h i c s t r u c t u r e is c o n s c i o u s l y a v a i l a b l e and c a n be r e p o r t e d .
OVERT JUDGMENTS
Whereas t h e a c c u r a c y and RT e x p e r i m e n t s imply t h a t v i s u a l r e c o g n i t i o n is s e n s i t i v e t o t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e , i t is a l s o of i n t e r e s t t o d e t e r m i n e t o what e x t e n t s u b j e c t s a r e aware of t h i s knowledge. For t h i s p u r p o s e , s e v e r a l o v e r t judgment e x p e r i m e n t s were conducted . The same 200 s t i m u l u s items i n Appendix 4 . 1 B were p r e s e n t e d t o n a t i v e E n g l i s h s p e a k i n g c o l l e g e s t u d e n t s and judgments i n t h e form of r a t i n g s and p a i r e d judgments were o b t a i n e d . Answers t o t h e f o l l o w i n g q u e s t i o n s were s o u g h t . Could t h e r a t e r s r e l i a b l y a s s i g n r a t i n g s of o r t h o g r a p h i c s t r u c t u r e t o t h e i t e m s ? Would t h e d imens ions u t i l i z e d by t h e r a t e r s d i s c r i m i n a t e t h e items a long our r e g u l a r i t y d imens ion , by p o s i t i o n a l f r e q u e n c y , or both? Would t h e r a t i n g s a s s i g n e d t o t h e items show any meaningfu l r e l a t i o n s h i p t o t h e i r p e r c e p t u a l a c c u r a c y and r e a c t i o n time r e s u l t s found i n t h e p r e v i o u s e x p e r i m e n t s ?
8 2 CHAPTER 4
STUDY 8: TYPICALITY RATINGS
Three sets of r a t i n g s were o b t a i n e d . I n t h e f i r s t one o n l y t h e 160 meaningless anagrams were r a t e d . I n t h e s e c o n d , t h e words were t r a n s f o r m e d i n t o t h e most r e g u l a r pseudowords p o s s i b l e by t h e s u b s t i t u t i o n of a s i n g l e l e t t e r and t h e s e pseudowords were r a t e d a l o n g w i t h t h e anagrams. I n t h e t h i r d , t h e words themselves were i n c l u d e d a l o n g w i t h t h e anagrams. These t h r e e p r o c e d u r e s were used t o o b t a i n t h e most r e l i a b l e r a t i n g s p o s s i b l e and t o d e t e r m i n e how a l t e r a t i o n s i n t h e t o t a l set of items r a t e d a f f e c t e d t h e r a t i n g s o f t h e anagrams. A l l t h r e e r a t i n g s were o b t a i n e d under n e a r l y i d e n t i c a l i n s t r u c t i o n s which asked t h e r a t e r s t o b a s e t h e i r judgments on t h e s i m i l a r i t y o f t h e items t o E n g l i s h words where s i m i l a r i t y was d e f i n e d a s t y p i c a l i t y of E n g l i s h s p e l l i n g . Beyond t h e s e g e n e r a l i n s t r u c t i o n s , no s p e c i f i c a t t e m p t s were made t o i l l u s t r a t e e i t h e r s p e c i f i c r e g u l a r i t y r u l e s o r p o s i t i o n a l - f r e q u e n c y c o n s t r a i n t s .
S u b j e c t s were asked t o r a t e how much t h e l e t t e r s t r i n g s look l i k e E n g l i s h words. The r a t i n g scale went from "most l i k e Engl i sh" t o " l e a s t l i k e E n g l i s h " on a s c a l e from 10 t o 1. C o l l e g e s t u d e n t s r a t e d t h e items i n one o f t h r e e c o n d i t i o n s . Seventy s u b j e c t s r a t e d o n l y t h e 160 anagrams. S i x t y - f i v e s u b j e c t s r a t e d t h e 160 anagrams p l u s 40 pseudowords which were d e r i v e d by m i s s p e l l i n g one l e t t e r i n each of t h e 40 word s t i m u l i . S i x t y - t h r e e s u b j e c t s r a t e d t h e 160 anagrams and t h e 40 words. S u b j e c t s were urged n o t t o a d o p t s t r a t e g i e s of t r y i n g t o see t h e items a s s i m i l a r t o s p e c i f i c words. Those s u b j e c t s t h a t r e c e i v e d a c t u a l words were t o l d t o d i s r e g a r d t h e s e m a n t i c c o n t e n t of t h e words and s i m p l y judge them on t h e b a s i s of t h e i r s i m i l a r i t y t o E n g l i s h s p e l l i n g . The method, p r o c e d u r e , and d e t a i l e d r e su l t s a r e p r e s e n t e d i n Appendix 4.8.
F i g u r e 4.20 shows t h e a v e r a g e r a t i n g s f o r t h e items f o r each of t h e t h r e e g r o u p s of s u b j e c t s . The r a t i n g s a s s i g n e d t o t h e 160 anagrams were v e r y s t a b l e a c r o s s t h e t h r e e r a t i n g c o n t e x t s . The s i x c o r r e l a t i o n s between a l l p o s s i b l e p a i r s of r a t i n g s a c r o s s t h e t h r e e c o n t e x t s were a l l .97. T h i s r e s u l t d e m o n s t r a t e s t h a t t h e r a t i n g s of t h e anagrams were n o t i n f l u e n c e d by t h e p r e s e n c e of a c t u a l words i n t h e sample of items t o be r a t e d . The f i g u r e a l s o shows t h a t t h e r a t i n g s were p r i m a r i l y de te rmined by t h e r e g u l a r i t y of t h e items r a t h e r t h a n by p o s i t i o n a l f r e q u e n c y . Although t h e e f f e c t of p o s i t i o n a l f requency was s t a t i s t i c a l l y s i g n i f i c a n t , t h e r e s u l t s show t h a t
EXPERIMENTS ON LETTER AND WORD PERCEPTION 8 3
r e g u l a r i t y produced a b o u t s e v e n times t h e e f f e c t t h a t p o s i t i o n a l f r e q u e n c y d i d .
The r e s u l t s i n d i c a t e t h a t when s u b j e c t s a r e asked t o r a t e items on t h e b a s i s of t h e s i m i l a r i t y t o E n g l i s h s p e l l i n g , t h e y t e n d t o e v a l u a t e t h e items i n terms o f n o t i o n s of r e g u l a r i t y r a t h e r t h a n i n t e r m s o f t h e p o s i t i o n a l f r e q u e n c y of t h e items. As c a n be s e e n i n t h e f i g u r e , t h e words were r a t e d a s more t y p i c a l t h a n even t h e r e g u l a r - h i g h anagrams. Even t h e pseudowords c r e a t e d by m i s s p e l l i n g t h e words by a s i n g l e l e t t e r produced h i g h e r r a t i n g s t h a n t h e r e g u l a r anagrams. T h i s r e s u l t means t h a t t h e word s t i m u l i and t h e i r m i s s p e l l i n g s were e i t h e r more t y p i c a l a c c o r d i n g t o t h e s u b j e c t ' s n o t i o n of E n g l i s h s p e l l i n g or t h a t t h e l e x i c a l c o n t e n t o f t h e words and p o s s i b l y t h e i r m i s s p e l l i n g s c o u l d n o t be ignored i n making t h e judgment .
If t h e r a t i n g s and t h e t a r g e t s e a r c h e x p e r i m e n t s are measur ing t h e same knowledge of o r t h o g r a p h i c s t r u c t u r e , t h e n a
WORD R-H R-L I-H I-L
F i g u r e 4 . 2 0 R a t i n g s from 10 (most l i k e E n g l i s h ) t o 1 ( l e a s t l i k e E n g l i s h ) as a f u n c t i o n of d i s p l a y t y p e i n S tudy 8 : T y p i c a l i t y R a t i n g s .
8 4 CHAPTER 4
c l o s e r e l a t i o n s h i p between t h e r a t i n g s and t h e RT and a c c u r a c y measures of t h e p r e v i o u s e x p e r i m e n t s s h o u l d be observed . Accord ingly , we examined t h e r e l a t i o n s h i p between t h e s e r a t i n g s and t h e p e r c e p t u a l per formance d a t a c o l l e c t e d i n S t u d i e s 1, 2 , and 3. Average RTs were o b t a i n e d f o r e a c h o f t h e 280 s t i m u l u s i t e m s by a v e r a g i n g t h e c o r r e c t r e s p o n s e RTs f o r t a r g e t and c a t c h t r i a l s from t h e r e a c t i o n time e x p e r i m e n t of Study 1 and t h e mixed-case exper iment o f S tudy 3. T h i s provided a n a v e r a g e RT f o r e a c h i tem based on a p p r o x i m a t e l y 204 o b s e r v a t i o n s . S i m i l a r l y , a n a v e r a g e a c c u r a c y was found f o r each item based on t h e t a r g e t and c a t c h t r i a l s f o r t h e s u b j e c t s i n t h e a c c u r a c y e x p e r i m e n t of S tudy 1 and t h e p r e c u e v e r s u s p o s t c u e exper iment of S tudy 2. The a v e r a g e a c c u r a c y o f e a c h item was based on 150 o b s e r v a t i o n s .
C o r r e l a t i o n s between t h e t h r e e r a t i n g s , a v e r a g e RT, and a v e r a g e a c c u r a c y a r e shown i n Table 4 . 4 . Two t h i n g s may be observed i n Table 4 . 4 . F i r s t , t h e c o r r e l a t i o n between t h e a c c u r a c i e s and RTs of a l l items was .56. T h e r e f o r e , d e s p i t e t h e magnitude of t h e observed d i f f e r e n c e s between RT and a c c u r a c y measures, b o t h e x p e r i m e n t a l p r o c e d u r e s appear t o r e v e a l a common p r o c e s s i n g component. T h i s w i l l become even more e v i d e n t i n t h e - c o r r e l a t i o n a l a n a l y s e s ( t o be d i s c u s s e d i n Chapter 5) which d e m o n s t r a t e t h a t b o t h item a c c u r a c y and RT tend t o show s i m i l a r c o r r e l a t i o n s w i t h v a r i o u s measures o f o r t h o g r a p h i c s t r u c t u r e .
The c o r r e l a t i o n s between item a c c u r a c y , RT, and t h e r a t i n g s a r e i l l u m i n a t i n g . C o r r e l a t i o n s between t h e two p e r c e p t u a l measures and t h e r a t i n g s a r e q u i t e h i g h . The p e r c e p t u a l measures and t h e r a t i n g s s h a r e 31% t o 53% common v a r i a n c e . Whereas t h e knowledge s t r u c t u r e s tapped by t h e r a t i n g p r o c e d u r e s need n o t n e c e s s a r i l y r e l a t e t o t h e knowledge s t r u c t u r e i n f e r r e d from t h e p e r c e p t u a l t a s k s , i t is e n c o u r a g i n g t o o b s e r v e t h a t t h e r e d o e s appear t o be a l a w f u l cor respondence . I t would appear t h a t what one knows a b o u t o r t h o g r a p h i c s t r u c t u r e n o t o n l y i n f l u e n c e s p e r c e p t i o n b u t a l s o i s amenable t o i n t e r r o g a t i o n by c o n s c i o u s p r o c e s s e s . A second encouraging a s p e c t of t h i s o b s e r v a t i o n is t h a t r a t i n g t a s k s and p e r c e p t u a l t a s k s may be regarded as converg ing measures o f o r t h o g r a p h i c s t r u c t u r e . I f bo th t a p a common d a t a base of o r t h o g r a p h i c s t r u c t u r e knowledge, t h e n w e can r e f i n e our unders tanding of t h i s knowledge s o u r c e by means of r a t i n g t a s k s as well a s p e r c e p t u a l t a sks . For t h e c o r r e l a t i o n a l a n a l y s e s i n Chapter 5 , i t e m a c c u r a c i e s , R T s , and r a t i n g s a r e e a c h r e g a r d e d
EXPERIMENTS ON LETTER AND WORD PERCEPTION 85
Table 4 . 4 C o r r e l a t i o n s among a v e r a g e a c c u r a c y , a v e r a g e RT, and t h e t h r e e r e g u l a r i t y r a t i n g s f o r t h e 200 s t i m u l u s i tems .
(1) ( 2 ) ( 3 ) ( 4 ) ( 5 )
(1) Average a c c u r a c y --
( 2 ) Average RT -.56 --
( 3 ) R a t i n g w i t h o u t words .58* -.56* --
( 4 ) R a t i n g w i t h pseudowords .72 -.61 .97 --
( 5 ) R a t i n g w i t h words .73 -.60 .97 .97 --
* C o r r e l a t i o n based on t h e 160 anagrams o n l y , a l l o t h e r c o r r e l a t i o n s based on a l l 200 s t i m u l u s items.
as r e l a t e d c o l l a t e r a l dependent measures p o t e n t i a l l y r e v e a l i n g a common o r t h o g r a p h i c s t r u c t u r e component.
STUDY 9: POSITIONAL-FREQUENCY RATINGS
The r a t i n g s o f S tudy 8 i n d i c a t e t h a t s u b j e c t s , when g i v e n r e l a t i v e l y n e u t r a l i n s t r u c t i o n s , b a s e t h e i r r a t i n g s more on r e g u l a r i t y t h a n on p o s i t i o n a l f r e q u e n c y . B e f o r e we can c o n c l u d e t h a t t h e r e a d e r ' s c o n s c i o u s knowledge is b e s t r e p r e s e n t e d by r e g u l a r i t y , i t is n e c e s s a r y t o d e t e r m i n e whether s u b j e c t s c a n be i n s t r u c t e d t o respond on t h e b a s i s of p o s i t i o n a l - f r e q u e n c y i n f o r m a t i o n . A c c o r d i n g l y , t h e r a t i n g exper iment w i t h o n l y 160 anagrams was r e p l i c a t e d b u t now t h e s u b j e c t s were g i v e n s p e c i f i c p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . The i n s t r u c t i o n s e x p l a i n e d t h e c o n c e p t of p o s i t i o n a l f r e q u e n c y a l o n g w i t h r e l e v a n t examples and t o l d t h e s u b j e c t s t o r a t e t h e i t e m s e x p l i c i t l y on t h i s b a s i s . The e x a c t i n s t r u c t i o n s ,
86 CHAPTER 4
9 -
8 -
7 -
6 -
6 5 -
a 4 -
3 -
2 -
method, and p r o c e d u r e a r e g i v e n i n t h e Appendix 4 . 9 . Except f o r t h e i n s t r u c t i o n s , t h e p r o c e d u r e r e p l i c a t e d t h e p r e v i o u s r a t i n g exper iment t h a t gave i n s t r u c t i o n s w i t h r e s p e c t t o t y p i c a l i t y o f E n g l i s h s p e l l i n g . The r e s u l t s and d e t a i l e d a n a l y s e s a r e g i v e n i n Appendix 4 . 9 .
F i g u r e 4 . 2 1 g i v e s t h e r e s u l t s o f t h i s e x p e r i m e n t s t r e s s i n g p o s i t i o n a l f r e q u e n c i e s a l o n g w i t h t h e r e s u l t s of t h e p r e v i o u s exper iment s t r e s s i n g t y p i c a l i t y . The r e s u l t s show t h a t t h e r a t i n g r e s p o n s e s were v e r y s i m i l a r w i t h both s e t s o f i n s t r u c t i o n s . However, p o s i t i o n a l f r e q u e n c y d i d m a k e more of a c o n t r i b u t i o n w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s t h a n w i t h t y p i c a l i t y i n s t r u c t i o n s . O v e r a l l , s u b j e c t s tended t o r a t e h i g h p o s i t i o n a l - f r e q u e n c y items a s s l i g h t l y h i g h e r t h a n low p o s i t i o n a l - f r e q u e n c y items t o a g r e a t e r d e g r e e w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s t h a n w i t h t y p i c a l i t y i n s t r u c t i o n s . Also , t h e e f f e c t of r e g u l a r i t y on t h e judgments
1-
I I 1 I I
TLPblfiY , .. " ... D-.-..O Poeltlonal Frequency
F i g u r e 4 . 2 1 R a t i n g s from 1 0 (most l i k e E n g l i s h ) t o 1 ( l e a s t l i k e E n g l i s h ) as a f u n c t i o n of d i s p l a y t y p e f o r t y p i c a l i t y i n s t r u c t i o n s (S tudy 8 ) and p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s (S tudy 9 ) .
EXPERIMENTS ON LETTER AND WORD PERCEPTION 87
was s l i g h t l y a t t e n t u a t e d w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s r e l a t i v e t o t y p i c a l i t y i n s t r u c t i o n s .
The r a t i n g e x p e r i m e n t s i n d i c a t e t h a t o r t h o g r a p h i c s t r u c t u r e i n terms of r e g u l a r i t y a p p e a r s t o be more c o n s c i o u s l y a v a i l a b l e t h a n s t r u c t u r e i n t e r m s of p o s i t i o n a l f r e q u e n c y . S u b j e c t s t e n d t o r a t e r e g u l a r items a s most l i k e E n g l i s h and i r r e g u l a r items as l e a s t l i k e E n g l i s h r e g a r d l e s s of whether t h e y were g i v e n t y p i c a l i t y i n s t r u c t i o n s O K p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . One l i m i t a t i o n i n t h e r a t i n g e x p e r i m e n t s may b e t h a t s u b j e c t s tend t o r a t e t h e items on t h e b a s i s of r e g u l a r i t y r e g a r d l e s s of t h e i n s t r u c t i o n s t h a t a r e g i v e n . T h e r e f o r e , a more d i r e c t index of t h e p s y c h o l o g i c a l r e a l i t y o f t h e s e two c o n c e p t s a s d e s c r i p t i o n s of o r t h o g r a p h i c S t r u c t u r e s h o u l d be o b t a i n e d .
STUDY l a : REGULARITY VERSUS POSITIONAL-FREQUENCY JUDGMENTS
I n o r d e r t o o b t a i n a more d i r e c t index of o r t h o g r a p h i c S t r u c t u r e , p r e c i s e r e g u l a r i t y i n s t r u c t i o n s were c o n t r a s t e d w i t h p r e c i s e p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . I t e m s from e a c h of t h e f o u r t y p e s of 160 anagrams were p a i r e d w i t h each o t h e r such t h a t items of one t y p e were p a i r e d w i t h items of t h e same t y p e o r w i t h items of t h e o t h e r t y p e s . Some s u b j e c t s were g i v e n p a i r s of items and asked t o p i c k t h e i t e m from each p a i r t h a t was most r e g u l a r . Other s u b j e c t s were g i v e n t h e same p a i r s and asked t o p i c k t h e i tem t h a t was h i g h e s t i n t e r m s of p o s i t i o n a l f r e q u e n c y . The i n s t r u c t i o n s , method, pKOCedUKe, and r e s u l t s a r e g i v e n i n Appendix 4.10. T h i s exper iment a l lowed a d i r e c t a s s e s s m e n t of t h e r e l a t i v e weight c a r r i e d by o r t h o g r a p h i c r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y i n t h e r e a d e r ' s e v a l u a t i o n of o r t h o g r a p h i c s t r u c t u r e . The judgments of t h e s e two g r o u p s of s u b j e c t s were t a b u l a t e d a s t h e p r o p o r t i o n of times t h e y c h o s e an item from one c a t e g o r y when it was p a i r e d w i t h a n item from a n o t h e r c a t e g o r y . These r e s u l t s a r e p r e s e n t e d a s T a b l e 4 . 5 where t h e c e l l s of t h e t a b l e g i v e t h e p r o p o r t i o n of times an i t e m from t h e column c a t e g o r y was s e l e c t e d when p a i r e d w i t h an item from t h e T O W c a t e g o r y .
Before d i s c u s s i n g t h e a c t u a l r e s u l t s i n Table 4 .5 , i t is i n s t r u c t i v e t o h y p o t h e s i z e how t h i s t a b l e s h o u l d have t u r n e d o u t i f t h e s u b j e c t s i n t h e two c o n d i t i o n s had a comple te knowledge o f r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y and had a p p l i e d t h i s knowledge i n accordance w i t h t h e i n s t r u c t i o n s . Whenever t h e two items d i f f e r e d on t h e d imens ion r e l e v a n t f o r
88 CHAPTER 4
Table 4.5 Paired-judgment preferences for the 200 stimuli under regularity and positional-frequency instructions. Cells represent proportion of times the column item was chosen over the row item. The numbers in parentheses give the hypothetical outcomes assuming that the subject had knowledge of both dimensions and followed instructions.
Regularity Instructions
R- H R- L I-H I-L
R- H .475 (.5)
R- L ,693 .445 (.5) C.5)
I-H .910 .a77 .523 (1.0) (1.0) (.5)
I-L .938 .908 .509 .518 11.0) (1.0) (.5) ( . 5 )
Positional Frequency Instructions
R- H R- L I-H I-L
R- H .527 (.5)
R- L .704 .488 (1.0) (.5)
I - H .866 .740 .525 (-5) (.0) (.5)
I-L .953 .a95 .687 .494 (1.0) (.5) (1.0) (.5)
EXPERIMENTS ON LETTER AND WORD PERCEPTION 89
Table 4.6 Chi -square f o r t h e two p r e d i c t e d outcomes a g a i n s t t h e observed outcomes f o r t h e two i n s t r u c t i o n c o n d i t i o n s i n s t u d y 10 .
P r e d i c t e d Outcome
P o s i t i o n a l I n s t r u c t i o n s R e g u l a r i t y Frequency
R e g u l a r i t y 93.63 1561.26
P o s i t i o n a l Frequency 258.90 1367.50
t h e judgment , t h e s u b j e c t s s h o u l d have a lways chosen t h e " c o r r e c t item," on t h a t d i m e n s i o n , i . e . , t h e one t h a t was more r e g u l a r or t h e one t h a t was h i g h e r i n p o s i t i o n a l f requency . Whenever t h e two items were a t e q u i v a l e n t l e v e l s on t h e r e l e v a n t d imens ion , t h e s u b j e c t s s h o u l d have chosen i n d i f f e r e n t l y between them. These " p e r f e c t " h y p o t h e t i c a l outcomes a r e a l s o shown i n Table 4.5.
Comparing t h e two p a n e l s o f Table 4.5 we o b s e r v e t h a t f o r bo th sets of i n s t r u c t i o n s , s u b j e c t s made c h o i c e s more c o n s i s t e n t w i t h t h e a p p l i c a t i o n of r e g u l a r i t y t h a n w i t h t h e a p p l i c a t i o n of p o s i t i o n a l f r e q u e n c y . I n o r d e r t o assess how w e l l t h e r e su l t s conformed t o what would be e x p e c t e d from p e r f e c t knowledge and u t i l i z a t i o n of r e g u l a r i t y o r p o s i t i o n a l f r e q u e n c y , t h e two p r e d i c t e d outcomes were compared w i t h t h e ac tua l outcomes under b o t h i n s t r u c t i o n c o n d i t i o n s . Table 4.6 g i v e s t h e Chi -square v a l u e s f o r compar isons of t h e two p r e d i c t e d outcomes a g a i n s t t h e observed outcomes f o r b o t h i n s t r u c t i o n c o n d i t i o n s . The value 's s u p p o r t t h e i n t e r p r e t a t i o n t h a t t h e s u b j e c t s ' performance is more a d e q u a t e l y d e s c r i b e d by r e g u l a r i t y t h a n p o s i t i o n a l f requency . However, though s u b j e c t s appear t o be u s i n g m o s t l y r e g u l a r i t y a s a b a s i s of t h e i r r a t i n g s , i n n e i t h e r c a s e d i d t h e r a t i n g s i n d i c a t e t h a t o n l y r e g u l a r i t y was u s e d . I f we compare t h e two p a n e l s of Table 4.5 t o each o t h e r , we s e e t h a t t h e r e was a n a d d i t i o n a l c o n t r i b u t i o n of p o s i t i o n a l f r e q u e n c y when s u b j e c t s were e x p l i c i t l y i n s t r u c t e d t o b a s e t h e i r judgments on f r e q u e n c y . E v i d e n t l y , s u b j e c t s c a n modify t h e i r judgments s l i g h t l y when g i v e n e x p l i c i t i n s t r u c t i o n s t o a t t e n d t o p o s i t i o n a l f r e q u e n c y .
CHAPTER 4
SUMMARY OF OVERT JUDGMENT EXPERIMENTS
The e x p e r i m e n t s s u p p o r t t h e i d e a t h a t knowledge of o r t h o g r a p h i c s t r u c t u r e is c o n s c i o u s l y a v a i l a b l e and c a p a b l e of r e p o r t . S u b j e c t s a re r e l a t i v e l y good a t a s s i g n i n g r a t i n g s on t h e b a s i s of ru le -governed r e g u l a r i t y b u t r e l a t i v e l y poor a t r a t i n g items on t h e b a s i s of s t a t i s t i c a l redun- dancy. S i m i l a r l y , choos ing which of a p a i r of items i s more r e g u l a r is r e l a t i v e l y e a s y whereas c h o o s i n g which is more f r e q u e n t is n e a r l y i m p o s s i b l e . The p o s t hoc c o r r e l a t i o n s i n Chapter 5 w i l l a l l o w a more d i r e c t and b r o a d e r a s s e s s m e n t of t h e n a t u r e of t h e knowledge u t i l i z e d i n o v e r t judgments of l e t t e r s t r i n g s .
APPENDIX 4 . 1 9 1
Appendix 4 . 1
D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S tudy 1: I n i t i a l R e p l i c a t i o n
Method
S u b j e c t s . One g r o u p of 1 4 I n t r o d u c t o r y Psychology s t u d e n t s p a r t i c i p a t e d i n t h e p o s t c u e a c c u r a c y t a s k f o r an t,t,>-, a day on each o f 2 c o n s e c u t i v e d a y s . The d a t a from t h r c a d d i t i o n a l sub jec t s were l o s t due t o computer sys tem f , i i l u r . S i x o t h e r s u b j e c t s were t e s t e d b u t t h e i r d a t a were n o t i n c l i r l e d because of i n a d m i s s i b l e o v e r a l l a c c u r a c y . Another g r o u p o f 14 IntKOdUCtOKy Psychology s t u d e n t s p a r t i c i p a t e d f o r a n hour e a c h day on 2 c o n s e c u t i v e d a y s i n t h e p r e c u e RT t a s k . A l l s u b j e c t s i n b o t h t a s k s passed a p r e l i m i n a r y v i s i o n t e s t e s t a b l i s h i n g a t l e a s t 20/40 a c u i t y f o r bo th e y e s . A l l s u b j e c t s were awarded r e s e a r c h p a r t i c i p a t i o n c r e d i t toward t h e i r psychology g r a d e .
S t i m u l i . A l i s t i n g of t h e 100 h i g h e s t and 108 l o w e s t summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y anagrams were o b t a i n e d f o r s e v e r a l hundred common s i x - l e t t e r words selected from t h e Kucera and F r a n c i s (1967) word l i s t . The l i s t i n g s o f t h e anagrams were produced by a computer program which g e n e r a t e d a l l 720 p o s s i b l e p e r m u t a t i o n s f o r each s i x - l e t t e r word. The p o s i t i o n a l f r e q u e n c y f o r each p e r m u t a t i o n was computed from t h e Mayzner and T r e s s e l t (1965) s i n g l e - l e t t e r c o u n t s f o r s i x - l e t t e r words by summing t h e p o s i t i o n - d e p e n d e n t f r e q u e n c y for e a c h l e t t e r . Words w i t h r e p e a t e d l e t t e r s were n o t used. From t h e 720 anagrams f o r e a c h s i x - l e t t e r word, two were chosen w i t h h i g h - p o s i t i o n a l f r e q u e n c i e s and two were chosen w i t h l o w - p o s i t i o n a l f r e q u e n c i e s . Wi th in e a c h f r e q u e n c y p a i r , one member was o r t h o g r a p h i c a l l y r e g u l a r ahd t h e o t h e r o r t h o g r a p h i c a l l y i r r e g u l a r . The r u l e s used f o r j u d g i n g r e g u l a r i t y a r e l i s t e d i n Appendix 4 . 1 A . L i s t e d i n Appendix 4 . 1 8 a r e t h e 200 s t i m u l u s i t ems-- the 40 words and t h e 4 anagrams of each word. One-hundred twenty p r a c t i c e s t i m u l i were g e n e r a t e d from 2 4 a d d i t i o n a l words. These i t e m s were n o t a s e v e n l y matched f o r r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y a s t h e e x p e r i m e n t a l i t e m s and a few c o n t a i n e d r e p e a t e d l e t t e r s .
Two o c c u r r e n c e s of each o f t h e 120 p r a c t i c e s t i m u l i were randomized f o r e a c h s u b j e c t ' s p r a c t i c e sequence and two o c c u r r e n c e s of e a c h of t h e 200 e x p e r i m e n t a l s t i m u l i were randomized f o r e a c h s u b j e c t ' s e x p e r i m e n t a l sequence . One o c c u r r e n c e was t e s t e d a s a t a r g e t t r i a l and one a s a c a t c h
92 CHAPTER 4
t r i a l . On t a r g e t t r i a l s . t h e l e t t e r was s e l e c t e d randomly w i t h rep lacement from t h e s i x l e t t e r s i n t h e t e s t s t r i n g . For c a t c h t r i a l s , a t a r g e t was s e l e c t e d randomly from t h e s e t of 26 l e t t e r s weighted by t h e i r p r o b a b i l i t y o f o c c u r r e n c e i n t h e s t i m u l u s s e t . If t h e s e l e c t e d l e t t e r was p r e s e n t i n t h e d i s p l a y s t r i n g , a d d i t i o n a l drawings w i t h rep lacement were made u n t i l a n a p p r o p r i a t e t a r g e t l e t t e r was s e l e c t e d . The l e t t e r s 1, k, 9, 5 , and 2 d i d n o t o c c u r i n t h e e x p e r i m e n t a l s t i m u l u s s t r i n g s and t h e r e f o r e were never t e s t e d .
The d i s p l a y s were p r e s e n t e d on a Beehive model v i d e o computer t e r m i n a l under t h e c o n t r o l o f a H a r r i s DC6024/5 computer . Hardware m o d i f i c a t i o n s p e r m i t t e d t h e t e r m i n a l ' s v i d e o t o be t u r n e d on and o f f wi th program-generated c o n t r o l s i g n a l s . The d i s p l a y s t r i n g s were loaded i n t o t h e memory b u f f e r of t h e t e r m i n a l w i t h t h e v i d e o o f f and t h e n t h e v i d e o was t u r n e d on f o r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n . The Beehive employs a P4, b lue-whi te phosphor which d e c a y s t o . l% of maximum luminance w i t h i n 32 msec. The exper iment was conducted i n a p a r t i a l l y darkened room t o enhance image c o n t r a s t .
A l l s i n g l e - l e t t e r t a r g e t and l e t t e r - s t r i n g t e s t d i s p l a y s were p r e s e n t e d i n l o w e r c a s e l e t t e r s . The Beehive u s e s a 5 x 7 d o t m a t r i x , 2.5 mm wide x 5 mm h i g h , A t t h e a v e r a g e s u b j e c t ' s viewing d i s t a n c e of a p p r o x i m a t e l y 38 cm, t h e s i x - l e t t e r s t r i n g s subtended a h o r i z o n t a l v i s u a l a n g l e of 2.25 d e g r e e s and a v e r t i c a l v i s u a l a n g l e of .75 d e g r e e . The d i s p l a y s were p r e s e n t e d i n t h e upper c e n t e r of t h e s c r e e n . The s i n g l e - l e t t e r t a r g e t was p o s i t i o n e d t o a p p e a r t h r e e c h a r a c t e r p o s i t i o n s t o t h e l e f t of t h e s t r i n g d i s p l a y , a h o r i z o n t a l v i s u a l a n g l e s e p a r a t i o n of .75 d e g r e e . To a c h i e v e a r a p i d and c o n t r o l l e d p r e s e n t a t i o n r a t e , t h e e n t i r e d i s p l a y sequence f o r a n item was d i s p l a y e d b e n e a t h a c a r d b o a r d mask a f f i x e d t o t h e f a c e of t h e c a t h o d e r a y t u b e ( C R T ) . A r e c t a n g u l a r window i n t h e mask s e r v e d a s a f i x a t i o n box and p e r m i t t e d o n l y t h e d e s i r e d p o r t i o n of t h e d i s p l a y t o be o b s e r v e d .
-___ Procedure . The s u b j e c t s i n t h e a c c u r a c y t a s k were informed t h a t t h e exposure d u r a t i o n would be b r i e f and would be a d j u s t e d d u r i n g t h e s e s s i o n t o m a i n t a i n a n a c c u r a c y o f 75%. A
t r i a l began w i t h t h e p r e s e n t a t i o n of t h e s i x - l e t t e r s t i m u l u s s t r i n g f o r a b r i e f d u r a t i o n . A f t e r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n , t h e d i s p l a y was s c r o l l e d upward on t h e CRT r e p l a c i n g t h e s t r i n g w i t h a masking s t i m u l u s c o n s i s t i n g of s i x u p p e r c a s e - Xs. The masking s t i m u l u s was p r e s e n t e d f o r 208 msec t h e n s c r o l l e d a g a i n t o p r e s e n t t h e t a r g e t l e t t e r . The t a r g e t l e t t e r remained i n view u n t i l t h e s u b j e c t responded, a t which t i m e t h e
% p a r a t u s .
APPENDIX 4 . 1 93
d i s p l a y was t e r m i n a t e d and a 500 msec i n t e r t r i a l i n t e r v a l begun.
The e x p o s u r e d u r a t i o n of t h e t e s t s t r i n g was i n d i v i d u a l l y d e t e r m i n e d f o r each s u b j e c t d u r i n g t h e p r a c t i c e t r i a l s . Because of t h e 60 Hz r e f r e s h r a t e o f t h e CRT one r e f r e s h c y c l e (16.7 msec) was chosen a s t h e b a s i c t i m e u n i t . The number of c y c l e s needed t o a c h i e v e a n o v e r a l l a c c u r a c y l e v e l of 75% was d e t e r m i n e d o n - l i n e u s i n g a v e r s i o n of t h e a d a p t i v e PEST a l g o r i t h m ( T a y l o r & Creelman, 1 9 6 7 ) . Exposure d u r a t i o n was n o t changed d u r i n g t h e e x p e r i m e n t a l t r i a l s . The i n i t i a l e x p o s u r e d u r a t i o n was 20 c y c l e s (334 msec) f o r a l l s u b j e c t s . The r a n g e of e x p o s u r e s needed by t h e 1 4 s u b j e c t s f o r 75% a c c u r a c y was 1 t o 1 2 c y c l e s w i t h a median e x p o s u r e d u r a t i o n o f 3 c y c l e s (50 msec).
The s u b j e c t s i n t h e RT t a s k were i n s t r u c t e d t o respond a s r a p i d l y and a s a c c u r a t e l y a s p o s s i b l e . A l l s u b j e c t s were a l s o t o l d t h a t one-ha l f o f t h e t r i a l s would be t a r g e t t r i a l s and one-ha l f would be c a t c h t r i a l s . The d i s p l a y sequence was a l t e r e d t o accommodate t h e p r e c u i n g . A t r i a l began w i t h t h e p r e s e n t a t i o n of t h e t a r g e t l e t t e r a t t h e l e f t of t h e f i x a t i o n window f o r 500 msec. The t a r g e t l e t t e r was t h e n t e r m i n a t e d and 1 sec l a t e r t h e s t i m u l u s s t r i n g was d i s p l a y e d . The s t i m u l u s remained i n view u n t i l t h e s u b j e c t responded, a t which time t h e d i s p l a y was t e r m i n a t e d and a 500 msec i n t e r v a l begun. A masking f i e l d was n o t used .
To a c q u a i n t s u b j e c t s i n b o t h t h e a c c u r a c y and RT t a s k s w i t h t h e r e s p o n s e p r o c e d u r e and v i s u a l d i s p l a y , e a c h d a y ' s s e s s i o n began w i t h 10 t r i a l s c o n s i s t i n g of o n l y t h e word YES o r NO i n s t e a d of t h e d i s p l a y s t r i n g . No t a r g e t l e t t e r was p r e s e n t e d . The s u b j e c t s p r e s s e d t h e c o r r e s p o n d i n g l y l a b e l e d r e s p o n s e b u t t o n s . The YES r e s p o n s e was a s s i g n e d t o e a c h s u b j e c t ' s p r e f e r r e d hand ( r i g h t hand f o r 9 of t h e 1 4 s u b j e c t s i n t h e a c c u r a c y t a s k ; 13 o f t h e 1 4 s u b j e c t s i n t h e RT t a s k ) .
The "yes-no" t r i a l s were fo l lowed by t h e 240 p r a c t i c e t r i a l s and t h e 400 e x p e r i m e n t a l t r i a l s . The p r a c t i c e t r i a l s were d i v i d e d i n t o f o u r 60 t r i a l b l o c k s and t h e e x p e r i m e n t a l t r i a l s were d i v i d e d i n t o f i v e 8 0 - t r i a l b l o c k s . A t t h e end of each b lock t h e s u b j e c t was g i v e n an o p p o r t u n i t y t o r e s t and r e c e i v e d feedback i n t h e form of a p e r c e n t c o r r e c t s c o r e o r RT and e r r o r r a t e , a s a p p r o p r i a t e , for t h e p r e c e d i n g b l o c k . A l l s u b j e c t s were t e s t e d i n two such s e s s i o n s s c h e d u l e d on c o n s e c u t i v e d a y s .
94 CHAPTER 4
Re s u l t s
O r t h o g r a p h i c s t r u c t u r e . Analyses o f v a r i a n c e were c a r r i e d o u t on t h e a v e r a g e p e r c e n t a g e c o r r e c t f o r e a c h s u b j e c t f o r e a c h of t h e 5 d i s p l a y t y p e s and t a r g e t v e r s u s c a t c h t r i a l s . For t h e accuracy t a s k , t h e main e f f e c t of d i s p l a y t y p e was s i g n i f i c a n t , - F ( 4 , 52) = 82.56, E < .001, and t h e d i f f e r e n c e s among t h e s e c o n d i t i o n s were t e s t e d w i t h s p e c i f i c c o n t r a s t s . Accuracy f o r words was 12% g r e a t e r t h a n f o r t h e b e s t pseudoword items ( r e g u l a r - h i g h ) , E (1, 52) = 40.54, E < .001. Three o r t h o g o n a l c o n t r a s t s ana logous t o a 2 x 2 a n a l y s i s o f v a r i a n c e f o r t h e f o u r nonword d i s p l a y t y p e s r e v e a l e d t h a t t h e r e g u l a r s t r i n g s were judged 8% more a c c u r a t e l y t h a n i r r e g u l a r s t r i n g s , E (1, 52) = 7.05, E < .01. High p o s i t i o n a l - f r e q u e n c y s t r i n g s were judged 5% more a c c u r a t e l y t h a n low p o s i t i o n a l - f r e q u e n c y s t r i n g s , E (1, 52) = 7.05, E < .01. The i n t e r a c t i o n of p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y was n o t s i g n i f i c a n t , 2 (1, 52) = 3.20, p > .05.
For t h e RT a n a l y s i s , RTs f o r i n c o r r e c t t r i a l s and c o r r e c t t r i a l RTs which exceeded 2 sec ( l e s s t h a n .2% o f t h e d a t a ) were exc luded from t h e a n a l y s e s l e a v i n g a p p r o x i m a t e l y 76 o f 80 p o s s i b l e o b s e r v a t i o n s p e r c e l l . For t h e RT d a t a , t h e r e was a l s o a s i g n i f i c a n t main e f f e c t of d i s p l a y t y p e , 1 ( 4 , 52) = 17.16, E < .001. T h i s main e f f e c t was examined w i t h t h e same s e t of s p e c i f i c c o n t r a s t s . The 7 msec advantage f o r words o v e r r e g u l a r - h i g h pseudowords was n o t s i g n i f i c a n t , E (1, 52) = 2.01, E > .10. Regular items were judged 23 msec f a s t e r t h a n i r r e g u l a r items, a s i g n i f i c a n t d i f f e r e n c e , E (1, 52) = 9.54, E < .005. N e i t h e r t h e 4 msec d i f f e r e n c e between h i g h and low p o s i t i o n a l f r e q u e n c y nor t h e i n t e r a c t i o n of r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y were s i g n i f i c a n t , b o t h Es < 1. E r r o r p e r c e n t a g e s were a n a l y z e d s i m i l a r l y t o t h e RTs. The main e f f e c t of d i s p l a y t y p e was n o t s i g n i f i c a n t , E ( 4 , 52) = 1.13.
S i m i l a r i t y a n a l y s e s . To t e s t f o r t h e e f f e c t s of s i m i l a r i t y between t h e t a r g e t l e t t e r and t h e l e t t e r s i n t h e d i s p l a y , t h e d a t a were f i r s t pooled a c r o s s d i s p l a y t y p e s . Each t r i a l ' s t a r g e t l e t t e r was c l a s s i f i e d a c c o r d i n g t o which l e t t e r s i n t h e d i s p l a y were l i k e l y t o be s e e n as v e r y s i m i l a r t o t h e t a r g e t . The c l a s s i f i c a t i o n was d e r i v e d from t h e l o w e r c a s e s i n g l e - l e t t e r c o n f u s a b i l i t y s t u d y p u b l i s h e d by Bouma ( 1 9 7 1 ) . A l e t t e r was counted a s s i m i l a r t o t h e t a r g e t l e t t e r i f t h e l e t t e r was e r r o n e o u s l y i d e n t i f i e d a s t h e t a r g e t more t h a n 5% o f t h e time. Table 4 . 2 p r e s e n t s t h e c l a s s i f i c a t i o n a c c o r d i n g t o t h i s a n a l y s i s . Each t r i a l was t h e n c l a s s i f i e d by t h e number o f n o n t a r g e t l e t t e r s i n t h e d i s p l a y t h a t were s imilar t o t h e
APPENDIX 4 . 1 95
t a r g e t a c c o r d i n g t o t h i s c r i t e r i o n . Roughly 46 , 33 , 1 3 , and 1 % of e a c h s u b j e c t ' s t r i a l s f e l l i n t o t h e c a t e g o r i e s z e r o , o n e , two, and t h r e e s i m i l a r l e t t e r s ( o t h e r t h a n t h e t a r g e t l e t t e r i t s e l f ) , r e s p e c t i v e l y .
For t h e a c c u r a c y t a s k d a t a , t h e e f f e c t of number s i m i l a r l e t t e r s was s i g n i f i c a n t . ( 3 , 39) = 7.14, p < .001. Accuracy on t a r g e t t r i a l s i n c r e a s e d some w i t h i n c r e a s e s i n t h e number of s i m i l a r l e t t e r s , whereas a c c u r a c y on c a t c h t r i a l s d e c r e a s e d s i g n i f i c a n t l y w i t h i n c r e a s e s i n t h e number of s imilar l e t t e r s , - F ( 3 , 39) = 22.28, p < .001.
For t h e RT t a s k , i n c r e a s i n g t h e number of s i m i l a r l e t t e r s produced a s i g n i f i c a n t i n c r e a s e i n RT, E ( 3 , 39) = 4.41 < .01. The i n c r e a s e was c l e a r l y l a r g e r on c a t c h t r i a l s t h a n t a r g e t t r i a l s , E ( 3 , 39) = 3.13, p < .05.
T a r g e t - c a t c h d i f f e r e n c e s . For t h e a c c u r a c y t a s k , a c c u r a c y was g r e a t e r f o r c a t c h t r i a l s ( 8 4 % ) t h a n f o r t a r g e t t r i a l s ( 7 2 % ) . E (1, 13) = 19.65, p < .001, and t h i s e f f e c t i n t e r a c t e d w i t h d i s p l a y t y p e s , ( 4 , 52) = 8.14 , < .001. O r t h o g r a p h i c s t r u c t u r e had a g r e a t e r e f f e c t on t a r g e t t h a n c a t c h t r i a l s . For t h e RT t a s k , t h e r e was a d i f f e r e n c e between t a r g e t and c a t c h t r i a l s . Catch t r i a l s were 47 msec s lower t h a n t a r g e t t r i a l s , E (1, 13) = 42.55, p < .001. However, t h i s e f f e c t d i d n o t i n t e r a c t w i t h d i s p l a y t y p e , 1 ( 4 , 52) = 1.49. T a r g e t - c a t c h d i f f e r e n c e s were a l s o r e f l e c t e d i n t h e e r r o r r a t e s i n t h e RT t a sk . T a r g e t t r i a l s e x p e r i e n c e d more e r r o r s ( 6 . 8 % ) t h a n d i d c a t c h t r i a l s ( 3 . 3 % ) , E (1, 13) = 29.88, p < .0001. There was no i n t e r a c t i o n w i t h d i s p l a y t y p e , E ( 4 , 52) = 1 . 2 4 .
96 CHAPTER 4
Appendix 4 . 1 A
Rules f o r t h e S e l e c t i o n of O r t h o g r a p h i c a l l y Regular and I r r e g u l a r S t r i n g s
These ru les were d e r i v e d by e x t e n d i n g t h e r u l e s g i v e n i n Venezky ( 1 9 7 0 ) , Venezky and Massaro (1979) , and Massaro e t a l . ( 1 9 7 9 ) . Among a l l p o s s i b l e anagrams of a word, a l e t t e r s t r i n g was regarded as o r t h o g r a p h i c a l l y i r r e g u l a r i f i t c o n t a i n e d a t l e a s t one of t h e f o l l o w i n g s p e l l i n g s :
a. p h o n o l o g i c a l l y i l l e g a l ( i n E n g l i s h ) i n i t i a l or f i n a l c l u s t e r ( e . g . , t l f ies , i a s G ) .
b. o r t h o g r a p h i c a l l y i l l e g a l s p e l l i n g for a n i n i t i a l or f i n a l consonant or consonant c l u s t e r ( e . g . , k e a g c , t l e r a v ) .
c. an i l l e g a l vowel s p e l l i n g ( e . g . , p r s a e d , n m t E ) . d . a p h o n o l o g i c a l l y i l l e g a l media l c l u s t e r ( e . g . , ilmpes,
L e t t e r s t r i n g s were regarded as r e g u l a r i f t h e y were p h o n o l o g i c a l l y l e g a l and c o n t a i n e d common vowel and c o n s o n a n t s p e l l i n g s .
i G s a ) .
APPENDIX 4 . 1 8 9 7
Appendix 4 . 1 B
The 200 S t i m u l u s Items Used i n S t u d i e s 1 - 1 0
The items l i s t e d a r e i n columns a c c o r d i n g t o t y p e , where W = word; R-H = r e g u l a r - l o w ; I-H = i r r e g u l a r - h i g h ; R-L = regular - low; and I - L = i r r e g u l a r - l o w . Each row c o n t a i n s a word and t h e f o u r anagrams g e n e r a t e d from i t .
R- H R-L I-H I - L - - Word
a c t i o n amount answer b a r e l y be long b r e a t h b r i d g e c h a r g e d o u b l e famous f i n g e r g a r d e n g a t h e r g l a n c e h a r d l y i t s e l f lawyer l o n g e r mas ter modern
c a i n o t mauton swaner b l a y e r g o b l e n t h a b e r begr i d c h a g e r bodule foamus f er i n g nagred t h a g e r c a l e n g hyr a l d s i f l e t w e r a l y l o g r e n t a m e r dormen
o n i c a t otanum erswan
g l e n o b t h e r a b g r e d i b g r e a c h e d o l u b osafum g r e f i n g r e d a n g r e a t h g l e c a n h y d r a 1 f l e s i t l y e r aw g l e r o n s t e r a m drenom
bye K a1
a i o c n t auotnm wnraes l b r a e y lnboeg b h r t e a i e r b g d ahcge r l eoubd uaomf s r f n i e g a rnged h r t a e g l c n a e g yr a h l d t l f ies rwlaey g l n o e r mr taes oermnd
i c n t o a nmtaou rnwesa r b l e y a e b g n l o r t b e h a e b r g d i h r e a g c obdeul ofmsua e f n g r i e d n r g a g r h e t a e c l n g a r d l h y a e f l s t i e y r lwa e g n r l o emr t s a rmedno
98 CHAPTER 4
APPENDIX 4 . 1 8 (COnt.)
Word
mother namely n e a r l y p e r m i t p l a y e r p o e t r y p u r e l y r e a s o n remain r e s u l t shared s i m p l e s i n g l e s p r e a d s t a r e d s t r e a m t r a v e l t r i a l s t u r n e d w i n t e r
R- H -
thomer manely l a r e n y p r ime t r a p l e y p e t o r y y u l p e r s a r o n e r amine s u r t e l s h r e a d p imsel s n i g e l p r ased s a r t e d t rames v a r t l e s a r t il d r u n e t t r iwen
R- L -
therom lyeman n y e l a r t r e p i m l y e r a p t y e r o p r y e l u p e r o s a n amer i n t r e s u l d r e a s h ems1 i p g l e s i n d r e s a p d r e s a t t resam t r e v a l t r i s a l t r e d u n t r e w i n
I-H -
mroteh lmnaey l r n a e y tmr i e p p l r aey y p t o e r l p y u e r s n a o e r mr a i e n l r t u e s s r d a e h i l m p e s i l g n e s p r saed s r t a e d m t r a e s a v r l e t i a s t l r r d n u e t w r n t e i
I -L -
hretmo emnyla enyr l a r t p e i m e p y l r a e r y t p o e r p l y u r n s e o a rniema e l s r t u h s r e d a l s e p m i n g l e s i d s e p r a d t s e r a e s r t m a t l e r a v i r l t s a e d t r n u r n t e w i
APPENDIX 4.2 99
Append ix 4 . 2
D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 2 : P r e c u e v e r s u s P o s t c u e
Method
S u b j e c t s . E i g h t e e n I n t r o d u c t o r y P s y c h o l o g y s t u d e n t s , 8 ma le and 1 0 f e m a l e , p a r t i c i p a t e d f o r a n h o u r e a c h d a y o n 2 c o n s e c u t i v e d a y s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t t o w a r d t h e i r p s y c h o l o g y g r a d e . The d a t a f rom a n a d d i t i o n a l 1 2 s t u d e n t s was l o s t d u e t o m a c h i n e m a l f u n c t i o n s and i n a d m i s s i b l e o v e r a l l a c c u r a c y . A l l s u b j e c t s p a s s e d a p r e l i m i n a r y v i s i o n t e s t e s t a b l i s h i n g a t l e a s t 20/40 a c u i t y f o r b o t h e y e s . None o f t h e s u b j e c t s had s e r v e d i n a n y o f o u r p r e v i o u s e x p e r i m e n t s . ~- S t i m u l i and a p p a r a t u s . The s t i m u l i , a p p a r a t u s , and
d i s p l a y s e q u e n c e f o r t h e p o s t c u e t a s k were i d e n t i c a l t o t h o s e o f t h e a c c u r a c y t a s k o f S t u d y 1 d e s c r i b e d i n Appendix 4 .1 . Fo r t h e p r e c u e t a s k , a t r i a l began w i t h t h e p r e s e n t a t i o n o f t h e t a r g e t l e t t e r a t t h e l e f t o f t h e f i x a t i o n window f o r 500 msec. The t a r g e t l e t t e r was t h e n t e r m i n a t e d and 1 sec l a t e r t h e s t r i n g was d i s p l a y e d f o r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n . A f t e r d i s p l a y i n g t h e s t i m u l u s s t r i n g , t h e mask ing s t i m u l u s was s c r o l l e d i n t o v i e w and r ema ined on t h e s c r e e n u n t i l t h e s u b j e c t r e s p o n d e d . The r a n g e o f e x p o s u r e d u r a t i o n s used f o r t h e p r e c u e t a s k was 1 t o 8 c y c l e s w i t h a med ian o f 2 c y c l e s . F o r t h e p o s t c u e t a s k t h e r a n g e was 2 t o 11 c y c l e s w i t h a med ian o f 3 c y c l e s .
P r o c e d u r e . H a l f t h e s u b j e c t s r e c e i v e d t h e p r e c u e t a s k t h e f i r s t d a y and t h e p o s t c u e t a s k t h e s e c o n d day . Fo r t h e r e m a i n i n g s u b j e c t s t h i s o r d e r was r e v e r s e d . Each d a y t h e a p p r o p r i a t e t a s k was e x p l a i n e d t o t h e s u b j e c t and p e r f o r m a n c e a c c u r a c y was s t r e s s e d . S u b j e c t s were t o l d t h a t o n e - h a l f o f t h e t r i a l s would b e t a r g e t and o n e - h a l f would b e c a t c h t r i a l s . A s i n S t u d y 1, t h e tes t s e q u e n c e c o n s i s t e d o f 1 0 "yes-no" t r i a l s , 4 6 0 - t r i a l p r a c t i c e b l o c k s d u r i n g wh ich e x p o s u r e was a d j u s t e d w i t h t h e a d a p t i v e a l g o r i t h m , and ,5 8 0 - t r i a l e x p e r i m e n t a l b l o c k s d u r i n g wh ich t h e e x p o s u r e r ema ined c o n s t a n t . A l l s u b j e c t s r e s p o n d e d " y e s " t o t a r g e t t r i a l s w i t h t h e i r p r e f e r r e d hand ( r i g h t hand f o r 1 7 o f t h e 1 8 s u b j e c t s ) .
100 CHAPTER 4
Re s u l ts
O r t h o g r a p h i c s t r u c t u r e . An a n a l y s i s o f v a r i a n c e was computed from t h e s u b j e c t s ' mean a c c u r a c i e s f o r t h e 2 x 2 x 5 c o m b i n a t i o n s o f t y p e o f t a s k ( p r e c u e v e r s u s p o s t c u e ) , t r i a l t y p e ( t a r g e t v e r s u s c a t c h ) , and d i s p l a y c o n d i t i o n ( w o r d , r e g u l a r - h i g h , r e g u l a r - l o w , i r r e g u l a r - h i g h , a n d i r r e g u l a r - l o w ) . The ma in e f f e c t o f d i s p l a y t y p e was s i g n i f i c a n t , E ( 4 , 6 8 ) = 63 .57 , E < .001, a n d p l a n n e d c o m p a r i s o n s were p e r f o r m e d a s i n S t u d y 1. Words were j u d g e d 8 % more a c c u r a t e l y t h a n t h e r e g u l a r - h i g h p o s i t i o n a l - f r e q u e n c y nonwords , E (1, 6 8 ) = 34.88, E < .001. F o r t h e anagram d i s p l a y t y p e s , r e g u l a r s t r i n g s were j u d g e d 6 % more a c c u r a t e l y t h a n i r r e g u l a r s t r i n g s , (1, 6 8 ) = 42.01, E < .001. High p o s i t i o n a l - f r e q u e n c y s t r i n g s were j p d g e d 5 % more a c c u r a t e l y t h a n low p o s i t i o n a l - f r e q u e n c y s t r i n g s , E (1, 68) = 30.63, E < .001. R e g u l a r i t y and p o s i t i o n a l f r e q u e n c y d i d n o t i n t e r a c t , E (1, 6 8 ) = 1.71, p > .15. The i n t e r a c t i o n o f t y p e o f t a s k w i t h d i s p l a y c o n d i t i o n was s i g n i f i c a n t , E ( 4 , 6 8 ) = 2 .99 , p < .024. The o v e r a l l e f f e c t s o f s t r u c t u r e were g r e a t e r i n t h e p o s t c u e t h a n t h e p r e c u e t a s k . A l t h o u g h a c c u r a c y f o r i r r e g u l a r - l o w p o s i t i o n a l f r e q u e n c y was e q u i v a l e n t i n t h e two t a s k s , t h e t r e n d s d i v e r g e d s t e a d i l y w i t h i n c r e a s i n g s t r u c t u r e s o t h a t a c c u r a c y f o r words was 6% g r e a t e r i n t h e p o s t c u e t h a n t h e p r e c u e t a s k . No o t h e r i n t e r a c t i o n s a p p r o a c h e d s i g n i f i c a n c e .
S i m i l a r i t y a n a l y s e s . A p o s t hoc s i m i l a r i t y a n a l y s i s was pe r fo rmed a s i n t h e p r e v i o u s e x p e r i m e n t . The a n a l y s i s o f v a r i a n c e i n c l u d e d a s f a c t o r s t h e t y p e o f t a s k , t h e t y p e o f t r i a l ( t a r g e t v e r s u s c a t c h ) , and t h e number o f s i m i l a r l e t t e r s . T h e r e was a ma in e f f e c t o f t h e number o f s i m i l a r l e t t e r s , z ( 3 , 51) = 2 .86 , E < . 0 5 , and a s i g n i f i c a n t i n t e r a c t i o n w i t h c a t c h and t a r g e t t r i a l s , 1 ( 3 , 5 1 ) = 3 .58 , p < .025. R e l a t i v e t o t h e p r e v i o u s a c c u r a c y e x p e r i m e n t shown i n F i g u r e 4.10, t h e p r e s e n t r e s u l t s shown i n F i g u r e 4.13 r e v e a l e d much s m a l l e r d e c r e a s e s o n c a t c h t r i a l s and l i t t l e c h a n g e on t a r g e t t r i a l s w i t h i n c r e a s e s i n t h e number o f s i m i l a r l e t t e r s . The same r e s u l t s were o b s e r v e d i n t h e p r e c u e and p o s t c u e t a s k s .
T a r g e t v e r s u s c a t c h t r i a l s . N e i t h e r t h e main e f f e c t o f t y p e o f t a s k ( p r e c u e v e r s u s p o s t c u e ) n o r t r i a l t y p e ( t a r g e t v e r s u s c a t c h ) was s i g n i f i c a n t ( b o t h Es < 1 ) ; however , t h e i r i n t e r a c t i o n was s i g n i f i c a n t , (1,17) = 8 . 6 3 , E < .009. I t i s a p p a r e n t from F i g u r e 4.14 t h a t s u b j e c t s were more a c c u r a t e on t a r g e t t h a n c a t c h t r i a l s i n t h e p r e c u e c o n d i t i o n , w h e r e a s t h i s b i a s was r e v e r s e d i n t h e p o s t c u e t a s k .
APPENDIX 4.3 1 0 1
Appendix 4.3
D e t a i l s of t h e Method, P r o c e d u r e , and R e s u l t s of S tudy 3: Mixed-Case
Method
S u b j e c t s . E i g h t e e n I n t r o d u c t o r y Psychology s t u d e n t s , 3 male and 1 5 f e m a l e s , p a r t i c i p a t e d f o r an hour each day on 2 c o n s e c u t i v e d a y s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . One a d d i t i o n a l s u b j e c t was l o s t f o r f a i l u r e t o complete t h e e x p e r i m e n t . A l l s u b j e c t s passed a p r e l i m i n a r y v i s i o n t e s t w i t h a t l e a s t 20/40 a c u i t y f o r bo th e y e s and no s u b j e c t had s e r v e d i n p r e v i o u s e x p e r i m e n t s .
S t i m u l i , a p p a r a t u s , p r o c e d u r e . The p r o c e d u r e and a p p a r a t u s were t h e same as i n t h e RT t a s k of S tudy 1 w i t h t h e f o l l o w i n g m o d i f i c a t i o n s . The t a r g e t l e t t e r p r e s e n t e d a t t h e beginning of each t r i a l was d i s p l a y e d i n both i t s u p p e r c a s e and l o w e r c a s e forms t o remind t h e s u b j e c t t h a t e i t h e r form might be p r e s e n t i n t h e s t i m u l u s d i s p l a y . These two l e t t e r s were shown f o r 500 msec f o l l o w e d by a 1 sec b lank i n t e r v a l and were c e n t e r e d a t what would be s e r i a l p o s i t i o n s 3 and 4 i n t h e s t i m u l u s d i s p l a y . The l e t t e r s t r i n g was t h e n d i s p l a y e d u n t i l t h e s u b j e c t responded. For a randomly s e l e c t e d one-ha l f of a l l t r i a l s , t h e f i r s t t h r e e l e t t e r s of t h e s t i m u l u s s t r i n g were p r e s e n t e d i n uppercase and t h e l a s t t h r e e l e t t e r s i n lowercase . For t h e remain ing t r i a l s t h i s o r d e r of c a s e s was r e v e r s e d .
A s i n t h e p r e v i o u s e x p e r i m e n t s , t h e s u b j e c t s s e r v e d i n two 1-hour s e s s i o n s on c o n s e c u t i v e d a y s . Each s e s s i o n c o n s i s t e d of 1 0 "yes-no" warm-up t r i a l s , 240 p r a c t i c e t r i a l s , and 400 e x p e r i m e n t a l t r i a l s . The i n s t r u c t i o n s t o t h e s u b j e c t s emphasized speed and a c c u r a c y of responding and encouraged s u b j e c t s t o t r y t o " r e a d " each d i s p l a y a s a whole a s t h e most e f f e c t i v e means of making f a s t and a c c u r a t e judgments ( J o h n s t o n & McClel land, 1 9 7 4 ) .
R e s u l t s
O r t h o g r a p h i c s t r u c t u r e . The s u b j e c t s ' mean RTs f o r t h e 10 combina t ions of t y p e of t r i a l ( t a r g e t and c a t c h ) and d i s p l a y t y p e (word, r e g u l a r - h i g h , r e g u l a r - l o w , i r r e g u l a r - h i g h , and i r r e g u l a r - l o w ) were a n a l y z e d . I n c o r r e c t t r i a l RTs and c o r r e c t t r i a l R T s exceeding 2 sec were e x c l u d e d . The e r r o r r a t e s v a r i e d between 1 . 0 % and 8 . 9 % . To d e t e r m i n e i f t h i s v a r i a b i l i t y i n
1 0 2 CHAPTER 4
e r r o r r a t e was a f f e c t i n g RT t r e n d s , t h e s u b j e c t s were ranked on e r r o r r a t e and d i v i d e d i n t o two g r o u p s ; t h e n i n e s u b j e c t s w i t h t h e l o w e s t e r r o r r a t e s formed one g r o u p and t h e remain ing s u b j e c t s t h e o t h e r . The a v e r a g e RT f o r t h e s u b j e c t s w i t h lower e r r o r r a t e s was 647 msec, whereas f o r t h e h i g h e r e r r o r r a t e s u b j e c t s , t h e mean RT was 756 msec, E (1, 16) = 3.47, p < .078. Grouping d i d n o t i n t e r a c t w i t h any o t h e r f a c t o r i n t h e a n a l y s i s .
The s i g n i f i c a n t main e f f e c t f o r d i s p l a y t y p e , E ( 4 , 64) =
65.23, p < .001, was a n a l y z e d i n t e r m s of t h e same compar isons examined i n t h e p r e v i o u s e x p e r i m e n t s . The 7 msec d i f f e r e n c e between words and r e g u l a r - h i g h pseudowords was n o t s i g n i f i c a n t , - F < 1. The compar isons among t h e anagrams r e v e a l e d t h a t t h e 30 msec d i f f e r e n c e between r e g u l a r and i r r e g u l a r anagrams was s i g n i f i c a n t , ( 1, 64) = 33.50, < .001. Also t h e 1 4 msec d i f f e r e n c e between h i g h and low p o s i t i o n a l - f r e q u e n c y items was s i g n i f i c a n t , E (1, 64) = 8.09, < .006. The i n t e r a c t i o n of r e g u l a r i t y w i t h p o s i t i o n a l f r e q u e n c y was n o t s i g n i f i c a n t , E < 1.
An a n a l y s i s of v a r i a n c e was c a l c u l a t e d on e r r o r r a t e s . T h e d i s p l a y t y p e main e f f e c t , E ( 4 , 68) = 2.86, p < .030, and t h e i n t e r a c t i o n of d i s p l a y t y p e w i t h t r i a l ( t a r g e t v e r s u s c a t c h ) , E ( 4 , 6 8 ) = 2.98, p < .025, were b o t h s i g n i f i c a n t . Although t h e t r e n d d o e s n o t seem t o be p a r t i c u l a r l y meaningfu l , t h e s o u r c e of t h e s e two e f f e c t s is t h e somewhat g r e a t e r e r r o r r a t e f o r t h e i r r e g u l a r i t e m s on t a r g e t t r i a l s .
S i m i l a r i t y a n a l y s e s . A r e s t r i c t e d s i m i l a r i t y a n a l y s i s was done on o n l y t h e l o w e r c a s e l e t t e r s i n t h e d i s p l a y s t r i n g s . Reac t ion times i n c r e a s e d 2 4 msec on c a t c h t r i a l s and d i d n o t change on t a r g e t t r i a l s wi th i n c r e a s e s from z e r o t o one s i m i l a r l e t t e r s , E (1, 1 7 ) = 5.84 , p < .05.
T a r g e t v e r s u s c a t c h t r i a l s . A s i n t h e p r e v i o u s RT t a s k , t a r g e t t r i a l s were judged more q u i c k l y (660 msec) t h a n were c a t c h t r i a l s (743 m s e c ) , E (1, 1 6 ) = 65.23, p < .001. Type of t r i a l d i d n o t i n t e r a c t w i t h t y p e of l e t t e r s t r i n g .
For t h e e r r o r d a t a , c a t c h t r i a l s ( 9 7 . 1 % ) were s i g n i f i c a n t l y more a c c u r a t e t h a n t a r g e t t r i a l s ( 9 3 . 8 % ) a s i n t h e RT d a t a of Study 1, 1 (1, 1 7 ) = 33.81, p < .001. However, t r i a l t y p e d i d i n t e r a c t w i t h d i s p l a y t y p e a s noted above.
APPENDIX 4 . 4 103
Appendix 4 . 4
D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 4 : L imi ted Viewing T i m e
S u b j e c t s . S i x t e e n I n t r o d u c t o r y Psychology s t u d e n t s , 8 males and 8 f e m a l e s , were t e s t e d f o r a s i n g l e 90-minute s e s s i o n and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . A s i n t h e p r e v i o u s e x p e r i m e n t s , a l l s u b j e c t s were t e s t e d f o r v i s u a l a c u i t y of a t l e a s t 20/40, a l l responded w i t h t h e i r p r e f e r r e d hand ( r i g h t hand f o r 1 5 of t h e 1 6 ) , and no s u b j e c t had p a r t i c i p a t e d i n t h e e a r l i e r e x p e r i m e n t s .
Procedure . The s t i m u l i and a p p a r a t u s were t h e same a s t h e p r e v i o u s e x p e r i m e n t s . An e x p e r i m e n t a l t r i a l began w i t h t h e p r e s e n t a t i o n of t h e lowercase t a r g e t l e t t e r p o s i t i o n e d w i t h i n t h e viewing r e c t a n g l e a t d i s p l a y s e r i a l p o s i t i o n 4 f o r 500 msec. A 1 sec b lank i n t e r v a l f o l l o w e d and t h e n t h e s t i m u l u s s t r i n g i n l o w e r c a s e was p r e s e n t e d f o r 200 msec. The s t i m u l u s was s c r o l l e d upward and r e p l a c e d by s i x uppercase Xs which s e r v e d a s a mask and remained i n view u n t i l t h e s u b j e c t responded. Fol lowing t h e s u b j e c t ' s r e s p o n s e t h e r e was a 500 msec i n t e r t r i a l i n t e r v a l .
The t e s t i n g s e s s i o n f o r e a c h s u b j e c t c o n s i s t e d of 10 "yes-no" warm-up t r i a l s , 240 p r a c t i c e t r i a l s , and 2 4 0 0 - t r i a l e x p e r i m e n t a l s e s s i o n s . A s i n a l l p r e v i o u s e x p e r i m e n t s , t r i a l s were grouped i n t o 80 t r i a l b l o c k s . Between b l o c k s s u b j e c t s were g i v e n a minute o r two of r e s t and feedback i n t h e form of a mean RT e r r o r p e r c e n t a g e f o r t h e b l o c k . A 5 minute r e s t was g i v e n between t h e two e x p e r i m e n t a l s e s s i o n s .
The s u b j e c t s were t o l d t h a t h a l f t h e t r i a l s would be t a r g e t t r i a l s and h a l f would be c a t c h t r i a l s . They were a l s o informed t h a t t h e s t i m u l u s d i s p l a y would be b r i e f and t h a t t h e y would have t o r e a d i t c a r e f u l l y . Speed and a c c u r a c y of responding were emphasized.
O r t h o g r a p h i c s t r u c t u r e . A s i n t h e p r e v i o u s RT s t u d i e s , t h e s u b j e c t s ' mean RT f o r each c e l l of t h e d e s i g n , e x c l u d i n g i n c o r r e c t t r i a l RTs and c o r r e c t RTs exceeding 2 s e c , were a n a l y z e d . The s u b j e c t s ' e r r o r r a t e s v a r i e d between 4.5% and 1 1 . 9 % , which is h i g h e r t h a n normal ly d e s i r e d f o r RT t a s k s . For
104 CHAPTER 4
t h i s r e a s o n , s u b j e c t s were a g a i n r a n k e d by e r r o r r a t e and d i v i d e d i n t o low and h i g h e r r o r r a t e g r o u p s . An a n a l y s i s o f v a r i a n c e i n d i c a t e d no e f f e c t o f g r o u p i n g t h e s u b j e c t s by e r r o r r a t e ( a l l F s < 1 ) . The a n a l y s e s o f t h e RT d a t a i n d i c a t e d no e f f e c t o f d i s p l a y t y p e , E ( 4 , 56 ) = 1 .27 . Only t h e d i s p l a y t y p e by t r i a l t y p e i n t e r a c t i o n was s i g n i f i c a n t . The n a t u r e o f t h i s i n t e r a c t i o n may b e s e e n i n F i g u r e 4.16. T a r g e t and c a t c h R T s a p p e a r t o t r a d e - o f f a c r o s s d i s p l a y t y p e s . T h i s p a t t e r n i s i n d i c a t i v e o f a s h i f t i n b i a s , o r a t l e a s t c o n f i d e n c e , a c r o s s t h e d i s p l a y t y p e s . A s s u b j e c t s become more r e l u c t a n t ( s l o w e r ) t o r e s p o n d " y e s " t h e y become more w i l l i n g ( f a s t e r ) t o r e s p o n d "no." For t h e mos t p a r t , t h i s p a t t e r n o f d e c r e a s i n g c o n f i d e n c e c o i n c i d e s w i t h t h e d e c l i n e i n o r t h o g r a p h i c s t r u c t u r e wh ich is a r e a s o n a b l e r e a c t i o n t o d i s p l a y s t h a t a r e more d i f f i c u l t t o r e s o l v e .
An a n a l y s i s o f t h e e r r o r d a t a r e v e a l e d o n l y a ma in e f f e c t o f d i s p l a y t y p e , E ( 4 , 6 0 ) = 6 .79 , E < .001. T h i s d i s p l a y t y p e main e f f e c t was examined w i t h t h e u s u a l s e t o f c o n t r a s t s . The d i f f e r e n c e i n e r r o r r a t e be tween words and r e g u l a r - h i g h i t ems was t o o s m a l l t o b e s i g n i f i c a n t , b u t t h e 1.8% d i f f e r e n c e be tween words and t h e a v e r a g e o f t h e r e g u l a r items was s i g n i f i c a n t , (1 .60 ) = 6 . 4 2 , p < -013 . The e r r o r r a t e was 1.7% s m a l l e r f o r r e g u l a r t h a n i r r e g u l a r items, ( 1 , 6 0 ) = 8 . 5 9 , E < .005. N e i t h e r t h e p o s i t i o n a l - f r e q u e n c y e f f e c t ( e r r o r r a t e d i f f e r e n c e o f o n l y 0 . 4 % , 1 < 1) n o r t h e i n t e r a c t i o n o f r e g u l a r i t y w i t h t h e p o s i t i o n a l f r e q u e n c y were s i g n i f i c a n t , (1, 6 0 ) = 1 .30 .
S i m i l a r i t y a n a l y s e s . Fo r r e s p o n s e a c c u r a c y , t h e number o f s i m i l a r n o n t a r g e t l e t t e r s had no e f f e c t o n e i t h e r t a r g e t o r c a t c h t r i a l s , 2 ' s > .1. For RTs, t h e e f f e c t o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s had no e f f e c t o n t a r g e t t r i a l s and a l a r g e e f f e c t o n c a t c h t r i a l s , 1 ( 3 , 4 5 ) = 1 4 . 2 4 , E < .001. RTs i n c r e a s e d o n l y 1 msec on t a r g e t t r i a l s and 67 msec on c a t c h t r i a l s w i t h i n c r e a s e s f rom z e r o t o t h r e e s i m i l a r l e t t e r s .
T a r g e t - c a t c h d i f f e r e n c e s . A s i n t h e p r e v i o u s p o s t c u e RT e x p e r i m e n t s t h e r e was a ma in e f f e c t o f t r i a l t y p e , E (1, 1 4 ) = 26 .62 , E < . 001 , w i t h t a r g e t t r i a l s ( 5 6 3 msec) b e i n g r e s p o n d e d t o more q u i c k l y t h a n c a t c h t r i a l s ( 6 3 5 msec). T h e r e was a l s o t h e i n t e r a c t i o n o f t r i a l t y p e w i t h d i s p l a y t y p e d i s c u s s e d above. For t h e e r r o r d a t a , t h e r e was n e i t h e r a s i g n i f i c a n t main e f f e c t o f t r i a l t y p e , E (1, 1 5 ) = 1 . 9 5 , n o r a s i g n i f i c a n t i n t e r a c t i o n w i t h d i s p l a y t y p e , E < 1.
APPENDIX 4 . 5 105
Appendix 4.5
D e t a i l s of Method, P r o c e d u r e , and R e s u l t s of S tudy 5: Speeded RT Task w i t h Good V i s u a l I n f o r m a t i o n
Method
S u b j e c t s . E leven I n t r o d u c t o r y Psychology s t u d e n t s , 10 female and 1 male , were t e s t e d f o r a s i n g l e 1-hour s e s s i o n and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . S u b j e c t s were t e s t e d i n f o u r g r o u p s ; t h r e e g r o u p s w i t h t h r e e p a r t i c i p a n t s and one w i t h two. A l l s u b j e c t s responded w i t h t h e i r p r e f e r r e d hand ( r i g h t hand f o r 9 of t h e 11). No s u b j e c t had p a r t i c i p a t e d i n an e a r l i e r e x p e r i m e n t .
Appara tus 4 s t i m u l i . The s t i m u l i were t h e same a s i n t h e p r e v i o u s e x p e r i m e n t s . The v i s u a l d i s p l a y s were g e n e r a t e d by a DEC LSI-11 computer under s o f t w a r e c o n t r o l and p r e s e n t e d on T e k t r o n i x Monitor 604 o s c i l l o s c o p e s ( T a y l o r , K l i t z k e , &
MaSSaKO, 1 9 7 8 ) . These m o n i t o r s employ a P31 phosphor w i t h a decay t o .l% of s t i m u l a t e d luminance w i t h i n 3 2 msec. The a l p h a b e t c o n s i s t e d of l o w e r c a s e n o n s e r i f e d l e t t e r s r e s e m b l i n g t h e t y p e f o n t U n i v e r s 55. For a n o b s e r v e r s e a t e d c o m f o r t a b l y a t a n e x p e r i m e n t a l s t a t i o n , t h e s i x - l e t t e r d i s p l a y s subtended a b o u t 1 . 9 d e g r e e of v i s u a l a n g l e h o r i z o n t a l l y and t h e d i s t a n c e from t h e t o p of a n a s c e n d e r t o t h e bot tom of a d e s c e n d e r was a b o u t . 4 d e g r e e . T h i s computer ized l a b o r a t o r y f a c i l i t y p e r m i t t e d t h e t e s t i n g of up t o f o u r s u b j e c t s i n p a r a l l e l . Each s u b j e c t r e c e i v e d t h e same v i s u a l d i s p l a y on h i s o r her d i s p l a y m o n i t o r , and t h e computer c o l l e c t e d i n d i v i d u a l s u b j e c t ' s r e s p o n s e s .
Procedure . The e x p e r i m e n t a l p r o c e d u r e was a r e s p o n s e - s i g n a l method (Reed, 1973) i n which t h e s u b j e c t e n d e a v o r s t o respond i n synchrony w i t h a s i g n a l which, i n t h i s c a s e , was t h e o f f s e t of t h e s t i m u l u s d i s p l a y s t r i n g . The e x a c t p r o c e d u r e was a s f o l l o w s . A t r i a l began w i t h t h e p r e s e n t a t i o n of a s i n g l e f i x a t i o n p o i n t i n t h e c e n t e r of t h e s c r e e n . A f t e r 250 msec t h e f i x a t i o n p o i n t was r e p l a c e d by t h e t e s t l e t t e r f o r 500 msec. The f i x a t i o n p o i n t r e t u r n e d f o r 250 msec f o l l o w e d by t h e d i s p l a y s t r i n g . The d i s p l a y was i n i t i a l l y p r e s e n t e d f o r 550 msec w i t h t h i s v a l u e r e v i s e d e v e r y 2 0 t h t r i a l t o a c h i e v e a n o v e r a l l a c c u r a c y o f 75% f o r t h e g r o u p of s u b j e c t s be ing t e s t e d . The t r i a l t e r m i n a t e d when a l l s u b j e c t s responded o r , i n t h e e v e n t t h a t a s u b j e c t f a i l e d t o r e s p o n d , a t t h e end of 4 sec. A 500 msec i n t e r t r i a l i n t e r v a l was g i v e n . A t t h e end o f e v e r y 20
106 CHAPTER 4
t r i a l s , each s u b j e c t was g i v e n feedback a b o u t h i s o r h e r performance i n t h e f o l l o w i n g manne'r. A t t r i a l t e r m i n a t i o n t h e word FEEDBACK was p r e s e n t e d a t t h e c e n t e r of t h e s c r e e n f o r 1 s e c . One-half second l a t e r two columns of numbers appeared on t h e s c r e e n , a s u b j e c t number and t h e s u b j e c t ' s a v e r a g e d e v i a t i o n from t h e d i s p l a y s t r i n g o f f s e t t o t h e r e s p o n s e i n msec. A n e g a t i v e d e v i a t i o n i n d i c a t e d an a v e r a g e r e s p o n s e p r i o r t o t h e d i s p l a y o f f s e t : a p o s i t i v e d e v i a t i o n i n d i c a t e d t h a t t h e a v e r a g e r e s p o n s e f e l l a f t e r t h e d i s p l a y o f f s e t . Each s u b j e c t ' s number was C l e a r l y p o s t e d a t h i s o r h e r s u b j e c t s t a t i o n t o f a c i l i t a t e remembering which feedback s c o r e was a p p r o p r i a t e . The feedback s c o r e s were v i s i b l e f o r 2.5 sec a f t e r which came t h e normal h a l f second i n t e r t r i a l i n t e r v a l . The s u b j e c t s ' i n s t r u c t i o n s a c q u a i n t e d them w i t h t h e t a s k and t h e g e n e r a l t y p e s of s t i m u l u s i t e m s . I t was s t r e s s e d t h a t t h e s u b j e c t s were t o be a s a c c u r a t e a s p o s s i b l e and y e t respond a s n e a r l y i n synchrony w i t h t h e s i g n a l a s p o s s i b l e . They were t o l d how t h e y would r e c e i v e feedback and a g a i n i t was s t r e s s e d t h a t t h e y s h o u l d endeavor t o m a i n t a i n a z e r o feedback s c o r e . A l l s u b j e c t s r e c e i v e d 120 p r a c t i c e t r i a l s fo l lowed by two e x p e r i m e n t a l s e s s i o n s of 400 t r i a l s each. A s h o r t r e s t b reak was g i v e n between t h e two e x p e r i m e n t a l s e s s i o n s .
A l l s u b j e c t s became a d e p t a t t h e t a s k by t h e end of t h e p r a c t i c e t r i a l s o r e a r l y i n t h e f i r s t e x p e r i m e n t a l s e s s i o n so t h a t t h e d i s p l a y o f f s e t t imes were r e a s o n a b l y s t a b l e t h r o u g h o u t t h e two s e s s i o n s . Average d i s p l a y o f f s e t times f o r t h e f o u r groups of s u b j e c t s were a s f o l l o w s : 4 1 2 , 634, 485, and 505 msec.
R e s u l t s
S e p a r a t e a n a l y s e s were made of t h e mean a c c u r a c i e s and t h e mean R T s f o r bo th c o r r e c t and i n c o r r e c t t r i a l s . For t h e a c c u r a c y d a t a t h e r e were no s i g n i f i c a n t e f f e c t s ( a l l Fs < 1) .
The a n a l y s i s of v a r i a n c e f o r t h e R T s inc luded t r i a l t y p e , d i s p l a y c o n d i t i o n , and c o r r e c t n e s s of t h e r e s p o n s e as f a c t o r s . There were s i g n i f i c a n t e f f e c t s of t y p e of t r i a l , (1, 10) =
8.04, < .017; c o r r e c t n e s s of r e s p o n s e , r (1, 1 0 ) = 19.99 , < .001; and t h e i n t e r a c t i o n of t h e s e two f a c t o r s , (1, 1 0 34.32, < .001. These e f f e c t s were a r e s u l t of s i g n i f i c a n t l y s lower c o r r e c t c a t c h t r i a l r e s p o n s e s seen F i g u r e 4.17. Although we observed t h e normal RT advantage c o r r e c t t a r g e t t r i a l s over c o r r e c t c a t c h t r i a l s , t h e i n c o r t a r g e t and i n c o r r e c t c a t c h t r i a l s n e a r l y c o i n c i d e d w i t h
- - t h e
i n f o r e c t t h e
APPENDIX 4.5 107
c o r r e c t t a r g e t t r i a l r e s p o n s e s . The main e f f e c t o f d i s p l a y t y p e , ( 4 , 40) = 3.17, p < .023, and t h e i n t e r a c t i o n of d i s p l a y t y p e w i t h c o r r e c t n e s s of r e s p o n s e and t y p e of t r i a l , ( 4 , 4 0 ) = 3.25, < .021, were s i g n i f i c a n t . Mean RT i n c r e a s e d from 477 msec f o r words t o 492 msec f o r i r r e g u l a r - l o w nonwords.
108 CHAPTER 4
Appendix 4.6
D e t a i l s of Method, P r o c e d u r e , and R e s u l t s of Study 6: Speeded RT T a s k w i t h Poor V i s u a l I n f o r m a t i o n
Method
S u b j e c t s . T h i r t e e n I n t r o d u c t o r y Psychology s t u d e n t v o l u n t e e r s p a r t i c i p a t e d as s u b j e c t s ; t h e d a t a of two were l o s t due t o a computer m a l f u n c t i o n . A l l s u b j e c t s were n a t i v e E n g l i s h s p e a k e r s , had normal or cor rec ted- to-normal v i s i o n , had n o t p a r t i c i p a t e d i n any of t h e o t h e r e x p e r i m e n t s , were r igh t -handed , and r e c e i v e d some c r e d i t toward t h e i r c o u r s e g r a d e f o r p a r t i c i p a t i n g .
M a t e r i a l s , a p p a r a t u s , p r o c e d u r e . The s t i m u l i and a p p a r a t u s were t h e same as i n S tudy 5 and a r e d e s c r i b e d i n Appendix 4.5. The i m p o r t a n t d i f f e r e n c e i n t h e p r e s e n t exper iment is t h a t t h e comple te t e s t l e t t e r s t r i n g was r o t a t e d 180 d e g r e e s i n t h e p i c t u r e p l a n e . R o t a t i n g t h e comple te t e s t s t r i n g r a t h e r t h a n t h e i n d i v i d u a l l e t t e r s s e p a r a t e l y c r e a t e s a d i s p l a y much e a s i e r t o read ( K o l e r s , 1 9 7 0 ) . The i n i t i a l d i s p l a y d u r a t i o n was l e n g t h e n e d t o 700 msec. The t a r g e t l e t t e r was s t i l l p r e s e n t e d u p r i g h t . S u b j e c t s responded " y e s " w i t h t h e i r dominant hand.
R e s u l t s
The means among l e t t e r - s t r i n g t y p e s i n d i c a t e d a 1.1% advantage of words over t h e b e s t pseudowords ( r e g u l a r - h i g h ) and a 1 .6% advantage of words o v e r a l l t y p e s of nonwords. Accuracy f o r r e g u l a r nonwords was 0.2% b e t t e r t h a n f o r i r r e g u l a r nonwords. Nonwords of h igh p o s i t i o n a l f r e q u e n c y had a 0 .5% advantage over nonwords of low p o s i t i o n a l f r e q u e n c y . A s might be e x p e c t e d from d i f f e r e n c e s t h i s s m a l l , t h e a n a l y s i s o f v a r i a n c e i n d i c a t e d no e f f e c t of l e t t e r - s t r i n g t y p e s , E < 1. Fur thermore , t h e r e was no d i f f e r e n c e between t a r g e t and c a t c h t r i a l s , E < 1, and no i n t e r a c t i o n , < 1.
The a c c u r a c y r e s u l t s of t h e p r e s e n t e x p e r i m e n t c a n be compared t o t h o s e of S tudy 5 w i t h u p r i g h t l e t t e r s t r i n g s . T h i s a n a l y s i s i n d i c a t e d no d i f f e r e n c e s of any kind between t h e two e x p e r i m e n t s ( f o r u p r i g h t - r o t a t e d , (1, 2 1 ) = 0.14; f o r t a r g e t - c a t c h , (1, 2 1 ) = 1.18; f o r t h e u p r i g h t - r o t a t e d x t a r g e t - c a t c h i n t e r a c t i o n , 1 (1, 21) = 0.07; f o r t h e l e t t e r - s t r i n g t y p e s , E ( 4 , 84) = 0.92; f o r t h e u p r i g h t - r o t a t e d x l e t t e r - s t r i n g i n t e r a c t i o n , ( 4 , 84) = 0.09; f o r t h e
APPENDIX 4.6 109
t a r g e t - c a t c h x l e t t e r - s t r i n g i n t e r a c t i o n , 1 ( 4 , 8 4 ) = 1 .27 ; and f o r t h e th ree -way i n t e r a c t i o n , ( 4 , 8 4 ) = 0 . 2 3 ) .
An e x a m i n a t i o n o f t h e r e a c t i o n t imes i n t h e r o t a t e d e x p e r i m e n t r e v e a l e d r e s u l t s s i m i l a r t o t h o s e o f t h e a c c u r a c y d a t a . Means were c a l c u l a t e d on c o r r e c t r e a c t i o n t imes t h a t d i d n o t exceed 2 , 0 0 0 msec ( 0 . 2 5 % e x c e e d e d ) . Words were a c t u a l l y r e s p o n d e d t o 9 msec s l o w e r t h a n r e g u l a r - h i g h nonwords . R e a c t i o n t imes were 9 msec l o n g e r f o r i r r e g u l a r nonwords t h a n f o r r e g u l a r nonwords and 8 msec l o n g e r f o r nonwords o f l ow r a t h e r t h a n o f h i g h p o s i t i o n a l f r e q u e n c y .
The a n a l y s i s o f v a r i a n c e i n d i c a t e d s i g n i f i c a n t l y l o n g e r r e a c t i o n t imes f o r c a t c h t r i a l s a s compared t o t a r g e t t r i a l s , - F (1, 11) = 46 .73 , p < - 0 0 1 , b u t no e f f e c t o f t y p e s , 2 ( 4 , 44 ) = 2.43, p < . 05 , a n d no i n t e r a c t = 1 . 6 0 , p < .l.
The r e a c t i o n t imes f o r t h e r o t a t e d l e t t e r were compared t o t h o s e f o r t h e u p r i g h t l e t t e r a v e r a g e r e a c t i o n t ime f o r r o t a t e d l e t t e r s t r i n g s l o n g e r t h a n f o r u p r i g h t l e t t e r s t r i n g s , F (1, 21
1 e t te r - s t r i ng o n , 1 ( 4 , 44 )
s t r i n g s a l s o s t r i n g s . The was 104 msec = 26 .94 , p < -
.001. C a t c h t r i a l s t o o k 66 msec l o n g e r t h a n t a r g e t t r i a l s , 1 (1, 2 1 ) = 75.84, p < . 001 , b u t t h i s d i d n o t i n t e r a c t w i t h w h e t h e r t h e l e t t e r s t r i n g s were r o t a t e d , (1, 2 1 ) = 1 . 2 6 . T h e r e was a n o v e r a l l d i f f e r e n c e o f l e t t e r - s t r i n g t y p e s , - F ( 4 , 8 4 ) = 5 . 7 7 , p < .001. L e t t e r - s t r i n g t y p e s d i d n o t i n t e r a c t w i t h t h e o t h e r f a c t o r s : w i t h r o t a t i o n , ( 4 , 8 4 ) =
0.49; w i t h t a r g e t - c a t c h t r i a l s , 1 ( 4 , 8 4 ) = 1 .18 ; a n d f o r t h e t h r e e - w a y i n t e r a c t i o n , E ( 4 , 8 4 ) = 1 .18 .
To examine d i f f e r e n c e s among d i s p l a y d u r a t i o n s , t h e d i s p l a y d u r a t i o n s f o r e a c h o f t h e 40 s e t s o f 20 t r i a l s were g r o u p e d i n t o 4 b l o c k s o f 10 s e t s e a c h . Each o f t h e c o n s e c u t i v e 4 b l o c k s t h u s r e p r e s e n t e d 1 0 d i s p l a y d u r a t i o n s f o r 1 0 s e t s o f 20 t r i a l s . An a n a l y s i s o f v a r i a n c e i n d i c a t e d no d i f f e r e n c e s among b l o c k s , ( 3 , 33 ) = 0 .67 , b u t d i d i n d i c a t e a d i f f e r e n c e among t h e 10 s e t s w i t h i n a b l o c k , E ( 9 , 9 9 ) = 4.25, 2 < . 001 , and a b l o c k by s e t i n t e r a c t i o n , E ( 2 7 , 297) = 2 . 2 1 , E < .005. These e f f e c t s r e f l e c t t h e o p e r a t i o n o f b o t h p r a c t i c e and f a t i g u e . I n i t i a l l y t h e d i s p l a y d u r a t i o n s d e c r e a s e d w i t h e x p e r i e n c e , b u t t h e n i n c r e a s e d toward t h e end o f t h e f i r s t 200 t r i a l s . F o l l o w i n g a b r e a k b e t w e e n h a l v e s o f t h e e x p e r i m e n t , d i s p l a y t i m e s a g a i n d e c r e a s e d u n t i l l a t e i n t h e s e c o n d h a l f o f t h e e x p e r i m e n t .
110 CHAPTER 4
The d i s p l a y d u r a t i o n s a l s o were compared between t h e u p r i g h t and r o t a t e d e x p e r i m e n t s . Although t h e a v e r a g e d i s p l a y d u r a t i o n was 498 msec f o r u p r i g h t p r e s e n t a t i o n and 556 msec f o r r o t a t e d p r e s e n t a t i o n , t h e e f f e c t was n o t s i g n i f i c a n t , (1, 2 1 ) = 2.64, nor was t h e r e an e f f e c t of t h e b l o c k s of 10 d i s p l a y d u r a t i o n s , E ( 3 , 63) = 1 . 5 6 , and t h e two f a c t o r s a l s o d i d n o t i n t e r a c t , E ( 3 , 63) = 2.53. There were , however, d i f f e r e n c e s among i n d i v i d u a l d i s p l a y d u r a t i o n s , ( 9 , 189) = 2.05, E < .05 , and d i s p l a y d u r a t i o n s i n t e r a c t e d w i t h e v e r y t h i n g e l se : w i t h u p r i g h t - r o t a t e d l e t t e r s t r i n g s , E ( 9 , 189) = 4.65, E < .001; w i t h b l o c k s , F ( 2 7 , 567) = 1.63 , p < .05 ; and i n a three-way i n t e r a c t i o n , (27 , 567) = 1 . 6 9 , E < .05. These i n t e r a c t i o n s r e f l e c t t h e s l i g h t f a t i g u e f a c t o r in t h e r o t a t e d e x p e r i m e n t and t h e absence of such i n t h e u p r i g h t e x p e r i m e n t . For t h e u p r i g h t s t i m u l i , t h e d i s p l a y d u r a t i o n s c o n t i n u e d t o d e c r e a s e t h r o u g h o u t t h e exper iment .
APPENDIX 4.7 111
Appendix 4.7
D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 7: High-Accuracy RT Task w i t h Poor V i s u a l I n f o r m a t i o n
Twelve s u b j e c t s were used and met t h e same c o n s t r a i n t s a s i n t h e speeded RT t a s k i n S tudy 6 (Appendix 4 . 6 ) . The same r o t a t e d s t i m u l i a l s o were used w i t h t h e f o l l o w i n g p r o c e d u r a l d i f f e r e n c e s . A t r i a l c o n s i s t e d of a 250 msec f i x a t i o n p o i n t fo l lowed by an u p r i g h t l e t t e r which was p r e s e n t e d f o r 5 0 0 msec a t t h e f i x a t i o n p o i n t and t h e n t h e r o t a t e d l e t t e r s t r i n g . The l e t t e r s t r i n g remained on t h e s c r e e n u n t i l t h e l a s t s u b j e c t ( u p t o f o u r a t a time) responded.
R e s u l t s
Means were c a l c u l a t e d f o r c o r r e c t r e a c t i o n times t h a t d i d n o t exceed 2,000 msec ( 1 . 4 % e x c e e d e d ) . R e a c t i o n times g e n e r a l l y i n c r e a s e d from words t o t h e i r r e g u l a r - l o w nonwords, - F ( 4 , 4 4 ) = 6 . 4 7 , E < .081. Regular -h igh nonwords a v e r a g e d 6 msec l o n g e r t h a n words, i r r e g u l a r nonwords r e s u l t e d i n r e a c t i o n times t h a t were 1 6 msec l o n g e r t h a n r e g u l a r nonwords, and nonwords of low p o s i t i o n a l f r e q u e n c y r e s u l t e d i n r e a c t i o n times t h a t were 18 msec l o n g e r t h a t nonwords of h igh p o s i t i o n a l f r e q u e n c y . The a v e r a g e r e a c t i o n times f o r c a t c h t r i a l s was 110 msec l o n g e r t h a n f o r t a r g e t t r i a l s , F (1, 11) = 1610.10, p < .001, b u t t h i s d i d n o t i n t e r a c t w i t h l e t t e r - s t r i n g t y p e s , 1 ( 4 ,
D i f f e r e n c e s between l e t t e r s t r i n g s were f u r t h e r examined by o r t h o g o n a l c o n t r a s t s . The d i f f e r e n c e between words and a l l nonwords was s i g n i f i c a n t , t ( 4 4 ) = 3 . 1 8 , p < .005, a s was t h e d i f f e r e n c e between r e g u l a r and i r r e g u l a r nonwords, t ( 4 4 ) =
1 . 6 8 3 , p = .05. However, t h e d i f f e r e n c e between nonwords of h igh and low p o s i t i o n a l f r e q u e n c y was n o t s i g n i f i c a n t , t ( 4 4 ) = 0 .94 . S i m i l a r l y , a Newman-Kuels t e s t i n d i c a t e d t h a t t h e 6 msec d i f f e r e n c e between words and t h e b e s t pseudowords ( r e g u l a r - h i g h ) was n o t s i g n i f i c a n t , p > .10.
A comparison of r e a c t i o n times between t h e i n i t i a l r e p l i c a t i o n e x p e r i m e n t u s i n g u p r i g h t s t i m u l i and t h e p r e s e n t s t u d y i n d i c a t e d t h a t r e a c t i o n times f o r r o t a t e d s t i m u l i averaged 2 7 9 msec l o n g e r t h a n f o r u p r i g h t s t i m u l i , (1, 2 4 ) = 4 2 . 3 5 , 2 < .0Ol. The d i f f e r e n c e between c a t c h and t a r g e t
4 4 ) = 0 .79 .
1 1 2 CHAPTER 4
t r i a l s was s i g n i f i c a n t , F (1, 24) = 1 5 3 . 4 4 , p < . 001 , a s was t h e t r i a l t y p e x r o t a t e d - u p r i g h t i n t e r a c t i o n , (1, 24) = 23.68, 2 < -001 . D i f f e r e n c e s be tween l e t t e r s t r i n g s were s i g n i f i c a n t , E ( 4 , 9 6 ) = 20.12, 2 < . 001 , b u t l e t t e r s t r i n g s d i d n o t i n t e r a c t w i t h a n y t h i n g : w i t h r o t a t e d - u p r i g h t , ( 4 , 9 6 ) = 0 .53 ; w i t h t a r g e t - c a t c h , E ( 4 , 9 6 ) = 0 . 5 3 ; and f o r t h e th ree -way i n t e r a c t i o n , ( 4 , 9 6 ) = 1.60.
APPENDIX 4.8 113
Appendix 4.8
D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 8 : T y p i c a l i t y R a t i n g s
The o v e r t judgment e x p e r i m e n t s c o n s i s t e d of a s k i n g s u b j e c t s t o make c o n s c i o u s judgments a b o u t t h e t e s t items. Three sets of r a t i n g judgments were o b t a i n e d under s i m i l a r i n s t r u c t i o n s and a r e d e s c r i b e d h e r e a s " T y p i c a l i t y R a t i n g s . " A f o u r t h r a t i n g was o b t a i n e d i n S tudy 9 under e x p l i c i t i n s t r u c t i o n s a s t o t h e n a t u r e of p o s i t i o n a l f r e q u e n c y and is d e s c r i b e d a s " P o s i t i o n a l - F r e q u e n c y R a t i n g s . " A f i n a l s e t of judgments i n S tudy 10 were o b t a i n e d by a "Paired-Judgment" p r o c e d u r e .
Method
R a t i n g Forms. Three r a t i n g forms were p r e p a r e d . The f i r s t form employed t h e 160 anagrams; t h e second form employed t h e 160 anagrams p l u s 40 pseudowords d e r i v e d from t h e o r i g i n a l words by t h e s u b s t i t u t i o n of a s i n g l e l e t t e r ; and t h e t h i r d form used t h e e n t i r e 200 s t i m u l u s s t r i n g s i n c l u d i n g t h e o r i g i n a l words. ( S e e Appendix 4 . 1 8 f o r t h e 40 words and t h e i r 160 anagrams; see Appendix 4.8A f o r t h e o n e - l e t t e r s u b s t i t u t i o n pseudowords) . Each l i s t was randomized and p r i n t e d w i t h 20 l e t t e r s t r i n g s p e r page. The s t r i n g s were typed i n l o w e r c a s e w i t h f i v e u n d e r s c o r e s typed t o t h e r i g h t of e a c h s t r i n g a s a s p a c e f o r w r i t i n g t h e s t r i n g ' s r a t i n g . The r a t i n g s c a l e t o be used was reproduced a t t h e t o p o f each page a s f o l l o w s :
"Most l i k e E n g l i s h 10 9 8 7 6 5 4 3 2 1 L e a s t l i k e E n g l i s h . "
The f o u r or f i v e p a g e s compr is ing each l i s t were assembled i n random o r d e r i n t o b o o k l e t s . Each b o o k l e t was p r e p a r e d w i t h an a p p r o p r i a t e s h e e t of i n s t r u c t i o n s . These i n s t r u c t i o n s a r e reproduced i n Appendix 4.8B, and 4.8C.
S u b j e c t s . One hundred n i n e t y - e i g h t I n t r o d u c t o r y Psychology s t u d e n t s f i l l e d o u t one of t h r e e r a t i n g forms. The r a t e r s p a r t i c i p a t e d i n g r o u p s of 8 t o 1 2 p e r s o n s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . The f i r s t 70 s u b j e c t s r a t e d t h e f i r s t form which c o n t a i n e d o n l y t h e 160 anagrams. The n e x t 65 s u b j e c t s f i l l e d o u t t h e second form which i n c l u d e d t h e 160 anagrams and t h e o n e - l e t t e r s u b s t i t u t i o n pseudowords made from t h e words. The f i n a l 63 s u b j e c t s r a t e d t h e t h i r d form which
1 1 4 CHAPTER 4
c o n t a i n e d t h e o r i g i n a l s e t o f 200 s t i m u l u s i tems ( i . e . , t h e 160 anagrams and t h e 40 w o r d s ) . Each s u b j e c t worked a t h i s o r h e r own s p e e d , and on t h e a v e r a g e , t o o k 1 5 t o 2 5 m i n u t e s t o r a t e t h e i tems.
-- P r o c e d u r e . - Each s e s s i o n began w i t h t h e e x p e r i m e n t e r r e a d i n g t h e i n s t r u c t i o n s w h i l e t h e s u b j e c t f o l l o w e d a l o n g . The f o r m a l i n s t r u c t i o n s were s u p p l e m e n t e d w i t h v e r b a l i n s t r u c t i o n s s t r e s s i n g " s i m i l a r i t y t o E n g l i s h s p e l l i n g " a s t h e p r i m a r y r a t i n g c r i t e r i o n . S u b j e c t s were u r g e d n o t t o a d o p t s t r a t e g i e s o f r a t i n g r e g u l a r i t y o n t h e b a s i s o f b e i n g a b l e t o t r a n s f o r m a s t r i n g i n t o a word t h r o u g h l e t t e r a d d i t i o n s , d e l e t i o n s , s u b s t i t u t i o n s , o r by making anagrams . The r a t e r s who r e c e i v e d t h e l i s t c o n t a i n i n g a c t u a l words were a l s o a s k e d t o d i s r e g a r d t h e s e m a n t i c c o n t e n t o f t h e words t o t h e f u l l e s t e x t e n t p o s s i b l e . F i n a l l y , t h e r e l a t i v e n a t u r e o f t h e s c a l e was s t r e s s e d . I t was i n d i c a t e d t h a t t h e p s y c h o l o g i c a l s c a l e s h o u l d s p a n t h e p r e s e n t e d s e t o f i tems and a l l 1 0 s c a l e v a l u e s s h o u l d be u s e d .
R e s u l t s
Average r a t i n g s were t a b u l a t e d b o t h w i t h i n s u b j e c t s and a c r o s s s u b j e c t s . For t h e w i t h i n s u b j e c t t a b u l a t i o n s , t h e s u b j e c t ' s r a t i n g s f o r t h e 40 s t i m u l i i n e a c h c a t e g o r y were a v e r a g e d . For t h e item a n a l y s e s , a n a v e r a g e f o r e a c h item was o b t a i n e d by a v e r a g i n g t h e r a t i n g s a s s i g n e d by e a c h s u b j e c t . T h e s e d a t a p e r m i t t e d a n a l y s e s t o d e t e r m i n e i f t h e r a t i n g s ' r e l i a b i l i t y r e f l e c t e d d i f f e r e n c e s i n mean r a t i n g s f o r t h e 4 o r 5 c a t e g o r i e s o f s t i m u l i . S i x one-way a n a l y s e s o f v a r i a n c e were computed f o r a l l p a i r w i s e c o m p a r i s o n s among t h e t h r e e i n s t r u c t i o n c o n d i t i o n s ; t h r e e a n a l y s e s were b a s e d on s u b j e c t s a s t h e s a m p l i n g v a r i a b l e and t h r e e were b a s e d on items a s t h e s a m p l i n g v a r i a b l e . The mean r a t i n g s were s o r e l i a b l e t h a t e r r o r v a r i a n c e s were u n i f o r m l y s m a l l i n a l l s i x a n a l y s e s ( s t a n d a r d e r r o r o f e s t i m a t e is t h e r a n g e o f .04 t o .68 s c a l e u n i t s f o r a l l s i x a n a l y s e s ) . With s u c h s m a l l e r r o r v a r i a n c e s , a l l p a i r w i s e d i f f e r e n c e s be tween c a t e g o r y means were r e l i a b l e a t t h e . 05 l e v e l .
A P P E N D I X 4.8A 115
Appendix 4.8A
The Pseudowords used i n S t u d y 8.
Word Pseudoword
a c t i o n amount answer b a r e l y belong b r e a t h b r i d g e c h a r g e d o u b l e famous f i n g e r g a r d e n g a t h e r g l a n c e h a r d l y i t s e l f 1 awye r l o n g e r m a s t e r modern
a p t i o n amaunt onswer p a r e l y be lang b r e e t h bradge c h u r g e g o u b l e vamous v i n g e r g u r d e n g i t h e r g l u n c e h e r d l y i t s o l f rawyer ronger moster madern
Word Pseudoword -
mother namely n e a r l y perm i t p l a y e r p o e t r y p u r e l y r e a s o n remain r e s u l t s h a r e d s imp1 e s i n g l e s p r e a d s t a r e d s t r e a m t r a v e l t r i a l s t u r n e d w i n t e r
mather nomely mear ly permat p l a d e r b o e t r y b u r e l y l e a s o n remoin r e s i l t s h a r e t sumple f i n g l e s p r e e d s t u r e d s t reem t r o v e 1 t r e a l s t a r n e d wunter
116 CHAPTER 4
Appendix 4.88
D i r e c t i o n s f o r T y p i c a l i t y R a t i n g s W i t h o u t Words and f o r T y p i c a l i t y R a t i n g s With Pseudowords
On t h e p a g e s wh ich f o l l o w a r e l e t t e r s t r i n g s made up t o l o o k l i k e E n g l i s h words . None of t h e s t r i n g s , however , is a n E n g l i s h word. Your t a s k is t o r a t e e a c h o n e o n a s c a l e o f 1 t o 1 0 a c c o r d i n g t o how much i t l o o k s l i k e a r e a l E n g l i s h word. S t r i n g s which a r e e x t r e m e l y c l o s e s h o u l d b e g i v e n h i g h r a t i n g s , w h i l e s t r i n g s which a r e n o t v e r y c l o s e s h o u l d b e g i v e n low r a t i n g s . S i n c e no r e a l words a r e i n c l u d e d , t h e h i g h e s t p o s s i b l e r a t i n g (10) s h o u l d b e g i v e n t o s t r i n g s wh ich you f e e l a r e mos t l i k e E n g l i s h words . S i m i l a r l y , a r a t i n g o f 1 s h o u l d be g i v e n t o t h e s t r i n g wh ich a r e l e a s t l i k e E n g l i s h words. The s t r i n g s h a v e b e e n s e l e c t e d t o r e p r e s e n t a l l p o s s i b l e l e v e l s o f s i m i l a r i t y t o E n g l i s h w i t h r o u g h l y e q u a l numbers a t e a c h l e v e l .
Skim o v e r t h e s t r i n g s on t h e f i r s t p a g e b e f o r e you b e g i n r a t i n g s o you h a v e a n i d e a o f t h e i r r a n g e o f v a r i a t i o n . T h e r e a r e 160(200) s t r i n g s i n a l l , d i v i d e d r andomly a c r o s s 4(5) p a g e s , s o e a c h page s h o u l d have r o u g h l y t h e same v a r i a t i o n a s a n y . o t h e r . You s h o u l d work a t a f a i r l y q u i c k and e v e n p a c e a l t h o u g h t h e r e is no t ime l i m i t .
APPENDIX 4 . 8 C 117
Appendix 4.8C
D i r e c t i o n s f o r T y p i c a l i t y R a t i n g s w i t h Words
On t h e pages which f o l l o w a r e l e t t e r s t r i n g s made up t o be s p e l l e d l i k e E n g l i s h words. Some of t h e s t r i n g s a r e , i n f a c t , E n g l i s h words, whereas o t h e r s t r i n g s a r e n o t E n g l i s h words. Independent of t h e meaning of t h e words, however, your t a s k is t o r a t e e a c h one on a sca le of 1 t o 10 a c c o r d i n g t o how much it is s p e l l e d l i k e t y p i c a l E n g l i s h s p e l l i n g . S t r i n g s which a r e e x t r e m e l y c l o s e s h o u l d be g i v e n h i g h r a t i n g s , w h i l e s t r i n g s which a r e n o t v e r y c l o s e s h o u l d be g i v e n low r a t i n g s . The h i g h e s t p o s s i b l e r a t i n g ( 1 0 ) s h o u l d be g i v e n t o s t r i n g s which you f e e l a r e s p e l l e d most l i k e E n g l i s h . S i m i l a r l y , a r a t i n g of 1 s h o u l d be g i v e n t o t h e s t r i n g s which a r e s p e l l e d l e a s t l i k e E n g l i s h . The s t r i n g s hae been s e l e c t e d t o r e p r e s e n t a l l p o s s i b l e l e v e l s of s i m i l a r i t y t o E n g l i s h s p e l l i n g w i t h r o u g h l y e q u a l numbers a t each l e v e l .
Skim o v e r t h e s t r i n g s on t h e f i r s t p a g e s b e f o r e you b e g i n r a t i n g so you have a n i d e a of t h e i r range of v a r i a t i o n . There a r e 200 s t r i n g s i n a l l , d i v i d e d randomly a c r o s s 5 p a g e s , s o each page s h o u l d have roughly t h e same v a r i a t i o n a s any o t h e r . You should work a t a f a i r l y q u i c k and even pace a l t h o u g h t h e r e is no time l i m i t .
118 CHAPTER 4
Appendix 4 . 9
The Method, P r o c e d u r e , and R e s u l t s of S tudy 9: P o s i t i o n a l - F r e q u e n c y R a t i n g s
Method
Rat ing forms were c o n s t r u c t e d by g e n e r a t i n g f r e s h c o p i e s of t h e form from Study 8 employing t h e 160 anagrams. E x p l i c i t p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s ( r e p r o d u c e d i n Appendix 4.9A) were s u b s t i t u t e d for t h e p r e v i o u s i n s t r u c t i o n s and t h e s c a l e a t t h e t o p o f each page was modi f ied t o r e a d :
"Most f r e q u e n t 10 9 8 7 6 5 4 3 2 1 L e a s t f r e q u e n t . "
A s b e f o r e , s u b j e c t s were t e s t e d i n small g r o u p s of 8 t o 1 0 ; t h e formal i n s t r u c t i o n s were read fo l lowed by v e r b a l emphas is of t h e s a l i e n t p o i n t s o f t h e i n s t r u c t i o n s ; and s u b j e c t s were g i v e n u n l i m i t e d time a l t h o u g h t h e y u s u a l l y completed t h e form i n 1 5 t o 25 minutes . F o r t y - n i n e I n t r o d u c t o r y Psychology s t u d e n t s r a t e d t h i s form.
R e s u l t s
As i n S tudy 8 , a v e r a g e r a t i n g s were t a b u l a t e d by l e t t e r - s t r i n g t y p e f o r each s u b j e c t and f o r e a c h s t i m u l u s item a c r o s s s u b j e c t s . Two a n a l y s e s o f v a r i a n c e were computed on t h e s e d a t a and, a s i n t h e p r e v i o u s r a t i n g s , a l l p o s s i b l e p a i r w i s e comparisons of t h e f o u r anagram c a t e g o r i e s were s i g n i f i c a n t .
APPENDIX 4.9A 119
Appendix 4.9A
D i r e c t i o n s f o r P o s i t i o n a l - F r e q u e n c y R a t i n g s
I t is a r e l a t i v e l y s i m p l e m a t t e r t o d e t e r m i n e t h e f r e q u e n c y w i t h which t h e d i f f e r e n t l e t t e r s of t h e a l p h a b e t a r e used a t v a r i o u s l o c a t i o n s i n words. I t is a n o t h e r m a t t e r t o d e t e r m i n e i f p e o p l e a r e aware of t h i s " p o s i t i o n a l f r e q u e n c y . " On t h e p a g e s which f o l l o w a r e l e t t e r s t r i n g s d e r i v e d by anagramming common E n g l i s h s i x - l e t t e r words. I n some i n s t a n c e s t h e l e t t e r s have been moved t o t h e p o s i t i o n s t h e y most commonly occupy i n s i x - l e t t e r words ( h i g h f requency p o s i t i o n s ) and i n some i n s t a n c e s t h e y have been moved t o l o c a t i o n s t h a t t h e y v e r y i n f r e q u e n t l y occupy i n s i x - l e t t e r words ( low f r e q u e n c y p o s i t i o n s ) . Your t a s k is t o r a t e each s t r i n g on a s c a l e of 1 t o 10 a c c o r d i n g t o how much you b e l i e v e t h a t t h e l e t t e r s i n t h e s t r i n g occupy t h e i r most f r e q u e n t p o s i t i o n s . The h i g h e s t p o s s i b l e r a t i n g ( 1 0 ) s h o u l d be g i v e n t o t h e s t r i n g s whose l e t t e r s a r e i n t h e i r most f r e q u e n t p o s i t i o n s . The l o w e s t r a t i n g (1) s h o u l d be g i v e n t o s t r i n g s whose l e t t e r s a r e i n t h e i r l e a s t f r e q u e n t p o s i t i o n s . The s t r i n g s have been c o n s t r u c t e d s o t h a t some s t r i n g s have a l l t h e i r l e t t e r s i n t h e i r most f r e q u e n t p o s i t i o n s , some s t r i n g s have t h e i r l e t t e r s i n t h e i r l e a s t f r e q u e n t p o s i t i o n s , and t h e remain ing s t r i n g s have l e t t e r s a t a l l v a r i o u s p o s i t i o n s of g r e a t e r o r l e s s e r f r e q u e n c y . Thus you s h o u l d f i n d s t r i n g s a p p r o p r i a t e t o a l l 10 l e v e l s of t h e s c a l e w i t h r o u g h l y e q u a l numbers a t each l e v e l .
Skim over t h e s t r i n g s on t h e f i r s t page b e f o r e you b e g i n r a t i n g so you have an i d e a of t h e i r r a n g e of v a r i a t i o n . There a r e 160 s t r i n g s i n a l l , d i v i d e d randomly a c r o s s f o u r p a g e s , s o each page s h o u l d have roughly t h e same v a r i a t i o n a s any o t h e r . You s h o u l d work a t a f a i r l y q u i c k and even pace even though t h e r e is no time l i m i t .
1 2 0 CHAPTER 4
Appendix 4.10
D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S tudy 10: R e g u l a r i t y v e r s u s P o s i t i o n a l - F r e q u e n c y Pa i red-Judgments
Method
Response forms. The pa i red- judgment forms were p r e p a r e d by f i r s t p a r t i t i o n i n g e a c h of t h e f o u r c a t e g o r i e s of anagrams i n t o f o u r randomly s e l e c t e d s u b s e t s o f 1 0 items e a c h . E i g h t y p a i r s were produced by p a i r i n g t h e 160 anagrams as f o l l o w s : One 10-i tem s u b s e t from each c a t e g o r y was matched t o a 10-i tem s u b s e t from a n o t h e r c a t e g o r y and t h e members of t h e s u b s e t p a i r e d o f f producing between c a t e g o r y p a i r s . T h i s l e f t one 10-i tem s u b s e t w i t h i n each c a t e g o r y whose members were p a i r e d w i t h each o t h e r t o form f i v e w i t h i n c a t e g o r y p a i r s . A t o t a l l i s t of 320 p a i r s was formed by per forming t h i s matching p r o c e d u r e f o u r times, r o t a t i n g t h e mating of t h e s u b s e t s w i t h i n each c a t e g o r y t o a c h i e v e a c o m p l e t e l y c o u n t e r b a l a n c e d l i s t where e v e r y i t e m was p a i r e d once w i t h a member of e v e r y o t h e r c a t e g o r y and once w i t h a member of i t s own c a t e g o r y . E i g h t such t o t a l l y d i f f e r e n t l i s t s were c o n s t r u c t e d and item b a l a n c i n g ( r i g h t - h a n d p a i r member v e r s u s l e f t - h a n d p a i r member) was randomized. The t o t a l e f f e c t was t o e n s u r e t h a t e v e r y item had a n e q u a l o p p o r t u n i t y t o be p a i r e d w i t h any o t h e r item.
Once c o n s t r u c t e d , t h e l i s t s were p r i n t e d w i t h 80 p a i r s p e r page. Each b o o k l e t was p r e f a c e d w i t h a s e t of i n s t r u c t i o n s which e i t h e r gave a d e t a i l e d d e s c r i p t i o n of r e g u l a r i t y o r p o s i t i o n a l f r e q u e n c y . I n both c a s e s , a p p r o p r i a t e examples were i n c l u d e d . The " r e g u l a r i t y " i n s t r u c t i o n s g r o u p chose t h e most r e g u l a r of each p a i r whereas t h e " p o s i t i o n a l - f r e q u e n c y ' ' i n s t r u c t i o n s g r o u p c h o s e t h e member w i t h t h e h i g h e s t p o s i t i o n a l f requency .
S u b j e c t s . F o r t y - e i g h t I n t r o d u c t o r y Psychology s t u d e n t s completed t h e pa i red- judgment t a s k . Of t h e s e r a t e r s , 2 2 r e c e i v e d " r e g u l a r i t y " i n s t r u c t i o n s and 26 r e c e i v e d " p o s i t i o n a l - f r e q u e n c y " i n s t r u c t i o n s . A l l s u b j e c t s r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t a s recompense.
Procedure . A s i n t h e p r e v i o u s r a t i n g s t u d i e s , s u b j e c t s were t e s t e d i n g r o u p s of 1 0 t o 15 and g i v e n u n l i m i t e d time t o complete t h e form. D u e t o t h e somewhat l e n g t h i e r form, s u b j e c t s took 20 t o 30 m i n u t e s t o comple te t h e form. Approximately one-half of t h e g r o u p s r e c e i v e d e x p l i c i t r e g u l a r i t y i n s t r u c t o n s (see Appendix 4.10A) , which d e s c r i b e d
APPENDIX 4.10 1 2 1
l e t t e r sequence r e g u l a r i t y , and r e q u i r e d t h a t t h e more r e g u l a r member of each p a i r be chosen . The remain ing g r o u p s r e c e i v e d e x p l i c i t p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s ( s e e Appendix 4 . 1 0 B ) which d e s c r i b e d s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y and r e q u i r e d t h a t t h e member of each p a i r w i t h t h e h i g h e r o v e r a l l p o s i t i o n a l f r e q u e n c y be chosen . A l l s u b j e c t s w i t h i n a g r o u p r e c e i v e d t h e same i n s t r u c t i o n s .
R e s u l t s
The p r o p o r t i o n s of times t h a t i t e m s from a n anagram c a t e g o r y were chosen over items from t h e same c a t e g o r y o r d i f f e r e n t c a t e g o r i e s a r e shown i n T a b l e 4.5. Table 4 .5 g i v e s t h e p r o p o r t i o n of times an i t e m from t h e column c a t e g o r y was s e l e c t e d when p a i r e d w i t h an i tem from t h e row c a t e g o r y . Comparing t h e two p a n e l s of Table 4.5 w e o b s e r v e t h a t s u b j e c t s i n b o t h i n s t r u c t e d c o n d i t i o n s made c h o i c e s more c o n s i s t e n t w i t h t h e a p p l i c a t i o n of r e g u l a r i t y t h a n w i t h t h e a p p l i c a t i o n of p o s i t i o n a l f r e q u e n c y a l t h o u g h both observed t a b l e s d i f f e r from t h e h y p o t h e s i z e d " p e r f e c t " outcome. Comparing t h e two p a n e l s of Table 4 .5 t o e a c h o t h e r , we see e v i d e n c e a g a i n t h a t s u b j e c t s c a n modify t h e i r judgments s l i g h t l y when g i v e n e x p l i c i t i n s t r u c t i o n s t o a t t e n d t o p o s i t i o n a l f r e q u e n c y .
122 CHAPTER 4
Appendix 4.10A
R e g u l a r i t y I n s t r u c t i o n s f o r Paired-Judgments
Our r e s e a r c h is d i r e c t e d a t d i s c o v e r i n g what it is we know a b o u t E n g l i s h words t h a t a l l o w s u s t o l o o k a t m e a n i n g l e s s s t r i n g s of l e t t e r s and judge how much t h e y resemble words. I n t r y i n g t o unders tand t h e s t r u c t u r e p r e s e n t i n words, we have focused on an i m p o r t a n t component p r o p e r t y - - r e g u l a r i t y o f l e t t e r sequencing . For example, t h e r e a r e many c o n s o n a n t sequences which begin words ( e . g . , @, a, e, th, e, e tc . ) and which end words ( e . g . , 9, el =, *, e t c . ) . There a r e common vowel sequences a s w e l l ( e . g . , 00, 9, G, sf e t c . ) . F i n a l l y , . t h e r e is r e g u l a r i t y i n how t h e s e c o n s o n a n t s and vowel g r o u p i n g s a r e t h e m s e l v e s sequenced w i t h i n words.
On t h e pages which f o l l o w a r e 320 p a i r s of m e a n i n g l e s s s i x - l e t t e r s t r i n g s which have been c o n s t r u c t e d t o v a r y a l o n g t h i s d imens ion of l e t t e r sequence r e g u l a r i t y . That is , some s t r i n g s p r e s e r v e normal l e t t e r sequencing w h i l e o t h e r s v i o l a t e normal sequencing t o a l e s s e r or g r e a t e r d e g r e e . The o b j e c t of t h i s e x p e r i m e n t is t o d e t e r m i n e t h e e x t e n t o f your knowledge by having you se lec t t h e more r e g u l a r s t r i n g i n each p a i r . You a r e t o e v a l u a t e b o t h members o f each p a i r and choose t h e one t h a t is more p e r m i s s i b l e i n te rms of r e g u l a r i t y of l e t t e r sequencing .
Before you b e g i n , s k i m o v e r t h e p a i r s on t h e f i r s t page t o g e t a f e e l f o r t h e t a s k . Once you b e g i n , t r y t o work a t a f a i r l y s t e a d y pace and n o t d w e l l t o o long on t h e p a i r s you f i n d d i f f i c u l t . You m u s t make a c h o i c e f o r each p a i r , g u e s s i n g i f n e c e s s a r y . Have you any q u e s t i o n s ?
APPENDIX 4.10B 123
Appendix 4.10B
P o s i t i o n a l - F r e q u e n c y I n s t r u c t i o n s f o r Pa i red-Judgments
Our r e s e a r c h is d i r e c t e d a t d i s c o v e r i n g what it is we know a b o u t E n g l i s h words t h a t a l l o w s u s t o look a t m e a n i n g l e s s s t r i n g s of l e t t e r s and judge how much t h e y resemble words. I n t r y i n g t o u n d e r s t a n d t h e s t r u c t u r e p r e s e n t i n words, w e have focused on an i m p o r t a n t component p r o p e r t y - - l e t t e r f r e q u e n c y . I n d i v i d u a l l e t t e r s and g r o u p s o f l e t t e r s occur w i t h v a r y i n g f r e q u e n c y a t d i f f e r e n t p o s i t i o n s w i t h i n words. For example, you can p r o b a b l y t h i n k o f words t h a t end i n fi and words t h a t end i n y, b u t fi is 10 t i m e s more f r e q u e n t t h a n y i n f i n a l p o s i t i o n . L i k e w i s e , 9 and & both occur a t t h e beginning of words, b u t is 50 times as f r e q u e n t i n i n i t i a l p o s i t i o n . I n g e n e r a l , c o n s o n a n t s a r e more f r e q u e n t t h a n vowels a t word i n i t i a l and word f i n a l p o s i t i o n s w i t h t h e e x c e p t i o n of f i n a l e , and s o on.
On t h e p a g e s which f o l l o w a r e 320 p a i r s of m e a n i n g l e s s s i x - l e t t e r s t r i n g s which have been c o n s t r u c t e d t o v a r y a l o n g t h e d imens ion of l e t t e r f r e q u e n c y by p o s i t i o n . That i s , some s t r i n g s have been c r e a t e d by p l a c i n g each l e t t e r i n i t s most f r e q u e n t p o s i t i o n i n s i x - l e t t e r E n g l i s h words. O t h e r s have t h e i r l e t t e r s p l a c e d i n l e s s f r e q u e n t p o s i t i o n s and s t i l l o t h e r s have t h e i r l e t t e r s i n t h e i r l e a s t f r e q u e n t p o s i t i o n s .
The o b j e c t of t h i s e x p e r i m e n t is t o d e t e r m i n e how w e l l you c a n judge when l e t t e r s a r e i n t h e i r most f r e q u e n t p o s i t i o n s . You a r e t o e v a l u a t e both members of each p a i r and choose t h e more " f r e q u e n t " of t h e two, e . g . , t h e s t r i n g which a p p e a r s t o have more of i ts l e t t e r s i n t h e i r more f r e q u e n t p o s i t i o n s .
Before you b e g i n , s k i m over t h e p a i r s on t h e f i r s t page t o g e t a f e e l f o r t h e t a s k . Once you b e g i n , t r y t o work a t a f a i r l y s t e a d y pace and n o t t o d w e l l t o o long on t h e p a i r s you f i n d d i f f i c u l t . You m u s t make a c h o i c e f o r e a c h p a i r , g u e s s i n g i f n e c e s s a r y . Have you any q u e s t i o n s ?
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5 Structural Descriptions
To p r o v i d e a more d e t a i l e d a n a l y s i s of o r t h o g r a p h i c s t r u c t u r e e f f e c t s , we conducted p o s t hoc c o r r e l a t i o n a l a n a l y s e s of t h e p e r c e p t u a l r e c o g n i t i o n and o v e r t judgment d a t a r e p o r t e d i n Chapter 4 . The independent v a r i a b l e s were based upon v a r i o u s f r e q u e n c y and r e g u l a r i t y measures . Even though f i r m c o n c l u s i o n s might n o t be r e a c h e d , we f e l t t h a t our sample of items was s u f f i c i e n t l y l a r g e and s u f f i c i e n t l y r e p r e s e n t a t i v e t h a t t h e s e c o r r e l a t i o n a l a n a l y s e s c o u l d p r o v i d e v a l i d i n d i c a t i o n s of which measures might w a r r a n t f u r t h e r t h e o r e t i c a l and e m p i r i c a l examinat ion .
Three dependent measures were d e r i v e d from t h e e x p e r i m e n t s r e p o r t e d i n Chapter 4 f o r each o f t h e 200 s t i m u l u s items, i . e . , t h e 40 words and t h e i r 4 anagrams. The f i r s t measure was t h e mean a c c u r a c y f o r each i tem averaged a c r o s s a l l t r i a l o c c u r r e n c e s i n t h e p o s t c u e a c c u r a c y exper iment of S tudy 1: I n i t i a l R e p l i c a t i o n and t h e precue and p o s t c u e e x p e r i m e n t s of S tudy 2: P r e c u e v e r s u s P o s t c u e . A c o r r e s p o n d i n g r e a c t i o n time (RT) measure was d e r i v e d by a v e r a g i n g t h e RTs f o r a l l t r i a l o c c u r r e n c e s o f each item i n t h e r e a c t i o n time e x p e r i m e n t s of S tudy 1: I n i t i a l R e p l i c a t i o n and Study 3 : Mixed-Case. The t h i r d measure was t h e a v e r a g e r a t i n g s from one of t h e r a t i n g e x p e r i m e n t s i n S tudy 8: T y p i c a l i t y R a t i n g s . The e x p e r i m e n t was t h e one i n which t h e words t h e m s e l v e s were r a t e d a l o n g w i t h t h e 160 anagrams. Each of t h e 200 s t i m u l u s items a l o n g w i t h i t s r e s p e c t i v e a c c u r a c y , r e a c t i o n t i m e , and r a t i n g i s p r e s e n t e d i n Appendix 5.1.
As d i s c u s s e d i n Chapter 3 , a l a r g e number of measures of o r t h o g r a p h i c s t r u c t u r e based upon c o u n t s of l e t t e r , “-gram, and word f r e q u e n c i e s may be computed. Q u a n t i t a t i v e measures based upon o r t h o g r a p h i c r u l e s a r e less r e a d i l y c o n s t r u c t e d . Although
126 CHAPTER 5
we d e v i s e d and t e s t e d one measure of r e g u l a r i t y based upon t h e r u l e s o u t l i n e d i n Chapter 3 , w e c o n c e n t r a t e d upon f r e q u e n c y measures and q u e s t i o n s r e l a t e d t o t h e i r c o n s t r u c t i o n . The s p e c i f i c issues were a s f o l l o w s . Should f r e q u e n c y c o u n t s be based upon c o u n t s of word t y p e s o r word t o k e n s ? What f r e q u e n c y s c a l e g i v e s t h e most p r e d i c t i v e index of per formance , raw f requency o r some t r a n s f o r m e d f requency s c a l e such as l o g f requency? Is p o s i t i o n a l dependency, i . e . , whether t h e c o u n t s p r e s e r v e p o s i t i o n of t h e "-gram i n t h e sampled word, a n i m p o r t a n t f a c t o r ? What "-gram u n i t g i v e s t h e most powerfu l measure: s i n g l e - l e t t e r , b igram, o r t r i g r a m c o u n t s ? What is t h e c o n t r i b u t i o n of l e x i c a l s t a t u s and word f r e q u e n c y t o performance? And f i n a l l y , what method of combining t h e f r e q u e n c i e s of t h e components of a l e t t e r s t r i n g p r o v i d e t h e b e s t o v e r a l l index of i ts s t r u c t u r e ? These q u e s t i o n s w i l l be d i s c u s s e d i n t h e f o l l o w i n g s e c t i o n s .
DESCRIPTIVE MEASURES
The s o u r c e of a l l our f requency measures is a word c o r p u s sampled by Kucera and F r a n c i s ( 1 9 6 7 ) . T h i s c o r p u s c o n s i s t e d of 500 samples o f a p p r o x i m a t e l y 2,000 words e a c h s e l e c t e d from 1 5 c a t e g o r i e s . A d e s c r i p t i o n of t h e c o r p u s , i t s s e l e c t i o n , and i t s p r o c e s s i n g a r e p r e s e n t e d by Kucera and F r a n c i s . We o b t a i n e d a magnet ic t a p e of t h e word c o u n t produced from t h e c o r p u s ( i . e . , t h e "Rank L i s t " i n t h e Kucera and F r a n c i s monograph). The words were s o r t e d i n t o 10 l i s t s c o n s i s t i n g of 1- t o 1 0 - l e t t e r words r e s p e c t i v e l y . Words l o n g e r t h a n 10 c h a r a c t e r s were d e l e t e d a s were items c o n t a i n i n g numbers, p u n c t u a t i o n , o r s p e c i a l c o d i n g s f o r c a p i t a l i z a t i o n s , f o r e i g n a l p h a b e t s , and unusual g r a p h i c f e a t u r e s o r symbols. T h i s r e s u l t e d i n 10 l i s t s of words, one f o r each l e t t e r l e n g t h . These word l ists formed t h e b a s i s f o r c o u n t s of s i n g l e l e t t e r s , b igrams, and t r i g r a m s .
T a b l e s were p r e p a r e d by c o u n t i n g t h e o c c u r r e n c e of each - n-gram a t t h e p o s i t i o n it o c c u r r e d i n words o f a g i v e n l e n g t h . Two c o u n t s were o t a i n e d . One was a t y p e c o u n t based upon t h e number of word t y p e s t h a t c o n t a i n e d a g i v e n E-gram, and t h e o t h e r was a token c o u n t based upon t h e t o t a l number of o c c u r r e n c e s of t h e word c o n t a i n i n g t h e "-gram. A p o s i t i o n - i n s e n s i t i v e c o u n t ( b u t s t i l l word l e n g t h d e p e n d e n t ) was a l s o o b t a i n e d f o r each "-gram by summing a c r o s s t h e
ORTHOGRAPHIC STRUCTURE AND R E C O G N I T I O N 1 2 7
p o s i t i o n - d e p e n d e n t c o u n t s . B e c a u s e Kuce ra and F r a n c i s m a i n t a i n e d a f a i t h f u l c o u n t o f t h e a c t u a l g r a p h i c p a t t e r n s found i n t h e c o r p u s , t h e i r l i s t c o n t a i n s r a r e w o r d s , t y p o g r a p h i c e r r o r s , f o r e i g n p e r s o n and p l a c e names, and o t h e r i d e o s y n c r a t i c i t ems . To l i m i t t h e i m p a c t o f s u c h items on o u r t a b u l a t i o n s , c u t - o f f l i m i t s were e s t a b l i s h e d f o r b o t h word f r e q u e n c y and number o f s a m p l e s . The c u t - o f f s were a minimum c o u n t o f a t l e a s t o n e o c c u r r e n c e i n t h r e e o f t h e 500 s a m p l e s . Thus , u n u s u a l words and u s a g e s , r e g a r d l e s s o f t h e i r f r e q u e n c y , were i g n o r e d u n l e s s t h e y o c c u r r e d i n t h r e e o r more s e p a r a t e s a m p l e s . I n t h i s way, w o r d s w i t h t h e minimum f r e q u e n c y o f t h r e e were c o u n t e d o n l y i f t h e y o c c u r r e d o n c e i n e a c h o f t h r e e s a m p l e s . A l t h o u g h t h i s l i m i t was a r b i t r a r y , i n s p e c t i o n o f t h e word l i s t i n t h e low f r e q u e n c y r a n g e i n d i c a t e d t h a t t h e s e were r e a s o n a b l e c u t - o f f s . The s i n g l e - l e t t e r t o k e n c o u n t s f o r word l e n g t h s 3 t h r o u g h 7 and t h e b i g r a m t o k e n c o u n t s f o r word l e n g t h s 3 t h r o u g h 7 a r e p r e s e n t e d a s A p p e n d i c e s 5 .2 and 5 . 3 , r e s p e c t i v e 1 y .
A l l o f t h e f r e q u e n c y m e a s u r e s t h a t w i l l b e d i s c u s s e d were d e r i v e d from t h e s e t a b l e s w i t h two e x c e p t i o n s , word f r e q u e n c y and E n g l i s h n e s s . The f r e q u e n c i e s o f t h e 40 w o r d s were t a k e n d i r e c t l y f rom t h e Kucera and F r a n c i s c o u n t . E n g l i s h n e s s is a m e a s u r e p r o p o s e d b y T r a v e r s and O l i v i e r ( 1 9 7 8 ) and was computed from t a b l e s s u p p l i e d t o u s by t h e a u t h o r s . E n g l i s h n e s s is a c o n t i n u e d p r o d u c t o f ;-gram p r o b a b i l i t i e s e s t i m a t e d t o t h e l e v e l o f t h i r d - o r d e r t r a n s i t i o n a l p r o b a b i l i t i e s . The f o r m u l a f o r s i x - l e t t e r words o r l e t t e r s t r i n g s i s a s f o l l o w s :
E n g l i s h n e s s (#LlL2L3L4L5L6#) =
- l o g [P(L11#)*P(L2l#Ll)*P(L3lLlL2)* P(L41L2L3)*P(L51L3L4)*P(L61L4L5)1 ( 4 )
where # r e p r e s e n t s a s p a c e and L i is t h e l e t t e r a t p o s i t i o n i . The term P ( L k l L ( k - Z ) L ( k - l ) ) i s e s t i m a t e d by t h e r a t i o o f t h e t r i g r a m f r e q u e n c y o f L ( k - Z ) L ( k - l ) L k t o t h e b i g r a m f r e q u e n c y L ( k - Z ) L ( k - l ) . I t s h o u l d b e n o t e d t h a t t h e s e f r e q u e n c y e s t i m a t e s a r e n o t p o s i t i o n s e n s i t i v e e x c e p t i n a s much a s t h e y a r e t i e d t o i n i t i a l p o s i t i o n o c c u r r e n c e s , i . e . , t h e i n i t i a l t r i g r a m # L 1 L 2 and i n i t i a l b i g r a m # L 1 . The c o u n t s a r e a l s o n o t w o r d - l e n g t h s p e c i f i c . The i n i t i a l term P ( L i l # ) i n t h e f o r m u l a is a c t u a l l y t h e f r e q u e n c y o f t h e i n i t i a l l e t t e r a s i t o c c u r s i n t h e f i r s t p o s i t i o n i n words o f a n y l e n g t h . The r a t i o n a l e f o r examin ing t h i s measure is t o p r o v i d e a c o m p a r i s o n t o t h e o t h e r f r e q u e n c y m e a s u r e s we w i l l examine . T r a v e r s and O l i v i e r ( 1 9 7 8 ) p r o v i d e d some e v i d e n c e t h a t t h e m e a s u r e had success i n
128 CHAPTER 5
d e s c r i b i n g performance i n a f u l l r e p o r t o f s h o r t p r e s e n t a t i o n s of l e t t e r s t r i n g s .
Our r e g u l a r i t y measure c o n s i s t e d of a c o u n t of t h e number of i r r e g u l a r i t i e s c o n t a i n e d i n each of t h e 2 0 0 s t i m u l u s items. T h e e x a c t r u l e s f o r t h e i r r e g u l a r i t y c o u n t a r e g i v e n i n T a b l e 5 .1 . An i r r e g u l a r i t y was counted f o r e a c h v i o l a t i o n of c e r t a i n s c r i b a l c o n s t r a i n t s , f o r each i m p e r m i s s i b l e vowel c l u s t e r and f o r each i m p o s s i b l e consonant c l u s t e r when c o n s i d e r e d a s p a r t of a monosyl lab le . The items were t r e a t e d a s m o n o s y l l a b l e s because a n a p p r o p r i a t e s y l l a b i c a t i o n is d i f f i c u l t t o impose on nonsense s t r i n g s . Without r i g i d c r i t e r i a , judgments f o r some anagrams would be u n r e a s o n a b l y a r b i t r a r y . Thus, we c h o s e t o t r e a t a l l s t r i n g s a s monosyl lab ic even though t h i s r e q u i r e d c l a s s i f i c a t i o n of some two s y l l a b l e words as c o n t a i n i n g i r r e g u l a r i t i e s a t s y l l a b l e b o u n d a r i e s . The c o u n t s of i r r e g u l a r i t i e s f o r e a c h of t h e items o f e a c h of t h e f i v e s t i m u l u s c a t e g o r i e s a r e shown i n Appendix 5.1.
TYPE VERSUS TOKEN COUNTS
The f i r s t g e n e r a l i ssue i n d e r i v i n g a f r e q u e n c y measure is whether t y p e c o u n t s or t o k e n c o u n t s a r e most a p p r o p r i a t e . C e r t a i n l y , t h e two methods of c o u n t i n g w i l l produce f requency measures t h a t have some d e g r e e of c o r r e l a t i o n . Even though it is p r o b a b l y p o s s i b l e t o f i n d o c c u r r e n c e s of “-grams o c c u r r i n g i n o n l y a small number of e x t r e m e l y f r e q u e n t words and o t h e r E-grams o c c u r r i n g i n many i n f r e q u e n t word t y p e s , on t h e a v e r a g e t h e g r e a t e r t h e t y p e count t h e g r e a t e r t h e t o k e n c o u n t . Only by examining s i t u a t i o n s where t h e two measures a r e r e l a t i v e l y u n c o r r e l a t e d can t h e importance of t h e two approaches be measured. T h u s , i f our items e x h i b i t a s t r o n g c o r r e l a t i o n between type- and token-based measures l i t t l e c a n be d e t e r m i n e d from our d a t a t o s u p p o r t one over t h e o t h e r . A t t h e same time, i f our sample is r e p r e s e n t a t i v e of a wide range of l e t t e r s t r i n g s and t h e two approaches a r e h i g h l y c o r r e l a t e d , t h e q u e s t i o n may be of no p r a c t i c a l s i g n i f i c a n c e . I n any s i t u a t i o n where such a measure would be u s e f u l , e i t h e r might be used w i t h e s s e n t i a l l y i d e n t i c a l e f f e c t .
We found t h a t t h e c o r r e l a t i o n s between comparable t y p e measures and token measures f o r our sample were v e r y h i g h . Measures based on s i n g l e l e t t e r s , b igrams, and t r i g r a m s ,
ORTHOGRAPHIC STRUCTURE AND RECOGNITION 129
Table 5 . 1 The r u l e s f o r t h e i r r e g u l a r i t y c o u n t of t h e 2 0 0 s t i m u l u s i t e m s
1.
2 .
3 .
4 .
5.
6.
7.
8.
Segment s t r i n g i n t o vowel and consonant s u b s t r i n g s . T rea t f i n a l -& a s i f i t were -9. T r e a t between vowels as a ( l e g a l ) consonant .
For each consonant s t r i n g , d e t e r m i n e minimal number of vowels which m u s t be i n s e r t e d t o make t h e s t r i n g pronounceable . I n i t i a l consonant c l u s t e r s m u s t be l e g a l i n i n i t i a l p o s i t i o n . F i n a l consonant c l u s t e r s m u s t be l e g a l i n f i n a l p o s i t i o n , i n c l u d i n g t h o s e f o l l o w e d by f i n a l - e . Medial c o n s o n a n t c l u s t e r s m u s t be l e g a l i n i n i t i a l p o s i t i o n .
Rate e a c h r e s u l t i n g c o n s o n a n t s u b s t r i n g f o r p o s i t i o n - s e n s i t i v e s c r i b a l r e g u l a r i t y ( c o u n t one f o r e a c h i r r e g u l a r s u b s t r i n g ) .
For each vowel s u b s t r i n g , d e t e r m i n e minimal number of c o n s o n a n t s which m u s t be i n s e r t e d t o c r e a t e s c r i b a l l y r e g u l a r sequences . Mark a s i r r e g u l a r i l l e g a l i n i t i a l and f i n a l vowel s u b s t r i n g s .
Count number of i n s e r t e d vowels and c o n s o n a n t s , p l u s number of s c r i b a l l y i r r e g u l a r consonant and vowel s u b s t r i n g s . T h i s y i e l d s an i r r e g u l a r i t y index .
The vowel s t r i n g s ", E, s, and (among more o b v i o u s c a s e s ) would be i l l e g a l vowel s t r i n g s . y would be i l l e g a l a s a vowel i n i n i t i a l p o s i t i o n and i, 2 , a, E, and 9 would be i l l e g a l i n f i n a l p o s t i o n . is l e g a l a s is y a s a s i n g l e , n o n - i n i t i a l vowel.
- h i s n o t a l lowed i n f i n a l p o s i t i o n u n l e s s preceded by c , 9, Or S .
y and y between vowels a r e t o be counted a s c o n s o n a n t s .
1 3 0 CHAPTER 5
both p o s i t i o n s e n s i t i v e and p o s i t i o n i n s e n s i t i v e , c o r r e l a t e d between . 8 4 and .99. With such h igh c o r r e l a t i o n s no meaningfu l d i s c r i m i n a t i o n can be made between t h e two approaches . F i g u r e 5 .1 shows some 5-gram c o r r e l a t i o n s based on t y p e and t o k e n c o u n t s : t h e two s e t s of c o u n t s g i v e h i g h l y s i m i l a r c o r r e l a t i o n s . For t h i s r e a s o n , u n l e s s o t h e r w i s e s t a t e d , we w i l l d i s c u s s o n l y measures based on t o k e n c o u n t s i n t h e remainder of t h i s c h a p t e r .
SCALE OF FREQUENCY
T h i s a n a l y s i s c o n c e r n s t h e f requency s c a l e t o be chosen i n computing f requency measures . While t h e e f f e c t s of f r e q u e n c y
Accuracy
0 Bigram Trigram B
I I I
LINEAR LOG LINEAR LOC
TYPE TOKEN
F i g u r e 5 . 1 C o r r e l a t i o n s of a c c u r a c y and r e a c t i o n times a s a f u n c t i o n of l i n e a r o r l o g and t y p e o r t o k e n p o s i t i o n - s e n s i t i v e s i n g l e - l e t t e r , b igram, and t r i g r a m c o u n t s .
ORTHOGRAPHIC STRUCTURE AND RECOGNITION 1 3 1
seem t o be p s y c h o l o g i c a l l y r e a l , i t is n o t n e c e s s a r y t h a t t h e m e n t a l r e p r e s e n t a t i o n s o f f r e q u e n c y d i r e c t l y r e f l e c t t h e f r e q u e n c y o f o b j e c t i v e c o u n t s . One a l t e r n a t i v e s c a l e t h a t h a s b e e n s u c c e s s f u l i n o t h e r r e s e a r c h i s a l o g a r i t h m i c ( b a s e 10) s c a l e . Not o n l y a r e t h e r e some d a t a t o s u g g e s t t h e p o s s i b i l i t y o f a l o g a r i t h m i c r e p r e s e n t a t i o n (Solomon 6, Pos tman , 1952 ; T a y l o r , 1977 ; T r a v e r s & O l i v i e r , 1 9 7 8 ) , b u t a l s o a l o g a r i t h m i c r e p r e s e n t a t i o n is c o n s i s t e n t w i t h r e c e n t s t u d i e s o f number r e p r e s e n t a t i o n ( S h e p a r d , 1 9 7 8 ) and w i t h many o t h e r p s y c h o l o g i c a l s c a l e s . T h e r e f o r e , w e computed a l l o f o u r f r e q u e n c y m e a s u r e s b a s e d upon b o t h r e g u l a r l i n e a r f r e q u e n c i e s and l o g f r e q u e n c i e s . F o r t h e s e m e a s u r e s , and a l l t r a n s f o r m e d s c a l e s ( t o b e d i s c u s s e d ) , l i n e a r - f r e q u e n c y t a b l e s f o r t h e p o s i t i o n - d e p e n d e n t "-grams were n o t r e s c a l e d b e f o r e m e a s u r e s were computed f o r a n y i tem. T h e r e f o r e , t h e two s e t s o f m e a s u r e s b e i n g c o r r e l a t e d were s u m s o f p o s i t i o n - d e p e n d e n t s i n g l e l e t t e r s , b i g r a m s , and t r i g r a m s d e r i v e d from e i t h e r l i n e a r - f r e q u e n c y o r l o g - f r e q u e n c y t a b l e s . I n n e a r l y e v e r y i n s t a n c e t h e l o g - f r e q u e n c y m e a s u r e was more h i g h l y c o r r e l a t e d w i t h t h e p e r f o r m a n c e m e a s u r e t h a n was l i n e a r f r e q u e n c y ( s e e , f o r e x a m p l e , F i g u r e 5 . 1 ) .
A l t h o u g h l o g f r e q u e n c i e s , f o r p u r p o s e s o f d e s c r i b i n g t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e on r e c o g n i t i o n p e r f o r m a n c e , were b e t t e r t h a n l i n e a r f r e q u e n c i e s , w e were a l s o i n t e r e s t e d i n compar ing t h e l o g s c a l e w i t h o t h e r t r a n s f o r m a t i o n s o f t h e l i n e a r f r e q e n c i e s . For t h i s i n v e s t i g a t i o n , w e c h o s e o u r b e s t f r e q u e n c y m e a s u r e , summed t o k e n p o s i t i o n - s e n s i t i v e b i g r a m s , and a p p l i e d a r a n g e o f t r a n s f o r m a t i o n s t o i t . A power f u n c t i o n o f t h e form
X y = a (5)
g a v e v a r i o u s s c a l e s d e p e n d i n g on t h e v a l u e o f t h e e x p o n e n t x . E x p o n e n t s o f 0 . 8 , 0 . 7 , 0 . 5 , 0 . 2 , and 0 . 1 were s e l e c t e d . The 0 .2 e x p o n e n t a p p r o x i m a t e s t h e l o g f u n c t i o n v e r y c l o s e l y i n t h e r a n g e o f f r e q u e n c y v a l u e s r e p r e s e n t e d by o u r s t i m l u i . The l a r g e r e x p o n e n t s y i e l d e d v a l u e s i n t e r m e d i a t e be tween t h o s e o f t h e l i n e a r and l o g s c a l e s w h i l e t h e 0 . 1 e x p o n e n t p roduced v a l u e s more e x t r e m e t h a n t h e l o g f u n c t i o n . The c o r r e l a t i o n b e t w e e n t h e s e b i g r a m m e a s u r e s and t h r e e p e r f o r m a n c e m e a s u r e s g rew m o n o t o n i c a l l y f rom t h e l i n e a r s c a l e m e a s u r e t o t h e l o g and 0.2 e x p o n e n t power f u n c t i o n where c o r r e l a t i o n s peaked and t h e n f e l l f o r ' t h e more e x t r e m e 0.1 e x p o n e n t power f u n c t i o n . The c o r r e l a t i o n s be tween a v e r a g e a c c u r a c y and t h e s e b i g r a m m e a s u r e s were . 6 3 f o r t h e l i n e a r s c a l e ; .77 f o r t h e l o g s c a l e ; and .68,
132 CHAPTER 5
.70, .74 , .77 , .75 f o r exponents of 0 . 8 , 0 .7 , 0 . 5 , 0 .2 , and 0 . 1 r e s p e c t i v e l y . These d a t a i n d i c a t e t h a t i f f requency measures a r e u t i l i z e d by t h e r e a d e r , t h e y appear t o be computed on l o g f r e q u e n c i e s , and so o n l y log- f requency measures w i l l be d i s c u s s e d f u r t h e r .
POSITION-SENSITIVE VERSUS POSITION-INSENSITIVE COUNTS
There have been many a t t e m p t s t o d e r i v e a measure of p e r c e p t a b i l i t y based upon p o s i t i o n - i n s e n s i t i v e f r e q u e n c y c o u n t s (Gibson 1964; Gibson, e t a l . , 1970; Postman & Conger, 1954; Spoehr & Smith , 1 9 7 5 ) . These a t t e m p t s have t y p i c a l l y shown t h a t c o u n t s t h a t accumula te f r e q u e n c i e s w i t h o u t r e g a r d t o p o s i t i o n g i v e i n a d e q u a t e measures . On t h e o t h e r hand, p o s i t i o n - s e n s i t i v e measures have r e c e i v e d some s u p p o r t as y i e l d i n g b e t t e r measures (Gibson e t a l . , 1970; Mason, 1975, McClelland & J o h n s t o n , 1 9 7 7 ) . We compared t h e two t y p e s of measures a g a i n s t our d a t a . Table 5 .2 shows t h e c o r r e l a t i o n s between t h e t h r e e per formance measures w i t h s i n g l e - l e t t e r , b igram, and t r i g r a m c o u n t s d e r i v e d from both p o s i t i o n - s e n s i t i v e and p o s i t i o n - i n s e n s i t i v e c o u n t s . The s t r i k i n g d i f f e r e n c e i n t h i s t a b l e is between t h e two d i f f e r e n t s i n g l e - l e t t e r measures . A s noted by e a r l i e r r e s e a r c h e r s ( e . g . , Postman & Conger, 1 9 5 4 ) , o v e r a l l l e t t e r f r e q u e n c y w i t h o u t r e g a r d t o p o s i t i o n i s n o t a v e r y powerfu l p r e d i c t o r of r e c o g n i t i o n performance. By c o n t r a s t , a p o s i t i o n - d e p e n d e n t s i n g l e - l e t t e r measure is a l m o s t a s powerfu l a s p o s i t i o n - i n s e n s i t i v e b igrams and t r i g r a m s f o r d e s c r i b i n g a c c u r a c y and RT. I t s h o u l d be noted t h a t p o s i t i o n - i n s e n s i t i v e c o u n t s d o b e t t e r a s t h e =-gram's l e n g t h i n c r e a s e s . For "-grams of a g i v e n l e n g t h , p o s i t i o n dependence seems t o l e a d t o a b e t t e r index of s t r u c t u r e a l t h o u g h t h e advantage is e s s e n t i a l l y e l i m i n a t e d f o r t r i g r a m c o u n t s . The a p p a r e n t s u p e r i o r i t y of p o s i t i o n - s e n s i t i v e bigrams over p o s i t i o n - s e n s i t i v e t r i g r a m s w i l l be d i s c u s s e d n e x t . For t h e remainder of t h e s e a n a l y s e s , p o s i t i o n - s e n s i t i v e c o u n t s w i l l be used.
ORTHOGRAPHIC STRUCTURE A N D RECOGNITION 1 3 3
T a b l e 5 .2 C o r r e l a t i o n s be tween t h e t h r e e d e p e n d e n t m e a s u r e s and summed l o g f r e q u e n c y c o u n t s , b o t h p o s i t i o n d e p e n d e n t and p o s i t i o n i n d e p e n d e n t .
!&pe o f F r e q u e n c y Measure Dependen t M e a s u r e s
RT R a t i n q A c c u r a c y - P o s i t i o n I n d e p e n d e n t
S i n g l e L e t t e r . 2 0 - . 3 6 . 0 4
Bigram . 5 9 - .55 . 7 3
T r i g r a m . 6 8 - .57 . 8 4
P o s i t i o n Dependen t
S i n g l e L e t t e r . 6 2
Bigram . 7 7
T r i g r am . 7 5
- .48 . 4 5
- . 6 4 . 8 3
- . 5 4 . 8 0
THE MOST EFFECTIVE FREQUENCY MEASURE
We h a v e n o t e d t h a t summed p o s i t i o n - s e n s i t i v e l o g b i g r a m f r e q u e n c i e s had t h e h i g h e s t c o r r e l a t i o n s w i t h our t h r e e p e r f o r m a n c e m e a s u r e s . T h i s measure, i n f a c t , had t h e h i g h e s t c o r r e l a t i o n s o f a n y of t h e a l m o s t 5 0 f o r m s o f f r e q u e n c y m e a s u r e s t h a t w e examined . Fo r e x a m p l e , p o s i t i o n - s e n s i t i v e s i n g l e l e t t e r s a c c o u n t f o r a n a v e r a g e o f 2 9 % o f t h e v a r i a n c e i n o u r t h r e e p e r f o r m a n c e m e a s u r e s , w h i l e p o s i t i o n - s e n s i t i v e b i g r a m s a c c o u n t f o r 5 7 % . A l t h o u g h it m i g h t b e e x p e c t e d t h a t l a r g e r !-grams s h o u l d n a t u r a l l y c a p t u r e more o r t h o g r a p h i c s t r u c t u r e t h a n s m a l l e r E-grams, we o b s e r v e d t h a t p o s i t i o n - s e n s i t i v e b i g r a m c o u n t s o f s e v e r a l k i n d s ( d i s c u s s e d be low) were b e t t e r t h a n c o m p a r a b l e f r e q u e n c y m e a s u r e s b a s e d
1 3 4 CHAPTER 5
upon t r i g r a m s . I t is p o s s i b l e t o h y p o t h e s i z e s e v e r a l r e a s o n s why t h i s s h o u l d be t h e c a s e . F i r s t , t h e sampling e r r o r i n t h e t r i g r a m t a b l e s may be l a r g e enough r e l a t i v e t o t h e sampling e r r o r i n t h e bigram t a b l e s t o a c c o u n t f o r t h e e f f e c t . The rough e q u i v a l e n c e between p o s i t ion- independent and p o s i t i o n - d e p e n d e n t t r i g r a m c o u n t s might have r e s u l t e d from a t r a d e - o f f between t h e a d v a n t a g e of p o s i t i o n s e n s i t i v i t y and t h e l a r g e r e r r o r v a r i a n c e f o r p o s i t i o n - s e n s i t i v e c o u n t s . Second, t r i g r a m s s imply may have reached a p o i n t of d i m i n i s h i n g r e t u r n s . With b igrams a c c o u n t i n g f o r 5 7 % of t h e v a r i a n c e , t h e r e s imply may be no room f o r n o t i c e a b l e improvements w i t h l a r g e r "-gram measures . F i n a l l y , i t c o u l d be t h a t bigram c o u n t s a r e more r e p r e s e n t a t i v e of t h e r e a d e r ' s knowledge and u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e . We w i l l r e t u r n t o t h i s q u e s t i o n i n a l a t e r s e c t i o n of t h i s c h a p t e r .
The measures t h a t have been d i s c u s s e d were based upon t h e s u m of t h e f r e q u e n c i e s f o r t h e component "-grams i n a l e t t e r s t r i n g . E n g l i s h n e s s was d e s c r i b e d a s a p r o d u c t of f r e q u e n c y r a t i o s and would appear t o p r o v i d e an i n t e r e s t i n g comparison i n te rms of how a f r e q u e n c y measure s h o u l d be computed from component "-gram f r e q u e n c i e s . The o b s e r v a t i o n t h a t l o g f requency i s a b e t t e r s c a l e narrows t h e d i s t a n c e between E n g l i s h n e s s and summed "-gram measures s i n c e E n g l i s h n e s s is computed a s t h e s u m o f t h e l o g a r i t h m s of f requency r a t i o s . I n a c t u a l compar ison , E n g l i s h n e s s proved t o be a l e s s powerfu l measure t h a n t h e p o s i t i o n - d e p e n d e n t bigram measure. I t c o r r e l a t e d - . 6 5 w i t h a v e r a g e a c c u r a c y , . 4 7 w i t h a v e r a g e RT, and - . a 2 w i t h t h e r a t i n g s .
I t o c c u r r e d t o u s t h a t t h e n o r m a l i z a t i o n p r o c e s s of d i v i d i n g a t r i g r a m f r e q u e n c y by t h e t o t a l f requency o f a l l r e l a t e d t r i g r a m s might have t h e p o t e n t i a l f o r producing an e x t r e m e l y powerfu l measure. That is e s s e n t i a l l y what E n g l i s h n e s s does e x c e p t t h a t it is based upon p o s i t i o n - i n s e n s i t i v e c o u n t s . T h i s would make p a r t i c u l a r l y good t h e o r e t i c a l s e n s e i n t h e case where p a r t i a l v i s u a l i n f o r m a t i o n was a v a i l a b l e and was used t o r e s o l v e O K e s t i m a t e unknown l e t t e r s . For example, i f some t r i g r a m xyz is c o n s i d e r e d a t some p o i n t i n a l e t t e r s t r i n g , t h e p r e d i c t a b i l i t y of z g i v e n t h e p r e c e e d i n g l e t t e r s xy is a f u n c t i o n of t h e f r e q u e n c y of xyz r e l a t i v e t o t h e t o t a l f r e q u e n c y of a l l t r i g r a m s xy-, where t h e f i n a l l e t t e r r a n g e s over t h e e n t i r e a l p h a b e t and t a k e s on a l l a c t u a l l y o c c u r r i n g v a l u e s . Of c o u r s e , c o n s t r a i n t s need n o t work o n l y f o r w a r d , t h e r a t i o s xyz/x-z and xyz/-yz a r e a l s o of i n t e r e s t . Analogously, r a t i o s of p a r t i c u l a r bigrams xy t o t h e g e n e r a l bigram s u m s x- and -y c a n be computed.
ORTHOGRAPHIC STRUCTURE AND R E C O G N I T I O N 1 3 5
T a b l e 5.3 C o r r e l a t i o n s between t h e per formance measures and summed bigram, E n g l i s h n e s s , and c o n s t r a i n t - r a t i o measures a l l based on l o g word-token f r e q u e n c i e s .
Frequency Measure Performance Measure
RT R a t i n g Accuracy -
Summed Bigrams .77 - .64 . 8 5
E n g l i s h n e s s - .65 .47 - . 8 2
X Y d X Y - .75 - .55 . 8 1
X Y z/x-z . 7 4 -. 56 . 8 2
X Y 4 - Y . 7 4 - .54 .80
XY/X- .76 - .64 . 8 6
XY1-Y .75 - .64 . 8 5
These f i v e c o n s t r a i n t r a t i o s s u g g e s t f i v e p o t e n t i a l l y i n t e r e s t i n g measures d e r i v e d by summing t h e f o u r t r i g r a m c o n s t r a i n t r a t i o s o r f i v e bigram c o n s t r a i n t r a t i o s f o r our s i x - l e t t e r s t r i n g s . Again, t h e measures were computed a s r a t i o s of l i n e a r f r e q u e n c i e s and a s r a t i o s of l o g f r e q u e n c i e s . The c o u n t s c o u l d be based on word-type f r e q u e n c i e s o r word-token f r e q u e n c i e s . I n t h i s c a s e , y e t a n o t h e r t y p e f r e q u e n c y i s p o s s i b l e , l e t t e r - t y p e f r e q u e n c y . L e t t e r - t y p e f r e q u e n c y i s s imply t h e number of l e t t e r s t h a t a c t u a l l y occur i n t h e f r e e v a r i a b l e p o s i t i o n . Thus, a t r i g r a m of t h e form s-r might c o n s i s t of a f a m i l y of e i g h t o r n i n e t r i g r a m s w h i l e q-i h a s o n l y a s i n g l e p o s s i b l e member. L e t t e r - t y p e f r e q u e n c y was t a k e n a s t h e r e c i p r o c a l number of t r i g r a m s i n a f a m i l y o r z e r o i f t h e f a m i l y h a s no n a t u r a l l y o c c u r r i n g member, i . e . , a l l i l l e g a l t r i g r a m s . A s i m i l a r l e t t e r - t y p e measure was c o n s t r u c t e d f o r b igrams. I n a l l , t h e r e were 3 0 measures computed from c o n s t r a i n t r a t i o s ( f i v e k i n d s of r a t i o s x two f r e q u e n c y s c a l e s x t h r e e k i n d s o f t y p e and t o k e n c o u n t s ) .
136 CHAPTER 5
The r e s u l t s f o r t h e s e c o n s t r a i n t - r a t i o measures m i r r o r e d t h e r e s u l t s f o r t h e s i m p l e summed fi-gram f r e q u e n c i e s . R a t i o s o f l o g f r e q u e n c i e s c o n s i s t e n t l y gave h i g h e r c o r r e l a t i o n s t h a n r a t i o s o f l i n e a r f r e q u e n c i e s . Word-token f r e q u e n c i e s and word-type f r e q u e n c i e s were n e a r l y i n d i s t i n g u i s h a b l e i n terms o f t h e i r c o r r e l a t i o n s w i t h t h e per formance measures ; t h e s e f requency measures c o r r e l a t e d w i t h each o t h e r a t .90 o r h i g h e r . L e t t e r - t y p e f r e q u e n c i e s c o r r e l a t e d s l i g h t l y less h i g h l y w i t h word-type and word-token f requency measures b u t a l s o d i d n o t c o r r e l a t e a s h i g h l y w i t h t h e performance measures . F i n a l l y , t h e bigram r a t i o measures gave s l i g h t l y h i g h e r c o r r e l a t i o n s wi th t h e performance measures t h a n d i d t h e t r i g r a m r a t i o s . A
r e p r e s e n t a t i v e sample of t h e s e measures i s shown i n T a b l e 5 .3 . C o r r e l a t i o n s among t h e f r e q u e n c y measures were q u i t e h i g h . The t h r e e t r i g r a m measures shown i n Table 5 . 3 c o r r e l a t e d w i t h e a c h
.a -
.6 -
.4 -
H . 2 -
B d . o - K K 0 -.2 - 0
-.4 - -.6 - - . 8 - o Blgram
x Trlgram
-1.0 I I I I I I I 1 2 3 4 5 6
SERIAL POSITION
F i g u r e 5 .2 C o r r e l a t i o n s o f a c c u r a c y and r e a c t i o n t i m e s w i t h s i n g l e - l e t t e r , b igram, and t r i g r a m f r e q u e n c i e s a s a f u n c t i o n of t h e i r r e s p e c t i v e s e r i a l p o s i t i o n s i n t h e s i x - l e t t e r s t r i n g s .
ORTHOGRAPHIC STRUCTURE AND RECOGNITION 137
o t h e r .98 or h i g h e r . L ikewise , t h e two bigram c o n s t r a i n t - r a t i o measures c o r r e l a t e d . 9 9 w i t h e a c h o t h e r . Given t h e u n i f o r m l y h igh c o r r e l a t i o n s between a l l t h e c o n s t r a i n t - r a t i o measures , i t i s i m p o s s i b l e t o d i s c r i m i n a t e among them. Fur thermore , t h e s e r a t i o s d o n o t a c c o u n t f o r any more v a r i a n c e t h a n t h e c o m p u t a t i o n a l l y s i m p l e r summed l o g bigram measure. For t h e s e r e a s o n s , t h e summed l o g bigram measure is t o be p r e f e r r e d over t h e c o n s t r a i n t r a t i o s .
Having found t h a t computing more complex measures was no more e f f e c t i v e t h a n summing t h e component bigrams of a l e t t e r s t r i n g , w e i n v e s t i g a t e d a s i m p l e r measure. We examined t h e c o r r e l a t i o n s of t h e f r e q u e n c i e s of each of t h e component - n-grams w i t h t h e per formance measures . Thus, t h e r e were s i x c o r r e l a t i o n s f o r s i n g l e - l e t t e r f r e q u e n c i e s , f i v e f o r bigram f r e q u e n c i e s , and f o u r f o r t r i g r a m f r e q u e n c i e s w i t h each
.3 t
.2 - 0
8 .l- o” 0
g 40-
30-
20 -
- 6
-6
- 4
K
- 6
SERIAL POSITION
F i g u r e 5 . 3 V a r i a n c e s of s i n g l e - l e t t e r and bigram o c c u r r e n c e s a long w i t h t h e i r observed c o r r e l a t i o n s w i t h a c c u r a c y measures a t t h e r e s p e c t i v e s e r i a l p o s i t i o n s i n t h e s i x - l e t t e r s t r i n g s .
138 CHAPTER 5
p e r f o r m a n c e m e a s u r e . F i g u r e 5.2 p r e s e n t s t h e r e s u l t s o f t h i s a n a l y s i s . A l t h o u g h some o f t h e i n d i v i d u a l "-grams d i d n e a r l y a s we l l a s t h e summed m e a s u r e s , no s i n g l e "-gram u n i t had a s h i g h a c o r r e l a t i o n a s i ts c o r r e s p o n d i n g summed m e a s u r e . I t i s a p p a r e n t f rom t h e f i g u r e t h a t t h e end l e t t e r p o s i t i o n s were t h e mos t i m p o r t a n t , b u t a s t h e 3-gram l e n g t h i n c r e a s e d t h e p o s i t i o n a l d i f f e r e n c e s w e re d i m i n i s h e d .
F i g u r e 5.2 shows t h a t t h e d e g r e e t o wh ich a p a r t i c u l a r - n-gram p r e d i c t s p e r f o r m a n c e is c r i t i c a l l y d e p e n d e n t o n i t s s e r i a l p o s i t i o n , e s p e c i a l l y f o r t h e s i n g l e - l e t t e r and t o some e x t e n t t h e b i g r a m c o u n t s . I n o r d e r t o e v a l u a t e w h e t h e r t h i s e f f e c t i s d u e t o t h e i n f o r m a t i o n a l c o n s t r a i n t s i n t h e s t i m u l i t h e m s e l v e s , w e d e r i v e d a m e a s u r e a f r e d u n d a n c y o r p r e d i c t a b i l i t y f o r e a c h s e r i a l p o s i t i o n . The v a r i a n c e o f l e t t e r o c c u r r e n c e s a t e a c h s e r i a l p o s i t i o n was computed b a s e d on t h e t a b l e o f f r e q u e n c i e s g i v e n i n Appendix 5 . 2 a n d 5.3. H igh v a r i a n c e s o c c u r t o t h e e x t e n t t h a t some l e t t e r s o c c u r more o f t e n t h a n o t h e r s . T h e s e v a r i a n c e m e a s u r e s f o r t h e s i n g l e - l e t t e r and b ig ram c o u n t s a r e shown i n F i g u r e 5.3. A s m i g h t b e e x p e c t e d from p h o n o l o g i c a l and s c r i b a l c o n s t r a i n t s , l e t t e r s a r e much more p r e d i c t a b l e i n i n i t i a l and f i n a l p o s i t i o n s t h a n i n t h e m i d d l e o f s i x - l e t t e r words. A l s o p r e s e n t e d i n F i g u r e 5 . 3 a r e t h e c o r r e s p o n d i n g c o r r e l a t i o n s w i t h t h e a c c u r a c y m e a s u r e . The v a r i a n c e and c o r r e l a t i o n m e a s u r e s a r e h i g h l y c o r r e l a t e d f o r s i n g l e - l e t t e r c o u n t s which means t h a t s u b j e c t s e x p l o i t r e d u n d a n c y d i r e c t l y t o t h e d e g r e e t h a t i t i s p r e s e n t . A l though t h i s c o r r e s p o n d e n c e m i g h t b e e x p e c t e d t o o c c u r n e c e s s a r i l y , t h e b ig ram r e s u l t s a r g u e t h e o p p o s i t e . A l t h o u g h t h e v a r i a n c e m e a s u r e s a r e r o u g h l y s i m i l a r f o r t h e f i r s t t h r e e s e r i a l p o s i t i o n s , t h e c o r r e l a t i o n s a r e much h i g h e r f o r t h e f i r s t two p o s i t i o n s t h a n f o r t h e t h i r d . I n a d d i t i o n , a l t h o u g h t h e f i n a l b ig ram is much more p r e d i c t a b l e t h a n t h e p e n u l t i m a t e b i g r a m , t h e c o r r e l a t i o n s d o n o t d i f f e r by much.
FREQUENCY VERSUS R E G U L A R I T Y
A m a j o r c o n c e r n o f t h e p r e s e n t r e s e a r c h h a s b e e n t o compare f r e q u e n c y w i t h r u l e - g o v e r n e d r e g u l a r i t y a s i n d i c e s o f s t r u c t u r e . We have d i s c u s s e d i n C h a p t e r 3 t h e form of e x p e r i m e n t a t i o n t h a t w i l l need t o b e c o n d u c t e d t o f u r t h e r d i f f e r e n t i a t e t h e s e two i n d i c e s . We h a v e p r e s e n t e d e v i d e n c e i n
ORTHOGRAPHIC STRUCTURE AND RECOGNITION 139
Chapter 4 t h a t r e g u l a r i t y i s a t l e a s t a s i m p o r t a n t f o r p e r c e p t u a l r e c o g n i t i o n and more i m p o r t a n t f o r o v e r t judgments a s is s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y . I n t h e p r e s e n t c h a p t e r , w e have shown t h a t s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y is a good measure b u t t h a t bigram p o s i t i o n a l f r e q u e n c y i s a b e t t e r measure. W e have examined s e v e r a l d imens ions of t h e f r e q u e n c y domain and p r e s e n t e d s e v e r a l f i n d i n g s a b o u t f r e q u e n c y measures . T h i s i n v e s t i g a t i o n of t h e q u a n t i t a t i v e a s p e c t s of f r e q u e n c y measures was r e l a t i v e l y d i r e c t and s t r a i g h t f o r w a r d .
A comparable i n v e s t i g a t i o n i s n o t p o s s i b l e f o r r e g u l a r i t y . We have made o n l y a v e r y modest s t a r t . A s an i n i t i a l e f f o r t t o q u a n t i f y r e g u l a r i t y , w e computed a s i m p l e c o u n t of o r t h o g r a p h i c i r r e g u l a r i t i e s based upon our p r e l i m i n a r y a t t e m p t a t a grammar of o r t h o g r a p h y ( s e e Table 5 . 1 ) . The r e s u l t d o e s r a t h e r w e l l i n c o r r e l a t i n g w i t h per formance measures b u t is n o t s u f f i c i e n t l y deve loped t o a l l o w f o r a d e c i s i v e comparison w i t h bigram f r e q u e n c y . The r e g u l a r i t y c o u n t c o r r e l a t e d .57 w i t h a v e r a g e a c c u r a c y , - . 53 w i t h a v e r a g e RT, and .85 w i t h t h e r a t i n g s . Although t h e s e c o r r e l a t i o n s w i t h t h e two r e c o g n i t i o n measures a r e q u i t e modest i n comparison w i t h t h e f r e q u e n c y measures d e s c r i b e d i n t h i s c h a p t e r , t h e c o r r e l a t i o n w i t h r a t i n g s i s comparable w i t h t h e b e s t f r e q u e n c y measure. While we h e s i t a t e t o draw s t r o n g c o n c l u s i o n s , i t would appear t h a t t h e r e is p o t e n t i a l f o r d e v e l o p i n g n o t o n l y r e f i n e d ru le -governed measures b u t a l s o q u a n t i t a t i v e l y u s e f u l s t r u c t u r e i n d i c e s based upon t h e s e r u l e s .
One major problem w i t h d i s t i n g u i s h i n g between f r e q u e n c y and r e g u l a r i t y measures of o r t h o g r a p h i c s t r u c t u r e is t h a t t h e s e two measures a r e n a t u r a l l y c o r r e l a t e d i n t h e w r i t t e n language . I t is p o s s i b l e t o u n t a n g l e t h e s e measures a s we d i d i n t h e p r e s e n t s t u d i e s . However, by i n d e p e n d e n t l y v a r y i n g s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y , we a c t u a l l y c r e a t e d l e t t e r s t r i n g s t h a t v a r i e d s y s t e m a t i c a l l y w i t h bigram f r e q u e n c y . Our r e g u l a r s t r i n g s were h i g h e r i n bigram f r e q u e n c y t h a n t h e c o r r e s p o n d i n g i r r e g u l a r s t r i n g s . T h e r e f o r e , r e g u l a r i t y and p o s i t i o n - s e n s i t i v e l o g bigram f r e q u e n c y c o r r e l a t e d . 7 5 9 i n our l i s t of 2 a 8 t e s t i t e m s . I n f u t u r e e x p e r i m e n t s , w e p l a n t o i n d e p e n d e n t l y v a r y t h e s e two measures of o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n and o v e r t judgment e x p e r i m e n t s .
140 CHAPTER 5
W I T H I N CLASS ANALYSIS
A l l of t h e a n a l y s e s p r e s e n t e d s o f a r i n t h i s c h a p t e r have examined c o r r e l a t i o n s between measures computed f o r t h e items a c r o s s t h e f i v e c l a s s e s of s t i m u l u s s t r i n g s . Whereas i t is v e r y i m p o r t a n t t o e x p l a i n t h i s between c l a s s v a r i a n c e , i t is e q u a l l y i m p o r t a n t t o examine how w e l l s e v e r a l measures of o r t h o g r a p h i c s t r u c t u r e e x p l a i n t h e v a r i a n c e w i t h i n e a c h c l a s s . To do t h i s , t h e c o r r e l a t i o n a l a n a l y s e s were r e p e a t e d s e p a r a t e l y f o r t h e words and t h e r e g u l a r - h i g h , r e g u l a r - l o w , i r r e g u l a r - h i g h , and i r r e g u l a r - l o w anagram c l a s s e s . F i g u r e 5 . 4 p r e s e n t s t h e c o r r e l a t i o n s f o r t h e t h r e e p o s i t i o n - s e n s i t i v e l o g
'":
.4
-.6
-.8 c
3 Bigram x Trigram
Reaction Time
-1.0 WORDS R-H R-L I-H I-L
F i g u r e 5 . 4 C o r r e l a t i o n s of a c c u r a c y and r e a c t i o n times a s a f u n c t i o n of s i n g l e - l e t t e r , b igram, and t r i g r a m f r e q u e n c i e s f o r each o f t h e f i v e - l e t t e r s t r i n g t y p e s .
ORTHOGRAPHIC STRUCTURE A N D RECOGNITION 1 4 1
n-gram c o u n t s w i t h t h e a c c u r a c y and RT p e r f o r m a n c e m e a s u r e s . A s c a n be s e e n i n t h e f i g u r e , t h e m o s t s i g n i f i c a n t r e s u l t is t h e r e l a t i v e l y p o o r c o r r e l a t i o n s o f p e r f o r m a n c e w i t h t r i g r a m f r e q u e n c i e s . S i n g l e l e t t e r and b i g r a m f r e q u e n c i e s d o a b o u t e q u a l l y w e l l o v e r a l l . F i n a l l y , a l l c o r r e l a t i o n s f o r t h e word RT d a t a were c l o s e t o z e r o . T h i s l a t t e r r e s u l t m i g h t i n d i c a t e t h a t l e x i c a l s t a t u s makes a u n i q u e c o n t r i b u t i o n i n t h e RT t a s k a t t e n u a t i n g t h e c o n t r i b u t i o n s o f o r t h o g r a p h i c s t r u c t u r e . F u t u r e r e s e a r c h w i l l b e n e c e s s a r y t o a d d r e s s t h i s i s s u e .
WORD FREQUENCY
An a d d i t i o n a l m e a s u r e o f i n t e r e s t i s word f r e q u e n c y . Word f r e q u e n c y h a s shown t o b e a good p r e d i c t o r o f word r e c o g n i t i o n ( B r o a d b e n t , 1 9 6 7 ) . Log word f r e q u e n c y c o r r e l a t e s .64 w i t h a v e r a g e a c c u r a c y a n d .62 w i t h r a t i n g s ; h o w e v e r , f o r j u s t t h e word i t e m s t h e c o r r e l a t i o n s a r e - .27 and -.11 r e s p e c t i v e l y . T h i s means t h a t word f r e q u e n c y c a n n o t b e d i r e c t l y r e s p o n s i b l e f o r t h e e f f e c t s o f o r t h o g r a p h y s i n c e much h i g h e r c o r r e l a t i o n s s h o u l d h a v e b e e n s e e n i n t h e c l a s s o f words . I n f a c t , a dummy v a r i a b l e a s s i g n i n g t h e v a l u e 1 t o a l l words and 0 t o a l l nonwords c o r r e l a t e s . 6 6 w i t h a v e r a g e a c c u r a c y a n d .63 w i t h r a t i n g s . Log word f r e q u e n c y c o r r e l a t e s .52 a n d .78 w i t h p o s i t i o n - s e n s i t i v e l o g b i g r a m and t r i g r a m f r e q u e n c i e s r e s p e c t i v e l y i n o u r s e t o f 200 i tems. T h e r e f o r e , l e x i c a l s t a t u s i t s e l f a p p e a r s t o c o n t r i b u t e v e r y l i t t l e beyond wha t c a n b e a c c o u n t e d f o r b y s u b l e x i c a l o r t h o g r a p h i c s t r u c t u r e .
YULTI P L E REGRESS1 ON
A s e r i e s o f m u l t i p l e r e g r e s s i o n a n a l y s e s were c a r r i e d o u t t o see how much o f t h e v a r i a n c e o f e a c h o f t h e d e p e n d e n t m e a s u r e s c o u l d b e a c c o u n t e d f o r b y some c o m b i n a t i o n o f d e s c r i p t i v e m e a s u r e s . F o r r e s p o n s e a c c u r a c y , l o g b i g r a m f r e q u e n c y , l o g word f r e q u e n c y , a n d l o g s i n g l e - l e t t e r f r e q u e n c y a c c o u n t e d f o r a t o t a l o f 68% o f t h e v a r i a n c e . No o t h e r d e s c r i p t i v e v a r i a b l e improved o n t h e 4 0 % o f t h e RT v a r i a n c e a c c o u n t e d f o r by l o g b i g r a m f r e q u e n c y . F i n a l l y , 88% o f t h e
1 4 2 CHAPTER 5
v a r i a n c e o f t h e r a t i n g j u d g m e n t s was a c c o u n t e d f o r by r e g u l a r i t y c o u n t , l o g t r i g r a m f r e q u e n c y , and l o g word f r e q u e n c y . These r e s u l t s show t h a t t h e knowledge o f o r t h o g r a p h i c s t r u c t u r e r e v e a l e d by a n o v e r t j udgmen t t a s k d o e s n o t r e v e a l i t s e l f t o t h e same d e g r e e i n p e r c e p t u a l r e c o g n i t i o n t a s k s . T h i s r e s u l t is n o t u n r e a s o n a b l e c o n s i d e r i n g t h e a d d i t i o n a l v i s u a l p r o c e s s i n g r e q u i r e m e n t s i n t h e p e r c e p t u a l r e c o g n i t i o n t a s k s . I n a d d i t i o n , t h e a c c u r a c y t a s k a l l o w s a s i g n i f i c a n t l y l a r g e r c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e t h a n d o e s t h e RT t a s k . The r e a s o n f o r t h i s d i f f e r e n c e a p p e a r s t o b e d u e t o t h e r e l a t i v e l y s m a l l c o n t r i b u t i o n o f v i s u a l p r o c e s s i n g t o t h e RT m e a s u r e compared t o t h e r e l a t i v e l y l a r g e c o n t r i b u t i o n o f v i s u a l p r o c e s s i n g t o t h e a c c u r a c y m e a s u r e ( s e e C h a p t e r 4 ) .
SUMMARY
The p o s t hoc c o r r e l a t i o n s were r e a s o n a b l y s u c c e s s f u l i n i l l u m i n a t i n g t h e r o l e o f a number o f v a r i a b l e s r e l e v a n t t o m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . Type and t o k e n c o u n t s were e q u a l l y good m e a s u r e s f o r o u r s t i m u l u s i t ems , w h e r e a s l o g c o u n t s were s i g n i f i c a n t l y b e t t e r t h a n l i n e a r c o u n t s . P o s i t i o n s e n s i t i v i t y i s c r i t i c a l , e s p e c i a l l y f o r s m a l l e r !-gram c o u n t s . F i n a l l y , p o s i t i o n - s e n s i t i v e l o g b ig ram f r e q u e n c y a p p e a r e d t o b e t h e mos t e f f e c t i v e m e a s u r e , a l t h o u g h t h e r e a p p e a r s t o b e some p o t e n t i a l f o r d e v e l o p i n g a n e q u a l l y good r e g u l a r i t y m e a s u r e .
A P P E N D I X 5 .1 143
Append ix 5 .1
S t i m u l u s Items and R e s u l t s
Each o f t h e 2 0 0 s t i m u l u s items and i t s r e s p e c t i v e a v e r a g e p e r c e n t a g e a c c u r a c y (Acc) , a v e r a g e RT, ave r . age r a t i n g , summed p o s i t i o n - se n s i t i v e l o g s i ng le- 1 e t t e r f r e q u e n c y , summed PO s- i t i o n - s e n s i t i v e l o g b i g ram f r e q u e n c y , summed p o s i t i o n - s e n s i t i v e l o g t r i g r a m f r e q u e n c y , l o g word f r e q u e n c y , and number o f i r r e g u l a r i t i e s .
1 4 4
WORDS
a c t i o n amount answer b a r e l y b e l o n g b r e a t h b r i d g e c h a r g e d o u b l e famous f i n g e r g a r d e n g a t h e r g l a n c e h a r d l y i t s e l f l a w y e r l o n g e r m a s t e r modern mothe r namely n e a r l y p e r m i t p l a y e r p o e t r y p u r e l y r e a s o n remain r e s u l t s h a r e d s imp1 e s i n g l e s p r e a d s t a r e d s t r e a m t r a v e l t r i a l s t u r n e d w i n t e r
Acc %
8 1 7 7 8 9 8 9 8 9 8 6 9 4 8 6 9 2 8 9 9 2 9 3 8 9 8 7 8 9 7 9 8 6 9 4 9 3 9 3 9 3 90 8 9 8 3 9 5 9 3 9 2 8 5 8 5 8 6 9 3 9 1 9 1 9 1 9 5 8 9 85 8 2 8 5 9 1
RT R a t i n g msec
644 6 56 6 4 4 6 3 5 6 0 3 6 2 9 6 5 4 6 4 2 6 2 1 6 3 9 6 5 3 6 1 9 6 7 3 637 6 6 1 6 3 7 646 6 2 7 6 2 7 6 1 6 6 1 0 6 6 2 6 2 0 590 6 1 9 6 4 2 6 0 7 605 6 3 8 6 3 6 6 4 0 6 2 2 6 3 2 6 1 1 6 7 2 6 1 6 6 2 2 6 2 3 6 7 5 6 2 1
8.8 9.3 8.2 9.3 9.5 9.3 8.9 9.4 8.9 8.9 9.5 9.7 9.4 9.3 9.4 9.2 8.7 9.6 9.7 9.5 9.5 9.4 9.3 9.6 9.6 9.2 9 .1 9 . 1 9 .5 9.7 9.4 9.4 9.2 9.2 9.4 9.5 9.6 9.2 9.3 9.7
CHAPTER 5
S i n g l e Bigram T r i g r a m Le t t e r
22.33 15.26 21.83 14.12 22.10 14 .08 23.30 1 5 . 6 3 22 .76 1 5 . 1 2 21.48 1 3 . 5 6 21.94 13 .05 22.28 1 4 . 5 1 22.13 13.56 22.05 13 .34 22.80 15.58 22 .75 14 .26 22.87 1 5 . 9 1 21.77 13 .70 22.49 14.87 21.03 1 3 . 6 3 21.60 12 .50 22.96 15.67 23.55 1 6 . 5 6 22.33 1 4 . 4 0 2 3 . 3 1 16 .47 22.53 14.84 22.52 14.76 22.52 14 .16 21 .85 1 4 . 6 1 22.80 12 .36 23.03 15 .85 22.46 15.60 22.19 1 4 . 4 2 23.02 14.56 23.55 15.92 22.94 1 5 . 0 1 23.02 14.58 22.60 1 3 . 4 2 23.44 16 .32 21.94 1 4 . 1 9 21.87 1 3 . 5 1 22.53 12 .64 23.42 15 .57 2 3 . 1 1 16.34
10.98 9.67 8.87 9.59 7 .99 8.36 8.58 9 . 6 1 7 .94 8.56 9 .78 9 .04
10.23 8.94 9 .06
1 0 . 2 5 6.99
10.20 10.54
9.64 1 1 . 1 0
8 .22 9 .47 9 . 0 1 9.47 8.09 9.33
1 0 . 7 6 9.15 9.74 9.74
10.78 9.30 8.78
10.10 9 .85 8.53 7.07
1 0 . 7 4
Word F r e q .
2.46 2 .24 2 .18 1.49 1.57 1.72 1.99 2.09 1 .75 1.95 1.60 1.78 1.30 1 .60 2.03 2.48 1 . 6 3 2.29 1 .86 2.30 2.33 1.52 2.15 1.89 1 . 7 1 1.94 1 .48 2.38 1.97 2.39 1 .60 2 . 2 1 2.24 1.92 1.78 1 . 7 1 1 .79 1 .59 2 . 5 1
10.32 1 . 9 2
# o f 1 r r .
1 0 1 0 0 0 0 0 0 0 0 1 0 0 2 1 0 0
0 0 0 0 1 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 1 1
APPENDIX 5.1
REGULAR-HIGH
1 4 5
c a i n o t mau ton s w a n e r b l a y e r g o b l e n t h a b e r b e g r i d c h a g e r b o d u l e foamus f e r i n g n a g r e d t h a g e r c a l e n g h y r a l d s i f l e t w e r a l y l o q r e n t a s m e r dormen t home K
m a n e l v l a r e n y p r i m e t r a p l e v p e t o r y y u l p e r s a r o n e r a m i n e s u r t e l s h r e a d p i m s e l s n i g e l p r a s e d s a r t e d t r a m e s v a r t l e s a r t i l d r u n e t t r i w e n
ACC
%
8 2 70 81 8 1 8 1 7 8 7 8 8 6 7 7 74 8 3 8 3 7 2 77 6 9 7 2 8 1 7 9 77 8 7 8 7 87 79 8 1 88 89 74 8 3 8 2 8 2 7 9 8 1 8 1 8 7 9 1 8 0 79 70 8 1 7 2
RT R a t i n g msec
6 4 5 620 615 666 638 6 37 640 673 6 7 3 670 617 659 612 659 677 640 649 604 648 625 654 639 656 629 634 6 4 5 662 6 3 5 6 0 5 610 675 6 4 1 604 639 622 582 638 672 636 672
6 .5 7 .5 7 .6 8.0 8 .6 7 .6 7.8 8 . 3 8 . 0 7 . 3 7 .7 7.0 7 .7 5.6 6.6 7.7 5.7 7 .4 7 .3 8 . 2 7 .3 8 .4 7 .2 8.0 7 .7 7 .3 8.0 7 .8 8 .2 7 .3 9 . 2 7 .7 6.8 8.4 8 . 4 8 . 3 7 .2 7 . 3 6 . 8 6.6
S i n g l e L e t t e r
22.69 22.49 22 .25 21.79 21.94 22 .42 22 .27 22.90 22 .78 21 .80 23.22 22.66 22.70 22.85 21 .84 23 .06 22.87 22.53 22 .92 22 .92 22.68 22.96 23.15 22.64 22.49 23.13 21 .17 23 .83 23 .29 23 .43 23 .19 22.48 22 .42 23 .18 24.44 22.80 22 .95 22 .85 22.49 21.90
Biqram T r i g r a m
13 .74 13 .54 13 .40 1 3 . 7 8 1 3 . 3 5 1 4 . 9 5 12 .89 15 .27 13 .92 10 .39 15 .85 13 .74 1 5 . 2 9 15 .50
9 .21 1 2 . 6 9 13 .87 12 .07 13 .94 14 .56 15 .54 1 5 . 3 3 14 .18 13 .97 11 .86 1 4 . 1 2 10 .87 1 4 . 6 3 14 .84 14 .64 13 .92 11 .77 12 .58 15 .33 16 .02 1 4 . 1 1 1 5 . 0 1 12 .89 13 .05 11 .54
4 .38 2 .28 5 .50 8 . 1 4 3 .60 5 .14 3.96 7 .54 2 .63 0 .00 9 . 7 3 4.75 6 .39 6 .17 3 .10 5 .33 3.36 3 .89 3 .87 6 .00 8 . 4 1 8 .76 5 .68 4 .78 2 .62 5 .36 5.09 6.14 8 . 4 2 5 . 2 3 7 .94 2 .36 1 .34 6 .16 6 .87 7 .74
3.90 2 .81 1.90
8 .74
Word # o f FKeq. I K K .
0 . 00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0.00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 1 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 0 0 .00 1 0 .00 0 0.00 0 0.00 1 0 .00 0 0 .00 1 0 .00 0 0 .00 0 0 .00 1 0 .00 0 0.00 1 0 .00 1 0 .00 0 0 .00 0
1 4 6 CHAPTER 5
REGULAR-LOW
AC C
%
o n i c a t 7 1 otanum 59
e r s w a n 7 1 b y e r a l 7 7 g l e n o b 7 9 t h e r a b 7 5 g r e d i b 6 6 g r e a c h 6 8 e d o l u b 6 8 osa fum 5 3 g r e f i n 8 1 g r e d a n 8 5 g r e a t h 8 3 g l e c a n 8 1 h y d r a 1 7 2 f l e s i t 7 1 l y e r a w 7 3 g l e r o n 8 0 s t e r a m 7 9 drenom 7 5 t he rom 8 0 lyeman 6 6 n y e l a r 7 7 t r e p i m 7 3 l y e r a p 7 5 t y e r o p 7 2 r y e l u p 7 3 e r o s a n 7 3 a m e r i n 7 7 t r e s u l 7 4 d r e a s h 7 3 ' e m s l i p 7 3 g l e s i n 7 1 d r e s a p 7 5 d r e s a t 8 7 t r e s a m 7 6 t r e v a l 8 4 t r i s a l 7 1 t r e d u n 7 2 t r e w i n 7 9
RT R a t i n g msec
637 6 .5 6 6 8 6.9 675 6.0 6 6 7 4.8 6 6 0 7.3 6 6 6 7.0 6 7 2 5.9 6 4 8 8.7 6 7 9 5.3 6 6 9 4.4 6 3 3 7.0 6 5 3 7.0 6 0 1 8 .1 6 4 8 6.5 6 5 4 7.6 6 2 1 7.6 6 9 0 6.8 6 2 1 8.0 6 2 6 7.6 6 2 7 7 . 1 6 5 8 7.6 6 9 3 8.1 6 5 6 5.3 6 4 5 7.2 7 0 2 5.9 6 4 7 5.3 6 8 4 6 . 1 6 2 1 6.9 6 3 8 7.0 6 3 6 6.9 6 8 6 7.9 638 6.7 6 3 2 7 . 1 6 5 2 6.8 6 4 7 6.3 6 3 5 7.0 6 6 3 8 . 1 608 7 . 1 6 4 1 7.7 6 5 1 7.3
S i n g l e Le t t e r
20.84 20.12 21 .01 20.60 19 .23 19.48 18.96 21.03 17.97 1 8 . 4 1 20.20 21.13 21.00 20.67 19.92 21.38 19.87 21.27 21 .21 21.10 21.07 20.53 20.64
20.67 19 .08 19.29 18.59 21.72 20.78 20.74 21.211 18.97 20.90 19.73 21.54 20.79 20.78 21.33 20.99 20.91
Bigram T r i q r a m
1 0 . 3 1 0.60 12.46 2.65
8 .35 0.00 8.29 1.20 9.63 1.74 9.68 3.39
10.13 5.34 13.62 5.69
4.79 0.00 5.98 0 .00
12.27 4.80 13.02 4.13 1 3 . 6 6 8 . 1 1 1 0 . 8 6 0.00
6.68 1.20 11 .58 1.00
6.87 0.00 1 2 . 3 2 2.12 11.08 2.84 1 2 . 9 3 3.93 12.72 3.39
9.64 2.16 7.45 1.95
10 .67 1.74 6.47 0.00 7.49 0.00 4.56 0.00
11.75 1.08 11.53 1.26 11.28 2.22 1 2 . 2 9 6.56
6.56 1.32 11 .50 2.71
9.52 2.48 1 1 . 2 1 2.48 11.26 2.52 1 1 . 9 1 1.74 13 .45 4.13
9.29 3.55 10.96 2.34
Word # o f F r e q . I r r .
0.00 0 0.00 0 0.00 1 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.00 1
0.00 0 0.00 1 0.00 1 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0
A P P E N D I X 5.1
I R R E G U L A R - H I G H
1 4 7
a i o c n t auotnm wnraes l b r a e y lnboeg b h r t e a i e r b g d a h c g e r leoubd uaomf s r f n i e g a rnged h r t a e g l c n a e q y r a h l d t l f i es rwlaey g l n o e r m r t a e s oermnd mroteh lmnaey l r n a e y t m r i e p p l r a e y y p t o e r l p y u e r s n a o e r mra ien l r t u e s s r d a e h i lmpes i l g n e s p r s a e d s r t a e d m t r a e s a v r l e t i a s t l r r d n u e t w r n t e i
Acc %
6 3 69 7 0 8 1 6 5 7 5 66 7 1 7 6 6 1 7 0 8 4 7 0 6 7 6 1 68 7 3 7 8 7 6 7 1 8 2 7 0 69 68 8 4 7 0 6 8 7 5 7 5 7 1 6 7 7 4 68 8 5 8 6 7 2 7 4 8 1 7 5 6 3
RT Rat ing msec
6 5 6 6 5 2 6 6 6 6 9 9 6 9 2 6 6 4 7 2 8 674 6 9 1 6 9 8 6 5 6 6 6 3 6 6 3 675 6 8 1 6 6 4 688 6 6 2 657 650 660 7 0 5 6 4 8 6 6 2 573 6 9 2 6 7 1 6 4 5 6 1 2 6 5 6 680 635 6 5 8 6 2 3 6 7 5 6 4 7 6 5 6 6 5 0 7 1 2 6 9 6
3 . 1 3.7 2.4 3.0 2 . 1 1.5 2.3 3.0 2.5 2.0 2.2 3.8 2.3 2.2 2.4 2.6 2.1 2.9 2.3 2.8 2.8 2.6 2.8 2.7 2.9 2.6 3.0 4.3 3.4 2.0 2 . 1 3.8 4.5 3.3 2.2 2.3 4.4 2.6 2 .1 2.4
S i n g l e L e t t e r
22.36 22.07 22.93 21.76 21.87 22.22 21.96 22.64 21.38 20.03 22.21 22.98 22.50 22.06 21.14 22.89 21.52 22.42 23.27 22.62 22.84 21.74 22.70 20.72 22.96 21.13 21.70 2 3 . 4 1 23.27 23.34 22.36 22.08 22.00 23.25 23.75 23.20 21 .71 22.67 21.74 20.67
Biqram Trigram
7.20 5.49 8.58 7.90 4.07 9.43 5.31 5.86
10.15 3 . 6 1 5.60
14 .28 5.98 3.46 9.17
10.79 6.14 9 .15 9.56
10 .37 8.68 5.91 7.39 7 . 8 1 8.90 8.56 6.44 5.96
11 .40 1 1 . 2 6
4.32 11 .74
8.80 9.44 9.92
10 .13 10 .12
9.07 7.91
11.47
0.00 1 .49 1.18 1 .18 0.60 1.59 1.32 2.73 0.00 0.00 1.83 6 .08 0.00 0.00 1.34 3.30 0.00 0.00 0 .00 2.30 2.53 0.00 0 .00 2 . 3 1 1.18 0.70 0.00 1.56 1.97 2.42 0.00 3.47 3.72 0.00 0.00 2 .82 3.63 4.33 0.00 2.76
Word # of FKeq.
0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .a0 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0.00 0.00 0.00
i K K .
2 3 3 2 3 4 3 2 2 4 2 1 3 3 2 2 3 2 3 3 2 3 3 2 2 3 2 2 2 2 4 2 2 2 3 2 2 3 2 3
1 4 8
IRREGULAR-LOW
CHAPTER 5
i c n t o a nmtaou rnwesa r b l e y a e b g n l o r t b e h a e b r g d i h r e a g c o b d e u l o fmsua e f n q r i e d n r g a g r h e t a e c l n q a r d l h y a e f l s t i e y r l w a e g n r l o emrtsa rmedno h r e t m o emnyla e n y r l a r t p e i m e p y l r a e r v t p o e r p l v u r n s e o a rn i ema e l s r t u h s r e d a l s e p m i n g l e s i d s e p r a d t s e r a e s r t m a t l e r a v i r l t s a e d t r n u
AC c %
6 2 55 6 5 6 7 6 9 7 2 5 8 6 8 7 3 6 2 7 1 6 7 7 7 6 5 5 3 6 6 6 7 6 7 6 6 7 1 6 9 7 3 7 8 67 7 0 7 1 66 6 3 6 9 7 1 7 5 6 9 6 5 8 2 7 7 7 4 67 7 0 7 1
RT R a t i n g msec
6 8 3 7 0 7 7 0 4 7 2 8 6 7 0 7 3 6 6 9 7 6 4 6 6 9 2 7 1 0 6 9 7 6 9 8 6 5 5 7 38 7 4 3 7 0 7 7 0 7 655 6 2 9 6 4 4 6 3 3 6 9 5 6 7 7 6 5 2 6 7 0 6 59 6 6 6 6 4 8 6 5 6 6 6 4 6 5 6 6 7 2 6 6 2 6 6 5 6 6 8 6 8 1 6 8 0 655 6 5 6
2.0 2.1 2.2 2.4 2.7 2.8 2.0 2.4 4.6 2.5 2.1 2.4 3.2 2.6 1.8 2.7 2.8 2.9 2.3 3.1 2.4 4.5 3.0 2.4 3.1 3.2 2.8 2.4 2.3 2.2 2.4 2.8 2.4 3.6 2.4 3.4 2.4 2.8 2.1
S i n g l e Le t t e r
20.38 19.06 20.26 18.96 19.04 19.78 18.09 20.49 19 .15 18.80 18.98 19.25 20.07 20.09 18.53 18.72 1 8 . 5 3 19 .24 20.19 19.48 19.84 19.05 20.20 20.65 19 .56 19.23 18.37 21.08 20.44 19.52 19.90 18.23 18 .25 19 .81 21.03 20.06 17.70 20.53 19.12
6.29 2.62 6.02 2.98 5.08 3.45 4.46 7.66 8.15 6.02 6.80
6.05 9 . 1 1 5.10 0.00 7.60 4.09 6 .11 4.25 3.88 5.25 4.15 8 .91 4.62 3.29 5.59 3.54 5.96 8.26 4.51 7.92 4.49 5.28 5.25
10.08 7.24 6.34 3.39 4.93
0.48 0.00 1.45 0.00 0.00 0.00 0.00 2.37 0.00 0.00 1.36
0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.03 0.00 0.00 0.00 0.00 0.00 0.00 1 . 5 1 0.48 0.00 0.70 0.00 2.00 0.00
5.92 0.00 1.28 0.00 0.00
Word # o f F r e q .
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 c1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
I r r .
3 4 3 2 4 3 3 2 1 3 3 4 2 2 4 2 4 4 4 3 3 2 2 2 2 2 2 4 2 4 3 3 2 2 3 4 2 4 3
APPENDIX 5.2 149
Append ix 5.2
S i n g l e - L e t t e r P o s i t i o n a l F r e q u e n c i e s (Token C o u n t s ) A c c o r d i n g t o S e r i a l P o s i t i o n and Word Leng th f o r Words
3 t o 7 L e t t e r s i n L e n g t h .
I n s t r u c t i o n s f o r Us ing F r e q u e n c y T a b l e s
The w o r d s u s e d t o o b t a i n t h e s i n g l e - l e t t e r f r e q u e n c i e s came from t h e Kuce ra and F r a n c i s ( 1 9 6 7 ) word c o u n t . Words which had a Kuce ra and F r a n c i s c o u n t o f a t l e a s t t h r e e and which a p p e a r e d i n a t l e a s t t h r e e d i f f e r e n t s ampled t e x t s were s e l e c t e d . They were t h e n s e p a r a t e d f o r e a c h word l e n g t h . T h e s e c o u n t s were m u l t i p l i e d b y t h e f r e q u e n c y o f e a c h o f t h e words s o t h a t t h e s i n g l e - l e t t e r f r e q u e n c i e s o f t h e t a b l e s a r e b a s e d on t o k e n r a t h e r t h a n t y p e c o u n t s ( see C h a p t e r 1 ) . T h i s s e l e c t i o n p r o c e d u r e y i e l d e d t h e f o l l o w i n g number of word t o k e n s f o r e a c h word l e n g t h : 210990, 153315 , 102699 , 76295, 68894 f o r 3 t h r o u g h 7 l e t t e r words , r e s p e c t i v e l y .
The number o f t imes e a c h l e t t e r o f t h e a l p h a b e t o c c u r r e d i n e a c h l e t t e r p o s i t i o n o f t h e words was c o u n t e d . T h e s e t o t a l s , a l o n g w i t h t h e i r s u m , a r e p r e s e n t e d i n t h e t a b l e s a s t h e f i r s t row o f numbers f o r e a c h l e t t e r . Thus , f o r e x a m p l e , f o r s i x - l e t t e r w o r d s , t h e l e t t e r 5 o c c u r r e d i n t h e s i x t h l e t t e r p o s i t i o n 231 t imes and o c c u r r e d i n a l l p o s i t i o n s a t o t a l o f 3 ,804 t imes . Below e a c h o f t h e f r e q u e n c i e s i s t h e b a s e 10 l o g a r i t h m o f t h e f r e q u e n c y c o u n t .
I t s h o u l d b e n o t e d t h a t f o r some s i n g l e l e t t e r s , t h e f r e q u e n c y o f o c c u r r e n c e is z e r o i n some p o s i t i o n s . The l o g a r i t h m o f z e r o is u n d e f i n e d , b u t f o r t h e p u r p o s e s o f t h e t a b l e s was s e t e q u a l t o z e r o .
150 C H A P T E R 5
S I N G L E L E T T E R F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 3
L E T T E R P O S I T I O N 1ST
A 39519 4.597
B 5902 3 .771
C 2466 3.392
D 2301 3 .362
E 760 2 .881
F 10988 4 .041
G 1967 3.294
H 21515 4 .333
I 2009 3 .303
J 515 2.712
K 182 2.260
L 1604 3 .205
M 4180 3 .621
2ND
28085 4 .448
3 .477
379 2.579
142 2 .152 11050 4 .043
644 2.809
498 2 .697 7 5 5 1 1 4.878 13084 4.117
0 0 .000
62 1 .792
3766 3.576
1 5 1 .176
3RD
2 2 1 2.344
364 2 . 5 6 1
1 8 6 2.270 37652 4 .576 82860 4.918
639 2 .806
790 2 .898
1 6 1 .204
7 . 845
0 0 .000
150 2.176
3192 3.504
3108 3 .492
SUM
67825 4 .831
6269 3.797
3 0 3 1 3.482 40095 4 .603 94670 4 .976 1 2 2 7 1 4 .089
3255 3 .513 97042 4.987 15100 4 .179
515 2.712
394 2 .595
8562 3 .933
7303 3.864
A P P E N D I X 5.2 151
S I N G L E L E T T E R F R E Q U E N C I E S FOR WORDS O F L E T T E R LENGTH 3
N
0
P
Q
R
s
T
U
V
W
X
Y
z
L E T T E R P O S I T I O N 1ST 2ND
7865 3.896 8900 3.949
1227 3.089
11 1.041
864 2.937 6354
3.803
73207 4.865
592 2.772
93 1.968
14079 4.149
0 0.000
3855 3.586
35 1.544
33973 4.531 23643 4.374
27 1.431
0 0.000
5591 3.747
736 2.867
1937 3.287
9472 3.976
41 1.613
2199 3.342
6 .778
126 2.100
0 0.000
3RD
6169 3.790 4829 3.684
474 2.676
0 0.000
16036 4.205 22017 4.343
16145 4.208
3307 3.519
73 1.863
5380 3.731
671 2.827
6704 3.825
0 0.000
SUM
48007 4.681 37372 4.573
1728 3.238
11 1.041
22491 4.352 29107 4.464
91289 4.960
13371 4.126
207 2.316
21658 4.336
677 2.831
111685 4.029
35 1.544
1 5 2 CHAPTER 5
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 4
LETTER POSITION 1ST
A 3077 3 .488
B 7266 3 .861
C 4530 3.656
D 4614 3 .664
E 3714 3.570
F 10556 4 . 0 2 3
G 3091 3 .490
H 9784 3 .991
I 2191 3 .341
J 2051 3 .312
K 2252 3 .353
L 7898 3 .898
M 10777 4 .032
2N D
26766 4 .428
244 2 .387
90 1 . 9 5 4
393 2.594 20802 4 .318
0 0 .000
1 2 8 2 .107 29988 4 .477 22145 4 .345
0 0 .000
8 5 1 . 9 2 9
2843 3 .454
50 1 .699
3RD
20259 4 .307
253 2 .403
6697 3 .826
2462 3 .391 21789 4 .338
1 6 4 8 3 .215
1 1 6 9 3 .068
376 2 . 5 7 5
9 6 6 1 3 .985
0 0 .000
3066 3 .487 1 1 2 2 5 4.050
6902 3 . 8 3 9
4TH
9 5 3 2 .979
301 2 .479
54 1 . 7 3 2 1 0 1 2 9 4 .006 32881 4 .517
528 2 .723
1 3 5 1 3 .131 1 2 3 2 2 4 .091
3 5 1 . 5 4 4
0 0 .000
5572 3 .746
7346 3 . 8 6 6
8373 3 . 9 2 3
SUM
51055 4 .708
8064 3 .907 1 1 3 7 1 4 .056 1 7 5 9 8 4 .245 79186 4 .899 1 2 7 2 4 4 .105
5739 3 .759 52470 4 .720 34032 4 .532
2051 3 .312 1 0 9 7 5 4.040 29312 4 .467 26102 4 .417
APPENDIX 5 .2
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 4
LETTER POSITION 1ST
N 2119 3 .326
0 4261 3 .630
P 3518 3 .546
Q 1 5 1 .176
R 3075 3 .488
S 1 0 8 1 5 4.034
T 30636 4 .486
U 1340 3 .127
V 1308 3 .117
W 22367 4.350
X 0 0 .000
Y 1996 3 .300
2 64 1 . 8 0 6
2N D
5 7 5 3 3.760 24056 4 .381
978 2 .990
0 0 .000
6514 3 .814
742 2.870
563 2 . 7 5 1
7042 3 .848
2843 3.454
555 2 .744
62 1 . 7 9 2
673 2.828
0 0 .000
3RD
8 2 6 5 3 .917 10798 4 .033
1040 3 .017
0 0 .000 13598 4 .133 1 0 0 9 1 4 .004 1 2 2 5 1 4 .088
2751 3 .439
5723 3 .758
1 5 2 6 3 .184
470 2.672
998 2.999
305 2.484
4TH
1 4 2 5 6 4 .154
3158 3 .499
1 7 1 5 3 .234
3 . 477 5335
3 .727 11497 4 .061 24894 4 .396
38 1 . 5 8 0
0 0 .000
2163 3 . 3 3 5
7 7 1 . 8 8 6 1 0 2 1 4 4 .009
1 2 0 2 .079
SUM
30393 4 .483 42273 4 . 6 2 6
7 2 5 1 3 .860
1 8 1 . 2 5 5 28522 4 .455 33145 4 .520 68344 4 .835 1 1 1 7 1 4 .048
9874 3 .994 2661 1 4 . 4 2 5
6 0 9 2 . 7 8 5 1 3 8 8 1 4 .142
489 2 .689
1 5 3
1 5 4 CHAPTER 5
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 5
LETTER POSITION
A
B
C
D
E
F
G
H
I
J
K
L
1ST
7359 3 .867
5264 3 .721
6416 3 .807
2379 3 .376
2189 3 .340
5614 3 .749
3565 3 .552
3348 3 .525
917 2 .962
525 2.720
618 2 .791
4187 3 .622
2ND
1 0 4 5 5 4 .019
2151 3 . 3 3 3
556 2 .745
6 2 5 2 .796
9 7 0 9 3 .987
1 5 1 8 3 .181
700 2 .845 1 8 8 0 8 4 .274
9 8 2 1 3 .992
0 0 .000
8 5 1 . 9 2 9
4783 3 .680
M 4220 1 3 5 7 3 .625 3 . 1 3 3 3 .323
3RD
1 2 3 0 6 4 .090
8 2 6 2 .917
9 3 8 2 .972
2681 3 .428 1484 5 4 .172
3 14 2 .497
3796 3 .579
1 7 4 0 3 .241 13572 4 .133
2 9 1 2 .464
1 1 8 2 3 .073
2801 3 .447
2103
4TH
5563 3 .745
4 38 2 .641
8 3 3 2 3 .921
2860 3 . 4 5 6 18479 4 .267
447 2 .650
1 4 7 5 3 . 1 6 9
2465 3.392
683 2 3 .835
0 0 .000
1 2 4 2 3 .094 1 1 7 0 8 4 .068
1 6 4 1 3 .215
5TH
5 2 3 2 .719
3 6 1 . 5 5 6
582 2 .765 1 1 8 4 5 4.074 21152 4 .325
493 2 .693
3349 3 .525
7039 3 .848
7 5 1 . 8 7 5
0 0 .000
2195 3 .341
4948 3 .694
404 2 .606
SUM
36206 4 .559
8 7 1 5 3 .940 1 6 8 2 4 4 .226 20390 4 .309 66374 4 .822
8386 3 .924 1 2 8 8 5 4 .110 33400 4.524 31217 4 .494
8 1 6 2 .912
5322 3 .726 28427 4 .454
9 7 2 5 3 . 9 8 8
APPENDIX 5 . 2 1 5 5
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 5
LETTER POSITION 1ST
N 2336 3 .368
0 3064 3 .486
P 4418 3 .645
Q 515 2 .712
R 3036 3 .482
S 11526 4 .062
T 1 4 0 4 3 4 . 1 4 7
U 2038 3 .309
V 938 2 .972
W 12634 4 .102
X 0 0 .000
Y 1547 3 .189
2 3 .477
2ND
2899 3 .462 18464 4 .266
1255 3 .099
1 1 5 2 . 0 6 1
7818
959 2 .982
5756 3 .760
3058 3 .485
687 2 .837
682 2 .834
1 5 1 2.179
287 2 .458
0 0 .000
3 .893
3RD
4331 3 .637 1 0 6 1 2 4 .026
1 0 4 6 3 .020
0 0 .000
8 5 2 3 3 .931
2106 3 .323
4727 3 .675
9278 3 .967
2979 3 .474
755 2.878
364 2 . 5 6 1
4 57 2 .660
1 2 6 2 .100
4TH
8 5 1 3 3 .930
2682 3 .428
8 7 9 2 .944
0 0 .000
9276 3 .967
8 1 0 8 3 .909
6054 3 .782
3139 3 . 4 9 7
1 2 3 9 3 .093
1 1 2 1 3 .050
7 . 845
1 0 2 2 .009
9 7 1 . 9 8 7
5TH
5318 3 .726
4 8 1 2 .682
7 4 7 2 .873
0 0 .000 1 1 7 9 1 4 .072 15072 4 .178 1 1 0 9 8 4 . 0 4 5
8 .90 3
9 . 954
395 2 .597
1 5 9 2 . 2 0 1
4977 3 .697
3 .477
SUM
23397 4.369 35303 4 .548
8 3 4 5 3 .921
6 30 2.799 40444 4 .607 37771 4 * 577 41678 4 .620 1 7 5 2 1 4.244
5852 3.767 15587 4 .193
681 2 .833
7370 3.867
229 2.360
1 5 6 CHAPTER 5
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 6
LETTER POSITION 1ST
A 5 5 2 9 3 . 7 4 3
B 5 1 1 6 3 .709
C 6 2 3 7 3 . 7 9 5
D 3 1 4 6 3 . 4 9 8
E 3 3 1 3 3 .520
F 3 9 5 3 3 * 597
G 1 7 1 2 3 . 2 3 4
H 2310 3 .364
I 1 6 6 8 3 . 2 2 2
J 5 4 1 2 . 7 3 3
K 2 2 5 2 .352
L 3918 3 . 5 9 3
M 4718 3 . 6 7 4
2ND
1 1 0 5 7 4 .044
284 2 . 4 5 3
1 7 5 3 3 .244
294 2 .468 1 4 3 0 8 4 . 1 5 6
90 3 2 .956
2 1 1 2 . 3 2 4
4 4 9 8 3 . 6 5 3
7 3 9 6 3 .869
0 0 .000
7 3 1 . 8 6 3
3 0 2 8 3 . 4 8 1
5 4 8 2 . 7 3 9
3RD
6 0 8 1 3 .784
1 1 0 2 3 . 0 4 2
3 7 6 5 3 .576
1 6 4 8 3 . 2 1 7
3 5 4 8 3 .550
2424 3 . 3 8 5
1 7 4 6 3 . 2 4 2
1 2 9 2 3 . 1 1 1
4374 3 . 6 4 1
1 4 0 2 . 1 4 6
7 3 2 2 . 8 5 5
4 4 1 7 3 . 6 4 5
3 9 1 2 3 . 5 9 2
4TH
4 2 2 6 3 .626
1 2 8 6 3 . 1 0 9
1 4 9 4 3 . 1 7 4
2 6 3 8 3 . 4 2 1
7 6 1 9 3 . 8 8 2
347 2 .540
2500 3 .398
2784 3 . 4 4 5 1 0 6 7 6 4 . 8 2 8
0 0 .000
2 0 0 2 3 . 3 0 1
3 4 4 8 3 .538
2 1 4 3 3 . 3 3 1
5TH
3 2 5 7 3 . 5 1 3
7 9 1 . 8 9 8
3384 3 . 5 2 9
1 2 8 4 3 . 1 0 9 2 3 1 1 1 4 .364
5 7 1 . 7 5 6
2 4 2 5 3 . 3 8 5
1 0 9 6 3 . 0 4 0
2 9 0 9 3 . 4 6 4
B 0 . 0 0 0
5 4 1 2 . 7 3 3
8 7 2 1 3 . 9 4 1
1 2 9 7 3 . 1 1 3
6TH
4 4 9 2 . 6 5 2
4 0 1 . 6 0 2
7 4 3 2 . 8 7 1 1 3 4 7 3 4 . 1 2 9 1 2 4 7 1 4 . 0 9 6
5 9 3 2 . 7 7 3
3784 3 . 5 7 8
2 5 3 1 3 . 4 0 3
4 5 1 . 6 5 3
0 0 . 0 0 0
2 3 1 2 .364
2 7 7 1 3 . 4 4 3
9 8 0 2 . 9 9 1
SUM
3 0 5 9 9 4 .486
7 9 0 7 3 . 8 9 8 1 7 3 7 6 4 .240 2 2 4 8 3 4 . 3 5 2 6 4 3 7 0 4 .809
8 2 7 7 3 . 9 1 8 1 2 3 7 8 4 . 0 9 3 1 4 5 1 1 4 . 1 6 2 2 7 0 6 8 4 . 4 3 2
6 8 1 2 . 8 3 3
3804 3 . 5 8 0 2 6 3 0 3 4 .420 1 3 5 9 8 4 . 1 3 3
APPENDIX 5 .2 1 5 7
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 6
LETTER POSITION 1ST
N 2043 3 .310
0 1398 3 .146
P 5827 3 .765
Q 70 1 . 8 4 5
R 4276 3 . 6 3 1
S 1 1 4 2 3 4 .058
T 3929 3 .594
U 1079 3 .033
V 1 0 7 3 3 . 0 3 1
W 2645 3 .422
X 0 0 .000
Y 140 2 .146
z 6 .778
2ND
3306 3 .519 10986 4.041
1154 3.062
1 6 6 2 .220
4923 3.692
862 2 .936
3427 3 .535
5252 3.720
1 8 3 2.262
308 2 .489
710 2 .851
665 2 .823
0 0 .000
3RD
4535 3 .657
6 7 1 5 3.827
1 3 9 8 3 .146
9 1 1 .959
9119 3.960
4710 3 .673
7 5 3 1 3 .877
2800 3 .447
1 6 0 6 3 .206
1 3 8 2 3 . 1 4 1
1 5 4 2 .188
999 3.000
74 1 .869
4TH
4451 3 .648
5 9 2 5 3 .773
2401 3 .380
6 4 1 . 8 0 6
3680 3 .566
2784 3 .445
7658 3 .884
5928 3 .773
984 2 .993
772 2 .888
1 3 1 .114
3 50 2 .544
1 2 2 2 .086
5TH
8 0 0 5 3 . 9 0 3
5 2 2 1 3 .718
786 2 .895
0 0 .000
6 1 8 8 3 . 7 9 2
2717 3 .434
3149 3 .498
1 0 2 7 3 .012
364 2 .561
1 1 0 2 . 0 4 1
3 . 477 4 94
2 .694 70
1 . 8 4 5
6TH
5286 3 .723
172 2 .236
1 0 9 2 .037
0 0 .000
8147 3 . 9 1 1 1 0 9 0 4 4 .038
6979 3 .844
6 1 1 . 7 8 5
0 0 .000
670 2 .826
3 1 1 . 4 9 1
5 8 2 5 3 .765
0 0 .000
S U M
27626 4 . 4 4 1 30417 4 .483 1 1 6 7 5 4 .067
391 2 .592 3 6 3 3 3 4 .560 33400 4 . 5 2 4 32673 4 .514 16147 4 .208
4210 3 .624
5887 3 .770
9 1 1 2 .960
8 4 7 3 3 .928
272 2 .435
158 CHAPTER 5
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 7
LETTER POSITION 1ST
A 4796 3 . 6 8 1
B 4147 3 .618
C 7268 3 .861
D 2846 3 .454
E 3068 3 .487
F 3548 3.550
G 1982 3 .297
H 3232 3 .509
I 1268 3 .103
J 471 2 .673
K 532 2 .726
L 1990 3 .299
M 3649 3 .562
2ND
6979 3 .844
407 2.610
946 2 .976
372 2 .571 1 5 6 5 5 4 .195
6 2 3 2 .794
663 2 .822
3963 3 .598
6 5 7 1 3 .818
0 0 .000
48 1 . 6 8 1
2524 3 .402
9 1 7 2 .962
3RD
7 3 5 3 3.866
690 2.839
3977 3.600
1 1 6 8 3 .067
4768 3 .678
1 1 6 2 3 . 0 6 5
1 4 9 3 3 .174
5 0 1 2 .700
4053 3 .608
1 6 7 2 .223
69 1 .839
3526 3 .547
2 9 2 3 3 .466
4TH
4582 3 .661
1 3 5 7 3 .133
2 9 2 1 3 .466
2263 3 .355
6532 3 . 8 1 5
8 5 9 2 .934
1564 3 .194
2243 3 .351
6 0 3 1 3 .780
2 54 2 .405
1280 3 .107
4545 3 .658
1730 3 .238
5TH
5253 3.720
6 1 1 2.786
1 7 3 5 3 .239
1 2 0 2 3.080 1 0 0 7 3 4 .003
4 58 2 .661
1 8 0 3 3 .256
2874 3 .458 1 5 1 1 5 4 .179
0 0 .000
524 2 .719
3125 3 .495
983 2 .993
6TH
5036 3.702
8 5 1 .929
2707 3.432
2059 3.314 1 6 8 3 5 4 .226
1 3 2 2 .121
2323 3 . 3 6 6
1 0 3 5 3 . 0 1 5
1 7 3 5 3 .239
0 0 .000
1 3 7 2 .137
4 4 3 3 3 .647
656 2 .817
7TH
567 2.754
1 9 1 . 2 7 9
3 55 2 .550
8884 3 .949
9106 3 .959
769 2.886
7 2 1 5 3 .858
1 6 4 4 3 .216
1 8 1 . 2 5 5
0 0 .000
1 2 0 2 .079
3830 3 .583
1 4 7 8 3 .170 4 .091
SUM
34566 4 .539
7316 3 .864 1 9 9 0 9 4 .299 18794 4 .274 66037 4 . 8 2 0
7 5 5 1 3 .878 1 7 0 4 3 4 .232 15492 4.190 34791 4 . 5 4 1
8 9 2 2 .950
2710 3 .433 23973 4 .380 1 2 3 3 6
APPENDIX 5 .2
SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 7
LETTER POSITION 1ST
N 1 6 2 8 3 .212
0 1460 3 .164
3 .783 Q 358
2 .554 R 3726
3 .571 S 8092
3 .908 T 3 7 3 1
3 .572 U 603
2 .780 V 1 0 4 3
3 .018 W 3289
3 .517 X 0
0 .000 Y 9 3
1 .968 2 7
.845
e 6067
2N D
3150 3 .498
8667 3 .938
1 2 1 1 3 . 0 8 3
1 1 3 2 .053
6 9 9 1 3 .845
558 2 .747
1976 3 .296
4693 3 .671
386 2 .587
1 6 1 2 .207
954 2 .980
366 2 . 5 6 3
0 0 .000
3RD
5166 3 . 7 1 3
5792 3 . 7 6 3
2154 3 .333
1 9 9 2.299
8487 3 .929
4162 3 .619
5538 3 . 7 4 3
2573 3.410
1 4 2 1 3 . 1 5 3
764 2 .883
314 2.497
392 2 .593
8 2 1 .914
4TH
3785 3 .578
2962 3 .472
2655 3 .424
26 1 .415
4046 3 .607
4055 3 .608
8 7 5 5 3.942
3082 3 .489
1 4 4 2 3 .159
1544 3 .189
0 0 .000
304 2 .483
77 1 .886
5TH 6TH
3401 1 1 6 2 3 3 . 5 3 2 4 . 0 6 5
5046 2700 3 .703 3 .431
994 576 2 .997 2 .760
2 3 0 1 . 3 6 2 0 .000
4 7 9 1 6193 3 .680 3 .792
1 2 2 4 4 2 3 3 3 .088 3 .627
4 2 1 5 3466 3 .625 3 .540
3862 1840 3 .587 3 .265
1 1 0 6 6 2 9 3 .044 2 .799
269 2 54 2 .430 2 .405
3 1 38 1 . 4 9 1 1 . 5 8 0
1 1 6 66 2 .064 1 .820
6 0 1 0 3 1 .778 2 .013
7TH
4650 3 .667
210 2 .322
1 3 8 2 .140
0 0 .000
4948 3 .694 1 2 0 5 4 4 .081
6324 3 .801
3 .477
0 0 .000
1 1 6 2 .064
1 1 4 2 .057
6 3 3 2 3 . 8 0 2
0 0 .000
1 5 9
SUM
3 3 4 0 3 4 .524 26837 4 .429 1 3 7 9 5 4 .140
719 2 .857 39182 4 .593 34378 4 .536 34005 4 .532 1 6 6 5 6 4 .222
6027 3 .780
6397 3 . 8 0 6
1 4 5 1 3 .162
7669 3 .885
329 2 .517
160 CHAPTER 5
Appendix 5 . 3
Bigram P o s i t i o n a l F r e q u e n c i e s (Token C o u n t s ) Accord ing t o S e r i a l P o s i t i o n and Word L e n g t h f o r Words
3 t o 7 L e t t e r s i n L e n g t h .
I n s t r u c t i o n s f o r u s i n g f r e q u e n c y t a b l e s
T h e s e c o u n t s were b a s e d on t h e same word t o k e n s a s were t h e s i n g l e - l e t t e r c o u n t s i n Appendix 5 . 2 . I n t h i s c a s e , however , e a c h word was b r o k e n down i n t o i t s b ig ram componen t s ( i . e . , b a t t l e - - - - > &, at, E, g , k) and t h e f r e q u e n c y o f o c c u r r e n c e o f e a c h o f t h e b i g r a m s was t a b u l a t e d f o r e a c h word l e n g t h . Fo r example , f o r s i x - l e t t e r w o r d s , t h e b i g r a m 9 o c c u r r e d a s t h e i n i t i a l b ig ram 1 8 5 t imes, a s t h e s e c o n d b ig ram 160 t imes, a s t h e t h i r d b i g r a m 1 4 8 t imes , e t c . N o t i c e t h a t 3 n e v e r o c c u r r e d a s t h e s i x t h b ig ram. A l s o n o t i c e t h a t t h e b ig ram do n e v e r o c c u r r e d a t a l l . A b i g r a m which d i d n o t o c c u r a t l e a s t o n c e f o r words o f a g i v e n l e n g t h was o m i t t e d from t h e l i s t i n g i n t h e t a b l e s .
I t s h o u l d b e n o t e d t h a t f o r some b i g r a m s , t h e f r e q u e n c y o f o c c u r r e n c e is z e r o i n some p o s i t i o n s . The l o g a r i t h m o f z e r o i s u n d e f i n e d , b u t f o r t h e p u r p o s e s o f t h e t a b l e s was se t e q u a l t o z e r o .
APPENDIX 5.2 1 6 1
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
AB 3 .477
AC 298 2.474
AD 9 8 1 .991
AF 5 .699
AG 473 2.675
A1 424 2.627
AK 0 0.000
AL 3008 3.478
AM 1 5 1.176
AN 3 0 2 3 2 4.480
A 0 0 0 .000
AP 1 8 1 . 2 5 5
AR 4736 3 .675
AS 1 4 4 2.158
A T 1 6 1 . 2 0 4
AU 25 1 . 3 9 8
AV 1 3 1 . 1 1 4
AW 5 .699
AX 6 .778
AY B 0.000
BA 348
2ND
1 2 1 .079
0 0 .000
5378 3 . 7 3 1
0 0 .000
7 5 1 . 8 7 5
0 0 .000
1 5 1 .176
3 3 1 .519
1 2 2 2 .086
3316 3 .521
24 1 . 3 8 0
9 8 1 . 9 9 1
1 3 2 4 3 .122
1 2 3 6 4 4 .092
414 2 .617
0 0 . 0 0 0
0 0 . 0 0 0
7 1 3 2.853
226 2 .354
3 9 7 1 3 .599
' 0 2 .542 0 .000
SUM
1 5 1.176
298 2.474
5476 3.738
5 .699
548 2.739
424 2.627
1 5 1.176
3 0 4 1 3.483
1 3 7 2.137
33548 4.526
24 1.380
1 1 6 2.064
6 0 6 0 3.782
1 2 5 0 8 4.097
4 30 2.633
2 5 1 .398
1 3 1 .114
7 1 8 2.856
2 3 2 2.365
3 9 7 1 3.599
348 2.542
1 6 2 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
BE 1 9 4 2 . 2 8 8
BI 492 2 . 6 9 2
BO 367 2 . 5 6 5
BU 4 5 0 1 3 . 6 5 3
C A 2108 3 .324
CE 0 0 .000
co 7 3 1 . 8 6 3
C R 48 1 . 6 8 1
CT 0 0 .000
CU 237 2 . 3 7 5
CY 0
DA 7 4 0 2 .869
DD 0 0 .000
DE 44 1 . 6 4 3
D I 1 1 5 2 3 . 0 6 1
DO 1 3 5 2 .130
DR 7 3 1 . 8 6 3
DS 0 0 . 0 0 0
DU 1 5 7 2 .196
EA 9 0 1 . 9 5 4
E B 0 0 .000
0 . 0 0 0
2 N D
3 . h77 0
0 . 0 0 0 0
0 .000 0
0 .000 0
0 . 0 0 0 6 0
1 . 7 7 8 0
0 . 0 0 0 0
0 . 0 0 0 307
2 .487 0
0 . 0 0 0 1 2
1 . 0 7 9 0
0 .000 1 3 2
2 . 1 2 1 0
0 . 0 0 0 0
0 . 0 0 0 0
0 .000 0
0 . 0 0 0 1 0
1 . 0 0 0 0
0 . 0 0 0 1 2 6
2 . 1 0 0 26
1 . 4 1 5
SUM
1 9 7 2 .294
492 2 .692
367 2 . 5 6 5
4 5 0 1 3 . 6 5 3
2 1 0 8 3 . 3 2 4
6 0 1 . 7 7 8
1 3 1 . 8 6 3
4 8 1 . 6 8 1
3 07 2 . 4 8 7
2 37 2 . 3 7 5
1 2 1 . 0 7 9
7 4 0 2 .869
1 3 2 2 . 1 2 1
4 4 1 . 6 4 3
1 1 5 2 3 . 0 6 1
1 3 5 2 .130
7 3 1 . 8 6 3
1 0 1 . 0 0 0
1 5 7 2 .196
2 1 6 2 .334
2 6 1 . 4 1 5
A P P E N D I X 5.2 1 6 3
B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 3
B I G R A M P O S I T I O N 1 S T
EC 0 0 .000
E D 0 0.000
E E 0 0.000
EG 25 1.398
E I 0 0.000
E L 3 .477
EM 0 0 .000
EN 410 2 .613
E O 0 0.000
E P 0 0.000
E R 30 1 . 4 7 7
E S 3 . 4 7 1
E T 58 1.763
EV 1 9 1.279
EW 0 0.000
EX 0 0.000
EY 1 2 2 2.086
FA 505 2.703
F E 679 2.832
FF 0 0.000
F I 1 6 1 2.207
2 N D
3 6 1.556
513 2.710
8 4 5 2.927
69 1 . 8 3 9
7 .845
1 6 1 . 2 0 4
8 ,903
1 0 8 3 3 .035
7 .845
1 3 1.114
3408 3 .532
1 5 5 2.190
2243 3 . 3 5 1
3 3 1 . 5 1 9
2262 3.354
9 7 1 . 9 8 7
1 0 3 2 .013
0 0 .000
0 0 . 0 0 0
6 3 9 2.805
0 0.000
SUM
3 6 1.556
513 2.710
8 4 5 2.927
9 4 1.973
7 .845
1 9 1 . 2 7 9
8 .903
1 4 9 3 3.174
7 .845
1 3 1.114
3438 3.536
1 5 8 2.199
2 3 0 1 3 .362
5 2 1 .716
2262 3 .354
9 7 1 . 9 8 1
225 2.352
505 2.703
679 2.832
6 3 9 2.806
1 6 1 2.207
1 6 4 C H A P T E R 5
B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R L E N G T H 3
B I G R A M P O S I T I O N 1ST
FL 5 1 1.708
FO 9 5 3 5 3.979
FT 0 0.000
FU 57 1.756
G A 1 5 4 2.188
G E 7 8 1 2.893
GG 0 0.000
G I 27 1 . 4 3 1
GO 8 1 9 2.913
GU 1 8 6 2 .270
HA 7 6 9 4 3.886
HE 3078 3.488
H I 9 7 4 7 3.989
HO 9 7 0 2.987
HU 26 1 .415
H Y 0 0.000
I A 0 0.000
I C 57 1 . 7 5 6
I D 0 0.000
I E 0 0 .000
I G 0 0.000
2ND
0 0.000
0 0.000
5 .699
0 0.000
0 0.000
2 27 2.356
1 2 1 . 0 7 9
0 0.000
259 2.413
0 0.000
0 0.000
7 2 8 3 0 4 .862
0 0.000
2252 3.353
0 0.000
429 2.632
48 1 .681
8 .903
1 3 0 1 3.114
1 6 9 2.228
455 2.658
SUM
5 1 1.708
9 5 3 5 3.979
5 .699
5 7 1 .756
1 5 4 2.188
1 0 0 8 3.003
1 2 1 .079
27 1 . 4 3 1
1 0 7 8 3.033
1 8 6 2.270
7 6 9 4 3.886
7 5 9 0 8 4 .880
9 7 4 7 3.989
3 2 2 2 3.508
26 1 .415
4 29 2.632
4 8 1 .681
6 5 1.813
1 3 0 1 3.114
1 6 9 2 .228
455 2.658
APPENDIX 5.2 1 6 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
IK 4 .602
IL 39 1 . 5 9 1
IM 0 0.000
IN 36 1 . 5 5 6
I 0 6 .778
IP 0 0 .000
IR 0 0.000
IS 0 0.000
IT 1858 3 .269
IV 9 .954
IX 0 0.000
J A 77 1.886
J E 63 1 . 7 9 9
JI 36 1 . 5 5 6
J O 3 3 3 2 .522
JU 6 .778
KA 2 1 1.322
KE 1 0 0 2 .000
KI 6 1 1 .785
KY 0 0 .000
LA 4 9 1 2 .691
2ND
0 0.000
9 3 1 .968
2 7 4 1 3 .438
1 6 8 2 .225
4 .602
88 1 . 9 4 4
352 2,547
6997 3.845
413 2.616
0 0 .000
247 2.393
0 0.000
0 0.000
0 0.000
0 0.000
0 0 .000
0 0 .000
4 .602
0 0 .000
58 1 . 7 6 3
1 7 1.230
SUM
4 .602
1 3 2 2 . 1 2 1
2 7 4 1 3.438
204 2.310
1 0 1 . 0 0 0
8 8 1 .944
352 2.547
6997 3 .845
2 2 7 1 3.356
9 .954
247 2.393
7 7 1 .886
63 1 .799
36 1 .556
333 2.522
6 .778
2 1 1.322
1 fl4 2.017
6 1 1 .785
58 1.763
508 2.706
1 6 6 C H A P T E R 5
BIGRAM F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 3
B I G R A M P O S I T I O N 1ST
LD 0 0.000
L E 6 1 8 2 .791
L I 1 1 3 2.053
L L 0 0 .000
LM 0 0.000
L O 377 2 .576
L T 5 .699
LU 0 0.000
L Y 0 0.000
MA 2690 3.430
ME 8 9 5 2.952
M I 1 3 1.114
MO 1 6 1 .204
MR 534 2.728
MU 3 2 1 .505
MY 0 0.000
NA 1 7 1 .230,
NC 0 0.000
ND 0 0 .000
N E 1 6 6 9 3.222
N I 3 ,477
2 N D
6 6 0 2.820
0 0.000
0 0.000
3040 3 .483
3 . 4 1 1
0 0.000
0 0 .000
8 .903
3 8 1.580
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
1 5 1 .176
0 0.000
20 1 . 3 0 1
29265 4.466
3 2 9 2 3.517
0 0.000
SUM
6 6 0 2.820
6 1 8 2 .791
1 1 3 2.053
3040 3.483
3 .417
377 2.576
5 .699
8 .903
3 8 1 . 5 8 0
2690 3 .430
8 9 5 2.952
1 3 1 . 1 1 4
1 6 1.204
534 2.728
32 1 .505
1 5 1 . 1 7 6
1 7 1 . 2 3 0
20 1 . 3 0 1
2 9 2 6 5 4.466
4 9 6 1 3.696
3 .477
APPENDIX 5.2 1 6 7
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
NK 0 0.000
NN 0 0.000
NO 6 1 6 1 3.790
NT 0 0 .000
NU 1 5 1 . 1 7 6
NY 0 0.000
OA 1 5 1 . 1 7 6
OB 0 0 .000
oc 24 1 .380
OD 44 1 . 6 4 3
OE 0 0.000
OF 6 3 9 2 .806
OG 0 0 . 0 0 0
01 93 1 .968
OL 6 6 0 2 .820
OM 0 0 . 0 0 0
ON 3292 3 . 5 1 7
00 0 0 . 0 0 0
OP 0 0 .000
OR 3 .477
0s 0 0 .000
2ND
7 . 8 4 5
38 1 . 5 8 0
0 0.000
6 .778
0 0 .000
1 3 4 5 3 .129
0 0.000
307 2.487
2 3 1 .362
3 57 2 .553
8 1 1.908
0 0 . 0 0 0
1 1 4 2.057
0 0.000
1 0 1.000
6 6 1 .820
3 0 6 2 .486
2 .926
230 2 .362
9 6 8 4 3.986
5 2 1 . 7 1 6
a 4 4
SUM
7 .845
3 8 1 . 5 8 0
6 1 6 1 3.790
6 .778
1 5 1 . 1 7 6
1 3 4 5 3.129
1 5 1 . 1 7 6
3 07 2 .487
47 1 . 6 7 2
4 0 1 2 .603
8 1 1 . 9 0 8
639 2.806
1 1 4 2.057
93 1.968
6 7 0
6 6
3 5 9 8 3.556
8 4 4 2 .926
230 2 .362
9 6 8 7 3 .986
52 1 . 7 1 6
2.826
1 . 8 2 0
1 6 8 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
OT 0 0.000
ou 3348 3.525
ov 0 0 .000
OW 7 8 2 2.893
ox 0 0 .000
OY 0 0.000
PA 253 2.403
PE 400 2 .602
PI 7 5 1 .875
PO 40 1 . 6 0 2
PR 22 1 . 3 4 2
PT 0 0.000
PU 437 2 .640
PY 0 0.000
QU 11 1 . 0 4 1
RA 2 1 2 2.326
RC 0 0.000
RE 248 2.394
RI 3 9 1 . 5 9 1
RM 0 0.000
RO 1 2 1 2.083
2 N D
5397 3.732
3 2 9 9 3.518
40 1 .602
2405 3 .381
1 0 1 2.004
327 2.515
0 0 .000
3 .477
0 0 .000
0 0.000
0 0.000
1 5 1 .176
0 0.000
9 . 9 5 4
0 0.000
30 1.477
4 1 1 . 6 1 3
4 3 9 6 3.643
0 0 .000
9 4 1.973
1 6 1.204
SUM
5 3 9 7 3.732
6 6 4 7 3 .823
4 0 1 .602
3187 3.503
1 0 1 2 .004
3 27 2.515
253 2.403
403 2.605
7 5 1 .875
40 1.602
2 2 1 . 3 4 2
1 5 1 .176
437 2.640
9 . 9 5 4
11 1 . 0 4 1
2 4 2 2.384
4 1 1 . 6 1 3
4644 3.667
3 9 1 . 5 9 1
9 4 1.973
1 3 7 2.137
APPENDIX 5.2 1 6 9
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
RS 0 0 .000
RT 0 0 .000
RU 240 2.380
RY 4 .602
S A 1 1 9 4 3.077
SE 1 4 1 4 3.150
3 .458
SI 439 2.642
SK 58 1 . 7 6 3
SL 5 .699
SO 1 8 5 2.267
SP 9 .954
ss 0 0.000
ST 0 0.000
SU 1 7 8 2 .250
TA 2 4 1 2.382
TC 0 0.000
TD 0 0 .000
TE 208 2.318
TH 69983 4 .845
TI 8 2 1 . 9 1 4
sn 2872
2N D
5 3 9 2.732
208 2.318
0 0.000
267 2.427
0 0.000
589 2.770
11 1 . 0 4 1
0 0.000
1 2 8 2.107
0 0.000
0 0.000
0 0 .000
5 .699
3 .477
0 0.000
0 0.000
5 8 1.763
5 .699
1 6 1.204
0 0.000
0 0 .000
SUM
5 39 2.732
208 2.318
240 2.380
2 7 1 2.433
1194 3.077
2003 3 .302
2883 3.460
439 2.642
1 8 6 2.270
5 .699
1 8 5 2.267
9 - 9 5 4
5 .699
3 .477
1 7 8 2.250
2 4 1 2.382
5 8 1 . 7 6 3
5 .699
224 2.350 6 9 9 8 3 4.845
8 2 1 .914
170 C H A P T E R 5
BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 3
BIGRAM P O S I T I O N 1ST
TO 1125 3.051
TR 140 2.146
TS 0 0.000
TU 16 1.204
TW 1412 3.150
UB 0 0.000
UD 0 0.000
UE 0 0.000
UG 0 0.000
UH 0 0.000
U M 0 0.000
UN 3 .477
uo 0 0.000
UP 0 0.000
UR 0 0.000
U S 589 2.770
U T 0 0.000
UY 0 0 * 000
VA 32 1.505
VE 0 0.000
V I 52 1.716
2N D
0 0.000
0 0.000 1858
3.269 0
0.000 0
0.000 19
1.279 41
1.613 166
2.220 65
1.813 5
,699 74
1.869 486
2.687 11
1.041 45
1.653 1268 103 37
568 134 853 121 083
0 0.000
32 1.505
0 0.000
S U M
1125 3.051
140 2.146 1858
3.269 16
1.204 1412
3.150 19
1.279 41
1.613 166
2.220 65
1.813 5
.699 74
1.869 489
2.689 11
1.041 45
1.653 1268
3.103 626
2.797 7134
3.853 121
2.083 32
1.505 32
1.505 52
1.716
APPENDIX 5.2 1 7 1
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3
BIGRAM POSITION 1ST
vo 9 . 9 5 4
VY 0 0 . 0 0 0
WA 1 1 2 0 3 4 . 0 4 9
WE 6 4 1 . 8 0 6
WH 2 6 5 6 3 . 4 2 4
WI 7 5 1 . 8 7 5
WN 0 0 . 0 0 0
wo 7 6 1 . 8 8 1
W R 5 . 6 9 9
XE 0 0 . 0 0 0
YE 5 6 9 2 . 7 5 5
YO 3 2 8 6 3 . 5 1 7
ZE 2 6 1 . 4 1 5
zo 9 . 9 5 4
2 N D
0 0 . 0 0 0
9 . 9 5 4
0 0 . 0 0 0
1 5 1 . 1 7 6
0 0 . 0 0 0
0 0 . 0 0 0
7 7 2 2 .888
1 4 1 2 3 .150
0 0 . 0 0 0
6 . 7 7 8
1 2 6 2 . 1 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
SUM
9 . 9 5 4
9 . 9 5 4
1 1 2 0 3 4 . 0 4 9
7 9 1 . 8 9 8
2 6 5 6 3 .424
7 5 1 . 8 7 5
7 7 2 2 . 8 8 8
1 4 8 8 3 . 1 7 3
5 . 6 9 9
6 . 7 7 8
6 9 5 2 . 8 4 2
3 2 8 6 3 .517
2 6 1 . 4 1 5
9 . 9 5 4
172 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
AB 236 2.373
AC 65 1.813
AD 54 1.732
AF 0 0.000
AG 69 1.839
AH 0 0.000
A1 62 1.792
AK 10 1.000
AL 1127 3.052
AM 33 1.519
AN 98 1.991
A0 0 0.000
AP 4 .602
AQ 0 0.000
AR 660 2.820
AS 62 1.792
AT 47 1.672
AU 44 1.643
AV 0 0.000
AW 461 2.664
AX 45 1.653
2ND
70 1.845 3085
3.489 1210
3.083 82
1.914 178
2.250 0
0.000 3156
3.499 1569
3.196 1667
3.222 1958
3.292 2519
3.401 64
1.806 124
2.093 0
0.000 2197
3.342 2345
3.370 988
2.995 51
1.708 4415
3.645 158
2.199 16
3RD
33 1.519
0 0.000 1191
3.076 28
1.447 39
1.591 31
1.491 0
0.000 55
1.740 593
2.773 231
2.364 2390
3.378 0
0.000 95
1.978 3
.477 1427
3.154 52
1.716 13013 4.114
0 0.000
0 0.000
74 1.869
0
SUM
339 2.530 3150
3.498 2455
3.390 110
2.041 286
2.456 31
1.491 3218
3.508 1634
3.213 3381
3.530 2222
3.347 5007
3.700 64
1.806 223
2.348 3
.477 4284 3.632 2459
3.391 14048 4.148
95 1.978 4415
3.645 693
2.841 61 ~-
1.204 0.000 1.785
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
AY 0 0.000
AZ 0 0.000
BA 1 5 7 9 3.198
BE 3186 3.503
BI 214 2.330
BL 217 2.336
BO 1 8 0 3 3.256
BR 1 4 1.146
BS 0 0.000
B T 0 0.000
BU 244 2.387
BY 9 .954
CA 1 8 3 7 3.264
CE 223 2.348
C H 7 3 1 . 8 6 3
CI 400 2.602
CK 0 0.000
CL 279 2.446
CO 1 5 1 4 3.180
CR 56 1.748
C T 0 0.000
2ND
7 6 3 2.883
1 5 1 2.179
0 0 .000
28 1 .447
0 0.000
216 2.334
0 0 .000
0 0 .000
0 0 .000
0 0.000
0 0 .000
0 0 .000
1 5 1 .176
0 0.000
1 4 1 .146
1 3 1.114
0 0 .000
0 0.000
0 0.000
9 .954
39 1 . 5 9 1
3RD
1 0 0 4 3 .002
0 0.000
47 1 .672
4 8 1 . 6 8 1
0 0.000
0 0.000
0 0.000
0 0.000
8 3 1 .919
1 3 1.114
0 0 .000
6 2 1 .792
0 0 .000
1 1 9 6 3.078
3267 3.514
0 0.000
1 7 0 6 3.232
0 0.000
2 1 1.322
0 0.000
4 58 2 . 6 6 1
SUM
1 7 6 7 3 .247
1 5 1 2.179
1 6 2 6 3 . 2 1 1
3 2 6 2 3 .513
214 2.330
433 2.636
1 8 0 3 3 .256
1 4 1 . 1 4 6
8 3 1 .919
1 3 1 . 1 1 4
244 2.387
7 1 1 . 8 5 1
1 8 5 2 3.268
1 4 1 9 3.152
3 3 5 4 3.526
413 2 .616
1 7 0 6 3 .232
2 7 9 2.446
1 5 3 5 3 .186
6 5 1 . 8 1 3
497 2.696
1 7 3
174 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
CU 148 2.170
CY 0 0.000
DA 1004 3.002
DD 0 0.000
DE 717 2.856
DG 0 0.000
DI 268 2.428
DL 0 0.000
DN 0 0.000
DO 2146 3.332
DR 238 2.377
DS 0 0.005
DU 234 2.369
DY 7 .845
E A 1296 3.113
EB 0 0.000
EC 10 1.000
ED 90 1.954
EE 0 0.050
EF 0 0.000
EG 35 1.544
2ND
0 0.000
0 0.000
44 1.643
24 1.380
204 2.310
78 1.892
0 0.000
19 1.279
3 .477
21 1.322
0 0.000
0 0.000
0 0.050
0 0.000 3589
3.555 13
1.114 119
2.076 16
1.204 5115
3.709 487
2.688 6 7
1.826
3RD
0 0.000
49 1.690
0 0.000
0 0.000 1851
3.267 3
.477 0
0.000 0
0.000 0
0.000 3
.477 0
0.000 204
2.310 0
0.000 401
2.603 529
2.723 0
0.000 0
0.000 1414
3.150 371
2.569 41
1.613 0
0.000
SUM
148 2.170
49 1.690 1048
3.020 24
1.380 2772
3.443 81
1.908 268
2.428 19
1.279 3
.477 2170
3.336 238
2.377 204
2.310 234
2.369 408
2.611 5414
3.734 13
1.114 129
2.111 1520
3.182 5486
3.739 528
2.723 102
2.009
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
EI 0 0.000
EK 0 0 .000
EL 1 7 6 2.246
EM 1 0 1 .000
EN 7 3 1 . 8 6 3
EO 0 0 . 0 0 0
EP 1 8 1 . 2 5 5
ER 3 .477
ES 0 0.000
ET 0 0.000
EU 0 0 .000
EV 1 5 8 8 3 . 2 0 1
EW 0 0 . 0 0 0
EX 7 .845
EY 4 0 8 2 . 6 1 1
FA 1 3 9 0 3.143
FE 1 2 3 3 3 . 0 9 1
FF 0 0 .000
FI 1 4 8 0 3 .170
FL 2 4 2 2.384
FO 1 2 0 4 3 . 0 8 1
2ND
46 1 .663
0 0.000
2 5 1 2 3 .400
0 0.000
1 1 5 8 3 .064
1 9 1 . 2 7 9
238 2.377
5130 3 .710
1 4 5 0 3 .161
1 8 6 2.270
0 0.000
1 0 1 . 0 0 0
1 5 9 2 . 2 0 1
454 2.657
34 1 . 5 3 1
0 0.000
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0.000
3 R D
0 0.000
3 4 4 2.537
276 2 . 4 4 1
2 1 4 9 3 .332
8 0 3 7 3 .905
0 0 . 0 0 0
534 2 .728
1 6 4 6 3 .216
1 3 9 4 3 .144
567 2.754
5 .699
0 0 .000
8 0 3 2.905
3 4 1 . 5 3 1
3 6 4 5 3 .562
6 .778
1 0 2 1 3 .009
5 .699
0 0 .000
0 8 .000
0 0.000
SUM
4 6 1 . 6 6 3
3 4 4 2 .537
2 9 6 4 3.472
2 1 5 9 3 .334
9 2 6 8 3 . 9 6 7
19 1 .279
7 9 0 2 .898
6 7 7 9 3 . 8 3 1
2 8 4 4 3 .454
7 5 3 2 .877
5 .699
1 5 9 8 3.204
9 6 2 2 .983
4 9 5 2 .695
4 0 8 7 3 . 6 1 1
1 3 9 6 3.145
2 2 5 4 3 .353
5 . 6 9 9
1 4 8 0 3 .170
2 4 2 2 .384
1 2 0 4 3 .081
1 7 5
1 7 6 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
FR 4662 3.669
FT 0 0.000
FU 3 4 5 2.538
FY 0 0 .000
GA 5 8 3 2.766
GE 1 0 3 2 .013
GG 0 0 .000
GH 0 0 .000
GI
GL
GN
2
1
0
3 GO
GR
6 4 7 8 1 1
6 1 7 8 5
0 0 0 0
296 1 1 3
292 2.465
GS 0 D . O O O
GU 1 0 9 2.037
HA 5393 3.732
HE 2247 3 .352
HI 658 2.818
HN 0 0.000
HO 1 2 7 6 3.106
HR 0 0.000
2 N D
0 0 .000
0 0 .000
0 0 .000
0 0.000
0 0.000
69 1 . 8 3 9
35 1 .544
0 0.000
0 0.000
2 1 1 . 3 2 2
0 0.000
3 .477
0 0.000
0 0.000
0 0.000
1 4 3 1 7 4 .156
9 1 52 3.962
5500 3 .740
0 0 .000
6 4 8 2.812
1 0 1.000
3RD
0 0 .000
6 0 1 2.779
0 0.000
7 .845
1 3 1 .114
304 2 .483
0 0.000
517 2.713
0 0.000
0 PI. 0 0 0
9 4 1 . 9 7 3
0 0 .000
0 0.000
2 4 1 2.382
0 0.000
0 0.000
4 .602
0 0 .000
362 2.559
1 0 1 . 0 0 0
0 0.000
SUM
4662 3.669
6 0 1 2.779
3 4 5 2.538
7 .845
5 9 6 2.775
476 2.678
35 1.544
517 2.713
6 4 7 2 . 8 1 1
8 2 1.914
9 4 1 .973
1 2 9 9 3.114
292 2.465
2 4 1 2.382
1 0 9 2.037
1 9 7 1 0 4.295
1 1 4 0 3 4.057
6158 3.789
362 2.559
1 9 3 4 3.286
1 0 1 .000
APPENDIX 5 . 2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
H U 201 2 .303
HY 9 . 954
I A 0 0.000
I B 0 0 .000
I C 0 0 .000
I D 2 2 1 2 .344
I E 0 0 .000
I F 0 0 .000
I G 3 .477
I K 0 0 .000
I L 9 - 9 5 4
I M 0 0 .000
I N 1 8 3 1 3 . 2 6 3
I 0 1 3 1 . 1 1 4
I P 0 0 .000
I R 46 1 . 6 6 3
I S 5 . 699
I T 59 1 . 7 7 1
IV 4 .602
I Z 0 0 .000
J A 261 2 .417
2ND
361 2 .558
0 0 .000
2 1 1 .322
11 1 . 0 4 1
447 2 .650
666 2 .823
433 2 .636
999 3 .000
6 3 1 2 . 8 0 0
1 4 2 6 3 .154
3093 3 .490
1 6 4 9 3 .217
2217 3 .346
30 1 . 4 7 7
1 3 4 2 .127
687 2 .837
839 2 .924
7847 3 .895
877 2 .943
1 3 8 2 .140
0 0 .000
3RD
0 0 .008
0 0 .000
44 1 . 6 4 3
0 0 .000
28 1 .447
2205 3 .359
0 0 .000
0 0 .000
0 0 .000
0 0 .000
4 27 2 .630
7 3 1 .863
698 2 .844
47 1 . 6 7 2
2 54 2 .405
292 2 .465
5199 3 .716
309 2 .490
0 0 .000
5 .699
0 0 .000
SUM
562 2 .750
9 .954
6 5 1 . 8 1 3
11 1 . 0 4 1
4 7 5 2 .677
3172 3 . 5 0 1
4 3 3 2 .636
999 3 .000
634 2 .802
1 4 2 6 3 .154
3529 3 .548
1 7 2 2 3 .236
4746 3 .676
9 0 1 . 9 5 4
388 2 .589
1 0 2 5 3 . 0 1 1
6 0 4 3 3 . 7 8 1
8 2 1 5 3 .915
8 8 1 2 .945
1 4 3 2 . 1 5 5
2 6 1 2 .417
1 7 7
1 7 8 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
J E 9 7 1 . 9 8 7
JI 7 . 8 4 5
J O 5 3 9 2 . 7 3 2
J U 1 1 4 7 3 . 0 6 0
K A 48 1 . 6 8 1
K E 5 2 8 2 . 7 2 3
K I 5 2 9 2 . 7 2 3
KL 0 0 . 0 0 0
K N 1 1 3 6 3 . 0 5 5
K O 11 1 . 0 4 1
KS 0 0 .000
LA 1 6 5 4 3 . 2 1 9
LB 0 0 .000
LD 0 0 .000
LE 1 2 2 8 3 .089
LF 0 0 .000
LG 0 0 . 0 0 0
L I 2835 3 . 4 5 3
LK 0 0 . 0 0 0
LL 0 0 . 0 0 0
LM 0 0 . 0 0 0
2ND
0 0 .000
0 0 . 0 0 0
0 0 .000
0 0 .000
20 1 . 3 0 1
0 0 .000
6 2 1 . 7 9 2
3 . 4 7 7
0 0 . 0 0 0
0 0 .000
0 0 .000
6 6 3 2 . 8 2 2
0 0 . 0 0 0
3 . 4 7 7 118
2 . 0 7 2 0
0 . 0 0 0 6
.778 7 9
1 . 8 9 8 0
0 .000 1 8
1 . 2 5 5 0
0 . 0 0 0
3RD
0 0 . 0 0 0
0 0 .000
0 0 .000
0 0 .000
0 0 . 0 0 0
3 0 4 8 3 .484
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 .000
1 8 1 . 2 5 5
1 0 1 . 0 0 0
7 . 8 4 5 1 2 6 4
3 . 1 0 2 8 6 6
2 .938 3 8 8
2 . 5 8 9 0
0 . 0 0 0 0
0 . 0 0 0 3 6 5
2 .562 5 3 7 9
3 . 7 3 1 1 5 7
2 . 1 9 6
SUM
9 7 1 . 9 8 7
7 . 8 4 5
5 3 9 2 . 7 3 2
1 1 4 7 3 .060
6 8 1 . 8 3 3
3 5 7 6 3 . 5 5 3
5 9 1 2 . 7 7 2
3 . 4 7 7 1 1 3 6
3 . 0 5 5 11
1 . 0 4 1 1 8
1 . 2 5 5 2327
3 .367 7
. 8 4 5 1 2 6 7
3 . 1 0 3 2 2 1 2
3 . 3 4 5 3 8 8
2 .589 6
. 7 7 8 2914
3 .464 365
2 .562 5 3 9 7
3 .732 1 5 7
2 .196
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
LO 2032 3.308
LP 0 0.000
LS 0 0.000
LT 0 0.000
LU 144 2.158
LV 0 0.000
LY 5 .699
MA 3631 3.560
MB 0 0.000
ME 504 2.702
MI 895 2.952
MM 0 0.000
MN 0 0.000
MO 3751 3.574
MP 0 0.000
MS 0 0.000
MU 1961 3.292
MY 35 1.544
NA 350 2.544
NC 0 0.000
ND 0 0.000
2N D
2 54 2.405
0 0.000 1245
3.095 4
.602 449
2.652 4
.602 0
0.000 0
0.000 0
0.000 19
1.279 14
1.146 10
1.000 0
0.000 0
0.000 0
0.000 0
0.000 7
.845 0
0.000 12
1.079 539
2.732 102
2.009
3RD
11 1.041
316 2.500
24 1.380
508 2.706
0 0.000
0 0.000 1930
3.286 54
1.732 82
1.914 6252
3.796 0
0.000 0
0.000 43
1.633 0
0.000 178
2.250 161
2.207 0
0.000 132
2.121 10
1.000 10
1.000 2140
3.330
SUM
2297 3.361
316 2.500 1269
3.103 512
2.709 593
2.773 4
.602 1935
3.287 3685
3.566 82
1.914 6775
3.831 909
2.959 10
1.000 43
1.633 3751
3.574 178
2.250 161
2.207 1968
167 2.223
372 2.571
549 2.740 2242
3.351
3.294
179
1 8 0 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
NE 1 1 9 6 3.078
NG 0 0.000
NI 1 8 1 2.258
NK 0 0.000
NL 0 0 .000
NN 0 0.000
NO 330 2.519
NS 0 0.000
NT 0 0 .000
N U 6 2 1.792
NV 0 0.000
NY 0 0.000
OA 1 3 1 .114
OB 8 .903
oc 0 0.000
OD 28 1.447
OE 0 0.000
OF 0 0 .000
OG 0 0.000
OH 3 8 1.580
01 2 5
2 N D
5 5 2 2.742
0 0.000
1 1 3 2.053
0 0.000
1 7 4 7 3.242
49 1 .690
7 5 5 2.878
0 0.000
1 8 7 7 3.273
0 0.000
7 .845
0 0.808
608 2.784
8 1 1.908
1 2 3 2.090
3 9 5 2.597
746 2.873
67 1 .826
7 8 1.892
362 2.559
1 8 9 1 .398 2.276
3 R D
1 7 0 1 3 .231
1 2 4 5 3.095
0 0.000
3 0 8 2 .489
0 0.000
2 5 1 .398
7 .845
304 2.483
1 3 4 9 3 .130
5 .699
0 0.000
1 1 6 1 3.065
0 0 .000
4 ,602
1 0 1.000
1 0 5 3 3.022
1 4 1.146
63 1.799
0 0.000
0 0.000
0 0.000
SUM
3 4 4 9 3.538
1 2 4 5 3 .095
294 2.468
3 08 2.489
1 7 4 7 3.242
74 1.869
1 0 9 2 3.038
304 2.483
3226 3.509
67 1.826
7 .845
1 1 6 1 3.065
6 2 1 2.793
9 3 1.968
1 3 3 2.124
1 4 7 6 3.169
7 6 0 2 .881
1 3 0 2.114
7 8 1.892
400 2.602
214 2.330
A P P E N D I X 5.2
BIGRAM F R E Q U E N C I E S FOR WORDS OF L E T T E R LENGTH 4
BIGRAM P O S I T I O N 1ST
OK 23 1 .362
OL 6 .778
OM 0 0.000
ON 2 4 2 2 3.384
00 0 0.000
OP 3 2 2 2 .508
OR 27 1 . 4 3 1
0s 0 0.000
OT 3 .477
ou 27 1 . 4 3 1
OV 1 2 5 1 3 .097
ow 58 1 . 7 6 3
ox 1 0 1.000
OY 0 0.000
P A 1 6 3 8 3 .214
P E 1 0 4 2.017
PH 65 1 . 8 1 3
P I 269 2.430
PL 560 2.748
PO 6 6 6 2 .823
P R 3 0 1.477
2 N D
3 9 1 . 5 9 1
1 3 6 3 3 .134
2934 3.467
1 8 5 4 3 .268
3703 3.569
330 2.519
4755 3,677
2065 3.315
9 9 3 2.997
1 5 8 2 3.199
410 2.613
1 2 0 9 3.082
0 0 .000
1 7 0 2.230
28 1 .447
332 2 . 5 2 1
0 0 .000
3 4 1 . 5 3 1
0 0 .000
552 2.742
0 0.000
3 R D
1 0 7 0 3.029
267 2.427
4952 3 .695
867 2.938
0 0 .000
302 2.480
4 5 1 2.654
6 4 1 .806
373 2.572
1 4 1.146
0 0.000
1 2 8 6 3 .109
5 .699
3 .477
40 1 . 6 0 2
558 2.747
0 0.000
0 0 .000
0 0.000
0 0 .000
0 0 .000
S U M
1 1 3 2 3 .054
1 6 3 6 3 .214
7 8 8 6 3 .897
5 1 4 3 3 . 7 1 1
3 7 0 3 3 .569
9 54 2 .980
5233 3 .719
2 1 2 9 3.328
1 3 6 9 3.136
1 6 2 3 3.210
1 6 6 1 3.220
2 5 5 3 3 .407
1 5 1 . 1 7 6
1 7 3 2.238
1 7 0 6 3 .232
9 9 4 2.997
6 5 1 . 8 1 3
3 0 3 2 . 4 8 1
5 6 0 2 .748
1 2 1 8 3 .086
3 0 1 . 4 7 7
181
1 8 2 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1 S T 2ND
PS 0 0 0 .000 0 .000
PT 0 0 0 .000 0 .000
PU 1 8 6 3 2 2 .270 1 . 5 0 5
PY 0 0 0 .000 0 .000
QU 1 5 0 1 .176 0 .000
RA 5 6 1 273 2 .749 2 .436
RB 0 0 0 .000 0 .000
RC 0 1 3 0 .000 1 . 1 1 4
RD 0 0 0 .000 0 .000
RE 706 8 6 0 2 .849 2.934
RF 0 0 0 .000 0 .000
RG 0 2 1 0 .000 1 .322
R I 424 1 7 6 2 .627 2 .246
RK 0 0 0 .000 0 .000
RL 0 0 0 .000 0 .000
RM 0 253 0 .000 2 .403
R N 0 0 0 .000 0 .000
RO 1 1 6 2 4586 3 . 0 6 5 3 .661
RP 0 0 0 .000 0 .000
R R 0 0 0 .000 0 .000
RS 0 0 0 .000 0 .000
3RD SUM
1 6 4 1 6 4 2 .215 2 . 2 1 5
240 240 2 .380 2.380
0 218 0 .000 2 .338
38 38 1 . 5 8 0 1 .580
0 1 5 0 .000 1 . 1 7 6
1 9 8 5 3 1 . 2 7 9 2 .931
27 27 1 . 4 3 1 1 . 4 3 1
0 1 3 0 .000 1 .114
747 747 2 .873 2 .873
7 3 7 5 8 9 4 1 3 . 8 6 8 3 .951
3 3 .477 .477
0 2 1 0 .000 1 . 3 2 2
6 606 .778 2 .782 1 4 7 5 1 4 7 5
3 .169 3 .169 283 283
2 .452 2 .452 792 1 0 4 5
2 .899 3 .019 5 5 5 5 5 5
2 .744 2 .744
1 . 8 8 1 3 .765 7 6 5824
1 3 1 3 1 .114 1 .114
22 22 1 . 3 4 2 1 . 3 4 2
280 288 2 .459 2 .459
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
RT 0 0.000
RU 2 2 2 2.346
RX 0 0.000
RY 0 0 .000
SA 3 2 1 1 3.507
sc 1 5 1 . 1 7 6
SE 1 1 6 0 3.064
SH 6 2 8 2.798
SI 8 3 7 2.923
SK 5 2 1 .716
SL 1 6 6 2.220
SM 7 .845
SN 7 1 1 . 8 5 1
SO 2387 3 .378
SP 1 3 9 2.143
ss 0 0 .000
S T 448 2 . 6 5 1
SU 1 6 6 5 3 .221
sw 29 1 .462
SY 0 0.000
TA 1 0 2 2 3 .009
2ND
6 6 1.820
266 2.425
0 0.000
0 0 .000
0 0.000
0 0 .000
6 7 5 2.829
0 0 .000
44 1 . 6 4 3
1 8 1 .255
5 .699
0 0 .000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
1 5 9 2 . 2 0 1
3 R D
8 4 5 2.927
1 4 1.146
8 .903
1 0 5 0 3 .021
0 0.000
6 .778
1 0 5 7 3.024
342 2.534
0 0.900
2 32 2.365
0 0 .000
0 0.000
0 0.000
1 0 8 0 3.033
3 .477
1 0 9 2 3 .038
6087 3.784
0 0.000
0 0 .000
1 9 2 2.283
173 2.238
SUM
9 1 1 2.960
5 0 2 2 . 7 0 1
8 . 9 0 3
1 0 5 0 3 . 0 2 1
3 2 1 1 3.507
2 1 1 .322
2 8 9 2 3 .461
9 7 0 2.987
8 8 1 2 .945
3 0 2 2 .480
1 7 1 2 .233
7 . 8 4 5
7 1 1 . 8 5 1
3467 3 .540
1 4 2 2 .152
1 0 9 2 3 .038
6 5 3 5 3.815
1 6 6 5 3 . 2 2 1
2 9 1 . 4 6 2
1 9 2 2.283
1 3 5 4 3 .132
1 8 3
1 8 4 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
B I G R A M POSITION 1ST
TC 0 0 .000
TE 6 9 3 2 . 8 4 1
TH 24777 4 . 3 9 4
T I 1 8 1 8 3 .260
TO 1 3 8 4 3 . 1 4 1
TR 4 5 3 2 . 6 5 6
TS 0 0 . 0 0 0
TT 0 0 .000
TU 282 2 .450
TW 7 . 8 4 5
TY 200 2 . 3 0 1
U A 0 0 . 0 0 0
U B 0 0 .000
uc 0 0 . 0 0 0
U D 0 0 . 0 0 0
U E 0 0 . 0 0 0
OF 0 0 .000
UG 2 1 1 . 3 2 2
U I 0 0 .000
U K 0 0 .000
U L 0 0 . 0 0 0
2ND
5 . 6 9 9
2 1 9 2 . 3 4 0
0 0 . 0 0 0
1 0 1 . 0 0 0
1 6 3 2 .212
0 0 .000
0 0 . 0 0 0
4 . 6 0 2
3 , 4 1 7
0 0 .000
0 0 . 0 0 0
2 8 1 . 4 4 7
7 8 1 . 8 9 2
2 3 6 6 3 .374
4 6 1 . 6 6 3
26 1 . 4 1 5
5 . 6 9 9
7 5 1 . 8 7 5
8 6 1 . 9 3 4
1 4 1 . 1 4 6
5 6 1 2 .749
3RD
0 0 . 0 0 0
9 9 0 2 . 9 9 6
8 1 6 5 3 .912
0 0 . 0 0 0
1 9 0 3 3 . 2 7 9
0 0 .000
5 3 6 2 . 7 2 9
1 2 1 . 0 7 9
0 0 . 0 0 0
0 0 .000
472 2 . 6 7 4
0 0 .000
1 4 8 2 . 1 7 0
0 0 . 0 0 0
2 3 1 . 3 6 2
3 8 9 2 .590
0 0 . 0 0 0
6 4 1 . 8 0 6
0 0 .000
3 . 4 7 7
9 4 1 . 9 7 3
SUM
5 . 6 9 9 1 9 0 2
3 .279 3 2 9 4 2 4 .518
1 8 2 8 3 . 2 6 2
3450 3 . 5 3 8
4 5 3 2 .656
536 2 . 7 2 9
1 6 1 . 2 0 4
2 8 5 2 . 4 5 5
7 . 8 4 5 6 7 2
2 . 8 2 7 2 8
1 . 4 4 7 2 2 6
2 .354 2 3 6 6
3 . 3 7 4 6 9
1 . 8 3 9 4 1 5
2 .618 5
. 6 9 9 1 6 0
2 . 2 0 4 8 6
1 . 9 3 4 1 7
1 . 2 3 0 6 5 5
2 . 8 1 6
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST
UM 0 0.000
UN 1 2 2 2.086
UP 495 2.695
UR 2 1 1 .322
US 6 7 5 2.829
UT 6 .778
ux 0 0 .000
UY 0 0.000
uz 0 0.000
VA 1 0 9 2 .037
VD 0 0 .000
VE 8 5 7 2.933
VI 252 2 . 4 0 1
vo 9 0 1 .954
VY 0 0.000
W A 1 1 1 7 3 .048
W D 0
W E 5289 3.723
W H 4407 3.644
WI 1 0 3 2 8 4.014
WK 0 0.000
9 . 0 0 0
2ND
8 9 1 . 9 4 9
447 2.650
1 4 1.146
8 0 1 2.904
2147 3.332
2 1 2 2 .326
0 0 .000
3 1 1 .491
1 6 1.204
1 2 1 . 0 7 9
0 0 .000
2759 3 . 4 4 1
7 2 1 .857
0 0 .000
0 0.000
470 2.672
0 0 .000
50 1 . 6 9 9
0 0 .000
2 2 1 . 3 4 2
0 0.000
3RD
1 9 1.279
1 6 1 .204
20 1 . 3 0 1
1 4 9 7 3 .175
387 2.588
6 1 1 . 7 8 5
30 1 . 4 7 7
0 0 .000
0 0 .000
4 .602
4 .602
5 6 6 1 3.753
0 0.000
0 0.000
54 1 . 7 3 2
4 . 6 0 2
3 .477
1 2 1.079
0 0.000
0 0 .000
1 4 1.146
SUM
1 0 8 2.033
5 8 5 2.767
5 2 9 2 .723
2 3 1 9 3 .365
3 2 0 9 3 .506
279 2 .446
3 0 1 . 4 7 7
3 1 1 . 4 9 1
1 6 1.204
1 2 5 2 .097
4 . 6 0 2
9 2 7 7 3.967
3 2 4 2 . 5 1 1
9 0 1 .954
5 4 1 . 7 3 2
1 5 9 1 3 .202
3 .477
5 3 5 1 3.728
4407 3.644
1 0 3 5 0 4 .015
1 4 1 . 1 4 6
1 8 5
1 8 6 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1 S T
WL 0 0 000
WN 0 0 000
WO 214 3 084
WR 1 2 1 .079
ws 0 0 .000
XE 0 0 .000
X I 0 0 .000
XT 0 0 .000
Y A 69 1 .839
Y D 0 0 .000
Y E 694 2 .841
YM 0 0 .000
Y N 0 0 .000
Y O 1227 3 .089
YP 0 0 .000
Y R 0 0 .000
YS 0 0 .000
YT 0 0 .000
YU 6 .I78
ZE 37 1 .568
2 1 1 6 1 .204
2ND
0 0 .000
1 3 1 .114
0 0 .000
0 0 .000
0 0 .000
1 7 1 . 2 3 0
4 5 1 . 6 5 3
0 0 .000
0 0 .000
0 0 .000
415 2 .618
9 .954
5 .699
0 0 .000
200 2 .301
9 , 9 5 4
0 0 .000
3 5 1 . 5 4 4
0 0 .000
0 0 .000
0 0 .000
3RD
27 1 . 4 3 1
1 1 6 9 3 .068
0 0 .000
0 0 .000
297 2 .473
0 0 .000
1 6 1 . 2 0 4
4 54 2 .657
0 0 .000
5 . 699
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 .000
989 2 .995
4 . 602
0 0 .000
1 6 3 2 .212
1 3 1 .114
SUM
27 1 . 4 3 1
1 1 8 2 3 .073
1214 3 .084
1 2 1 . 0 7 9
297 2 .473
1 7 1 . 2 3 0
6 1 1 . 7 8 5
454 2 .657
6 9 1 .839
5 .699 1 1 0 9
3 .045 9
.954 5
.699 1 2 2 7
3 .089 200
2 . 3 0 1 9
, 9 5 4 989
2 .995 39
1 . 5 9 1 6
200 2 .301
29 1 . 4 6 2
, 7 7 8
APPENDIX 5.2 187
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4
BIGRAM POSITION 1ST 2ND 3RD SUM
ZO 11 0 0 11 1.041 0.000 0.000 1.041
ZY 0 0 14 14 0.000 0.000 1.146 1.146
z z 0 0 115 115 0.000 0.000 2.061 2.061
1 8 8 C H A P T E R 5
BIGRAM F R E Q U E N C I E S FOR WORDS OF L E T T E R LENGTH 5
BIGRAM P O S I T I O N 1 S T 2 N D 3 RD 4TH SUM
AA 7 .845
A B 2 1 5 1 3 .333
AC 1 0 9 2.037
AD 308 2.489
A F 1 0 7 0 3 .029
AG 6 8 6 2.836
AH 1 0 9 2 .037
A 1 45 1 . 6 5 3
AJ 0 0.000
AK 0 0.000
A L 8 7 5 2.942
AM 3 9 6 2.598
AN 1 7 6 2.246
A 0 0 0.000
AP 204 2.310
AR 410 2.613
A S 489 2.689
A T 69 1.839
0 0.000
438 2 . 6 4 1
3 0 9 2.490
2 37 2.375
5 .699
2 4 1 2 .382
4 .602
5 8 1 2.764
247 2.393
6 4 4 2.809
8 1 0 2.908
362 2 .559
9 9 4 2.997
0 0.000
384 2.584
1 9 3 4 3.286
884 2 .946
1 4 4 9 3 .161
1 0 1 .000
3 .477
1 6 2 5 3 .211
5 4 1 2.733
1 7 1 2.233
3 1 5 2.498
0 0.000
1 0 8 8 3.037
0 0.000
1 2 0 2 .079
1 0 6 6 3.028
3 0 5 2 .484
1 3 1 2 3.118
1 7 1 .230
1 2 2 2.086
2670 3 .427
1 0 4 1 3 .017
1 2 6 0 3 .100
0 0.000
0 0.000
1 4 1 . 1 4 6
2 8 5 2 .455
3 .477
0 0.000
26 1 .415
7 .845
0 0 .000
225 2.352
1 6 1 6 3.208
111 2.045
1 2 2 8 3.089
0 0.000
3 2 1 .505
394 2.595
468 2 .670
7 3 6 2.867
1 7 1 .230
2 5 9 2 3.414
2057 3.313
1 3 7 1 3.137
1 2 4 9 3 .097
1 2 4 2 3 .094
1 3 9 2.143
1 7 2 1 3.236
247 2.393
9 8 9 2.995
4367 3.640
1 1 7 4 3.070
3 7 1 0 3.569
1 7 1 . 2 3 0
7 4 2 2.870
5408 3.733
2 8 8 2 3 .460
3 5 1 4 3.546
AU 8 274 8 0 290 .903 2.438 .903 0.000 2.462
AV 6 2 3 3 2 4 1 6 0 8 1 0 1.792 2 .521 2.619 0 .000 2.908
AW 1 8 5 1 2 9 8 1 5 310 2.267 1 . 0 7 9 1 . 9 9 1 1 . 1 7 6 2 .491
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
AX 0 0.000
AY 0 0.000
A2 0 0.000
BA 745 2.872
BB 0 0.000
BE 1556 3.192
BI 269 2.430
BL 654 2.816
BO 668 2.825
BR 984 2.993
BS 0 0.000
BT 0 0.000
BU 372 2.571
BY 16 1.204
CA 731 2.864
cc 0 0.000
CE 121 2.083
CH 925 2.966
CI 161 2.207
CK 0 0.000
CL 1097 3.040
2ND
65 1.813 211
2.324
38 1.580
0 0.000
7 .845
0 0.000
7 .845
0 0.000
2115 3.325
0 0.000
0 0.000
b7 0.000
18 1.255
4 .602 86
1.934
43 1.633
146 2.164
3 .477
7 .845
0 0.000
0 0.000
3RD
0 0.000
74 1.869
44 1.643
61 1.785
60 1.778 144
2.158
77 1.886
287 2.458
162 2.210
3 .477
0 0.000
12 1.079
20 1.301
0 0.000
337 2.528
0 0.000
187 2.272
3 .477
12 1.079 112
2.049 81
4TH SUM
19 84 1.279 1.924 384 669
2.584 2.825
0 82 0.000 1.914
0 806 0.000 2.906
0 67 0.000 1.826 161 1861
2.207 3.270
21 374 1.322 2.573
0 94 1 0.d00 2.974
4 2949 .602 3.470
0 987 0.000 2.994
80 80 1.903 1.903
114 126 2.057 2.100
0 410 0.000 2.613
58 78 1.763 1.892
0 1154 0.c100 3.062
0 43 0.000 1.633 2712 3166 3.433 3.501
4479 5410 3.651 3.733
0 180 0.000 2.255 1000 1112 3.000 3.046
0 1178 1.908 0.000 3.071
189
190 C H A P T E R 5
BIGRAM F R E Q U E N C I E S FOR WORDS OF L E T T E R LENGTH 5
BIGRAM P O S I T I O N 1ST
CO 2783 3.445
C R 457 2 .660
cs 0 0 .000
C T 0 0.000
CU 1 1 3 2.053
CY 28 1.447
DA 4 1 2 2 .615
DD 0 0.000
DE 5 2 2 2.718
DG 0 0.000
D I 1 1 2 2.049
DL 0 0.000
DM 0 0.000
DO 450 2.653
OR 7 7 5 2.889
D S 0 0 .000
DT 0 0.000
DU 5 2 1 . 7 1 6
DW 11 1 . 0 4 1
DY 45 1 . 6 5 3
EA 573 2.758
2ND
1 3 4 2.127
8 2 1.914
0 0.000
4 2 1 . 6 2 3
1 3 1.114
0 0.000
50 1.699
2 1 1 2.324
208 2.318
4 4 1 .643
11 1 . 0 4 1
7 . 8 4 5
3 7 1.568
2 1 1 . 3 2 2
0 0.000
0 0.000
0 0.000
2 5 1 .398
11 1 . 0 4 1
0 0.000
3 8 6 5 3.587
3 R D
1 8 1 . 2 5 5
0 0.000
0 0.000
1 0 0 2.000
88 1.944
0 0 .000
3 2 1 2 .507
3 4 1 . 5 3 1
1 8 1 4 3.259
1 4 3 2 .155
225 2.352
5 9 1 . 7 7 1
0 0 .000
30 1.477
9 .954
1 9 1 .279
1 4 1 . 1 4 6
1 3 1 . 1 1 4
0 FI. 0 0 0
0 0.000
2 0 8 2 3.318
4TH
0 0 .000
0 0 .000
7 .845
8 7 1 .940
0 0.000
47 1 .672
5 .699
0 0.000
5 58 2.747
0 0.000
0 0.000
0 0 .000
0 0.000
11 1 . 0 4 1
0 0.000
1 7 3 6 3.240
0 0.000
3 .477
0 0.000
547 2 .738
1 2 1.079
S U M
2 9 3 5 3 .468
5 3 9 2 .732
7 .845
2 29 2.360
214 2.330
7 5 1 .875
7 8 8 2.897
245 2.389
3 1 0 2 3 .492
1 8 7 2.272
3 4 8 2.542
66 1 .820
37 1.568
5 1 2 2 .709
7 84 2 .894
1 7 5 5 3 .244
1 4 1 .146
9 3 1 .968
2 2 1 .342
592 2 .772
6 5 3 2 3 .815
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
EB 0 0 .000
EC 0 0 . 0 0 0
E D 8 9 1 . 9 4 9
E E 0 0 .000
EF 0 0 .000
EG 1 4 1 . 1 4 6
E H 0 0 .000
E I 104 2 .017
E K 0 0 .000
E L 77 1 . 8 8 6
EM 64 1 . 8 0 6
E N 303 2 . 4 8 1
EO 0 0 .000
EP 6 . 778
E Q 90 1 . 9 5 4
E R 79 1 . 8 9 8
ES 3 1 1 . 4 9 1
ET 11 1 . 0 4 1
E U 0 0 .000
EV 597 2 . 7 7 6
EW 0 0 .000
2ND
44 1 . 6 4 3
18 1 . 2 5 5
4 1 1 . 6 1 3
8 8 3 2.946
27 1 . 4 3 1
628 2 .798
5 . 699
7 6 3 2 .883
0 0 .000
474 2 .676
3 1 1 . 4 9 1
6 8 5 2 .836
0 0 .000
1 2 3 2 .090
0 0 .000
494 2 .694
1 6 6 2 .220
1 2 8 2 .107
0 0 .000
1 0 8 8 3 .031
1 5 1 2 .179
3RD
4 . 602
2 6 1 2 .417
237 2 .375
930 2 .968
1 0 1 . 0 0 0
1 8 1 . 2 5 5
0 0 .000
2688 3 .429
1 5 1 2 .179
490 2 .690
589 2 .770
486 2.687
0 0 .000
216 2 .334
0 0 .000
4347 3 .638
2095 3 . 3 2 1
1 7 8 2 .250
9 .954
3 . 477
5 1 1 .708
4TH
0 0 .000
0 0 .000
2 8 2 5 3 . 4 5 1
6 6 5 2 .823
210 2 .322
0 0 . 0 0 0
0 0 .000
0 0 .000
9 5 9 7 8 752 8 7 6
1 9 279 686 227
3 . 477
1 2 6 2 .100
0 0 . 0 0 0
7346 3 . 8 6 6
3937 3 . 5 9 5
297 2 .473
0 0 .000
0 0 .000
7 1 1 . 8 5 1
SUM
4 8 1 . 6 8 1
279 2 .446
3192 3 .504
2478 3 .394
247 2 .393
660 2 .820
5 . 6 9 9 3555
3 . 5 5 1 246
2 .391 1 7 9 3
3 .254 7 0 3
2 .847 3160
3 .500 3
. 477 471
2 . 6 7 3 9 0
1 . 9 5 4 1 2 2 6 6 4 .089
6229 3 .794
614 2 .788
9 .9 54 1 6 8 8
3 .227 273
2 .436
1 9 1
1 9 2 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST 2N D
EX 151 8 9 2 .179 1 . 9 4 9
EY 0 6 0 .000 . 7 7 8
FA 6 2 8 0 2 . 7 9 8 0 . 0 0 0
FE 2 4 5 0 2 .389 0 . 0 0 0
FF 0 8 0 0 . 0 0 0 1 . 9 0 3
F I 2400 0 3 . 3 8 0 0 .000
FL 3 9 5 0 2 .597 0 . 0 0 0
FO 1 1 7 1 0 3 .069 0 . 0 0 0
FR 5 4 1 0 2 . 7 3 3 0 .000
FS 0 0 0 .000 0 .000
FT 0 1 4 3 8 0 .000 3 . 1 5 8
FU 234 0 2 .369 0 .000
GA 1 6 0 5 7 8 2 .204 2 . 7 6 2
G E 3 44 .477 1 . 6 4 3
G G 0 0 0 . 0 0 0 0 . 0 0 0
G H 1 5 0 1 . 1 7 6 0 .000
G I 6 6 5 4 2 . 8 2 3 .602
G L 2 0 1 0 2 . 3 0 3 0 .000
GM 0 0 0 . 0 0 0 0 . 0 0 0
GN 0 0 0 . 0 0 0 0.000
G O 5 2 1 9 2 . 7 1 7 .954
3RD
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 1 2 2 . 0 4 9
0 0 . 0 0 0
0 0 . 0 0 0
6 3 1 . 7 9 9
0 0 .000
El 0 . 0 0 0
0 0 . 0 0 0
1 2 2 2 . 0 8 6
1 7 1 . 2 3 0
4 56 2 . 6 5 9
290 2 .462
1 8 1 . 2 5 5
2 4 1 3 3 . 3 8 3
1 6 2 2 .210
5 6 1 . 7 4 8
4 . 6 0 2
6 8 1 . 8 3 3
6 9 1 . 8 3 9
4TH
9 3 1 . 9 6 8
3 4 2 2 . 5 3 4
0 0 . 0 0 0
8 4 1 . 9 2 4
1 8 9 2 . 2 7 6
0 0 .000
0 0 . 0 0 0
0 0 .000
0 0 .000
1 2 1 . 0 7 9
1 6 2 2 . 2 1 0
0 0 . 0 0 0
0 0 . 0 0 0
1 0 4 0 3 . 0 1 7
3 . 4 7 7
1 3 8 2 . 1 4 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 . 8 4 5
7 2 1 . 8 5 7
SUM
3 3 3 2 . 5 2 2
3 4 8 2 . 5 4 2
6 2 8 2 .798
4 4 1 2 . 6 4 4
2 6 9 2 . 4 3 0
2 4 0 0 3 . 3 8 0
4 5 8 2 . 6 6 1
1 1 7 1 3 . 0 6 9
5 4 1 2 . 7 3 3
1 2 1 . 0 7 9
1 7 2 2 3 . 2 3 6
2 5 1 2 . 4 0 0
1 1 9 4 3 .077
1 3 7 7 3 . 1 3 9
2 1 1 . 3 2 2
2 5 6 6 3 . 4 0 9
8 3 1 2 . 9 2 0
2 57 2 . 4 1 0
4 . 6 0 2
7 5 1 . 8 7 5
6 7 1 2 . 8 2 7
APPENDIX 5 .2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
B I G R A M POSITION 1ST
G R 1 7 6 3 3 . 2 4 6
GS 0 0 . 0 0 0
G U 2 3 3 2 .367
G Y 4 . 6 0 2
HA 6 1 1 2 . 7 8 6
H E 8 2 3 2 . 9 1 5
H I 1 0 5 2 . 0 2 1
H N 0 0 . 0 0 0
H O 1 4 0 4 3 . 1 4 7
H R 0 0 . 0 0 0
HS 0 0 . 0 0 0
HT 0 0 . 0 0 0
H U 399 2 . 6 0 1
H Y 6 . 7 7 8
I A 0 0 . 0 0 0
IB 0 0 . 0 0 0
IC 0 0 . 0 0 0
I D 2 1 1 2 . 3 2 4
I E 0 0 . 0 0 0
I F 0 0 . 0 0 0
I G 0 0 . 0 0 0
2ND
5 1 1 . 7 0 8
0 0 . 0 0 0
0 0 . 0 0 0
1 4 1 . 1 4 6
9 2 4 2 . 9 6 6
8 5 0 7 3 . 9 3 0
6 2 0 9 3 . 7 9 3
0 0 . 0 0 0
2 4 2 1 3 .384
7 1 3 2 . 8 5 3
0 0 . 0 0 0
0 0 . 0 0 0
27 1 . 4 3 1
7 , 8 4 5
8 7 1 . 9 4 0
9 3 1 . 9 6 8
1 9 1 . 2 7 9
2 57 2 . 4 1 0
534 2 . 7 2 8
1 8 0 2 . 2 5 5
2468 3 . 3 9 2
3RD
1 4 9 2 . 1 7 3
0 0 .000
111 2 . 0 4 5
0 0 .000
0 0 .000
1 7 1 7 3 . 2 3 5
4 . 6 0 2
6 . 7 7 8
8 . 9 0 3
5 . 6 9 9
0 0 .000
0 0 .000
0 0 .000
0 0 . 0 0 0
1 4 4 2 . 1 5 8
1 2 1 . 0 7 9
4 2 4 5 3 . 6 2 8
2 2 9 2 . 3 6 0
594 2 . 7 7 4
1 9 9 2 . 2 9 9
26 1 . 4 1 5
4TH
0 0 . 0 0 0
1 9 2 2 . 2 8 3
0 0 . 0 0 0
2 3 1 . 3 6 2
0 0 . 0 0 0
11 1 . 0 4 1
5 . 6 9 9
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
2 8 1 . 4 4 7
2 4 1 3 3 . 3 8 3
0 0 . 0 0 0
4 . 6 0 2
1 2 3 2 . 0 9 0
0 0 . 0 0 0
5 5 5 2 . 7 5 2
3 3 3 2 . 5 2 2
1 1 2 2 . 0 4 9
2 7 1 . 4 3 1
0 0 . 0 0 0
SUM
1 9 6 3 3 . 2 9 3
1 9 2 2 . 2 8 3
344 2 . 5 3 7
4 1 1 . 6 1 3
1 5 3 5 3 .186 1 1 0 5 8 4 . 0 4 4
6 3 2 3 3 . 8 0 1
6 . 7 7 8 3 8 3 7
3 . 5 8 4 7 1 8
2 . 8 5 6 2 8
1 . 4 4 7 2 4 1 3
3 . 3 8 3 4 2 6
2 . 6 2 9 1 7
1 . 2 3 0 3 54
2 . 5 4 9 1 0 5
2 . 0 2 1 4 8 2 9
3 . 6 8 4 1 0 3 0
3 . 0 1 3 1 2 4 0
3 . 0 9 3 4 06
2 . 6 0 9 2494
3 . 3 9 7
1 9 3
194 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
I1 0 0.000
IK 0 0.000
IL 0 0.000
IM 131 2.117
IN 228 2.358
I0 8 .903
IP 0 0.000
IR 47 1.672
IS 169 2.228
IT 106 2.025
IV 17 1.230
IX 0 0.000
I2 0 0.000
JA 142 2.152
JE 86 1.934
JI 11 1.041
JO 155 2.190
JU 131 2.117
KA 27 1.431
KE 21 1.322
KI 68
2N D
0 0.000
82 1.914
535 2.728
438 2.641
1401 3.146
24 1.380
26 1.415
1914 3.282
2 26 2.354
264 2.422
1053 3.022
196 2.292
24 1.380
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
82 1.833 1.914
3RD
0 0.000
20 1.301
2279 3.358
91 1.959
3331 3.523
255 2.407
92 1.964
325 2.512
305 2.484
1217 3.085 174
2.241
0 0.000
34 1.531
0 0.000
0 0.000
0 0.000
291 2.464
0 0.000
0 0.000
1151 3.061
5 .699
4TH
4 .602
0 0.000
722 2.859
98 1.991
1090 3.037
156 2.193
34 1.531
2752 3.440
447 2.650
339 2.530
0 0.000
30 1.477
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
3 58 2.554
0 0.000
SUM
4 .602 102
2.009
3536 3.549
7 58 2.880
6050 3.782
443 2.646
152 2.182
5038 3.702
1147 3.060 1926 3.285
1244 3.095
226 2.354
58 1.763
142 2.152
86 1.934
11 1.041
446 2.649
131 2.117
27 1.431
1530 3.185
155 2.190
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
KL 0 0 . 0 0 0
K N 490 2 .690
KO 1 2 1 . 0 7 9
KS 0 0 .000
K U 0 0 . 0 0 0
K Y 0 0 .000
LA 1 1 1 9 3.049
L B 0 0 . 0 0 0
LC 0 0 .000
L D 0 0 . 0 0 0
LE 1 0 6 3 3 . 0 2 7
LF 0 0 .000
LG 0 0 . 0 0 0
LH 0 0 . 0 0 0
L I 9 5 8 2 . 9 8 1
L K 0 0.0063
L L 1 0 1 . 0 0 0
LM 0 0 .000
L O 8 7 8 2 . 9 4 3
LP 0 0 * 000
LS 0 0 .000
2N D
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 . 4 7 7
0 0 . 0 0 0
1 9 7 5 3 . 2 9 6
1 6 1 . 2 0 4
5 . 6 9 9
1 0 8 2 . 0 3 3
574 2 . 7 5 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0.6300
2 8 8 2 . 4 5 9
0 0 . 0 0 0
1 2 1 2 . 0 8 3
6 - 7 7 8 1 4 6 1
3 . 1 6 5 0
0 . 0 0 0 4
.602
3RD
8 . 9 0 3
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
1 8 1 . 2 5 5
1 1 3 2 . 0 5 3
3 .477
0 0 . 0 0 0
4 9 1 . 6 9 0
7 3 1 2 . 8 6 4
8 . 9 0 3
5 . 6 9 9
5 . 6 9 9
2 3 2 2 . 3 6 5
6 5 1 . 8 1 3
789 2 . 8 9 7
39 1 . 5 9 1
405 2 . 6 0 7
5 3 1 . 7 2 4
38 1 . 5 8 0
4TH SUM
0 8 0 . 0 0 0 . 9 0 3
0 490 0 . 0 0 0 2 . 6 9 0
0 1 2 0 . 0 0 0 1 . 0 7 9
8 1 2 8 1 2 2 .910 2 . 9 1 0
0 3 0 . 0 0 0 . 4 7 7
7 2 9 0 1 . 8 5 7 1 . 9 5 4
2 8 3 2 3 5 1 . 4 4 7 3 . 5 1 0
0 1 9 0 . 0 0 0 1 . 2 7 9
0 5 0 . 0 0 0 . 6 9 9
5 7 1 5 5 8 7 2 3 . 7 5 7 3 . 7 6 9
1 8 3 7 4 2 0 5 3 . 2 6 4 3 .624
1 2 2 0 1 . 0 7 9 1 . 3 0 1
0 5 0 . 0 0 0 . 6 9 9
0 5 0 . 0 0 0 . 6 9 9
0 1 4 7 8 0 . 0 0 0 3 . 1 7 0
3 6 8 . 4 7 7 1 . 8 3 3 1 8 0 6 2 7 2 6
3 . 2 5 7 3 . 4 3 6 19 6 4
1 . 2 7 9 1 . 8 0 6 1 0 2 7 5 4
1 . 0 0 0 3 . 4 4 0 4 5 7
. 6 0 2 1 . 7 5 6 1 0 0 6 1 0 4 8
3 . 0 0 3 3 . 0 2 0
1 9 5
1 9 6 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
LT 0 0 . 0 0 0
LU 111 2 . 0 4 5
L V 0 0 .000
LY 4 8 1 . 6 8 1
MA 9 7 8 2 .990
MB 0 0 .000
ME 6 5 0 2 . 8 1 3
M I 1 1 0 9 3 . 0 4 5
ML 0 0 .000
M M 0 0 . 0 0 0
MN 0 0 . 0 0 0
MO 1 2 3 6 3 . 0 9 2
MP 0 0 . 0 0 0
YS 0 0 . 0 0 0
MU 2 4 1 2 . 3 8 2
MY 6 . 7 7 8
N A 2 8 1 2 . 4 4 9
NC 0 0 .000
ND 0 0 .000
N E 1 0 2 5 3 . 0 1 1
NG 0 0 . 0 0 0
2ND
24 1 . 3 8 0
1 9 1 2 . 2 8 1
6 . 7 7 8
4 . 6 0 2
6 9 3 2 . 8 4 1
0 0 .000
3 4 1 . 5 3 1
1 1 5 2 . 0 6 1
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
416 2 .619
9 6 1 . 9 8 2
0 0 .000
3 . 4 7 7
0 0 .000
6 1 1 . 7 8 5
6 2 1 . 7 9 2
9 2 2 2 . 9 6 5
1 4 4 2 . 1 5 8
1 6 2 2 .210
3RD
4 0 1 . 6 0 2
200 2 . 3 0 1
2 6 1 . 4 1 5
0 0 . 0 0 0
5 8 1 2 .764
44 1 . 6 4 3
1 1 6 2 3 . 0 6 5
1 0 5 2 . 0 2 1
1 2 1 . 0 7 9
46 1 . 6 6 3
6 . 7 7 8
1 0 7 2 . 0 2 9
3 6 1 . 5 5 6
0 0 .000
4 . 6 0 2
0 0 . 0 0 0
1 7 8 2 .250
9 6 6 2 . 9 8 5
7 5 1 2 . 8 7 6
8 6 1 2 . 9 3 5
370 2 . 5 6 8
4TH
2 1 3 2 .328
0 0 .000
0 0 . 0 0 0
1 0 5 5 3 . 0 2 3
6 7 1 . 8 2 6
27 1 . 4 3 1
2 8 3 2 .452
22 1 . 3 4 2
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 .000
27 1 . 4 3 1
1 0 9 8 3 . 0 4 1
0 0 .000
1 1 7 2 . 0 6 8
1 0 1 2 . 0 0 4
0 0 .000
1 3 3 1 3 .124
607 2 .783
3346 3 .525
SUM
2 7 1 2 . 4 4 2
5 0 2 2 . 7 0 1
3 2 1 . 5 0 5
1 1 0 7 3 . 0 4 4
2 3 1 9 3 . 3 6 5
7 1 1 . 8 5 1
2 1 2 9 3 . 3 2 8
1 3 5 1 3 . 1 3 1
1 2 1 . 0 7 9
4 6 1 . 6 6 3
6 . 7 7 8 1 7 5 9
3 . 2 4 5 1 5 9
2 . 2 0 1 1 0 9 8
3 . 0 4 1 2 4 8
2 . 3 9 4 1 2 3
2 . 0 9 0 6 2 1
2 . 7 9 3 1 0 2 8
3 .012 3004
3 . 4 7 8 2637
3 . 4 2 1 3 8 7 8
3 . 5 8 9
APPENDIX 5 .2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
NI 4 6 7 2 . 6 6 9
NJ 0 0 . 0 0 0
NK 0 0 . 0 0 0
NL 0 0 . 0 0 0
NN 0 0 . 0 0 0
NO 5 4 6 2 . 7 3 7
NP 0 0 . 0 0 0
NR 0 0 . 0 0 0
NS 0 0 . 0 0 0
N T 0 0 . 0 0 0
NU 1 7 1 . 2 3 0
NX 0 0 . 0 0 0
NY 0 0 . 0 0 0
OA 3 . 4 7 7
OB 0 0 .000
oc 7 7 1 . 8 8 6
OD 1 7 1 . 2 3 0
OE 0 0 . 0 0 0
OF 4 4 8 2 . 6 5 1
OG 0 0 . 0 0 0
OH 0 0 . 0 0 0
2 N D
4 4 1 2 .644
4 4 1 . 6 4 3
8 . 9 0 3
4 . 6 0 2
5 8 1 . 7 6 3
3 7 0 2 . 5 6 8
2 0 1 . 3 0 1
0 0 . 0 0 0
3 8 1 . 5 8 0
5 6 5 2 . 7 5 2
0 0 .000
0 0 .000
0 0 . 0 0 0
5 7 3 2 . 7 5 8
1 0 8 2 .033
4 0 0 2 . 6 0 2
4 1 9 2 . 6 2 2
1 1 4 2 . 0 5 7
5 . 5 9 9
6 1 1 . 7 8 5
9 . 9 5 4
3 R D
5 3 1 . 7 2 4
0 0 . 0 0 0
1 1 3 2 . 0 5 3
0 0 . 0 0 0
1 1 3 2 . 0 5 3
1 5 2 2 .182
0 0 .000
9 9 1 . 9 9 6
34fJ 2 . 5 3 1
3 1 3 2 . 4 9 6
2 2 1 . 3 4 2
0 0 . 0 0 0
0 0 . 0 0 0
1 0 5 2. fJ21
2 3 1 . 3 6 2
2 9 5 2 . 4 7 0
2 5 9 2 .413
4 4 1 . 6 4 3
1 5 1 . 1 7 6
0 0 . 0 0 0
0 0 . 0 0 0
4TH
0 0 . 0 0 0
0 0 . 0 0 0
7 1 1 2 . 8 5 2
0 0 . 0 0 0
6
3 8 1 . 5 8 0
0 0 . 0 0 0
0 0 . 0 0 0
8 1 9 2 . 9 1 3
1 4 0 3 3 . 1 4 7
0 0 . 0 0 0
9 . 9 5 4
1 4 2 2 . 1 5 2
0 0 . 0 0 0
0 0 . 0 0 0
3 . 4 7 7
3 6 1 2 . 5 5 8
11 1 . 0 4 1
4 5 1 . 6 5 3
0 0 . 0 0 0
0 0 . 0 0 0
. 7 i a
SUM
9 6 1 2 . 9 8 3
4 4 1 . 6 4 3
8 3 2 2 . 9 2 0
4 . 6 0 2
1 7 7 2 . 2 4 8
1 1 0 6 3 . 0 4 4
2 0 1 . 3 0 1
9 9 1 . 9 9 6
1 1 9 7 3 . 0 7 8
2 2 8 1 3 . 3 5 8
3 9 1 . 5 9 1
9 .9 5 4
1 4 2 2 . 1 5 2
6 8 1 2 . 8 3 3
1 3 1 2 . 1 1 7
7 7 5 2 . 8 8 9
1 0 5 6 3 . 0 2 4
1 6 9 2 . 2 2 8
5 1 3 2 . 7 1 0
6 1 1 . 7 8 5
9 . 9 5 4
1 9 7
1 9 8 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
01 3 . 4 7 7
OK 0 0 .000
O L 9 8 1 . 9 9 1
OM 0 0 . 0 0 0
ON 5 3 1 . 7 2 4
00 0 0 .000
OP 6 3 1 . 7 9 9
OR 404 2 . 6 0 6
0s 9 . 9 5 4
OT 1 7 0 2 3 . 2 3 1
O U 1 0 5 2 . 0 2 1
ov 11 1 . 0 4 1
OW 7 1 1 . 8 5 1
ox 0 0 . 0 0 0
OY 0 0 . 0 0 0
0 2 0 0 .000
PA 8 3 8 2 . 9 2 3
PE 3 1 8 2 . 5 0 2
PH 1 4 3 2 . 1 5 5
P I 297 2 . 4 7 3
PL 1 1 1 7 3 . 0 4 8
2ND
1 3 0 6 3 . 1 1 6
50 1 . 6 9 9
4 8 9 2 .689
7 7 5 2 . 8 8 9
8 2 0 2 . 9 1 4
6 6 3 2 . 8 2 2
1 0 9 2 . 0 3 7
2 7 2 6 3 .436
2 7 9 2 . 4 4 6
6 6 3 2 . 8 2 2
7 6 4 9 3 .884
500 2 . 6 9 9
5 8 1 2 . 7 6 4
1 4 1 . 1 4 6
94 1 . 9 7 3
5 7 1 . 7 5 6
3 0 1 2 .479
446 2 . 6 4 9
0 0 . 0 0 0
7 1 1 . 8 5 1
3 0 1 . 4 7 7
3 RD
6 9 1 . 8 3 9
4 1 1 2 . 6 1 4
3 7 3 2 . 5 7 2
9 9 1 . 9 9 6
1 4 7 5 3 .169
7 2 4 2 . 8 6 0
1 2 9 2 . 1 1 1
7 59 2 .880
1 6 1 9 3 . 2 0 9
4 29 2 . 6 3 2
2 3 4 2 3 . 3 7 0
4 4 9 2 . 6 5 2
972 2 . 9 8 8
7 . 8 4 5
1 0 1 . 0 0 0
4 . 6 0 2
52 1 . 7 1 6
5 0 1 2 . 7 0 0
0 0 . 0 0 0
7 2 1 . 8 5 7
1 4 6 2 . 1 6 4
4TH
0 0 . 0 0 0
6 3 1 . 7 9 9
8 . 9 0 3
4 6 1 . 6 6 3
3 9 6 2 . 5 9 8
3 . 4 7 7
2 5 1 . 3 9 8
1 2 4 3 3 . 0 9 4
2 8 1 . 4 4 7
8 8 1 . 9 4 4
0 0 . 0 0 0
9 . 9 5 4
309 2 . 4 9 0
0 0 .000
44 1 . 6 4 3
0 0 .000
5 . 6 9 9
1 3 4 2 . 1 2 7
3 9 1 . 5 9 1
0 0 .000
0 0 .000
SUM
1 3 7 8 3 . 1 3 9
524 2 . 7 1 9
9 6 8 2 . 9 8 6
9 2 0 2 . 9 6 4
2 7 4 4 3 . 4 3 8
1 3 9 0 3 . 1 4 3
3 2 6 2 . 5 1 3
5 1 3 2 3 . 7 1 0
1 9 3 5 3 . 2 8 7
2 8 8 2 3 . 4 6 0 1 0 0 9 6 4 . 0 0 4
9 6 9 2 . 9 8 6
1 9 3 3 3 . 2 8 6
2 1 1 . 3 2 2
1 4 8 2 . 1 7 0
6 1 1 . 7 8 5
1 1 9 6 3 . 0 7 8
1 3 9 9 3 . 1 4 6
1 8 2 2 . 2 6 0
440 2 . 6 4 3
1 2 9 3 3 . 1 1 2
APPENDIX 5.2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5
B I G R A M POSITION 1ST
PO 1 0 2 8 3 . 0 1 2
PP 0 0 .000
PR 6 1 5 2 .789
PS 0 0 .000
PT 0 0 . 0 0 0
PU 6 2 1 . 7 9 2
PY 0 0 . 0 0 0
QU 5 1 5 2 . 7 1 2
R A 7 2 5 2 .860
R B 0 0 . 0 0 0
RC 0 0 . 0 0 0
RD 0 0 . 0 0 0
R E 486 2 .687
RF 0 0 . 0 0 0
RG 0 0 . 0 0 0
RH 1 0 8 2 . 0 3 3
R I 9 6 9 2 . 9 8 6
RK 0 0 . 0 0 0
R L 0 0 . 0 0 0
RM 0 0 . 0 0 0
R N 0 0 . 0 0 0
2ND
1 5 1 2 .179
1 3 7 2 . 1 3 7
9 8 1 . 9 9 1
1 4 1 . 1 4 6
4 . 6 0 2
3 . 4 7 7
0 0 . 0 0 0
1 1 5 2 . 0 6 1
1 2 7 8 3 .107
5 8 1 . 7 6 3
0 0 . 0 0 0
376 2 . 5 7 5
1 9 0 6 3 . 2 8 0
0 0 .000
8 4 1 . 9 2 4
0 0 .000
1 5 0 8 3 . 1 7 8
0 0 . 0 0 0
0 0 . 0 0 0
6 4 1 . 8 0 6
2 3 1 . 3 6 2
3RD
2 5 1 . 3 9 8
1 0 3 2 . 0 1 3
0 0 .000
1 0 1 . 0 0 0
1 1 7 2 . 0 6 8
20 1 . 3 0 1
0 0 . 0 0 0
0 0 . 0 0 0
292 2 . 4 6 5
1 7 1 . 2 3 0
419 2 . 6 2 2
482 2 . 6 8 3
1 0 5 8 3 . 0 2 4
0 0 . 0 0 0
404 2 . 6 0 6
0 0 .000
2 5 5 2 .407
1 9 9 2 . 2 9 9
1 3 1 9 3 . 1 2 0
408 2 . 6 1 1
9 0 1 . 9 5 4
4TH
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
4 9 1 2 . 6 9 1
1 0 8 2 . 0 3 3
0 0 . 0 0 0
9 8 1 . 9 9 1
0 0 . 0 0 0
1 2 3 2 . 0 9 0
0 0 . 0 0 0
0 0 . 0 0 0
8 2 4 2 . 9 1 6
4 1 5 7 3 . 6 1 9
7 . 8 4 5
0 0 . 0 0 0
0 0 . 0 0 0
1 6 1 . 2 0 4
9 1 1 . 9 5 9
1 2 1 . 0 7 9
7 1 1 . 8 5 1
1 1 6 2 .064
SUM
1 2 0 8 3 . 0 8 2
240 2 . 3 8 0
7 1 3 2 . 8 5 3
5 1 5 2 . 7 1 2
2 2 9 2 . 3 6 0
8 5 1 . 9 2 9
9 8 1 . 9 9 1
6 3 0 2 . 7 9 9
2 4 1 8 3 . 3 8 3
7 5 1 . 8 7 5
4 1 9 2 . 6 2 2
1 6 8 2 3 . 2 2 6
7 6 0 7 3 . 8 8 1
7 . 8 4 5
4 8 8 2 . 6 8 8
1 0 8 2 . 0 3 3
2 7 4 8 3 . 4 3 9
290 2 . 4 6 2
1 3 3 1 3 . 1 2 4
5 4 3 2 . 7 3 5
2 29 2 . 3 6 0
1 9 9
200 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
RO 548 2 .739
RP 0 0 .000
RR 0 0 .000
RS 0 0 .000
RT 0 0 .000
RU 200 2 .301
RV 0 0 .000
RY 0 0 .000
SA 375 2 .574
SC 370 2 .568
SE 9 4 3 2 .975
SH 1 6 5 5 3 .219
SI 1 0 2 5 3 .011
SK 8 5 1 .929
SL 254 2 .405
SM 766 2 .884
SN 6 1 1 . 7 8 5
S O 750
SP 8 9 6 2 .952
SQ 25 1 . 3 9 8
SS 0 0 .000
2 .875
2ND
1 9 2 6 3 .285
0 0 .000
6 4 1 . 8 0 6
0 0 .000
0 0 .000
512 2 .709
0 0 .000
1 9 1 .279
24 1 . 3 8 0
9 . 954
6 . 7 7 8
6 . 778
222 2 .346
398 2 .600
7 . 8 4 5
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 .000
3RD 4TH
1 3 1 1 1 5 2 .117 2 .061
1 0 9 7 2 2 .037 1 . 8 5 7
362 0 2 .559 0 .000
1 7 1 8 1 4 1 6 3 .235 3 .151
1 0 2 8 997 3 .012 2 .999
6 1 5 1 . 7 8 5 .699
1 7 1 0 2 .233 0 .000
0 1254 0 .000 3 .098
5 5 6 1 . 7 4 0 .778
7 0 . 8 4 5 0 .000
519 4720 2 . 7 1 5 3 .674
0 289 0 .000 2 .461
700 0 2 .845 0 .000
5 1 7 1 . 7 0 8 .845
6 0 . 778 0 .000
0 3 0 .000 .477
0 0 0 .000 0 .000
3 1 7 1 . 4 9 1 . 8 4 5
5 2 5 .699 1 . 3 9 8
0 0 0 .000 0 .000
1 9 1 1 7 787 2 .281 1 .230 2 .896
SUM
2720 3 . 4 3 5
1 8 1 2 .258
4 26 2 .629
3134 3 .496
2025 3 .306
7 7 8 2 .891
1 7 1 2 .233
1 2 7 3 3 . 1 0 5
460 2 . 6 6 3
386 2 .587
6 1 8 8 3 .792
1 9 5 0 3 .290
1 9 4 7 3 .289
541 2 .733
267 2 .427
769 2 .886
6 1 1 . 7 8 5
788 2 .897
926 2 .967
2 5 1 .398
9 9 5 2 .998
A P P E N D I X 5.2 2 0 1
B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 5
B I G R A M P O S I T I O N 1ST 2 N D 3 R D 4 T H SUM
ST
su
sw
S Y
T A
T C
T D
T E
T H
T I
T L
T O
3855 3 .586
1 5 6 2.193
3 0 6 2 .486
4 .602
8 0 9 2.908
0 0.000
0 0 .000
6 2 4 2 .795
9 6 6 9 3.985
517 2 .713
0 0.000
8 7 0 2 .940
0 499 0 .000 2.698
9 6 216 1.982 2.334
0 0 0 .000 0 .000
0 0 0.000 0 .000
1 5 5 1 362 3 . 1 9 1 2.559
0 2 68 0 .000 2.428
0 3 0.000 .477
372 3129 2 .571 3.495
1 7 1 3 44 3.234 1 .643
8 56 5 9 1 2.932 2.772
1 2 8 1 1.079 1.908
7 6 4 9 8 2.883 1 . 9 9 1
2 2 3 6 3.349
0 0.000
0 0.000
28 1.447
5 0 1 . 6 9 9
0 0 . 0 0 0
0 0 .000
2 1 0 4 3.323
2068 3 .316
0 0.000
0 0 . 0 0 0
3 6 1 . 5 5 6
6 5 9 0 3 .819
4 6 8 2 .670
3 0 6 2.486
3 2 1 . 5 0 5
2772 3.443
268 2.428
3 - 4 7 7
6 2 2 9 3.794
1 3 4 9 4 4 .130
1 9 6 4 3 .293
93 1 .968
1 7 6 8 3 .247
T R 1 2 1 2 6 0 8 5 0 1 3 5 7 3 .084 1 .778 1.929 0 . 0 0 0 3.133
TS 0 0 0 1 1 7 3 1 1 7 3 0 .080 0.000 0.000 3 .069 3 .069
TT 0 29 58 2 9 1 1 6 0 .000 1 . 4 6 2 1 . 7 6 3 1 .462 2.064
T U 1 0 9 3 0 1 8 0 4 1 8 2.037 2.479 .903 0 .000 2 . 6 2 1
TW 1 0 9 0 0 0 1 0 9 2 .037 0.000 0 .000 0 . 0 Q 0 2 .037
T Y 1 2 4 9 8 0 5 9 1 8 1 3 2.093 1 . 9 9 1 0.00B 2.772 2 .910
T Z 0 0 0 3 3 0 . 0 0 0 0 .000 0 .000 .477 .477
UA 0 5 1 2 1 1 0 2 6 2 0 .000 1 . 7 0 8 2.324 0 .000 2 .418
UB 0 6 2 1 3 8 9 2 0 9 0.000 1.792 2.140 . 9 5 4 2 .320
202 C H A P T E R 5
BIGRAM F R E Q U E N C I E S FOR WORDS OF L E T T E R LENGTH 5
BIGRAM P O S I T I O N 1 S T
uc 0 0.000
UD 0 0.000
UE 0 0 .000
UF 0 0.000
UG 0 0.000
U I 0 0 .000
U L 5 .699
U M 0 0.000
UN 1 5 8 8 3 . 2 0 1
00 0 0 .000
U P 8 6 1 . 9 3 4
UR 8 5 1 .929
US 2 6 1 2.417
UT 1 3 1.114
u x 0 0 .000
u z 0 0 .000
VA '262 2.418
V E 7 0 1 . 8 4 5
V I 294 2.468
VO 3 0 9 2.490
VY 3 .477
2N D
4 9 1.690
1 1 0 2 . 0 4 1
1 6 1 2.207
0 0.000
1 0 8 2.033
7 7 3 2 .888
3 0 1 2 .479
384 2.584
283 2.452
2 1 1 . 3 2 2
28 1 . 4 4 7
3 5 1 2 .545
304 2 .483
6 5 1 . 8 1 3
0 0.000
7 .845
1 4 1.146
583 2 .766
9 .954
8 1 1.908
0 0.000
3 R D
2 2 5 2.352
268 2.428
6 6 1.820
4 4 1 .643
1 7 6 2.246
1 2 9 2 . 1 1 1
4 4 4 2 3.648
57 1 .756
1 5 4 1 3 .188
0 0.000
0 0 .000
463 2.666
9 0 2 2 .955
6 1 6 2.790
0 0.000
0 0.000
5 1 1.708
2 5 7 0 3 .410
2 77 2.442
8 1 1 . 9 0 8
0 0.000
4 T H
0 0.000
1 0 8 2.033
4 2 5 2.628
0 0.000
0 0.000
0 0 .000
1 7 1.230
3 7 1 .568
5 1 1 . 7 0 8
0 0.000
402 2.604
5 6 1 . 7 4 8
1 5 0 2.176
1 8 7 6 3.273
8 .903
0 0.000
0 0.000
1 1 2 5 3 . 0 5 1
0 0.000
0 0 .000
1 1 4 2.057
SUM
274 2.438
4 8 6 2.687
6 5 2 2.814
4 4 1 .643
284 2 .453
9 0 2 2 .955
4 7 6 5 3 .678
478 2.679
3463 3 .539
2 1 1 .322
516 2.713
9 5 5 2.980
1 6 1 7 3.209
2 5 7 0 3.410
8 .903
7 . 8 4 5
327 2.515
4 3 4 8 3.638
580 2 .763
2 .673
1 1 7 2 .068
4 i i
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5
B I G R A M POSITION 1ST
WA 9 6 1 2 . 9 8 3
WD 0 0 . 0 0 0
WE 2 0 1 2 . 3 0 3
WF 0 0 .000
WH 6 1 8 4 3 . 7 9 1
W I 207 2 . 3 1 6
WL 0 0 . 0 0 0
WN 0 0 . 0 0 0
WO 4632 3 . 6 6 6
WR 446 2 . 6 4 9
ws 0 0 . 0 0 0
wu 0 0 . 0 0 0
WY 3 . 4 7 7
X A 0 0 . 0 0 0
X E 0 0 . 0 0 0
X I 0 0 . 0 0 0
xo 0 0 . 0 0 0
XT 0 0 . 0 0 0
X Y 0 0 . 0 0 0
Y A 6 8 1 . 8 3 3
Y B 0 0 . 0 0 0
2ND
1 6 5 2 . 2 1 7
0 0 .000
1 7 2 2 .236
1 7 1 . 2 3 0
0 0 . 0 0 0
1 7 8 2 .250
0 0 .000
6 7 1 . 8 2 6
3 5 1 . 5 4 4
0 0 . 0 0 0
0 0 . 0 0 0
48 1 . 6 8 1
0 0 .000
27 1 . 4 3 1
11 1 . 0 4 1
6 3 1 . 7 9 9
0 0 . 0 0 0
50 1 . 6 9 9
0 0 . 0 0 0
3 . 4 7 7
0 0 , 0 0 0
3RD
0 0 . 0 0 0
7 . 8 4 5
569 2 . 7 5 5
0 0 .000
0 0 . 0 0 0
6 8 1 . 8 3 3
3 8 1 . 5 8 0
7 3 1 . 8 6 3
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 4 1 . 8 6 9
2 1 1 2 . 3 2 4
3 . 4 7 7
2 5 1 . 3 9 8
5 1 1 . 7 0 8
0 0 .000
7 8 1 . 8 9 2
1 3 4 2 . 1 2 7
4TH
0 0 . 0 0 0
53 1 . 7 2 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 5 1 . 1 7 6
7 3 8 2 .868
0 0 . 0 0 0
0 0 . 0 0 0
3 1 1 2 . 4 9 3
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 .845
0 0 . 0 0 0
0 0 . 0 0 0
SUM
1 1 2 6 3 . 0 5 2
6 0 1 . 7 7 8
9 4 2 2 . 9 7 4
1 7 1 . 2 3 0
6 1 8 4 3 . 7 9 1
4 5 3 2 . 6 5 6
5 3 1 . 7 2 4
8 7 8 2 . 9 4 3
4667 3 . 6 6 9
446 2 . 6 4 9
3 1 1 2 . 4 9 3
4 8 1 . 6 8 1
7 . 8 4 5 101
2 .004 2 2 2
2 . 3 4 6 6 6
1 . 8 2 0 2 5
1 . 3 9 8 1 0 1
2 . 0 0 4 7
. 8 4 5 1 4 9
2 . 1 7 3 1 3 4
2 . 1 2 7
2 0 3
204 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5
BIGRAM POSITION 1ST
Y C 0 0 . 0 0 0
Y D 0 0 .000
Y E 9 5 2 2 . 9 7 9
Y I 3 5 1 . 5 4 4
Y L 0 0 . 0 0 0
YM 0 0 . 0 0 0
Y N 0 0 .000
Y O 492 2 .692
YP 0 0 .000
Y R 0 0 .000
YS 0 0 . 0 0 0
YT 0 0 . 0 0 0
Z A 0 0 . 0 0 0
Z E 0 0 . 0 0 0
Z I 0 0 . 0 0 0
Z O 3 . 4 7 7
Z Y 0 0 . 0 0 0
Z Z 0 0 . 0 0 0
2N D
24 1 . 3 8 0
0 0 . 0 0 0
0 0 . 0 0 0
18 1 . 8 9 2
11 1 . 0 4 1
6 . 7 7 8
0 0.000
0 0 .000
1 2 3 2 . 0 9 0
3 6 1 . 5 5 6
0 0 . 0 0 0
6 . 7 7 8
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3RD
2 1 1 . 3 2 2
0 0 . 0 0 0
3 5 1 . 5 4 4
5 . 6 9 9
1 1 3 2 . 0 5 3
3 . 4 7 7
1 2 1 . 0 7 9
3 8 1 . 5 8 0
1 4 1 . 1 4 6
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
8 4 1 . 9 2 4
1 2 1 . 0 7 9
1 5 1 . 1 7 6
0 0 . 0 0 0
1 5 1 . 1 7 6
4TH
0 0 .000
1 0 1 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
18 1 . 2 5 5
0 0 . 0 0 0
0 0 . 0 0 0
7 4 1 . 8 6 9
0 0 . 0 0 0
3 . 4 7 7
4 8 1 . 6 8 1
0 0 . 0 0 8
0 0 . 0 0 0
4 6 1 . 6 6 3
0 0 . 0 0 0
SUM
4 5 1 . 6 5 3
1 0 1 . 0 0 0
987 2 . 9 9 4
1 1 8 2 .012
1 2 4 2 . 0 9 3
9 . 9 5 4
1 2 1 . 0 7 9
5 4 8 2 . 7 3 9
1 3 7 2 . 1 3 7
3 6 1 . 5 5 6
7 8 1 . 8 9 2
6 . 7 7 8
3 . 4 1 7
1 3 2 2 . 1 2 1
1 2 1 . 0 7 9
18 1 . 2 5 5
4 6 1 . 6 6 3
1 5 1 . 1 7 6
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
AA 0 0 . 0 0 0
A B 1 7 0 2 . 2 3 0
AC 9 6 7 2 . 9 8 5
AD 1 4 1 2 . 1 4 9
A E 8 . 9 0 3
AF 232 2 . 3 6 5
AG 1 9 2 2 . 2 8 3
AH 0 0 . 0 0 0
A 1 1 2 1 . 0 7 9
A J 0 0 . 0 0 0
AK 0 0 . 0 0 0
A L 1 0 9 4 3 . 0 3 9
AM 2 0 2 2 . 3 0 5
A N 604 2 . 7 8 1
AP 1 8 5 2 . 2 6 7
AQ 0 0 . 0 0 0
A R 9 0 6 2 .957
AS 344 2 . 5 3 7
AT 2 5 3 2 . 4 0 3
AU 1 3 9 2 . 1 4 3
AV 49 1 . 6 9 0
2N D
0 0 . 0 0 0
1 2 2 2 . 0 8 6
406 2 . 6 0 9
1 3 1 2 . 1 1 7
6 . 7 7 8
6 4 1 . 8 0 6
1 0 2 2 . 0 0 9
0 0 . 0 0 0
494 2 . 6 9 4
3 . 4 7 7
470 2 .672
1 4 3 0 3 . 1 5 5
7 4 3 2 . 8 7 1
1 3 7 7 3 . 1 3 9
1 6 0 2 . 2 0 4
0 0 . 0 0 0
1 8 3 0 3 .262
7 1 5 2 . 8 5 4
1 9 5 0 3 .290
3 6 8 2 . 5 6 6
3 8 8 2 . 5 8 9
3RD
0 0 .000
1 4 0 2 .146
332 2 . 5 2 1
3 6 3 2 .560
0 0 . 0 0 0
11 1 . 0 4 1
2 2 1 2 . 3 4 4
22 1 . 3 4 2
324 2 . 5 1 1
0 0 . 0 0 0
1 0 3 2 . 0 1 3
472 2 . 6 7 4
8 5 1 . 9 2 9
8 9 5 2 . 9 5 2
1 4 8 2 . 1 7 0
6 . 7 7 8
8 6 5 2 . 9 3 7
4 37 2 , 6 4 0
9 67 2 . 9 8 5
9 6 1 . 9 8 2
2 5 7 2 . 4 1 0
4TH
7 . 8 4 5
0 0 . 0 0 0
277 2 . 4 4 2
1 6 7 2 . 2 2 3
1 5 1 . 1 7 6
0 0 .000
1 5 6 2 .193
0 0 . 0 0 0
462 2 . 6 6 5
0 0 . 0 0 0
4 6 1 . 6 6 3
2 7 0 2 . 4 3 1
3 1 6 2 .500
4 9 1 2 . 6 9 1
7 1 1 . 8 5 1
0 0 . 0 0 0
9 3 3 2 . 9 7 0
151 2 . 1 7 9
370 2 . 5 6 8
0 0 . 0 0 0
1 3 1 . 1 1 4
5TH
0 0 . 0 0 0
0 0 . 0 0 0
4 . 6 0 2
1 8 5 2 . 2 6 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 0 1 . 0 0 0
1 5 5 8 3 . 1 9 3
8 3 1 . 9 1 9
3 1 0 2 .491
4 . 6 0 2
0 0 . 0 0 0
2 7 8 2 . 4 4 4
220 2 . 3 4 2
1 9 3 2 . 2 8 6
57 1 . 7 5 6
0 fl.000
SUM
7 . 8 4 5
432 2 . 6 3 5
1 9 8 6 3 . 2 9 8
987 2 .994
29 1 . 4 6 2
3 07 2 .487
6 7 1 2 . 8 2 7
22 1 . 3 4 2
1 2 9 2 3 . 1 1 1
3 . 4 7 7
6 2 9 2 .799
4 8 2 4 3 . 6 8 3
1 4 2 9 3 .155
3 6 7 7 3 .565
568 2.754
6 . 7 7 8 4 8 1 2
3 . 6 8 2 1 8 6 7
3 . 2 7 1 3 7 3 3
3 . 5 7 2 660
2 . 8 2 0 7 0 7
2 . 8 4 9
2 0 5
2 06 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
AW 3 1 1 . 4 9 1
AX 0 0 . 0 0 0
AY 0 0 . 0 0 0
AZ 0 0 .000
BA 376 2 . 5 7 5
BB 0 0 . 0 0 0
B E 3 0 2 2 3 .480
B I 1 2 1 2 . 0 8 3
B J 0 0 .000
BL 1 0 1 2 . 0 0 4
BM 0 0 . 0 0 0
BO 5 3 5 2 .728
BR 5 3 3 2 .727
BS 0 0 . 0 0 0
BT 0 0 . 0 0 0
BU 4 2 5 2 .628
BW 0 0 .000
BY 3 . 4 7 7
CA 1 4 6 8 3 . 1 5 7
cc 0 0 .000
CE 320 2 . 5 0 5
2N D
6 2 1 . 7 9 2
9 . 9 5 4
200 2 . 3 0 1
2 7 1 . 4 3 1
0 0 . 0 0 0
0 0 . 0 0 0
7 . 8 4 5
0 0.000
6 8 1 . 8 3 3
3 . 4 7 7
0 0 . 0 0 0
2 5 1 . 3 9 8
6 9 1 . 8 3 9
58 1 . 7 6 3
4 2 1 . 6 2 3
1 2 1 . 0 7 9
0 0 .000
0 0 . 0 0 0
3 6 1 . 5 5 6
1 6 7 2 . 2 2 3
44 1 . 6 4 3
3RD
11 1 . 0 4 1
3 . 4 7 7
2 8 2 2 . 4 5 0
4 1 1 . 6 1 3
5 3 1 . 7 2 4
8 5 1 . 9 2 9
1 5 5 2 .190
1 0 6 2 . 0 2 5
0 0 . 0 0 0
490 2 .690
1 8 1 . 2 5 5
92 1 . 9 6 4
3 3 1 . 5 1 9
8 . 9 0 3
3 1 1 . 4 9 1
24 1 . 3 8 0
7 . 8 4 5
0 0 .000
436 2 . 6 3 9
0 0 . 0 0 0
5 6 7 2 .754
4TH 5TH
3 1 0 . 4 7 7 1 . 0 0 0
3 20 . 4 7 7 1 . 3 0 1
472 3 2 5 2 . 6 7 4 2 . 5 1 2
3 0 . 4 7 7 0 . 0 0 0
5 8 0 1 . 7 6 3 0 . 0 0 0
8 0 . 9 0 3 0 . 0 0 0 7 5 5 3
2.884 . 4 7 7 2 1 0
1 . 3 2 2 0 . 0 0 0 0 0
0 .000 0 . 0 0 0 266 0
2 . 4 2 5 0 . 0 0 0 0 0
0 . 0 0 0 0 .000 1 5 2 0
2 . 1 8 2 0 . 0 0 0 0 0
0 . 0 0 0 0 . 0 0 0 0 1 6
0 .000 1 . 2 0 4 1 6 0
1 . 2 0 4 0 . 0 0 0 0 0
0 .000 0 . 0 0 0 0 0
0 . 0 0 0 0 . 0 0 0 0 6 0
0 . 0 0 0 1 . 7 7 8 1 1 5 4 5
2 .064 1 . 6 5 3 4 0
. 6 0 2 0 . 0 0 0 9 2 9 1 2 6 7
2 . 9 6 8 3 . 1 0 3
SUM
1 1 7 2 .068
3 5 1 . 5 4 4
1 2 7 9 3 . 1 0 7
7 1 1 . 8 5 1
4 87 2 . 6 8 8
9 3 1 . 9 6 8
3 9 5 2 3 . 5 9 7
2 4 8 2 .394
6 8 1 . 8 3 3
8 6 0 2 . 9 3 4
1 8 1 . 2 5 5
8 0 4 2 . 9 0 5
6 3 5 2 . 8 0 3
8 2 1 . 9 1 4
8 9 1 . 9 4 9
4 6 1 2 . 6 6 4
7 . 8 4 5
5 3 1 . 7 9 9
2 1 0 1 3 . 3 2 2
1 7 1 2 . 2 3 3
3 1 2 7 3 . 4 9 5
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
CH 1371 3.137
CI 177 2.248
CK 0 0.000
CL 438 2.641
CN 0 0.000
CO 2059 3.314
CR 311 2.493
cs 0 0.000
CT 0 0.000
cu 83 1.919
CY 10 1.000
DA 329 2.517
DD 0 0.000
DE 1235 3.092
DF 0 0.000
DG 0 0.000
DH 0 0.000
DI 392 2.593
DJ 0 0.000
DL 0 0.000
DM 0 0.000
2N D
546 2.737
0 0.000
0 0.000
0 0.000
0 0.000
35 1.544
370 2.568
0 0.000
555 2.144
0 0.000
0 0.000
0 0.000
22 1.342
16 1.204
0 0.000
5 .699
4 .602
87 1.940
16 1.204
0 0.000
10 1.000
3RD
174 2.241
538 2.731
468 2.670
23 1.362
15 1.176
998 2.999 119
2.076
0 0.000
297 2.473
130 2.114
0 0.000
19 1.279
310 2.491
604 2.781
3 .477
123 2.090
0 0.000
379 2.579
0 0.000
0 0.000
3 .477
4TH
13 1.114
46 1.663
186 2.270
102 2.009
0 0.000
60 1.778
0 0.000
0 0.000
5 .699
33 1.519
0 0.000
2 54 2.405
0 0.000
1285 3.109
0 0.000
105 2.021
8 .903
101 2.004
0 0.000 469
2.671
0 0.000
5TH
779 2.892
0 0.000
167 2.223
0 0.000
0 0.000
27 1.431
0 0.000
51 1.708
761 2.881
0 0.000
287 2.458
45 1.653
0 0.000
460 2.663
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
SUM
2883 3.460 761
2.881
821 2.914
563 2.751
15 1.176 3179 3.502
800 2.903
51 1.708
1618 3.209
246 2.391
297 2.473
647 2.811
332 2.521
3600 3.556
3 .477
233 2.367
12 1.079
959 2.982
16 1.204 469
2.671
13 1.114
207
208 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
DN 0 0 .000
DO 2 9 3 2 .467
DR 236 2 . 3 7 3
D S 0 0 . 0 0 0
DT 0 0 .000
DU 6 4 9 2 .812
DV 0 0 . 0 0 0
DW 1 2 1 . 0 7 9
DY 0 0 .000
E A 2 3 1 2 . 3 6 4
E B 0 0 . 0 0 0
EC 1 5 1 . 1 7 6
E D 1 3 4 2 . 1 2 7
E E 0 0 . 0 0 0
EF 3 5 8 2 . 5 5 4
EG 0 0 .000
E H 0 0 . 0 0 0
E I 3 4 4 2 .537
E J 0 0 . 0 0 0
E K 0 0 . 0 0 0
E L 8 9 1 . 9 4 9
2N D
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
2 3 1 . 3 6 2
6 6 1 . 8 2 0
4 5 1 . 6 5 3
0 0 . 0 0 0
1 8 7 5 3 . 2 7 3
7 4 1 . 8 6 9
1 6 3 8 3 . 2 1 4
1 3 1 2 . 1 1 7
7 7 7 2 . 8 9 0
1 1 8 0 3 .072
4 28 2 . 6 3 1
304 2 . 4 8 3
1 9 6 2 .292
1 0 1 . 0 0 0
0 0 . 0 0 0
586 2 .768
3RD
20 1 . 3 0 1
8 . 9 0 3
1 5 1 . 1 7 6
5 6 1 . 7 4 8
5 . 6 9 9
a 8 1 . 9 4 4
0 0 . 0 0 0
1 5 1 . 1 7 6
0 0 .000
410 2 . 6 1 3
11 1 . 0 4 1
1 0 9 2 . 0 3 7
282 2 . 4 5 0
274 2 . 4 3 8
8 5 1 . 9 2 9
11 1 . 0 4 1
0 0 . 0 0 0
111 2 . 0 4 5
0 0 . 0 0 0
24 1 . 3 8 0
1 6 3 2 . 2 1 2
4TH 5TH
0 0 0 . 0 0 0 0 . 0 0 0
3 9 8 0 2 . 6 0 0 0 . 0 0 0
11 0 1 . 0 4 1 0 . 0 0 0
3 5 3 5 . 4 7 7 2 . 7 2 8
0 1 0 0 . 0 0 0 1 . 0 0 0
4 0 . 6 0 2 0 . 0 0 0
0 0 0 .000 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
0 234 0 . 0 0 0 2 . 3 6 9
5 9 3 6 2 . 7 7 3 . 7 7 8
8 0 . 9 0 3 0 . 0 0 0 7 4 3 0
2 . 8 7 1 0 .000 3 5 8 5 8 5
1 . 9 2 9 3 . 9 3 4 7 0 3 224
2 . 8 4 7 2 . 3 5 0 6 1 3 0
. 7 7 8 2 . 1 1 4 3 0
. 4 7 7 0 . 0 0 0 0 0
0 . 0 0 0 0 . 0 0 0 3 1 3
. 4 7 7 1 . 1 1 4 0 0
0 . 0 0 0 0 . 0 0 0 1 8 5
1 . 2 5 5 . 6 9 9 1 5 0 9 3 2 5
3 .179 2 . 5 1 2
SUM
20 1 . 3 0 1
6 9 9 2 . 8 4 4
262 2 . 4 1 8
594 2 . 7 7 4
1 5 1 . 1 7 6
7 6 4 2 .883
66 1 . 8 2 0
7 2 1 . 8 5 7
234 2 . 3 6 9
3 1 1 5 3 . 4 9 3
9 3 1 . 9 6 8
2505 3 .399
9 2 1 7 3 . 9 6 5
1 9 7 8 3 .296
1 7 5 9 3 . 2 4 5
442 2 . 6 4 5
304 2 . 4 8 3
6 5 7 2 .824
1 0 1 . 0 0 0
47 1 . 6 7 2
2 6 7 2 3 .427
APPENDIX 5 .2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
EM 62 1 . 7 9 2
E N 886 2 .947
E O 0 0 .000
EP 0 0 .000
E Q 2 3 1 . 3 6 2
E R 7 3 1 . 8 6 3
ES 1 4 4 2 .158
ET 32 1 . 5 0 5
E U 1 4 3 2 .155
EV 1 2 6 2 .100
EW 0 0 .000
E X 649 2 .812
E Y 4 . 602
E Z 0 0 .000
FA 997 2 .999
FE 1 6 5 2 .217
FF 0 0 .000
F I 8 0 3 2 .905
FL 218 2 .338
FO 926 2 .967
FR 573 2 .758
2ND
685 2 .836
936 2 . 9 7 1
976 2 .989
3 4 3 2 .535
0 0 .000
1 5 5 1 3 .191
769
1 0 7 1 3.030
9 .954
312 2 .494
1 7 7 2 .248
97 1 . 9 8 7
1 8 3 2 .262
0 0 .000
0 0 .000
0 0 .000
7 9 1 2.898
0 0 .000
1 0 1 .000
0 0 .000
1 0 2 2 .009
2 .886
3RD
360 2 .556
8 0 3 2 .905
1 2 9 2 .111
7 6 1 . 8 8 1
0 0 .000
2 52 2 .401
8 2 1 . 9 1 4
2 53 2 .403
0 0 .000
6 3 1 . 7 9 9
3 3 1 . 5 1 9
1 0 1 . 0 0 0
7 . 845
0 0 .000
57 1 .756
434 2 .637
1 6 2 2 .210
301 2 .479
3 1 1 . 4 9 1
1 2 5 6 3 .099
52 1 . 7 1 6
4TH
4 8 1 . 6 8 1
1 2 7 4 3 .105
3 .477
314 2 .497
0 0 .000
1 4 6 1 3 .165
6 0 1 2 .779
1 3 0 2 .114
3 2 1 . 5 0 5
28 1 . 4 4 7
24 1 . 3 8 0
0 0 . 0 0 0
0 0 .000
3 3 1 . 5 1 9
0 0 .000
1 8 5 2 .267
1 2 1 . 0 7 9
5 1 1 . 7 0 8
1 2 1 . 0 7 9
0 0 .000
0 0 .000
5TH
4 3 5 2 .638
1 0 9 9 3 . 0 4 1
1 2 1 . 0 7 9
3 5 1 . 5 4 4
0 0 .000
6964 3 .843
3 7 3 5 3 .572
1164 3 .066
4 . 6 0 2
0 0 .000
8 7 1 . 9 4 0
4 . 602
284 2 . 4 5 3
0 0 .000
0 0 .000
6 . 778
9 .9 54
0 0 .000
0 0 .000
0 0 .000
0 0 .000
S U M
1590 3 . 2 0 1
4998 3 . 6 9 9
1 1 2 0 3 .049
7 6 8 2 .885
2 3 1 . 3 6 2 1 0 3 0 1 4 .013
5 3 3 1 3 .727
2650 3 . 4 2 3
1 8 8 2 .274
529 2 . 7 2 3
3 2 1 2 .507
760 2 .881
478 2 .679
3 3 1 . 5 1 9
1054 3 . 0 2 3
790 2 .898
974 2 .989
1 1 5 5 3 . 0 6 3
271 2 .433
2182 3 . 3 3 9
727 2 .862
209
210 CHAPTER 5
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
FS 0 0 .000
FT 0 0 .000
FU 271 2 .433
FY 0 0 .000
G A 1 9 6 2 .292
G E 322 2 .508
G G 0 0 .000
G H 1 6 1 . 2 0 4
G I 1 3 8 2 .140
G L 8 8 1 . 9 4 4
GM 0 0 .000
G N 0 0 .000
G O 1 1 9 2 .076
G R 6 6 1 2 .820
GS 0 0 .000
GT 0 0 .000
G U 1 7 2 2 .236
GY 0 0 .000
H A 834 2 .921
H E 493 2 .693
H I 316
2ND 3RD 4TH
0 9 0 0 .000 .954 0 .000
0 9 9 26 0 .000 1 . 9 9 6 1 . 4 1 5
0 2 3 6 1 0 .000 1 . 3 6 2 1 . 7 8 5
0 0 0 0 .000 0 .000 0 .000
0 1 2 9 8 6 0 .000 2 .111 1 . 9 3 4
1 0 0 1 2 4 1 8 5 1 2 .000 2 .093 3 .022
0 1 1 7 0 0 .000 2 .068 0 .000
0 544 722 0 .000 2 .736 2 .859
0 226 1 5 0 0 .000 2 .354 2 .176
0 11 205 0 .000 1 . 0 4 1 2 .312
0 0 4 0 .000 0 .000 .602
1 9 1 2 4 0 1 . 2 7 9 2 .093 0 .000
0 36 3 3 0 .000 1 . 5 5 6 1 .519
9 2 1 3 4 2 3 1 . 9 6 4 2 . 1 2 7 1 . 3 6 2
0 0 0 0 .000 0 .000 0 .000
0 0 1 1 6 0 .000 0 .000 2 .064
0 3 0 1 1 1 0 0 .000 2 .479 2 . 0 4 1
0 0 0 0 .000 0 .000 0 .000
8 4 8 3 4 29 2 .928 1 . 5 3 1 1 .462
328 399 1 7 3 9 2 .516 2 . 6 0 1 3 .240
586 287 370
5TH
2 3 1 . 3 6 2
0 0 .000
0 0 .000
1 9 1 . 2 7 9
0 0 .000
844 2 .926
0 0 .000
872 2 .941
0 0 .000
0 0 .000
0 0 .000
1 3 2 2 .121
3 .477
0 0 .000
462 2 . 6 6 5
0 0 .000
0 0 .000
1 1 2 2 .049
18 1 . 2 5 5
1 7 1 . 2 3 0
0
SUM
32 1 . 5 0 5
1 2 5 2 .097
355 2 . 5 5 0
1 9 1 . 2 7 9
4 1 1 2 .614
2441 3 .388
1 1 7 2 .068
2154 3 .333
514 2 .711
304 2 .483
4 . 6 0 2
2 7 5 2 .439
1 9 1 2 .281
9 1 0 2 .959
462 2 . 6 6 5
1 1 6 2 .064
583 2 .766
1 1 2 2 .049
1 7 6 3 3 .246
2976 3.474
1 5 5 9 2 .500 2 .768 2 .458 2 .568 0 . 0 0 0 3 .193
APPENDIX 5 . 2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1 S T
HL 0 0 . 0 0 0
HM 0 0 . 0 0 0
HN 0 0 . 0 0 0
HO 4 6 3 2 . 6 6 6
HR 0 0 . 0 0 0
HS 0 0 . 0 0 0
HT 0 0 . 0 0 0
HU 204 2 . 3 1 0
HW 0 0 . 0 0 0
HY 0 0 .000
IA 0 0 . 0 0 0
IB 0 0 . 0 0 0
IC 3 . 4 7 7
I D 1 6 1 . 2 0 4
IE 0 0 . 0 0 0
IF 0 0 . 0 0 0
IG 1 9 1 . 2 7 9
I1 0 0 .000
IK 0 0 . 0 0 0
IL 0 0 . 0 0 0
IM 1 3 8 2 . 1 4 0
2 N D
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 9 9 1 3 .299
3 6 1 2 .558
0 0 . 0 0 0
0 0 . 0 0 0
3 5 9 2.555
3 . 4 7 7
22 1 . 3 4 2
5 6 1 . 7 4 8
4 3 1 . 6 3 3
284 2 . 4 5 3
322 2 . 5 0 8
2 5 3 2 . 4 0 3
1 0 0 2 . 0 0 0
8 7 0 2 . 9 4 0
0 0 . 0 0 0
1 6 9 2 . 2 2 8
5 4 8 2 . 7 3 9
4 2 1 2 . 6 2 4
3RD
0 0 .000
0 0 .000
4 3 1 . 6 3 3
524 2 . 7 1 9
5 . 6 9 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
4 3 1 . 6 3 3
2 5 1 . 3 9 8
1 6 9 2 . 2 2 8
1 9 5 2 .290
2 0 3 2 . 3 0 7
3 2 1 . 5 0 5
452 2 . 6 6 5
7 . 8 4 5
0 0 .000
346 2 . 5 3 9
1 0 7 2 . 0 2 9
4TH
9 9 1 . 9 9 6
7 . 8 4 5
0 0 . 0 0 0
2 4 1 2 . 3 8 2
0 0 . 0 0 0
0 0 .000
244
5 5 1 . 7 4 0
0 0 . 0 0 0
0 0 . 0 0 0
5 3 5 2 . 7 2 8
0 0 .000
1 0 6 0 3 . 0 2 5
3 4 8 2 . 5 4 2
1 0 4 7 3 .020
3 5 1 . 5 4 4
1 3 2 2 . 1 2 1
0 0 . 0 0 0
92 1 . 9 6 4
570 2 . 7 5 6
9 7 1 . 9 8 7
2 . 3 8 7
5TH SUM
0 9 9 0 . 0 0 0 1 . 9 9 6
2 2 29 1 . 3 4 2 1 . 4 6 2
0 4 3 0 . 0 0 0 1 . 6 3 3
0 3 2 1 9 0 . 0 0 0 3 . 5 0 8
0 3 6 6 0 . 0 0 0 2 . 5 6 3
2 7 3 2 7 3 2 . 4 3 6 2 . 4 3 6
7 0 3 9 4 7 2 . 8 4 7 2 . 9 7 6
0 6 1 8 0 . 0 0 0 2 . 7 9 1
0 3 0 . 0 0 0 . 4 7 7
6 3 8 5 1 . 7 9 9 1 . 9 2 9
9 9 7 3 3 1 . 9 9 6 2 . 8 6 5
0 6 8 0 . 0 0 0 1 . 8 3 3
7 3 9 2 2 5 5 2 . 8 6 9 3 . 3 5 3
1 6 8 1 0 4 9 2 . 2 2 5 3 . 0 2 1
4 6 1 5 4 9 1 . 6 6 3 3 .190
0 1 6 7 0 . 0 0 0 2 . 2 2 3
8 1 4 9 1 . 9 0 3 3 . 1 7 3
1 6 2 3 1 . 2 0 4 1 . 3 6 2
0 2 6 1 0 . 0 0 0 2 .417
1 4 2 1 6 0 6 2 . 1 5 2 3 .206
2 7 7 9 0 1 . 4 3 1 2 . 8 9 8
2 1 1
212 C H A P T E R 5
BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 6
BIGRAM P O S I T I O N 1ST
I N 8 7 3 2 . 9 4 1
I0 0 0.000
I P 0 0.000
IQ 0 0.000
I R 1 7 1 . 2 3 0
I S 298 2 .474
I T 3 0 4 2.483
I U 0 0.000
I V 0 0.000
I X 0 0.000
I 2 0 0.00Q
J A 5 0 1.699
J E 1 1 9 2.076
J O 1 7 6 2.246
J U 1 9 6 2.292
KA 3 1 1 . 4 9 1
KE 6 .778
K I 1 5 2 2.182
KL 0 0 .000
KN 25 1.398
KO 11 1 . 0 4 1
2 N D
8 2 8 2.918
1 8 1.255
29 1.462
9 1 1.959
389 2.590
8 0 0 2.903
1 7 5 7 3.245
0 0 .000
394 2.595
2 1 1.322
3 .477
0 0.000
0 0 .000
0 0.000
0 0.000
0 0.000
1 6 1 .204
57 1 .756
0 0.000
0 0 .000
0 0.000
3 RD
9 1 6 2 .962
3 6 1 .556
5 .699
58 1 .763
3 2 5 2.512
3 9 2 2.593
9 0 1 2 .955
0 0 .000
1 2 2 2 .086
0 0 .000
3 0 1 .477
0 0.000
8 4 1 . 9 2 4
1 3 1 . 1 1 4
43 1 . 6 3 3
0 0.000
1 7 6 2.246
543 2 .735
7 .845
0 0 .000
6 .778
4 T H
4190 3.622
1 1 0 0 3 .041
33 1 .519
0 0.000
406 2.609
480 2.681
235 2 .371
1 0 8 2.033
208 2.318
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0 .000
1 9 2 7 3.285
1 2 1 .079
42 1.623
0 0.000
7 .845
5 T H
9 1 5 2 .961
3 1 1 .491
3 4 1 . 5 3 1
0 0.000
7 3 1 .863
1 6 7 2.223
444 2.647
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
0 0 .000
0 0.000
0 0 .000
2 2 1 .342
1 2 7 2.104
0 0.000
Q 0.000
0 0 .000
0 0.000
SUM.
7 7 2 2 3.888
1 1 8 5 3.074
1 0 1 2.004
1 4 9 2.173
1 2 1 0 3.083
2137 3.330
3 6 4 1 3.561
1 0 8 2.033
7 2 4 2.860
2 1 1 . 3 2 2
33 1 .519
50 1 .699
203 2.307
1 8 9 2.276
239 2.378
53 1.724
2252 3 .353
7 6 4 2.883
49 1.690
25 1.398
24 1.380
APPENDIX 5.2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
KS 0 0 .000
K U 0 0 .000
K Y 0 0 . 0 0 0
LA 5 1 8 2.714
L B 0 0 .000
L D 0 0 .000
L E 7 1 8 2.856
LF 0 0 * 0 0 0
LG 0 0 .000
L I 1 6 0 5 3 . 2 0 5
LK 0 0 .000
L L 0 0 .000
LM 0 0 . 0 0 0
L N 0 0 .000
L O 9 7 8 2 . 9 9 0
LP 0 0 . 0 0 0
LS 0 0 . 0 0 0
LT 0 0 . 0 0 0
L U 8 1 1 . 9 0 8
LV 0 0 . 0 0 0
LW 0 0 . 0 0 0
2ND
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
9 1 4 2 . 9 6 1
47 1 . 6 7 2
28 1 . 4 4 7
210 2 . 3 2 2
52 1 . 7 1 6
0 0 . 0 0 0
1 7 3 2 . 2 3 8
0 0 . 0 0 0
7 8 1 . 8 9 2
432 2 . 6 3 5
0 0 .000
536 2 . 7 2 9
0 0 .000
0 0 .000
0 0 .000
57 1 . 7 5 6
0 0 . 0 0 0
4 58 2 . 6 6 1
3RD
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
3 2 1 2 . 5 0 7
0 0 . 0 0 0
1 8 9 2 . 2 7 6
316 2 .500
0 0 .000
1 0 1 . 0 0 0
7 7 3 2 . 8 8 8
234 2 . 3 6 9
1 4 7 1 3 .168
1 1 7 2 . 0 6 8
11 1 . 0 4 1
1 9 3 2 .286
7 9 1 . 8 9 8
7 8 1 . 8 9 2
1 4 4 2 . 1 5 8
4 1 3 2 . 6 1 6
6 8 1 . 8 3 3
0 0 . 0 0 0
4TH
0 0 . 0 0 0
1 4 1 . 1 4 6
0 0 .000
1 5 5 2 . 1 9 0
0 0 . 0 0 0
9 3 1 . 9 6 8
1 6 3 5 3 . 2 1 4
0 0 . 0 0 0
0 0 .000
5 7 7 2 . 7 6 1
0 0 . 0 0 0
3 9 1 2 . 5 9 2
0 0 . 0 0 0
0 0 . 0 0 0
3 4 2 2 . 5 3 4
0 0 . 0 0 0
0 0 . 0 0 0
1 9 4 2 . 2 8 8
4 . 6 0 2
5 3 1 . 7 2 4
0 0 . 0 0 0
5TH
3 6 0 2 . 5 5 6
0 0 . 0 0 0
3 2 1 . 5 0 5
1 9 1 . 2 7 9
0 0 . 0 0 0
1 0 0 4 3 . 0 0 2
3 4 9 9 3 . 5 4 4
4 5 4 2 . 6 5 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
81 1 . 9 0 8
0 0 . 0 0 0
0 0 . 0 0 0
1 3 1 . 1 1 4
0 0 . 0 0 0
500 2 . 6 9 9
2 59 2 . 4 1 3
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
S U M
3 6 0 2 . 5 5 6
1 4 1 . 1 4 6
3 2 1 . 5 0 5
1 9 2 7 3 . 2 8 5
47 1 . 6 7 2
1 3 1 4 3 . 1 1 9
6 3 7 8 3 . 8 0 5
5 0 6 2 . 7 0 4
1 0 1 . 0 0 0
3 1 2 8 3 . 4 9 5
234 2 . 3 6 9
2 0 2 1 3 . 3 0 6
5 4 9 2 . 7 4 0
11 1 . 0 4 1
2062 3 .314
7 9 1 . 8 9 8
5 7 8 2 . 7 6 2
597 2 . 1 7 6
5 5 5 2 . 7 4 4
1 2 1 2 . 0 8 3
458 2 . 6 6 1
2 1 3
214 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION ~~~
1ST
LY 1 8 1 . 2 5 5
MA 1 4 9 3 3 .174
MB 0 0 .000
ME 8 0 1 2 .904
MI 436 2 .639
ML 0 0 .000
M M 0 0 .000
MN 0 0 .000
MO 1637 3 .214
MP 0 0 .000
MS 0 0 .000
MT 0 0 .000
M U 215 2 .332
MY 1 3 6 2.134
NA 512 2 .709
N B 0 0 .000
NC 0 0 .000
N D 0 0 .000
N E 519 2 .715
NF 0 0 .000
N G 0 0 .000
2ND
4 3 1 .633
48 1 . 6 8 1
1 2 1 . 0 7 9
27 1 . 4 3 1
8 5 1 . 9 2 9
0 0 .000
5 .699
0 0 .000
223 2 .348
1 3 5 2 .130
0 0 .000
0 0 .000
9 . 954
4 . 6 0 2
1 1 3 2 .053
4 . 602
216 2 .334
297 2 .473
1 2 8 2 .107
3 5 1.544
1 0 7 2 .029
3RD
0 0 .000
346 2 .539
788 2 .897
420 2 .623
6 1 3 2 .787
7 . 8 4 5
433 2 .636
1 9 1 .279
7 07 2 .849
532 2 .726
1 0 1 . 0 0 0
0 0 .000
3 7 1 . 5 6 8
0 0 .000
1 9 3 2 .286
0 0 .000
1 5 7 2 .196
717 2 .856
236 2 .373
6 . 778 7 7 3
2 .888
4TH
4 . 602
540 2.732
1 2 1 .079
988 2 .995
1 9 4 2.288
7 9 1 . 8 9 8
0 0 .000
9 .954
248 2 .394
3 2 1 . 5 0 5
6 . 778
28 1 .447
7 . 845
0 0 .000
6 6 1 . 8 2 0
0 0 .000
544 2 .736
284 2 .453
1 3 6 2 3 .134
0 0 .000
765 2 .884
5TH
2892 3 .461
28 1 .447
0 0 .000
1 0 2 2 3 .009
7 . 845
0 0 .000
0 0 .000
1 0 5 2 .021
0 0 .000
0 0 .000
1 2 0 2 .079
0 0 .000
0 0 .000
1 5 1 . 1 7 6
5 1 1 .708
0 0 .000
0 0 .000
2237 3 .350
447 2.650
0 0 .000
3776 3 .577
SUM
2957 3 .471
2455 3 .390
812 2 .910
3258 3 .513
1 3 3 5 3 .125
8 6 1 . 9 3 4
4 38 2 .641
1 3 3 2 .124
281 5 3 .449
699 2 .844
1 3 6 2 .134
28 1 . 4 4 7
268 2 .428
1 5 5 2 .190
9 3 5 2 . 9 7 1
4 . 602
917 2 .962
3535 3 .548
2692 3 .430
4 1 1 . 6 1 3
5 4 2 1 3 .734
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
NI 68 1.833
NJ 0 0.000
NK 0 0.000
NL 0 0.000
NM 0 0.000
NN 0 0.000
NO 450 2.653
NP 0 0.000
NR 0 0.000
NS 0 0.000
NT 0 0.000
NU 494 2.694
NV 0 0.000
NW 0 0.000
NY 0 0.000
NZ 0 0.000
OA 0 0.000
OB 114 2.057
oc 46 1.663
OD 3 .477
OE 0 0.000
2N D
673 2.828
43 1.633
10 1.000
165 2.217
0 0.000
113 2.053
430 2.633
9 .954
25 1.398
445 2.648
231 2.364
3 .477
35 1.544
12 1.079
206 2.314
6 .778
131 2.117
214 2.330
624 2.795 4 36
2.639 119
2.076
3RD
380 2.580
0 0.000
72 1.857
6 .778
3 .477
582 2.765
72 1.857
0 0.000
22 1.342
118 2.072
955 2.980
176 2.246
51 1.708
4 .602
12 1.079
0 0.000
28 1.447
7 .845
67 1.826
71 1.851
0 0.000
4TH
71 1.851
0 0.000
100 2.000
75 1.875
0 0.000
67 1.826
286 2.456
0 0.000
0 0.000
0 0.000
7 51 2.876
63 1.799
0 0.000
0 0.000
0 0.000
17 1.230
116 2.064
0 0.000
3 .477 123
2.090 32
1.505
5TH
9 .954
0 0.000
5 .699
0 0.000
0 Q.OOO
0 0.000
0 0.000
0 0.000
0 0.000
3 07 2.487
1086 3.036
0 0.000
0 0.000
0 0.000
87 1.940
0 0.000
0 0.000
0 0.000
0 0.000 4 07
2.610 12
1.079
SUM
1201 3.080
43 1.633
187 2.272
246 2.391
3 .477
762 2.882
1238 3.093
9 .954
47 1.672
870 2.940
3023 3.480
736 2.867
86 1.934
16 1.204
305 2.484
23 1.362
275 2.439
335 2.525 740
2.869 1040
3.017 163
2.212
215
216 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
OF 313 2 .496
OG 0 0 .000
OH 0 0 .000
01 0 0 .000
OK 0 0 .000
OL 2 1 1 . 3 2 2
OM 0 0 .000
ON 8 . 9 0 3
00 0 0 .000
OP 1 9 7 2.294
OR 1 7 8 2 .250
0s 0 0 .000
OT 323 2 .509
ou 8 2 1 . 9 1 4
ov 8 . 9 0 3
OW 38 1 .580
ox 6 1 1 . 7 8 5
OY 6 . 778
0 2 0 0 .000
PA 8 4 9 2 .929
PE 1450 3 .161
2ND
1 2 5 2 .097
9 . 954
30 1 .477
314 2 .497
1 0 1 . 0 0 0
1 1 8 9 3 .075
7 8 1 2 .893
8 4 9 2 .929
592 2 .772
1 0 4 2 .017
1 5 2 3 3 . 1 8 3
428 2 . 6 3 1
8 5 3 2 . 9 3 1
1 6 0 6 3 .206
407 2 .610
598 2 .777
0 0 .000
26 1 . 4 1 5
1 8 1 . 2 5 5
44 1 . 6 4 3
278 2 .444
3 RD
28 1 .447
7 . 845
0 0 .000
1 1 6 2 .064
5 3 1 2 .725
1 1 4 2 .057
1 7 9 2 . 2 5 3
1 0 5 2 . 0 2 1
1 9 3 2 .286
1 0 0 7 3 .003
392 2 .593
2 68 2 .428
72 1 . 8 5 7
2869 3 .458
1 3 0 2 .114
504 2 .702
0 0 .000
0 0 .000
27 1 . 4 3 1
1 2 7 2 .104
5 1 1 2 .708
4TH
0 0 .000
0 0 .000
0 0 .000
30 1 . 4 7 7
39 1 . 5 9 1
8 5 1 . 9 2 9
4 8 1 2 .682
1 0 3 0 3 . 0 1 3
526 2 .721
1 7 1 2 .233
2101 3 .322
8 0 3 2 . 9 0 5
1 0 7 2 .029
1 2 3 2 .090
62 1 . 7 9 2
8 3 1 .919
0 0 .000
1 0 1 . 0 0 0
0 0 .000
0 0 .000
639 2 .806
STH
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 .000
598 2 .777
223 2 .348
2267 3 . 3 5 5
0 0 .000
22 1 . 3 4 2
762 2 .882
3 5 1 . 5 4 4
288 2 .459
0 0 .000
0 0.000
5 7 3 2 .758
3 . 477
3 1 1 . 4 9 1
0 0 .000
0 0 .000
1 9 7 2 .294
SUM
466 2 .668
1 6 1 . 2 0 4
3 0 1 .477
460 2 .663
580 2 . 7 6 3
2007 3 .303
1 6 6 4 3 . 2 2 1
4259 3 .629
1 3 1 1 3 .118
1 5 0 1 3 .176
4956 3 .695
1 5 3 4 3 .186
1 6 4 3 3 .216
4680 3 .670
607 2 .783
1 7 9 6 3 .254
6 4 1 . 8 0 6
7 3 1 . 8 6 3
4 5 1 . 6 5 3
1 0 2 0 3 .009
3075 3 .488
APPENDIX 5 . 2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
PH 1 0 8 2 . 0 3 3
P I 3 1 3 2 . 4 9 6
PK 0 0 . 0 0 0
PL 6 8 8 2 . 8 3 8
PO 1 0 7 5 3 . 0 3 1
PP 0 0 .000
PR 6 1 0 2 . 7 8 5
PS 7 . 8 4 5
PT 0 0 . 0 0 0
PU 7 2 7 2 . 8 6 2
PW 0 0 .000
PY 0 0 . 0 0 0
Qu 7 0 1 . 8 4 5
RA 8 1 7 2 . 9 1 2
RB 0 0 . 0 0 0
RC 0 0 . 0 0 0
RD 0 0 . 0 0 0
R E 2 6 4 3 3 .422
RG 47 0 . 0 0 0
RH 30 1 . 4 7 7
R I 312 2 .494
2ND
3 5 1 . 5 4 4
1 9 3 2 . 2 8 6
6 . 7 7 8
3 . 4 7 7
1 0 1 2 . 0 0 4
1 9 5 2 . 2 9 0
239 2 . 3 7 8
11 1 . 0 4 1
22 1 . 3 4 2
0 0 . 0 0 0
27 1 . 4 3 1
0 0 . 0 0 0
1 6 6 2 .220
674 2 . 8 2 9
9 . 9 5 4
2 1 1 . 3 2 2
7 3 1 . 8 6 3
7 0 9 2 . 8 5 1
9 1 1 . 9 5 9
0 0 .000
1 2 3 1 3 .090
3RD
9 . 9 5 4
1 5 6 2 . 1 9 3
3 . 4 7 7
1 2 1 . 0 7 9
2 3 3 2 . 3 6 7
2 9 8 2 . 4 7 4
6 . 7 7 8
7 . 8 4 5
1 9 1 . 2 7 9
1 7 1 . 2 3 0
0 0 . 0 0 0
0 0 . 0 0 0
9 1 1 . 9 5 9
269 2 . 4 3 0
1 3 2 2 . 1 2 1
404 2 . 6 0 6
360 2 . 5 5 6
1 4 3 6 3 . 1 5 7
417 2 .620
0 0 . 0 0 0
1 7 5 6 3 . 2 4 5
4TH
15 1 . 1 7 6
5 2 1 . 7 1 6
0 0 . 0 0 0
1 5 6 4 3 . 1 9 4
46 1 . 6 6 3
3 . 4 7 1
0 0 . 0 0 0
7 . 8 4 5
0 0 . 0 0 0
7 5 1 . 8 7 5
0 0 . 0 0 0
0 0 . 0 0 0
6 4 1 . 8 0 6
4 1 1 . 6 1 3
44 1 . 6 4 3
5 2 8 2 . 7 2 3
1 1 8 2 . 0 7 2
9 0 9 2 . 9 5 9
3 8 1 2 . 5 8 1
0 0 . 0 0 0
2 6 8 2 . 4 2 8
5TH
5 5 1 . 7 4 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 1 1 2 . 3 2 4
2 9 8 2 . 4 7 4
0 0 . 0 0 0
0 0 . 0 0 0
2 5 1 . 3 9 8
0 0 . 0 0 0
40 1 . 6 0 2
40 1 . 6 0 2
0 0 . 0 0 0
8 7 5 2 . 9 4 2
2 3 6 4 3 . 3 7 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
S U M
2 2 2 2 .346
7 1 4 2 .854
9 . 9 5 4 2 267
3 . 3 5 5 1 4 5 5
3 . 1 6 3 496
2 . 6 9 5 8 5 5
2 . 9 3 2 243
2 .386 3 39
2 . 5 3 0 8 1 9
2 . 9 1 3 27
1 . 4 3 1 2 5
1 . 3 9 8 3 9 1
2 .592 1 8 4 1
3 . 2 6 5 2 2 5
2 . 3 5 2 9 5 3
2 .979 1 4 2 6
3.154 8 0 6 1
3.906 8 8 9
2 . 9 4 9 3 0
1 . 4 7 7 3 5 6 7
3 . 5 5 2
2 1 7
2 1 8 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
RK 0 0 .000
RL 0 0 .000
RM 0 0 . 0 0 0
RN 0 0 . 0 0 0
R O 254 2 . 4 0 5
RP 0 0 .000
R R 0 0 . 0 0 0
RS 0 0 .000
RT 0 0 .000
RU 220 2 . 3 4 2
RV 0 0 . 0 0 0
RY 0 0 .000
SA 530 2 . 7 2 4
SC 7 2 2 2 . 8 5 9
SD 0 0 .000
SE 1 8 4 6 3 .266
SH 1 4 6 4 3 . 1 6 6
S I 8 3 6 2 . 9 2 2
SK 7 3 1 . 8 6 3
SL 2 9 1 2 .464
SM 1 4 6
2ND
0 0 . 0 0 0
0 0 . 0 0 0
1 5 1 . 1 7 6
3 0 1 . 4 7 7
1 5 2 0 3 .182
0 0 . 0 0 0
1 0 0 2 .000
0 0 . 0 0 0
1 5 4 2 . 1 8 8
8 5 1 . 9 2 9
4 . 6 0 2
207 2 . 3 1 6
11 1 . 0 4 1
7 4 1 . 8 6 9
0 0 . 0 0 0
5 8 1 . 7 6 3
6 . 7 7 8
0 0 . 0 0 0
6 7 1 . 8 2 6
1 9 6 2 .292
0
3RD
5 4 2 2 . 7 3 4
1 4 0 2 . 1 4 6
7 4 5 2 .872
5 6 1 2 . 7 4 9
9 5 3 2 .979
5 0 1 . 6 9 9
3 1 1 2 . 4 9 3
340 2 . 5 3 1
2 8 6 2 . 4 5 6
1 2 4 2 . 0 9 3
2 9 3 2 . 4 6 7
0 0 . 0 0 0
3 5 1 . 5 4 4
220 2 . 3 4 2
4 4 1 . 6 4 3
6 7 7 2 . 8 3 1
2 7 6 2 . 4 4 1
8 9 7 2 . 9 5 3
2 5 1 . 3 9 8
3 . 4 7 7
3 4 2 . 1 6 4 0 .000 1 . 5 3 1
4TH
1 5 1 . 1 7 6
237 2 . 3 7 5
1 4 1 . 1 4 6
1 0 1 . 0 0 0
1 9 9 2 . 2 9 9
0 0 .000
4 2 1 . 6 2 3
489 2 . 6 8 9
3 6 3 2 .560
2 2 1 . 3 4 2
0 0 . 0 0 0
0 0 . 0 0 0
6 1 1 . 7 8 5
4 . 6 0 2
0 0 .000
1 3 8 4 3 . 1 4 1
3 . 4 7 7
2 2 8 2 . 3 5 8
4 5 1 . 6 5 3
0 0 . 0 0 0
1 3 1 . 1 1 4
5TH
44 1 . 6 4 3
0 0 .000
49 1 . 6 9 0
3 9 9 2 . 6 0 1
3 2 1 . 5 0 5
0 0 . 0 0 0
0 0 . 0 0 0
1 2 0 0 3 . 0 7 9
6 0 2 2 . 7 8 0
0 0 . 0 0 0
0 0 .000
5 4 3 2 . 7 3 5
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
8 1 9 2 . 9 1 3
1 8 8 2 . 2 7 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 3 1 . 1 1 4
SUM
6 0 1 2 . 7 7 9
377 2 . 5 7 6
8 2 3 2 . 9 1 5
1 0 0 0 3 . 0 0 0
2958 3 . 4 7 1
5 0 1 . 6 9 9
4 5 3 2 . 6 5 6
2 0 2 9 3 . 3 0 7
1 4 0 5 3 . 1 4 8
4 5 1 2 . 6 5 4
2 9 7 2 . 4 7 3
7 5 0 2 . 8 7 5
6 3 7 2 . 8 0 4
1 0 2 0 3 . 0 0 9
44 1 . 6 4 3
4784 3 . 6 8 0
1 9 3 7 3 .287
1 9 6 1 3 . 2 9 2
210 2 . 3 2 2
490 2 . 6 9 0
2 0 6 2 . 3 1 4
APPENDIX 5.2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
SN 36 1.556
SO 886 2.947
SP 698 2.844
SQ 143 2.155
SR 0 0.000
ss 0 0.000
ST 2484 3.395
SU 704 2.848
sw 83 1.919
SY 481 2.682
TA 519 2.715
TC 0 0.000
TE 203 2.307
TF 0 0.000
TH 1419 3.152
TI 145 2.161
TL 0 0.000
TM 0 0.000
TO 508 2.706
TP 0 0.000
TR 614 2.788
2ND
0 0.000
0 0.000
56 1.748
0 0.000
15 1.176
313 2.496
59 1.771
0 0.000
0 0.000
7 .845
1251 3.097
0 0.000
57 1.756
0 0.000
363 2.560
31 1.491
0 0.0011
7 .845
202 2.305
0 0.000
807 2.948
3RD
0 0.000
25 1.398
21 1.322
0 0.000
0 0.000
562 2.750
1132 3.054
6 07 2.783
152 2.182
0 0.000
416 2.619
0 0.000
505 2.703
16 1.204
1739 3.240
1352 3.131
50 1.699
0 0.000
74 1.869
35 1.544
63 1.799
4TH
0 0.000
817 2.912
0 0.000
0 0.000
3 .477
0 0.000
142 2.152
84 1.924
0 0.000
0 0.000
142 2.152
76 1.881
4357 3.639
0 0.000
335 2.525
197 2.294
1462 3.165
0 B.000
685 2.836
0 0.000
130 2.114
5TH
0 0.000
0 0.000
0 0.000
0 0.000
0 0.000
565 2.752
1104 3.043
0 0.000
0 0.000
28 1.447
38 1.580
0 0.000
380 2.580
0 0.000
637 2.804
0 0.000
0 0.000
0 0.000
54 1.732
0 0.000
0 0.000
SUM
36 1.556
1728 3.238
775 2.889
143 2.155
18 1.255
1440 3.158
4921 3.692
1395 3.145
235 2.371
516 2.713
2366 3.374
76 1.881
5502 3.741
16 1.204
4493 3.653
1725 3.237
1512 3.180
7 .a45
1523 3.183
35 1.544 1694 3.229
219
220 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
TS 0 0 .000
TT 0 0 .000
TU 370 2 .568
TW 1 4 4 2 .158
TY 7 .845
UA 0 0 .000
UB 0 0 .000
uc 0 0 .000
UD 0 0 .000
U E 0 0 .000
UF 0 0 .000
UG 0 0 .000
U I 0 0 .000
U L 0 0 .000
U M 0 0 .000
O N 874 2 .942
uo 0 0 .000
UP 74 1 . 8 6 9
UR 3 1 1 . 4 9 1
us 6 9 1 . 8 3 9
UT 3 1 1 . 4 9 1
2ND
304 2 .483
1 9 9 2 .299
1 8 3 2 .013
0 0 .000
2 3 1 . 3 6 2
44 1 . 6 4 3
577 2 .761
52 1 . 7 1 6
203 2 .307
9 6 1 .982
5 9 1 . 7 7 1
1 3 4 2 .127
1 3 3 2 .124
209 2 .320
7 59 2 .880
3 3 3 2 .522
3 1 1 . 4 9 1
1 8 8 2 .274
1544 3 .189
316 2 .500
492 2 .692
3RD
5 8 1 . 7 6 3
2414 3 . 3 8 3
809 2 .908
0 0 .000
0 0 .000
1 7 5 2 .243
8 2 1 . 9 1 4
29 1 . 4 6 2
7 3 1 . 8 6 3
5 . 699
4 . 602
316 2 .500
44 1 . 6 4 3
47 1 . 6 7 2
4 0 1 .602
352 2 .547
0 0 .000
1 5 0 2 .176
1 0 8 6 3 .036
356 2 . 5 5 1
4 1 1 . 6 1 3
4TH
0 0 .000
118 2 .072
148 2 .170
0 0 .000
8 . 903
374 2 .573
7 . 845
1 4 5 2 .161
54 1 . 7 3 2
394 2 .595
4 . 602 8 8 3
2 .946 48
1 . 6 8 1 1 1 4 5
3 .059 3 1 1
2 .493 934
2 .970 43
1 . 6 3 3 1 6 2
2 .210 1 0 7 8
3 .033 1 7 7
2 .248 1 4 9
2 .173
5TH
1 2 5 6 3 .099
5 . 699
0 0 .000
0 0 .000
779 2 .892
4 . 602
0 0 .000
0 0 .000
4 . 6 0 2
3 4 3 2 . 5 3 5
0 0 .000
0 0 .000
0 0 .000
6 4 1 . 8 0 6
1 2 8 2 .107
4 . 602
0 0 .000
1 4 1 . 1 4 6
6 2 1 . 7 9 2
338 2 .529
62 1 . 7 9 2
SUM
1 6 1 8 3 .209
2736 3 .437
1 4 3 0 3 .155
1 4 4 2 .158
817 2 . 9 1 2
597 2 .776
666 2 . 8 2 3
226 2 .354
334 2 .524
8 3 8 2 .923
67 1 . 8 2 6
1 3 3 3 3 .125
225 2 .352
1 4 6 5 3 . 1 6 6
1 2 3 8 3 .093
2497 3 .397
7 4 1 . 8 6 9
588 2 .769
3801 3 .580
1 2 5 6 3 .099
7 7 5 2 .889
APPENDIX 5 .2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
B I G R A M POSITION 1ST
u u 0 0 . 0 0 0
ux 0 0 .000
UY 0 0 . 0 0 0
uz 0 0 . 0 0 0
VA 3 8 3 2 . 5 8 3
VE 1 2 3 2 . 0 9 0
V I 3 0 9 2 . 4 9 0
VO 2 5 1 2 . 4 0 0
vu 7 . 8 4 5
WA 8 9 8 2 . 9 5 3
WB 0 0 .000
WD 0 0 . 0 0 0
WE 2 2 6 2 .354
WH 9 0 1 . 9 5 4
W I 9 1 0 2 . 9 5 9
WL 0 0 .000
WM 0 0 .000
WN 0 0 . 0 0 0
WO 3 4 1 2 .533
WR 1 8 0 2 . 2 5 5
ws 0 0 .000
2ND
0 0 .000
27 1 . 4 3 1
3 5 1 . 5 4 4
20 1 . 3 0 1
0 0 . 0 0 0
1 6 3 2 . 2 1 2
0 0 .000
20 1 . 3 0 1
0 0 .000
3 6 1 . 5 5 6
0 0 . 0 0 0
0 0 .000
1 4 7 2 . 1 6 7
4 . 6 0 2
7 9 1 . 8 9 8
0 0 . 0 0 0
0 0 .000
38 1 . 5 8 0
4 . 6 0 2
0 0 .000
0 0.000
3RD
0 0 .000
0 0 .000
0 0 .000
0 0 .000
48 1 . 6 8 1
322 2 . 5 0 8
1 1 8 5 3 . 0 7 4
5 1 1 . 7 0 8
0 0 . 0 0 0
1 0 3 9 3 . 0 1 7
16 1 . 2 0 4
2 8 1 . 4 4 7
1 4 5 2 . 1 6 1
0 0 . 0 0 0
8 7 1 . 9 4 0
0 0 . 0 0 0
1 0 1 . 0 0 0
5 . 6 9 9
0 0 . 0 0 0
0 0 . 0 0 0
3 . 4 7 7
4TH
2 0 1 . 3 0 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 9 1 . 2 7 9
9 2 9 2 . 9 6 8
1 3 1 . 1 1 4
2 3 1 . 3 6 2
0 0 . 0 0 0
6 5 1 . 8 1 3
0 0 . 0 0 0
1 2 1 . 0 7 9
4 1 8 2 . 6 2 1
0 0 . 0 0 0
7 . 8 4 5
1 1 5 2 . 0 6 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
5TH
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
1 7 1 . 2 3 0
3 4 7 2 . 5 4 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
8 . 9 0 3
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 . 4 7 7
0 0 . 0 0 0
51 1 . 7 0 8
0 0 . 0 0 0
0 0 . 0 0 0
4 8 1 . 6 8 1
SUM
20 1 . 3 0 1
3 1 1 . 4 9 1
3 5 544
20 3 0 1 467 6 6 9 884
3 .275 1 5 0 7
3.178 3 4 5
2 .538 7
, 8 4 5 2 0 3 8
3 . 3 0 9 1 6
1 . 2 0 4 4 8
1 . 6 8 1 9 3 6
2 . 9 7 1 94
1 . 9 7 3 1 0 8 3
3 . 0 3 5 1 1 8
2 . 0 7 2 1 0
1 . 0 0 0 9 4
1 . 9 7 3 3 4 5
2 . 5 3 8 1 8 0
2 . 2 5 5 51
1 . 7 0 8
221
2 2 2 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION 1ST
WT 0 0 .000
WY 0 0 . 0 0 0
XA 0 0 .000
xc 0 0 . 0 0 0
X E 0 0 . 0 0 0
XF 0 0 . 0 0 0
X I 0 0 .000
XL 0 0 . 0 0 0
xo 0 0 .000
XP 0 0 . 0 0 0
XT 0 0 .000
xu 0 0 .000
X Y 0 0 .000
YA 26 1 . 4 1 5
YC 0 0 . 0 0 0
Y D 0 a . O O O
Y E 8 9 1 . 9 4 9
YG 0 0 .000
Y H 0 0 . 0 0 0
Y I 7 . 8 4 5
Y L 0 0 . 0 0 0
2ND
0 0 . 0 0 0
0 0 .000
0 0 .000
2 7 6 2 . 4 4 1
5 . 6 9 9
1 8 1 . 2 5 5
4 2 1 . 6 2 3
0 0 .000
11 1 . 0 4 1
1 6 9 2 .228
1 4 6 2 . 1 6 4
0 0 . 0 0 0
4 3 1 . 6 3 3
0 0 .000
7 . 8 4 5
5 . 6 9 9
4 . 6 0 2
0 0 .000
0 0 .000
0 0 .000
0 0 . 0 0 0
3RD
6 . 7 7 8
4 3 1 . 6 3 3
9 . 9 5 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
49 1 . 6 9 0
6 . 7 7 8
0 0 .000
0 0 .000
1 0 1 . 0 0 0
8 0 1 . 9 0 3
0 0 . 0 0 0
1 7 1 . 2 3 0
7 . 8 4 5
6 - 7 7 8
1 5 1 . 1 7 6
4 3 1 . 6 3 3
20 1 . 3 0 1
4 3 5 2 .638
49 1 . 6 9 0
4TH
1 5 5 2 . 1 9 0
0 0 .000
0 0 .000
0 0 . 0 0 0
1 3 1 . 1 1 4
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
3 3 2 2 . 5 2 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
5TH
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
3 . 4 7 7
0 0 . 0 0 0
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
SUM
1 6 1 2 .207
4 3 1 . 6 3 3
9 . 9 5 4
2 7 6 2 . 4 4 1
18 1 . 2 5 5
1 8 1 . 2 5 5
9 1 1 . 9 5 9
6 . 7 7 8
11 1 . 0 4 1
1 6 9 2 . 2 2 8
1 5 6 2 . 1 9 3
8 0 1 . 9 0 3
4 6 1 . 6 6 3
4 3 1 . 6 3 3
1 4 1 . 1 4 6
11 1 . 0 4 1
440 2 . 6 4 3
4 3 1 . 6 3 3
20 1 . 3 0 1
442 2 . 6 4 5
49 1 . 6 9 0
APPENDIX 5 .2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6
BIGRAM POSITION ~~
1ST
Y M 0 0 .000
Y N 0 0 . 0 0 0
Y O 18 1 . 2 5 5
YP 0 0 . 0 0 0
Y R 0 0 . 0 0 0
YS 0 0 . 0 0 0
YT 0 0 . 0 0 0
YW 0 0 . 0 0 0
Z A 0 0 . 0 0 0
Z E 0 0 . 0 0 0
Z I 0 0 . 0 0 0
Z L 0 0 . 0 0 0
20 6 . 7 7 8
Z Y 0 0 . 0 0 0
z z 0 0 . 0 0 0
2N D
54 1 . 7 3 2
1 2 1 . 0 7 9
0 0 . 0 0 0
1 0 1 . 0 0 0
22 1 . 3 4 2
5 5 1 2 . 7 4 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3RD
9 .954
0 0 . 0 0 0
326 2 . 5 1 3
0 0 .000
0 0 . 0 0 0
0 0 .000
2 6 1 . 4 1 5
46 1 . 6 6 3
2 2 1 . 3 4 2
11 1 . 0 4 1
11 1 . 0 4 1
0 0 . 0 0 0
0 0 . 0 0 0
6 . 7 7 8
24 1 . 3 8 0
4TH
6 . 7 7 8
0 0 . 0 0 0
1 2 1 . 0 7 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 3 1 . 8 6 3
8 . 9 0 3
24 1 . 3 8 0
0 0 . 0 0 0
0 0 . 0 0 0
17 1 . 2 3 0
5TH
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
8 . 9 0 3
482 2 . 6 8 3
0 0 .000
0 0 . 0 0 0
1 7 1 . 2 3 0
4 7 1 . 6 7 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
6 . 7 7 8
0 0 . 0 0 0
S U M
6 9 1 . 8 3 9
1 6 1 . 2 0 4
3 56 2 . 5 5 1
1 0 1 . 0 0 0
3 0 1 . 4 7 7
1 0 3 3 3 .014
26 1 . 4 1 5
46 1 . 6 6 3
3 9 1 . 5 9 1
1 3 1 2 .117
1 9 1 . 2 7 9
24 1 . 3 8 0
6 . 7 7 8
1 2 1 . 0 7 9
4 1 1 . 6 1 3
2 2 3
224 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION ~~~
1ST
AB 1 7 8 2 .250
AC 356 2 . 5 5 1
AD 285 2 .455
AE 0 0 .000
AF 1 5 0 2 .176
AG 629 2 .799
A H 0 0 .000
A 1 34 1 . 5 3 1
A J 0 0 .000
AK 0 0.000
A L 439 2 .642
AM 315 2.498
AN 1162 3 .065
A0 0 0 .800
AP 253 2 .403
AQ 1 4 1 . 1 4 6
A R 304 2 .483
AS 238 2 .377
AT 1 8 9 2 .276
AU 44 1 . 6 4 3
AV 157 2.196
2ND
1 0 1 2 .004
5 2 1 2 .717
8 7 1 . 9 4 0
4 . 602
5 .699
6 6 1 .820
0 0 .000
433 2.636
3 .477
4 . 602
574 2 .759
7 8 1 . 8 9 2
740 2 .869
4 . 6 0 2
465 2 .667
0 0 .000
1 9 3 6 3 .287
480 2 .681
972 2 .988
1 2 5 2 .097
8 0 1 . 9 0 3
3 RD
6 4 1 . 8 0 6
543 2 .735
593 2 .773
0 0 .000
81 1 .908
1 7 5 2 .243
0 0 .000
8 3 8 2 .923
0 0 .000
40 1 .602
652 2 .814
4 59 2 .662
894 2 . 9 5 1
5 . 699
232 2 . 3 6 5
4 . 602 1 1 6 0
3 .064 5 5 5
2 .744 477
2 .679 3
.477 2 58
2 .412
4TH
1 6 6 2 .220
6 5 1 . 8 1 3
1 8 0 2 .000
0 0 .000
0 0 .000
200 2 .301
6 . 778
270 2 .431
0 0 .000
67 1 . 8 2 6
650 2 .813
8 9 1 . 9 4 9
582 2 .765
0 0 .000
67 1 . 8 2 6
0 0 .000
365 2 .562
111 2 .045
8 5 3 2 . 9 3 1
9 0 8 2 .958
2 1 1 . 3 2 2
5TH
5 .699
432 2 .635
328 2 .516
11 1 . 0 4 1
0 0 .000
6 3 5 2 .803
0 0 .000
6 6 1 2 .820
0 0 .000
40 1 . 6 0 2
1 8 5 2 .267
40 1 . 6 0 2
1 0 8 6 3 . 0 3 6
0 0 .000
3 1 9 2 .504
0 0 .000
9 5 3 2 .979
1 3 8 2 .140
393 2 .594
5 .699
4 . 602
6TH
0 0 .000
5 . 699
1 8 0 2 . 2 5 5
0 0 .000
0 0 .000
3 . 477
0 0 .000
0 0 .000
0 0 .000
0 0 .000
3015 3 .479
561 2 .749
352 2 .547
0 0 .000
4 . 602
0 0 .000
547 2 .738
8 2 1 . 9 1 4
32 1 . 5 0 5
3 . 477
0 0 .000
SUM
514 2 .711
1 9 2 2 3 .284
1 5 7 3 3 .197
1 5 1 . 1 7 6
236 2 .373
1 7 0 8 3 .232
6 . 778 2236
3 .349 3
.477 151
2 .179 5515
3 . 7 4 2 1 5 4 2
3 .188 4816
3 .683 9
. 954 1 3 4 0
3 .127 18
1 . 2 5 5 5265
3 . 7 2 1 1604
3 .205 2916
3 . 4 6 5 1 0 8 8
3 .037 520
2 .716
APPENDIX 5 . 2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
AW 49 1 . 6 9 0
AX 0 0 . 0 0 0
AY 0 0 . 0 0 0
A2 0 0 . 0 0 0
BA 3 0 8 2 . 4 8 9
BB 0 0 . 0 0 0
BD 0 0 . 0 0 0
BE 2 4 1 3 3 . 3 8 3
BI 1 5 0 2 . 1 7 6
BJ 0 0 . 0 0 0
BL 1 8 2 2 . 2 6 0
BO 1 9 5 2 . 2 9 0
BR 7 0 2 2 .846
BS 0 0 .000
BT 0 0 . 0 0 0
BU 1 9 7 2 . 2 9 4
BV 0 0 . 0 0 0
BY 0 0 . 0 0 0
CA 8 1 3 2 . 9 1 0
cc 0 0 . 0 0 0
CE 7 8 2 2 . 8 9 3
2N D
26 1 . 4 1 5
1 0 1 2 . 0 0 4
1 5 4 2 . 1 8 8
20 1 . 3 0 1
1 7 1 . 2 3 0
0 0 .000
6 . 7 7 8
1 3 1 . 1 1 4
7 9 1 . 8 9 8
6 5 1 . 8 1 3
2 1 1 . 3 2 2
8 . 9 0 3
11 1 . 0 4 1
9 5 1 . 9 7 8
0 0 .000
0 0 . 0 0 0
9 2 1 . 9 6 4
0 0 . 0 0 0
4 5 1 . 6 5 3
1 5 7 2 . 1 9 6
26 1 . 4 1 5
3RD
8 5 1 . 9 2 9
0 0 .000
202 2 . 3 0 5
3 3 1 . 5 1 9
50 1 . 6 9 9
6 3 1 . 7 9 9
8 . 9 0 3
1 7 7 2 .248
4 3 1 . 6 3 3
1 6 1 2 . 2 0 7
8 . 9 0 3
1 4 1 . 1 4 6
1 2 7 2 . 1 0 4
8 . 9 0 3
0 0 . 0 0 0
3 1 1 . 4 9 1
0 0 . 0 0 0
0 0 * 0 0 0
1 0 5 9 3 . 0 2 5
1 0 8 2 . 0 3 3
1 5 3 2 . 1 8 5
4TH
1 0 1 . 0 0 0
17 1 . 2 3 0
3 5 1 . 5 4 4
0 0 . 0 0 0
1 7 5 2 . 2 4 3
2 3 1 . 3 6 2
0 0 . 0 0 0
5 0 2 2 . 7 0 1
7 3 1 . 8 6 3
0 0 . 0 0 0
3 9 7 2 . 5 9 9
9 8 1 . 9 9 1
4 . 6 0 2
0 0 . 0 0 0
9 . 9 5 4
7 6 1 . 8 8 1
0 0 . 0 0 0
0 0 . 0 0 0
1 1 9 2 . 0 7 6
Q 0 . 0 0 0
7 1 1 2 . 8 5 2
5TH
0 0 . 0 0 0
0 0 . 0 0 0
1 8 1 . 2 5 5
0 0 . 0 0 0
3 . 4 7 7
0 0 . 0 0 0
0 0 .000
1 8 8 2 . 2 7 4
3 3 1 . 5 1 9
0 0 . 0 0 0
3 6 4 2 . 5 6 1
1 7 1 . 2 3 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
Q 0 . 0 0 0
6 . 7 7 8
5 1 6 2 . 7 1 3
24 1 . 3 8 0
5 3 5 2 . 7 2 8
6TH SUM
0 1 7 0 0 . 0 0 0 2 . 2 3 0
0 1 1 8 0 . 0 0 0 2 . 0 7 2
2 5 2 6 6 1 2 . 4 0 1 2 . 8 2 0
0 5 3 0 . 0 0 0 1 . 7 2 4
0 5 5 3 0 . 0 0 0 2 . 7 4 3
0 8 6 0 . 0 0 0 1 . 9 3 4
0 1 4 0 . 0 0 0 1 . 1 4 6
7 3300 . 8 4 5 3 . 5 1 9
0 3 7 8 0 . 0 0 0 2 . 5 7 7
0 226 0 . 0 0 0 2 . 3 5 4
0 9 7 2 0 . 0 0 0 2 . 9 8 8
0 332 0 .000 2 . 5 2 1
0 8 4 4 0 . 0 0 0 2 . 9 2 6
1 8 1 2 1 1 . 2 5 5 2 . 0 8 3
0 9 0 . 0 0 0 . 9 5 4
0 304 0 . 0 0 0 2 . 4 8 3
0 9 2 0 . 0 0 0 1 . 9 6 4
6 0 6 6 1 . 7 7 8 1 . 8 2 0
1 9 4 2746 2 . 2 8 8 3 . 4 3 9
0 289 0 .000 2 . 4 6 1
1 2 9 1 3498 3 . 1 1 1 3 . 5 4 4
2 2 5
2 2 6 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
CH 1 0 7 5 3 . 0 3 1
C I 9 4 1 . 9 7 3
CK 0 0 . 0 0 0
C L 7 4 8 2 . 8 7 4
CN 0 0 . 0 0 0
CO 2 9 8 3 3 . 4 7 5
CQ 0 0 .000
C R 4 1 3 2 .616
CS 0 0 .000
CT 0 0 .000
cu 344 2 .537
CY 1 6 1 . 2 0 4
DA 1 4 0 2 .146
D B 0 0 .000
DC 0 0 . 0 0 0
DD 0 0 . 0 0 0
DE 1 5 4 6 3 .189
DF 0 0 . 0 0 0
DG 0 0 . 0 0 0
DH 0 0 .000
D I 517 2 . 7 1 3
2N D
267 2 .427
1 3 1 2 .117
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
1 0 1 2 .004
27 1 . 4 3 1
56 1 . 7 4 8
6 . 7 7 8
1 2 5 2 . 0 9 7
5 . 6 9 9
0 0 .000
1 8 1 . 2 5 5
0 0 . 0 0 0
0 0 .000
8 1 1 . 9 0 8
1 0 1 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
5 . 6 9 9
6 3 1 . 7 9 9
3RD
2 0 2 2 . 3 0 5
554 2 .744
307 2 . 4 8 7
2 9 3 2 .467
3 . 4 7 7
372 2 . 5 7 1
8 . 9 0 3
4 9 1 . 6 9 0
0 0 . 0 0 0
7 1 9 2 .857
1 4 5 2 . 1 6 1
5 . 6 9 9
3 . 4 7 7
0 0 . 0 0 0
0 0 .000
9 8 1 . 9 9 1
3 8 5 2 . 5 8 5
0 0 . 0 0 0
37 1 . 5 6 8
7 . 8 4 5
2 8 5 2 . 4 5 5
4TH
7 1 8 2 . 8 5 6
5 1 3 2 .710
304 2 . 4 8 3
7 2 1 . 8 5 7
0 0 . 8 0 0
1 5 6 2 . 1 9 3
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 34 2 . 3 6 9
9 4 1 . 9 7 3
0 0 . 0 0 0
40 1 . 6 0 2
9 . 9 5 4
4 . 6 0 2
1 3 1 . 1 1 4
5 0 2 2 . 7 0 1
1 8 1 . 2 5 5
4 1 1 . 6 1 3
0 0 . 0 0 0
1 0 0 4 3 . 0 0 2
5TH
3 2 1 . 5 0 5
1 3 9 2 . 1 4 3
2 2 1 . 3 4 2
1 2 7 2 . 1 0 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
340 2 . 5 3 1
0 0 . 0 0 0
0 0 . 0 0 0
9 6 1 . 9 8 2
3 . 4 7 7
0 0 . 0 0 0
0 0 . 0 0 0
7 2 7 2 .862
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
5 . 6 9 9
6TH
7 8 1 . 8 9 2
0 0.000
3 2 1 . 5 0 5
0 0 .000
0 0 . 0 0 0
27 1 . 4 3 1
(1 0.000
0 0 .000
1 0 3 2 . 0 1 3
9 1 1 2 .960
0 0 . 0 0 0
7 1 1 . 8 5 1
46 1 . 6 6 3
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
6 2 9 2 . 7 9 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
SUM
2 3 7 2 3 . 3 7 5
1 4 3 1 3 . 1 5 6
6 6 5 2 . 8 2 3
1 2 4 0 3 . 0 9 3
3 . 4 7 7 3 6 3 9
3 . 5 6 1 3 5
1 . 5 4 4 5 1 8
2 . 7 1 4 1 0 9
2 .037 2329
3 . 3 6 7 5 8 8
2 . 7 6 9 9 2
1 . 9 6 4 3 4 3
2 . 5 3 5 1 2
1 . 0 7 9 4
. 6 0 2 1 9 2
2 . 2 8 3 3 7 9 9
3 . 5 8 0 18
1 . 2 5 5 7 8
1 . 8 9 2 1 2
1 . 0 7 9 1 8 7 4
3 . 2 7 3
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1 S T
D J 0 0 . 0 0 0
DL 0 0 . 0 0 0
DM 0 0 . 0 0 0
D N 0 0 . 0 0 0
DO 218 2 . 3 3 8
DR 372 2 . 5 7 1
DS 0 0 . 0 0 0
DT 0 0 . 0 0 0
DU 3 2 1 . 5 0 5
DV 0 0 . 0 0 0
DW 0 0 . 0 0 0
DY 2 1 1 . 3 2 2
E A 2 3 1 2 . 3 6 4
E B 0 0 . 0 0 0
EC 8 5 1 . 9 2 9
E D 7 0 1 . 8 4 5
E E 0 0 . 0 0 0
EF 236 2 . 3 7 3
E G 0 0 . 0 0 0
E H 0 0 . 0 0 0
E I 0 0 . 0 0 0
2ND
6 .778
0 0 . 0 0 0
20 1 . 3 0 1
0 0 .000
4 5 1 . 6 5 3
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
7 . 8 4 5
1 1 0 2 . 0 4 1
3 . 4 7 7
4 . 6 0 2 2239
3 . 3 5 0 28
1 . 4 4 7 1 7 5 3
3 . 2 4 4 6 1 4
2 . 7 8 8 560
2 . 7 4 8 3 8 6
2 . 5 8 7 2 6 1
2 . 4 1 7 4 8
1 . 6 8 1 2 4 3
2 . 3 8 6
3 R D
0 0 .000
20 1 . 3 0 1
0 0 .000
11 1 . 0 4 1
3 5 1 . 5 4 4
1 2 9 2 . 1 1 1
5 . 6 9 9
4 . 6 0 2
1 3 8 2 . 1 4 0
0 0 . 0 0 0
11 1 . 0 4 1
0 0 . 0 0 0
9 3 4 2 . 9 7 0
4 . 6 0 2
4 54 2 . 6 5 7
6B 1 . 7 7 8
226 2 . 3 5 4
8 . 9 0 3
1 8 1 . 2 5 5
0 0 . 0 0 0
28 1 . 4 4 7
4TH
0 0 . 0 0 0
7 8 1 . 8 9 2
0 0 . 0 0 0
4 . 6 0 2
1 1 6 2 . 0 6 4
1 7 8 2 . 2 5 0
0 0 . 0 0 0
0 0 . 0 0 0
2 5 1 2 . 4 0 0
0 0 . 0 0 0
5 . 6 9 9
0 0 . 0 0 0
6 8 3 2 . 8 3 4
0 0 . 0 0 0
3 3 6 2 . 5 2 6
1 5 9 2 . 2 0 1
1 0 5 2 . 8 2 1
2 0 3 2 . 3 0 7
3 2 1 . 5 0 5
7 2 1 . 8 5 7
2 5 1 2 . 4 0 0
5TH
0 0 . 0 0 0
1 3 6 2 .134
1 3 1 . 1 1 4
0 0 . 0 0 0
1 9 9 2 . 2 9 9
5 . 6 9 9
0 (jl. 0 0 0
7 . 8 4 5
11 1 . 0 4 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 6 4 2 . 5 6 1
52 1 . 7 1 6
6 40 2 . 8 0 6
2 1 0 2 . 3 2 2
9 1 9 2 . 9 6 3
2 3 1 . 3 6 2
267 2 . 4 2 7
0 0 . 0 0 0
3 5 1 . 5 4 4
6TH
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 . 8 4 5
0 0 . 0 0 0
8 67 2 .938
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
510 2 .708
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
7 7 6 0 3 .890
2 8 1 . 4 4 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 2 7
SUM
6 . 7 7 8
234 2 . 3 6 9
3 3 1 . 5 1 9
1 5 1 . 1 7 6
6 2 0 2 .792
684 2 . 8 3 5
8 7 2 2 . 9 4 1
11 1 . 0 4 1
439 2 . 6 4 2
1 1 0 2 . 0 4 1
1 9 1 . 2 7 9
5 3 5 2 . 7 2 8
4 4 5 1 3 . 6 4 8
84 1 . 9 2 4
3268 3 . 5 1 4
8 8 7 3 3 . 9 4 8
1 8 3 8 3 . 2 6 4
8 56 2 . 9 3 2
5 7 8 2 . 7 6 2
1 2 0 2 . 0 7 9
5 57 2 . 7 4 6
228 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
E J 0 0 .000
EK 0 0 .000
E L 1 3 9 2 .143
EM 1 6 8 2 .225
E N 747 2 .873
E O 0 0.000
EP 1 2 1 .079
E Q 7 0 1 . 8 4 5
E R 37 1 .568
ES 4 5 1 . 6 5 3
ET . 58 1 . 7 6 3
E U 0 0 .000
EV 205 2 .312
EW 0 0 .000
E X 954 2 .980
EY 11 1 . 0 4 1
E Z 0 0 .000
FA 674 2 .829
FE 554 2 .744
FF 0 0 .000
F I 707 2 .849
2N D
11 1 . 0 4 1
0 0 .000
8 6 9 2 .939
696 2 .843
1 7 5 1 3 .243
9 7 1 .987
265 2 .423
1 3 5 2 .130
1 9 8 5 3 .298
1 2 1 4 3.084
1 5 5 7 3 .192
50 1 .699
766 2 .884
48 1 . 6 8 1
57 1 . 8 2 6
1 2 1 .079
0 0 .000
0 0 .000
0 0 .000
5 9 5 2 .775
0 0 .000
3 RD
0 0 .000
7 4 1 .869
372 2 .571
1 6 7 2 .223
291 2 .464
0 0 .000
1 7 5 2 .243
0 0 .000
7 6 1 2 .881
574 2 .759
476 2 .678
0 0 .000
111 2 . 0 4 5
3 2 1 . 5 0 5
0 0 .000
3 .477
0 0 .000
9 5 1 .978
4 0 3 2 . 6 0 5
59 1 . 7 7 1
2 3 1 2 .364
4TH
0 0 .000
0 0 .000
200 2 . 3 0 1
1 4 6 2 .164
1 1 5 9 3.064
1 2 3 2 .090
20 1 . 3 0 1
0 0 .000
2156 3 .334
59 1 . 7 7 1
1 4 7 2 .167
1 0 1 .000
6 2 1 2 .793
47 1 .672
0 0 .000
0 0 .000
3 .477
3 18 2 .502
94 1 . 9 7 3
1 0 1 2 .004
98 1 . 9 9 1
5TH
0 0 .000
0 0 .000
1 0 0 7 3 . 0 0 3
270 2 .431
1 5 0 5 3 .178
27 1 . 4 3 1
8 5 1 . 9 2 9
0 0 .000
2492 3 .397
1 1 0 0 3 .041
6 9 3 2 .841
36 1 . 5 5 6
264 2 .422
9 .954
38 1 . 5 8 0
26 1 . 4 1 5
11 1 . 0 4 1
7 . 8 4 5
1 7 1 . 2 3 0
0 0 .000
1 6 6 2 .220
6TH
0 0 .000
0 0 .000
1 2 7 2 .104
3 1 3 2 .496
1 2 0 5 3 .081
0 0 .000
0 0 .000
0 0 .000
4146 3 .618
2944 3 .469
9 6 1 . 9 8 2
0 0 .000
0 0 .000
4 . 602
9 1 1 . 9 5 9
1 2 1 2 . 0 8 3
0 0 .000
0 0 .000
0 0 .000
20 1 . 3 0 1
0 0 .000
SUM
11 1 . 0 4 1
74 1 . 8 6 9
2714 3 .434
1760 3 .246
6 6 5 8 3 . 8 2 3
2 47 2 .393
557 2 .746
2 0 5 2 .312 11577 4 .064
5936 3 .773
3027 3 . 4 8 1
9 6 1 .982
1 9 6 7 3 .294
1 4 0 2 .146
1150 3 .061
1 7 3 2 . 2 3 8
1 4 1 . 1 4 6
1094 3 .039
1 0 6 8 3 .029
7 7 5 2 .889
1 2 0 2 3 .080
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1 S T
FL 206 2 . 3 1 4
FO 6 6 8 2 . 8 2 5
FR 4 2 1 2 . 6 2 4
FS 0 0 . 0 0 0
FT 0 0 . 0 0 0
FU 318 2 . 5 0 2
FW 0 0 . 0 0 0
FY 0 0 . 0 0 0
GA 1 5 7 2 . 1 9 6
G D 0 0 . 0 0 0
G E 9 1 0 2 . 9 5 9
G G 0 0 . 0 0 0
G H 6 . 7 7 8
G I 1 5 1 . 1 7 6
G L 1 1 7 2 . 0 6 8
GM 0 0 . 0 0 0
G N 4 . 6 0 2
G O 25 1 . 3 9 8
G R 7 0 8 2 . 8 5 0
GS 0 0 . 0 0 0
GT 0 0 . 0 0 0
2ND
0 0 . 0 0 0
0 0 . 0 0 0
28 1 . 4 4 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
6 2 6 2 . 7 9 7
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
3 . 4 7 7
0 0 .000
0 0 . 0 0 0
34 1 . 5 3 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
3RD
29 1 . 4 6 2
161 2 . 2 0 7
1 0 1 . 0 0 0
0 0 .000
7 6 1 . 8 8 1
9 8 1 . 9 9 1
0 0 .000
0 0 . 0 0 0
1 0 7 2 . 0 2 9
0 0 . 0 0 0
8 9 1 . 9 4 9
1 4 4 2 .158
2 2 1 2 .344
1 2 0 2 . 0 7 9
3 6 1 2 . 5 5 8
1 9 1 . 2 7 9
7 1 1 . 8 5 1
0 0 .000
94 1 . 9 7 3
0 0 . 0 0 0
0 0 .000
4TH
1 9 1 . 2 7 9
1 3 7 2 . 1 3 7
0 0 . 0 0 0
0 0 . 0 0 0
5 5 1 . 7 4 0
19 1 . 2 7 9
18 1 . 2 5 5
0 0 . 0 0 0
4 7 1 . 6 7 2
26 1 .415
4 2 9 2 . 6 3 2
4 3 1 . 6 3 3
1 6 1 2 .207
327 2 . 5 1 5
5 6 1 . 7 4 8
0 0 . 0 0 0
0 0 . 0 0 0
4 . 6 0 2
4 1 6 2 . 6 1 9
0 0 . 0 0 0
3 4 1 . 5 3 1
5TH
7 2 1 . 8 5 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
8 . 9 0 3
1 8 8 2 . 2 7 4
0 0 . 0 0 0
0 0 . 0 0 0
1 8 1 . 2 5 5
0 0 . 0 0 0
7 6 8 2 . 8 8 5
0 0 . 0 0 0
9 07 2 . 9 5 8
46 1 . 6 6 3
0 0 . 0 0 0
0 0 . 0 0 0
4 1 1 . 6 1 3
0 0 . 0 0 0
0 11.000
4 . 6 0 2
0 0 . 0 0 0
6TH
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 3 1 . 3 6 2
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
8 9 1 . 9 4 9
2 1 1 . 3 2 2
0 0 . 0 0 0
9 2 7 2 .967
0 0 . 0 0 0
974 2 . 9 8 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 5 8 2 . 1 9 9
1 0 6 2 . 0 2 5
0 0 . 0 0 0
1 0 2 2 . 0 0 9
0 0 . 0 0 0
2 2 9
S U M
3 2 6 2 . 5 1 3
9 6 6 2 . 9 8 5
459 2 . 6 6 2
2 3 1 . 3 6 2
1 3 9 2 . 1 4 3
6 2 3 2 . 7 9 4
1 8 1 . 2 5 5
8 9 1 . 9 4 9
9 7 6 2 .989
2 5 1 . 4 1 5
3 1 2 3 3 . 4 9 5
1 8 7 2 . 2 7 2
2269 3 .356
5 1 1 2 . 7 0 8
5 3 4 2 .728
1 9 1 . 2 7 9
3 0 8 2 . 4 8 9
1 3 5 2 . 1 3 0
1 2 1 8 3 . 0 8 6
1 0 6 2 . 0 2 5
3 4 1 . 5 3 1
230 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
GU 40 1 . 6 0 2
G Y 0 0 . 0 0 0
H A 4 2 7 2 . 6 3 0
H E 5 0 5 2 . 7 0 3
HF 0 0 . 0 0 0
H I 1 0 3 3 3 .014
H L 0 0 . 0 0 0
HM 0 0 . 0 0 0
H N 0 0 .000
H O 8 6 3 2 .936
HR 0 0 .000
HS 0 0 . 0 0 0
HT 0 0 .000
H U 4 0 1 2 . 6 0 3
HW 0 0 . 0 0 0
HY 3 . 4 7 7
I A 0 0 . 0 0 0
I B 0 0 . 0 0 0
I C 0 0 . 0 0 0
I D 1 7 1 . 2 3 0
I E 0 0 . 0 0 0
2ND
0 0 .000
0 0 . 0 0 0
8 8 4 2 .946
7 8 1 2 . 8 9 3
0 0 . 0 0 0
3 8 5 2 . 5 8 5
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
7 6 1 2 . 8 8 1
1 0 5 3 3 .022
0 0 . 0 0 0
0 0 .000
27 1 . 4 3 1
0 0 . 0 0 0
7 2 1 . 8 5 7
5 5 1 . 7 4 0
2 0 3 2 .307
526 2 . 7 2 1
57 1 . 7 5 6
4 1 1 . 6 1 3
3RD
2 6 7 2 . 4 2 1
0 0 .000
6 7 1 . 8 2 6
1 9 1 . 2 7 9
0 0 . 0 0 0
1 4 8 2 .170
9 . 9 5 4
0 0 . 0 0 0
3 4 1 . 5 3 1
217 2 .336
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 . 8 4 5
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
40 1 . 6 0 2
2 8 8 2 . 4 5 9
1 0 8 2 . 0 3 3
446 2 . 6 4 9
4TH
2 1 1 . 3 2 2
0 0 .000
3 9 7 2 .599
1 5 5 2 . 1 9 0
9 . 9 5 4
7 3 1 2 .864
0 0 .000
0 0 .000
0 0 . 0 0 0
7 9 4 2 . 9 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 1 7 2 . 0 6 8
0 0 . 0 0 0
4 0 1 . 6 0 2
0 0 . 0 0 0
7 9 1 . 8 9 8
8 5 1 . 9 2 9
8 8 8 2 . 9 4 8
4 3 2 2 . 6 3 5
8 5 3 2 . 9 3 1
5TH
1 9 1 . 2 7 9
0 0 . 0 0 0
3 2 1 . 5 0 5
2568 3 . 4 1 0
0 0 . 0 0 0
56 1 . 7 4 8
5 8 1 . 7 6 3
1 2 1 . 0 7 9
0 0 . 0 0 0
8 5 1 . 9 2 9
0 0 . 0 0 0
0 0 . 0 0 0
6 0 1 . 7 7 8
3 . 4 7 7
0 0 . 0 0 0
0 0 . 0 0 0
7 1 9 2 . 8 5 7
0 0 . 0 0 0
7 9 4 2 . 9 0 0
4 9 8 2 . 6 9 7
1 3 2 3 3 .122
6TH
0 0 . 0 0 0
3 5 1 . 5 4 4
0 0 . 0 0 0
3 2 1 . 5 0 5
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
26 1 . 4 1 5
9 0 7 2 . 9 5 8
0 0 . 0 0 0
0 0 . 0 0 0
7 0 1 . 8 4 5
7 6 1 . 8 8 1
0 0 . 0 0 0
350 2 . 5 4 4
4 9 1 . 6 9 0
6 9 1 . 8 3 9
SUM
3 4 7 2 . 5 4 0
3 5 1 . 5 4 4
1 8 0 7 3 . 2 5 7
4 0 6 0 3 . 6 0 9
9 . 9 5 4 2 3 5 3
3 . 3 7 2 6 7
1 . 8 2 6 1 2
1 . 0 7 9 3 4
1 . 5 3 1 2 7 2 0
3 . 4 3 5 1 0 5 3
3 . 0 2 2 2 6
1 . 4 1 5 1 0 8 4
3 . 0 3 5 4 38
2 . 6 4 1 40
1 . 6 0 2 1 4 5
2 . 1 6 1 9 2 9
2 . 9 6 8 3 2 8
2 . 5 1 6 2846
3 . 4 5 4 1 1 6 1
3 . 0 6 5 2 7 3 2
3 .436
APPENDIX 5.2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1ST
I F 0 0 . 0 0 0
I G 34 1 . 5 3 1
I K 0 0 . 0 0 0
I L 32 1 . 5 0 5
I M 2 4 9 2 . 3 9 6
I N 8 2 5 2 . 9 1 6
I 0 0 0 . 0 0 0
I P 0 0 . 0 0 0
I Q 0 0 . 0 0 0
I R 18 1 . 2 5 5
I S 42 1 . 6 2 3
I T 5 1 1 . 7 0 8
I U 0 0 . 0 0 0
I V 0 0 .000
I X 0 0 . 0 0 0
I 2 0 0 . 0 0 0
J A 111 2 . 0 4 5
J E 1 9 1 . 2 7 9
J O 1 3 0 2 . 1 1 4
J U 2 1 1 2 .324
K A 2 1 1 . 3 2 2
2ND
9 0 1 . 9 5 4
489 2 . 6 8 9
3 . 4 7 7
7 9 1 2 . 8 9 8
8 9 9 2 . 9 5 4
1 0 6 8 3 . 0 2 9
6 7 1 . 8 2 6
1 6 1 . 2 0 4
6 .778
1 6 2 2 . 2 1 0
9 2 7 2 . 9 6 7
957 2 . 9 8 1
0 0 . 0 0 0
1 1 7 2 . 0 6 8
7 5 1 . 8 7 5
22 1 . 3 4 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
0 0 .000
3RD
1 2 6 2 . 1 0 0
9 8 1 . 9 9 1
0 0 .000
429 2 . 6 3 2
280 2 .447
538 2 . 7 3 1
24 1 . 3 8 0
1 0 0 2 . 0 0 0
0 0 .000
8 0 1 . 9 0 3
1 9 2 2 . 2 8 3
9 7 6 2 .989
22 1 . 3 4 2
2 9 1 2 . 4 6 4
0 0 . 0 0 0
1 5 1 . 1 7 6
3 . 4 7 7
7 6 1 . 8 8 1
6 2 1 . 7 9 2
26 1 . 4 1 5
4 . 6 0 2
4TH 5TH 6TH
3 8 9 3 0 1 . 5 8 0 1 . 9 6 8 0 . 0 0 0
1 9 5 161 0 2 . 2 9 0 2 . 2 0 7 0 . 0 0 0
20 1 9 7 1 . 3 0 1 1 . 2 7 9 . 8 4 5
2 0 1 3 9 3 1 2 6 2 . 3 0 3 2 . 5 9 4 2 . 1 0 0
2 5 2 5 2 1 9 2 . 4 0 1 1 . 7 1 6 1 . 2 7 9
9 4 1 7 7 8 7 5 8 2 2 . 9 7 4 3 . 8 9 1 2 .834
9 3 3 1 3 5 1 6 2 . 9 7 0 3 . 1 3 1 . 7 7 8
1 0 4 39 1 . 0 0 0 . 6 0 2 1 . 5 9 1
1 2 0 0 1 . 0 7 9 0 . 0 0 0 0 . 0 0 0
1 6 6 264 2 1 2 . 2 2 0 2 . 4 2 2 1 . 3 2 2
220 7 0 4 47 2 . 3 4 2 2 . 8 4 8 1 . 6 7 2
4 1 9 6 3 6 2 3 5 2 . 6 2 2 2 . 8 0 3 2 . 3 7 1
0 4 8 0 0 . 0 0 0 1 . 6 8 1 0 . 0 0 0
2 1 6 1 9 0 0 2 . 3 3 4 2 . 2 7 9 0 . 0 0 0
1 4 0 9 1 . 1 4 6 0 . 0 0 0 . 9 5 4
5 7 1 . 7 5 6
0 0 . 0 0 0
2 54 2 . 4 0 5
0 0 . 0 0 0
0 0 . 0 0 0
2 0 1 . 3 0 1
7 9 0 1 . 8 9 8 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
0 0 0 .000 0 . 0 0 0
2 3 1
SUM
347 2 . 5 4 0
977 2 . 9 9 0
4 9 1 . 6 9 0
1 9 7 2 3 . 2 9 5
1 7 5 1 3 . 2 4 3 1 1 8 4 1 4 . 0 7 3
2 3 8 1 3 . 3 7 7
1 6 9 2 . 2 2 8
18 1 . 2 5 5
7 1 1 2 . 8 5 2
2 1 3 2 3 . 3 2 9
3274 3 . 5 1 5
7 0 1 . 8 4 5
8 1 4 2 . 9 1 1
9 8 1 . 9 9 1
1 7 3 2 . 2 3 8
1 1 4 2 . 0 5 7
349 2 . 5 4 3
1 9 2 2 . 2 8 3
237 2 . 3 7 5
4 5 1 . 6 5 3
232 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
K E 2 1 3 2 . 3 2 8
K I 1 8 3 2 .262
KL 0 0 .000
K M 0 0 .000
K N 1 0 4 2 .017
K O 0 0 .000
KP 0 0 .000
K R 11 1 . 0 4 1
KS 0 0 .000
K U 0 0 .000
KW 0 0 .000
K Y 0 0 .000
LA 3 1 2 2 . 4 9 4
L B 0 0 .000
LC 0 0 . 0 0 0
L D 0 0 . 0 0 0
L E 7 0 6
LF 0 0 . 0 0 0
LG 0 0 . 0 0 0
L H 0 0 . 0 0 0
L I 497 2 . 6 9 6
2 .849
2ND
0 0 .000
4 3 1 . 6 3 3
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
5 . 6 9 9
8 9 0 2 . 9 4 9
0 0 .000
1 3 1 . 1 1 4
1 3 1 . 1 1 4
429 2 . 6 3 2
0 0 .000
0 0 .000
0 0 . 0 0 0
2 1 9 2 . 3 4 0
3RD
3 . 4 7 7
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
4 7 1 . 6 7 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
11 1 . 0 4 1
0 0 . 0 0 0
3 4 1 2 . 5 3 3
3 . 4 7 7
7 3 1 . 8 6 3
1 3 5 2 . 1 3 0
2 2 6 2 . 3 5 4
88 1 . 9 4 4
2 1 1 . 3 2 2
1 4 1 . 1 4 6
3 7 8 2 . 5 7 7
4TH 5TH
2 7 6 3 94 2 . 4 4 1 2 . 5 9 5
8 9 8 0 2 . 9 5 3 0 . 0 0 0
3 1 2 7 . 4 7 7 2 . 1 0 4
7 0
0 0 0 . 0 0 0 0 . 0 0 0
1 5 0 1 . 1 7 6 0 . 0 0 0
1 6 0 1 . 2 0 4 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
3 9 0 1 . 5 9 1 0 . 0 0 0
0 3 0 . 0 0 0 . 4 7 7
6 0 . 7 7 8 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
. a 4 5 0 . 0 0 0
5 2 5 4 6 5 2 . 7 2 0 2 . 6 6 7
0 0 0 . 0 0 0 0 . 0 0 0
0 0 0 . 0 0 0 0 . 0 0 0
7 1 0 1 . 8 5 1 0 . 0 0 0
6 6 1 1 4 7 8 2 .820 3 . 1 7 0
5 0 . 6 9 9 0 . 0 0 0
0 9 0 . 0 0 0 . 9 5 4
0 0 0 . 0 0 0 0 . 0 0 0
2 3 8 0 7 3 3 . 3 7 7 1 . 8 6 3
6TH SUM
5 6 9 4 2 1 . 7 4 8 2 . 9 7 4
0 1 1 2 8 0 . 0 0 0 3 . 0 5 2
0 1 3 0 0 . 0 0 0 2 . 1 1 4
0 7 0 . 0 0 0 . 8 4 5
0 1 5 1 0 . 0 0 0 2 . 1 7 9
0 1 5 0 . 0 0 0 1 . 1 7 6
0 1 6 0 . 0 0 0 1 . 2 0 4
0 11 0 . 0 0 0 1 . 0 4 1
81 1 2 0 1 . 9 0 8 2 . 0 7 9
0 3 0 . 0 0 0 . 4 7 7
0 1 7 0 . 0 0 0 1 . 2 3 0
0 5 0 . 0 0 0 . 6 9 9
5 9 2 5 9 2 1 . 7 7 1 3 . 4 1 4
0 3 0 . 0 0 0 . 4 7 7
0 8 6 0 . 0 0 0 1 . 9 3 4
1 8 2 37 1 . 2 5 5 2 . 3 7 5
9 9 3 4 4 9 3 2 .997 3 . 6 5 3
7 3 3 8 2 6 2 . 8 6 5 2 . 9 1 7
0 3 0 0 . 0 0 0 1 . 4 7 7
0 1 4 0 . 0 0 0 1 . 1 4 6
9 3 5 5 6 . 9 5 4 3 . 5 5 1
APPENDIX 5 . 2 2 3 3
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1ST
LK 0 0 . 0 0 0
L L 0 0 . 0 0 0
LM 0 0 .000
L N 0 0 . 0 0 0
L O 429 2 . 6 3 2
LP 0 0 . 0 0 0
L R 0 0 . 0 0 0
LS 0 0 . 0 0 0
LT 0 0 . 0 0 0
LU 39 1 . 5 9 1
LV 0 0 . 0 0 0
LW 0 0 . 0 0 0
LY 7 . 8 4 5
MA 9 0 1 2 . 9 5 5
MB 0 0 . 0 0 0
ME 1 2 2 2 3 . 0 8 7
MF 0 0 . 0 0 0
M I 8 3 3 2 . 9 2 1
ML 0 0 . 0 0 0
M M 0 0 . 0 0 0
MN 0 0 . 0 0 0
2ND
0 0 .000
1 3 3 2 . 1 2 4
0 0 . 0 0 0
0 0 . 0 0 0
4 2 5 2 . 6 2 8
0 0 . 0 0 0
2 7 3 2 . 4 3 6
0 0 .000
22 1 . 3 4 2
8 7 1 . 9 4 0
4 . 6 0 2
0 0 .000
1 6 1 . 2 0 4
213 2 . 3 2 8
3 0 1 . 4 7 7
2 7 3 2 . 4 3 6
0 0 . 0 0 0
7 8 1 . 8 9 2
0 0 . 0 0 0
1 9 1 . 2 7 9
0 0 .000
3RD 4TH 5TH 6TH
1 5 4 7 0 0 2 . 1 8 8 . 8 4 5 0 . 0 0 0 0 . 0 0 0
1 5 2 8 2 0 9 5 6 9 1 1 0 3 .184 2 . 3 2 0 2 . 7 5 5 2 . 0 4 1
4 0 0 7 - 6 0 2 0 . 0 0 0 0 . 0 0 0 . 8 4 5
2 5 0 0 47 1 . 3 9 8 0 . 0 0 0 0 . 0 0 0 1 . 6 7 2
2 2 5 2 8 8 1 1 3 1 6 2 .352 2 .459 2 . 0 5 3 1 . 2 0 4
7 6 0 0 0 1 . 8 8 1 0 . 0 0 0 0 . 0 0 0 0 . 0 0 0
0 0 3 5 0 0 . 0 0 0 0 . 0 0 0 1 . 5 4 4 0 .000
1 3 0 253 484 1 . 1 1 4 0 . 0 0 0 1 . 3 0 1 2 . 6 8 5
1 0 7 1 3 3 292 3 3 2 .029 2 . 1 2 4 2 . 4 6 5 1 . 5 1 9
9 2 214 27 0 1 . 9 6 4 2 . 3 3 0 1 . 4 3 1 0 .000
1 3 1 6 44 0 1 . 1 1 4 1 . 2 0 4 1 . 6 4 3 0 . 0 0 0
5 1 9 0 0 . 6 9 9 1 . 2 7 9 0 . 0 0 0 0 . 0 0 0
5 1 7 0 1 9 2 4 . 6 9 9 1 . 2 3 0 0 . 0 0 0 3 . 2 8 4
235 4 4 0 1 6 2 5 8 2 . 3 7 1 2 . 6 4 3 2 . 2 1 0 1 . 7 6 3
5 6 1 1 1 4 7 0 2 . 7 4 9 2 . 0 5 7 . 8 4 5 0 . 0 0 0
2 5 1 2 4 1 4 4 2 246 2 . 4 0 0 2 . 3 8 2 2 . 6 4 5 2 .391
4 3 4 0 0 1 . 6 3 3 . 6 0 2 0 . 0 0 0 0 .000
306 2 9 7 3 5 0 2 . 4 8 6 2 . 4 7 3 1 . 5 4 4 0 . 0 0 0
5 11 0 0 . 6 9 9 1 . 0 4 1 0 . 0 0 0 0 . 0 0 0
1 7 7 3 8 2 5 0 2 . 2 4 8 1 . 5 8 0 1 . 3 9 8 0 . 0 0 0
0 7 3 6 1 3 0 . 0 0 0 . 8 4 5 1 . 5 5 6 1 . 1 1 4
S U M
1 6 1 2 . 2 0 7
2 5 4 9 3 . 4 0 6
11 1 . 0 4 1
7 2 1 . 8 5 7
1 4 9 6 3 . 1 7 5
7 6 1 . 8 8 1
3 0 8 2 . 4 8 9
5 1 7 2 . 7 1 3
587 2 . 7 6 9
4 59 2 . 6 6 2
7 7 1 . 8 8 6
24 1 . 3 8 0
1 9 6 9 3 . 2 9 4
2009 3 . 3 0 3
7 1 2 2 . 8 5 2
2 6 7 5 3 . 4 2 7
47 1 . 6 7 2
1 5 4 9 3 .190
1 6 1 . 2 0 4
2 59 2 . 4 1 3
56 1 . 7 4 8
234 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
M O 471 2 , 6 7 3
MP 0 0 .000
MR 0 0 .000
MS 0 0 .000
MU 1 8 0 2 . 2 5 5
MY 42 1 . 6 2 3
NA 358 2 .554
N B 0 0 .000
N C 0 0 .000
N D 0 0 .000
N E 394 2 .595
NF 0 0 .000
N G 0 0 .000
N H 0 0 .000
N I 3 .477
N J 0 0 .000
N K 0 0 .000
N L 0 0 .000
NM 0 0 .000
N N 0 0 .000
N O 5 8 5 2 .767
2ND
90 1 . 9 5 4
1 9 7 2 .294
0 0 .000
0 0 .000
1 7 1 .230
0 0 .000
1 3 1 2 .117
3 . 477
1 9 5 2 .290
1 2 7 2 .104
38 1 .580
3 6 1 .556
498 2 .697
50 1 . 6 9 9
220 2 .342
77 1 .886
47 1 . 6 7 2
7 . 8 4 5
9 .954
1 5 1 . 1 7 6
782 2 . 8 9 3
3RD
1 3 6 2 .134
6 0 2 2 .780
4 . 602 6 0 3
2 .780 0
0 .000 0
0 .000 476
2 .678 0
0 .000 448
2 .651 596
2 .775 7 1 8
2 .856 5 5
1 .740 3 29
2 .517 6
. 7 7 8 1 9 3
2 .286 0
0 .000 1 1 5
2 . 0 6 1 3
. 477 4
. 6 0 2 373
2 .572 1 5 0
2 .176
4TH
1 4 5 2 .161
348 2 .542
0 0 .000
8 . 9 0 3
7 7 1 . 8 8 6
0 0 .000
8 1 1 . 9 0 8
1 3 1 .114
228 2.358
244 2 .387
4 24 2 .627
2 5 1 .398
309 2 .490
0 0 .000
1 2 3 1 3 .090
0 0 .000
7 3 1 . 8 6 3
3 5 1 . 5 4 4
0 0 .000
1 4 9 2 .173
1 4 2 2 . 1 5 2
5TH
0 0 .000
1 1 7 2 .068
0 0 .000
0 0 .000
1 5 9 2 . 2 0 1
0 0 .000
9 2 1 .964
0 0 .000
509 2 .707
450 2 .653
638 2 .805
0 0 .000
230 2 .362
0 0 .000
8 7 1 . 9 4 0
0 0 .000
0 0 .000
2 1 1 . 3 2 2
0 0 .000
3 2 1 . 5 0 5
1 0 1 . 0 0 0
6TH S U M
0 8 4 2 0 .000 2 . 9 2 5
0 1 2 6 4 0 .000 3 . 1 0 2
0 4 0 .000 . 6 0 2
227 8 3 8 2 .356 2 . 9 2 3
0 4 3 3 0 .000 2 .636
1 1 2 1 5 4 2 . 0 4 9 2 .188
38 1 1 7 6 1 . 5 8 0 3 .070
0 1 6 0 .000 1 . 2 0 4
0 1 3 8 0 0 .000 3 .140
530 1 9 4 7 2 .724 3 .289
502 2714 2 .701 3 .434
0 1 1 6 0 .000 2 .064
7212 8578 3 .858 3 . 9 3 3
0 56 0 .000 1 . 7 4 8
9 1 7 4 3 .954 3 . 2 4 1
0 7 7 0 .000 1 . 8 8 6
0 2 3 5 0 .000 2 . 3 7 1
0 6 6 0 .000 1 .820
0 1 3 0 .000 1 . 1 1 4
0 559 0 .000 2 .755
1 0 1 6 7 9 1 . 0 0 0 3 .225
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1 S T
NQ 0 0 . 0 0 0
N R 0 0 . 0 0 0
NS 0 0 . 0 0 0
NT 0 0 . 0 0 0
N U 288 2 . 4 5 9
NV 0 0 . 0 0 0
N X 0 0 . 0 0 0
NY 0 0 . 0 0 0
N Z 0 0 . 0 0 0
OA 0 0 . 0 0 0
OB 229 2 . 3 6 0
oc 5 1 1 . 7 0 8
OD 0 0 . 0 0 0
O E 0 0 . 0 0 0
OF 237 2 . 3 7 5
OG 0 0 . 0 0 0
O H 0 0 . 0 0 0
01 0 0 . 0 0 0
OJ 0 0 . 0 0 0
O K 0 0 . 0 0 0
OL 7 . 8 4 5
2ND
2 8 1 . 4 4 7
3 .477
3 57 2 . 5 5 3
242 2 . 3 8 4
6 9 1 . 8 3 9
8 8 1 . 9 4 4
7 1 1 . 8 5 1
46 1 . 6 6 3
11 1 . 0 4 1
1 3 0 2 .114
8 7 1 . 9 4 0
460 2 . 6 6 3
4 3 1 . 6 3 3
0 0 .000
0 0 .000
39 1 . 5 9 1
3 4 1 . 5 3 1
1 1 5 2 . 0 6 1
5 . 6 9 9
0 0 .000
8 8 8 2 . 9 4 8
3 RD
1 0 1 . 0 0 0
1 0 1 . 0 0 0
2 38 2 . 3 7 7
1 1 1 0 3 . 0 4 5
2 9 3 2 . 4 6 7
29 1 . 4 6 2
0 0 .000
1 0 1 . 0 0 0
0 0 . 0 0 0
47 1 . 6 7 2
318 2 . 5 0 2
295 2 . 4 7 0
1 8 5 2 .267
22 1 . 3 4 2
4 8 1 . 6 8 1
3 9 9 2 . 6 0 1
0 0 . 0 0 0
37 1 . 5 6 8
9 3 1 . 9 6 8
230 2 . 3 6 2
1 6 2 2 . 2 1 0
4TH
0 0 . 0 0 0
0 0 . 0 0 0
8 9 1 . 9 4 9
7 3 2 2 . 8 6 5
1 0 1 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 2 1 . 0 7 9
5 1 1 . 7 0 8
5 . 6 9 9
1 4 1 . 1 4 6
0 0 . 0 0 0
7 . 8 4 5
9 . 9 5 4
1 3 1 . 1 1 4
2 7 1 . 4 3 1
0 0 . 0 0 0
24 1 . 3 8 0
7 0 1 . 8 4 5
5TH
0 0 . 0 0 0
6 . 7 7 8 9 4 6
2 . 9 7 6 3 3 2
2 . 5 2 1 4 2
1 . 6 2 3 0
0 . 0 0 0 0
0 . 0 0 0 3
. 4 7 7 3
. 4 7 7 0
0 . 0 0 0 0
0 . 0 0 0 8
. 9 0 3 2 4 9
2 . 3 9 6 5 8
1 . 7 6 3 0
0 . 0 0 a 2 9
1 . 4 6 2 0
0 . 0 0 0 8 0
1 . 9 0 3 0
0 . 0 0 0 3
. 4 7 7 3 2 9
2 . 5 1 7
6T9
0 0 . 0 0 0
0 0 . 0 0 0
1 1 9 7 3 . 0 7 8
1 6 5 3 3 . 2 1 8
0 0 . 0 0 0
0 0 . 0 0 0
5 . 6 9 9
467 2 . 6 6 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 5 1 . 3 9 8
0 0 . 0 0 0
1 6 1 . 2 0 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 6 1 . 5 5 6
264 2 . 4 2 2
2 3 5
SUM
3 8 1 . 5 8 0
1 9 1 . 2 7 9
2 8 2 7 3 . 4 5 1
4069 3 . 6 0 9
7 0 2 2 . 8 4 6
1 1 7 2 . 0 6 8
7 6 1 . 8 8 1
526 2 . 7 2 1
1 4 1 . 1 4 6
1 8 9 2 . 2 7 6
6 8 5 2 . 8 3 6
8 1 9 2 . 9 1 3
516 2 . 7 1 3
8 0 1 . 9 0 3
3 0 8 2 . 4 8 9
476 2 . 6 7 8
47 1 . 6 7 2
2 59 2 . 4 1 3
9 8 1 9 9 1
2 9 3 2 4 6 7
7 2 0 3 236
2 36 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST 2ND 3RD 4TH 5TH 6TH
OM 25 1 .398
ON 5 . 699
00 0 0 .000
OP 3 3 1 2 .520
OQ 0 0 .000
OR 200 2 .301
0s 0 0 .000
OT 0 0 .000
ou 3 4 3 2 .535
ov 24 1 . 3 8 0
ow 0 0 .000
ox 0 0 .000
OY 8 . 9 0 3
PA 949 2 .977
PD 0 0 .000
PE 810 2.908
PF 0 0 .000
PG 0 0 .000
PH 57 1 .756
P I 317 2 .501
PK 0 0 .000
942 2.974
1 0 4 4 3 .019
356 2 .551
1 4 0 2 .146
0 0 .000
1 3 3 7 3 .126
99 1 . 9 9 6
704 2 .848
1 3 4 8 3 .130
1 6 4 2 .215
6 8 1 2 .833
0 0 .000
5 1 1 . 7 0 8
59 1 . 7 7 1
3 .477
508 2 .706
0 0 .000
3 .477
4 . 602
1 6 0 2 .204
0 0.000
1 3 3 2 .124
1 4 3 2 .155
5 5 1 . 7 4 0
379 2 .579
0 0 .000
274 2 .438
1 8 7 2 , 2 7 2
1 0 2 3 3 .010
1 1 0 8 3 .045
238 2 .377
413 2 .616
0 0 .000
3 . 477
7 9 1 .898
0 0 .000
3 79 2 .579
0 0 .000
0 0 .000
3 .477
2 6 5 2 .423
7 . 845
1 2 5 2.097
1 5 0 2 .176
208 2 .318
2 1 1 . 3 2 2
11 1 . 0 4 1
526 2 .721
1 1 5 2 . 0 6 1
8 2 1 . 9 1 4
1 1 0 1 3 .042
2 29 2 .360
98 1 . 9 9 1
0 0 .000
64 1 .806
4 03 2 .605
0 0 .000
2 6 3 2 .420
29 1 . 4 6 2
0 0 .000
40 1 . 6 0 2
382 2 .582
0 0 .000
1 9 4 2 .288
92 5 2 .966
1 5 3 2 .185
6 . 778
0 0 .000
1 1 0 5 3 . 0 4 3
278 2 .444
57 1 . 7 5 6
1 2 6 1 3 .101
5 3 1 . 7 2 4
2 4 5 2 .389
0 0 .000
1 3 1 .114
0 0 .000
0 0 .000
571 2 .757
0 0 .000
0 0 .000
0 0 .000
2 3 1 . 3 6 2
0 0 .000
229 2 .360
1664 3 .221
0 0 .000
8 9 1 . 9 4 9
0 0 .000
1 9 5 2 .290
0 0 .000
1 3 1 . 1 1 4
0 0 .000
0 0 .000
1 1 2 2 .049
9 . 954
4 8 1 . 6 8 1
0 0 .000
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 .000
22 1 . 3 4 2
0 0 .000
0 0.000
SUM
1 6 4 8 3 . 2 1 7
3 9 3 1 3 .595
772 2 .888
966 2 . 9 8 5
11 1 . 0 4 1
3637 3 . 5 6 1
6 7 9 2 .832
1 8 7 9 3 .274
5161 3 .713
7 08 2 .850
1 5 4 9 3 .190
9 .954
1 8 7 2 .272
1490 3 .173
3 . 477 2531
3 .403 29
1 . 4 6 2 3
. 477 1 2 6
2 .100 1 1 4 7
3 .060 7
. 8 4 5
APPENDIX 5 . 2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
PL 468 2 . 6 7 0
PM 0 0 . 0 0 0
PO 412 2 . 6 1 5
PP 0 0 . 0 0 0
PR 2 7 3 0 3 . 4 3 6
PS 3 . 4 7 7
PT 0 0 . 0 0 0
PU 3 2 1 2 .507
PW 0 0 . 0 0 0
PY 0 0 . 0 0 0
QU 358 2 . 5 5 4
R A 3 1 1 2 . 4 9 3
RB 0 0 . 0 0 0
RC 0 0 . 0 0 0
RD 0 0 . 0 0 0
R E 2 7 8 1 3 .444
RF 0 0 . 0 0 0
RG 0 0 . 0 0 0
R H 1 2 1 . 0 7 9
R I 1 1 8 2 . 0 7 2
RK 0 0 . 0 0 0
2N D
0 0 . 0 0 0
0 0 .000
5 1 1 . 7 0 8
294 2 . 4 6 8
5 1 1 . 7 0 8
3 . 4 7 7
G3 1 . 7 9 9
6 . 7 7 8
6 . 7 7 8
0 0 .000
1 1 3 2 . 0 5 3
7 7 4 2 .889
5 . 6 9 9
8 . 9 0 3
9 3 1 . 9 6 8
1 4 6 3 3 . 1 6 5
0 0 .000
6 3 1 . 7 9 9
0 0 . 0 0 0
1 4 5 7 3 . 1 6 3
0 0 . 0 0 0
3RD
3 6 1 2 . 5 5 8
0 0 .000
2 2 3 2 .348
397 2 .599
1 6 6 2 .220
5 . 6 9 9
1 4 1 2 . 1 4 9
1 2 8 2 .107
0 0 .000
0 0 . 0 0 0
1 9 9 2 .299
280 2 .447
5 0 1 . 6 9 9
1 7 3 2 .238
1 0 2 2 . 0 0 9
8 7 0 2 . 9 4 0
340 2 . 5 3 1
2 1 2 2 . 3 2 6
307 2 . 4 8 7
8 5 8 2 . 9 3 3
3 5 0 2 . 5 4 4
4TH
2 8 9 2 . 4 6 1
6 .77 8
5 8 5 2 . 7 6 7
4 3 7 2 . 6 4 0
0 0 . 0 0 0
1 5 1 . 1 7 6
1 6 0 2 . 2 0 4
4 6 1 . 6 6 3
0 0 . 0 0 0
0 0 . 0 0 0
2 6 1 . 4 1 5
4 5 6 2 . 6 5 9
8 . 9 0 3
9 9 1 . 9 9 6
3 7 1 . 5 6 8
6 6 1 2 . 8 2 0
1 3 1 . 1 1 4
1 8 3 2 . 2 6 2
0 0 . 0 0 0
12c15 3 . 0 8 1
7 . 8 4 5
5TH
3 49 2 . 5 4 3
0 0 . 0 0 0
0 0 . 0 0 0
2 6 1 . 4 1 5
0 0 . 0 0 0
1 9 1 . 2 7 9
6 . 7 7 8
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 3 1 . 3 6 2
2 0 5 9 3 . 3 1 4
1 8 1 . 2 5 5
4 1 1 . 6 1 3
1 9 0 2 . 2 7 9
1 2 1 9 3 .086
0 0 . 0 0 0
1 8 1 . 2 5 5
0 0 . 0 0 0
7 4 1 . 8 6 9
5 3 1 . 7 2 4
6TH
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 1 3 2 . 4 9 6
2 0 3 2 .307
0 0 .000
0 0 .000
3 8 1 . 5 8 0
0 0 .000
3 2 1 . 5 0 5
1 5 1 . 1 7 6
0 0 .000
317 2 .501
1 0 8 7 3 .036
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 9 1 . 5 9 1
2 3 7
SUM
1 4 6 7 3 . 1 6 6
6 . 7 7 8 1 2 7 1
3 . 1 0 4 1 1 5 4
3 . 0 6 2 2 9 4 7
3 . 4 6 9 358
2 . 5 5 4 5 7 3
2 . 7 5 8 5 0 1
2 . 7 0 0 6
. 7 7 8 3 8
1 . 5 8 0 7 1 9
2 .857 3 9 1 2
3 . 5 9 2 9 6
1 . 9 8 2 3 2 1
2 . 5 0 7 7 3 9
2 . 8 6 9 8 0 8 1
3 .907 3 5 3
2 .548 476
2 . 6 7 8 3 1 9
2 . 5 0 4 3 7 1 2
3 . 5 7 0 4 4 9
2 . 6 5 2
238 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
R L 0 0 . 0 0 0
RM 0 0 .000
RN 0 0 . 0 0 0
RO 247 2 . 3 9 3
RP 0 0 .000
RQ 0 0 . 0 0 0
RR 0 0 . 0 0 0
RS 0 0 . 0 0 0
RT 0 0 . 0 0 0
RU 257 2 . 4 1 0
RV 0 0 . 0 0 0
RW 0 0 . 0 0 0
RY 0 0 . 0 0 0
S A 1 6 3 2 . 2 1 2
S B 0 0 . 0 0 0
sc 454 2 .657
SD 0 0 . 0 0 0
SE 1 6 5 5 3 . 2 1 9
SF 0 0 . 0 0 0
SH 554 2 .744
S I 569 2 . 7 5 5
2ND
40 1 . 6 0 2
3 . 4 7 7
0 0 .000
2 6 4 0 3 . 4 2 2
0 0 . 0 0 0
0 0 .000
111 2 . 0 4 5
3 . 4 7 7
1 2 3 2 .090
1 8 2 2 . 2 6 0
0 0 . 0 0 0
0 0 .000
26 1 . 4 1 5
0 0 .000
0 0 . 0 0 0
22 1 . 3 4 2
0 0 . 0 0 0
1 7 1 . 2 3 0
0 0 .000
2 3 1 . 3 6 2
0 0 . 0 0 0
3RD
1 9 9 2 .299
3 7 2 2 . 5 7 1
494 2 . 6 9 4
1 0 4 7 3 .020
2 0 7 2 . 3 1 6
4 . 6 0 2
6 3 0 2 . 7 9 9
4 59 2 . 6 6 2
8 4 2 2 . 9 2 5
5 . 6 9 9
5 0 2 2 . 7 0 1
1 4 2 2 . 1 5 2
42 1 . 6 2 3
1 5 1 . 1 7 6
1 3 1 2 . 1 1 7
1 0 4 2 . 0 1 7
3 . 4 7 7
2 4 1 2 .382
0 0 . 0 0 0
204 2 .310
416 2 .619
4TH
1 8 3 2 . 2 6 2
9 0 1 . 9 5 4
2 2 2 2 . 3 4 5
2 8 9 2 . 4 6 1
4 1 1 . 5 1 3
0 0 .000
52 1 . 7 1 6
8 6 1 . 9 3 4
3 7 3 2 . 5 7 2
2 3 1 . 3 6 2
3 . 4 7 7
1 5 1 . 1 7 6
0 0 . 0 0 0
1 2 8 2 . 1 0 7
0 0 .000
0 0 . 0 0 0
5 9 1 . 7 7 1
1 2 8 3 3 .108
0 0 . 0 0 0
1 8 9 2 . 2 7 6
1 1 5 4 3 . 0 6 2
5TH
2 1 9 2 . 3 4 0
2 0 1 . 3 0 1
4 5 1 . 6 5 3
3 0 2 2 . 4 8 0
6 . 7 7 8
0 0 . 0 0 0
7 . 8 4 5
5 3 1 . 7 2 4
3 8 8 2 . 5 8 9
5 . 6 9 9
7 4 1 . 8 6 9
0 0 . 0 0 0
0 0 . 0 0 0
1 8 1 . 2 5 5
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
7 7 7 2 . 8 9 0
1 6 1 . 2 0 4
0 0 . 0 0 0
5 8 1 . 8 3 3
6TH
0 0 .000
1 0 9 2 .037
4 50 2 . 6 5 3
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
2 2 9 9 3 . 3 6 2
3 56 2 . 5 5 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 4 8 5 3 . 1 7 2
5 . 6 9 9
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 8 3 2 3 . 2 6 3
0 0 . 0 0 0
4 5 5 2 .658
0 0 . 0 0 0
SUM
6 4 1 2 .807
594 2 . 7 7 4
1 2 1 1 3 . 0 8 3
4 5 2 9 3 . 6 5 6
254 2 . 4 0 5
4 . 6 0 2
8 0 0 2 . 9 0 3
2 9 0 0 3 . 4 6 2
2 0 8 2 3 . 3 1 8
472 2 .674
5 7 9 2 . 7 6 3
1 5 7 2 . 1 9 6
1 5 5 3 3 . 1 9 1
329 2 . 5 1 7
1 3 1 2 . 1 1 7
580 2 . 7 6 3
6 2 1 . 7 9 2
5 8 0 5 3 . 7 6 4
1 6 1 . 2 0 4
1 4 2 5 3 . 1 5 4
2207 3 . 3 4 4
APPENDIX 5.2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
SK 48 1 . 6 8 1
SL 1 8 6 2 . 2 7 0
SM 1 6 0 2 . 2 0 4
SN 56 1 . 7 4 8
S O 6 6 5 2 . 8 2 3
S P 586 2 . 7 6 8
SQ 29 1 . 4 6 2
S R 0 0 . 0 0 0
SS 0 0 . 0 0 0
ST 1 5 8 6 3 . 2 0 0
SU 1 1 2 4 3 . 0 5 1
sw 84 1 . 9 2 4
SY 1 7 3 2 . 2 3 8
TA 2 0 3 2 . 3 0 7
TB 0 0 . 0 0 0
TC 0 0 .000
TD 0 0 . 0 0 0
TE 374 2 .573
TF 0 0 . 0 0 0
TG 0 0 .000
TH 1 8 1 3 3 . 2 5 8
2ND
0 0 .000
30 1 . 4 7 7
0 0 . 0 0 0
0 0 .000
8 . 9 0 3
7 0 1 . 8 4 5
3 . 4 7 7
0 0 . 0 0 0
1 6 8 2 . 2 2 5
8 . 9 0 3
206 2 .314
0 0 . 0 0 0
3 . 4 7 7
584 2 . 7 6 6
0 0 .000
4 . 6 0 2
0 0 . 0 0 0
1 6 1 2 . 2 0 7
0 0 . 0 0 0
0 0 . 0 0 0
3 8 1 . 5 8 0
3RD
3 . 4 7 7
1 4 1 . 1 4 6
5 . 6 9 9
0 0 .000
2 9 1 . 4 6 2
4 1 5 2 . 6 1 8
0 0 .000
5 .699
6 66 2 . 8 2 3
1 5 5 0 3 . 1 9 0
317 2 .501
44 1 . 6 4 3
0 0 .000
214 2 . 3 3 0
3 . 4 7 7
312 2 . 4 9 4
27 1 . 4 3 1
426 2 . 6 2 9
3 . 4 7 7
4 . 6 0 2 1 2 4 2
3 . 0 9 4
4TH
2 2 1 . 3 4 2
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
2 9 0 2 . 4 6 2
2Y 1 . 4 6 2
0 0 . 0 0 0
0 0 . 0 0 0
3 2 6 2 . 5 1 3
3 3 8 2 . 5 2 9
2 3 3 2 .367
0 0 . 0 0 0
0 0 . 0 0 0
8 2 6 2 . 9 1 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 4 1 2 3 . 1 5 0
3 . 4 7 7
8 . 9 0 3 1 6 7 5
3 . 2 2 4
5TH
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
1 7 0 2 . 2 3 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
31 1 . 4 9 1
1 4 0 2 . 1 4 6
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 6 7 2 . 2 2 3
0 0 .000
3 5 1 . 5 4 4
0 0 . 0 0 0
2777 3 . 4 4 4
0 0 . 0 0 0
0 0 . 0 0 0
9 6 1 . 9 8 2
6TH
6 . 7 7 8
0 0 . 0 0 0
30 1 . 4 7 7
0 0 . 0 0 0
1 7 1 . 2 3 0
0 0 . 0 0 0
0 0 .000
0 0 .000
6 4 4 2 . 8 0 9
1 2 0 4 3 . 0 8 1
0 0 . 0 0 0
0 0 .000
40 1 . 6 0 2
3 5 1 . 5 4 4
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
5 9 5 2 . 7 7 5
0 0 . 0 0 0
0 0 . 0 0 0
1 1 5 2 . 0 6 1
2 3 9
SUM
7 9 1 . 8 9 8
234 2 . 3 6 9
1 9 9 2 . 2 9 9
5 6 1 . 7 4 8
1 1 7 9 3 . 0 7 2
1 1 0 0 3 . 0 4 1
3 2 1 . 5 0 5
5 . 6 9 9 1 8 3 5
3 . 2 6 4 4 8 2 6
3 . 6 8 4 1 8 8 0
3 . 2 7 4 1 2 8
2 . 1 0 7 2 1 6
2 . 3 3 4 2 0 2 9
3 .307 3
. 4 7 7 3 5 1
2 . 5 4 5 27
1 . 4 3 1 5 7 4 5
3 .759 6
. I 7 8 1 2
1 . 0 7 9 4 9 7 9
3 . 6 9 7
240 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1ST
TI 62 1 .792
TL 0 0 .000
TN 0 0 .000
TO 283 2 .452
TP 0 0 .000
TR 693 2 .841
TS 7 . 845
TT 0 0 .000
TU 1 9 2 2 .283
TW 28 1 . 4 4 7
TY 7 6 1 . 8 8 1
U A 0 0.000
U B 0 0 .000
'JC 0 0 .000
O D 0 0 .000
U E 0 0 .000
UF 0 0 .000
UG 0 0 .000
U I 0 0 .000
U K 0 0 .000
U L 0 0 .000
2N D
6 8 1 . 8 3 3
3 5 1 .544
0 0 .000
297 2 .473
0 0 .000
278 2 .444
0 0 .000
1 7 7 2 .248
3 3 1 2 .520
0 0 .000
3 .477
204 2 .310
233 2 .367
269 2 .430
44 1 . 6 4 3
8 3 1 . 9 1 9
40 1 . 6 0 2
7 1 1 . 8 5 1
217 2 .336
4 . 602
1 3 8 2 .140
3RD
7 7 3 2 .888
57 1 .756
36 1 .556
6 4 1 . 8 0 6
8 . 9 0 3
1 7 6 2 .246
210 2 .322
1 0 0 7 3 .003
203 2 .307
7 7 3 2 .888
0 0 .000
294 2 .468
29 1 . 4 6 2
1 1 2 2 .049
3 37 2 .528
42 1 . 6 2 3
8 . 9 0 3
127 2 .104
1 9 1 . 2 7 9
0 0 .000
2 8 1 . 4 4 7
4TH
2558 3 . 4 0 8
1 0 8 2 . 0 3 3
46 1 . 6 6 3
6 3 3 2 .801
0 0 .000
484 2 . 6 8 5
0 0 .000
244 2.387
747 2 .873
11 1 . 0 4 1
0 0 .000
57 1 .756
1 4 2 2 .152
1 0 5 2 . 0 2 1
1 5 1 . 1 7 6
7 1 1 . 8 5 1
0 0 .000
7 8 3 2 .894
214 2 .330
0 0 .000
490 2 .690
5TH
97 1 .987
378 2 .577
0 0 .000
246 2 .391
0 0 .000
390 2 . 5 9 1
0 0 .000
1 9 1 . 2 7 9
1 0 1 . 0 0 0
0 0 .000
0 0 .000
1 0 2 2 .009
0 0 .000
224 2 .350
1 3 4 2 .127
107 2 .029
0 0 .000
974 2 .989
57 1 . 7 5 6
0 0 .000
9 5 1 . 9 7 8
6TH
0 0 .000
0 0 .000
0 0 .000
1 7 1 . 2 3 0
0 0 .000
0 0 .000
1 6 7 8 3 . 2 2 5
1 6 1 .204
0 0 .000
0 0 .000
1 0 1 0 3 .004
0 0 .000
4 . 6 0 2
0 0 .000
5 .699
-77 1 . 8 8 6
0 0 .000
0 0 .000
0 0 .000
0 0 .000
1 8 8 2 .274
SUM
3558 3 .551
578 2 .762
82 1 . 9 1 4
1 5 4 0 3 .188
8 . 9 0 3 2021
3 .306 1 8 9 5
3 .278 1 4 6 3
3 .165 1 4 8 3
3 . 1 7 1 8 1 2
2 .910 1 0 8 9
3 .037 6 57
2 .818 408
2 .611 710
2 .851 5 3 5
2 .728 380
2 .580 48
1 . 6 8 1 1 9 5 5
3 .291 507
2 .705 4
. 602 9 3 9
2 .973
APPENDIX 5 . 2
B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1ST
UM 0 0 . 0 0 0
U N 247 2 . 3 9 3
uo 0 0 . 0 0 0
UP 29 1 . 4 6 2
U R 1 2 1 . 0 7 9
US 2 2 3 2 . 3 4 8
UT 9 2 1 . 9 6 4
U Z 0 0 . 0 0 0
VA 374 2 . 5 7 3
VE 1 9 6 2 .292
V I 409 2 . 6 1 2
vo 6 0 1 . 7 7 8
vu 4 . 6 0 2
WA 498 2 . 6 9 7
WB 0 0 . 0 0 0
WD 0 0 . 0 0 0
WE 5 5 9 2 .747
WF 0 0 . 0 0 0
WH 446 2 . 6 4 9
W I 1 0 1 8 3 . 0 0 8
WK 0 0 .000
2 N D
216 2 . 3 3 4
481 2 . 6 8 2
3 . 4 7 7
337 2 . 5 2 8
1 1 8 5 3 . 0 7 4
6 3 1 2 . 8 0 0
5 0 8 2 . 7 0 6
29 1 . 4 6 2
5 . 6 9 9
2 9 8 2 .474
5 6 1 . 7 4 8
27 1 . 4 3 1
0 0 .000
4 4 1 . 6 4 3
0 0 .000
0 0 .000
3 2 1 . 5 0 5
1 0 1 . 0 0 0
0 0 . 0 0 0
4 3 1 . 6 3 3
11 1 . 0 4 1
3 RD
29 1 . 4 6 2
8 1 2 2 .910
0 0 .000
3 4 1 . 5 3 1
3 1 3 2 .496
2 9 1 2 .464
9 8 1 . 9 9 1
0 0 .000
1 3 0 2 . 1 1 4
7 9 0 2 . 8 9 8
3 5 8 2 . 5 5 4
1 4 3 2 . 1 5 5
0 0 .000
7 7 1 . 8 8 6
1 0 1 . 0 0 0
11 1 . 0 4 1
576 2 . 7 6 0
0 0 .000
29 1 . 4 6 2
0 0 . 0 0 0
0 0 . 0 0 0
4TH
2 1 2 2 . 3 2 6
1 2 0 2 . 0 7 9
1 0 1 . 0 0 0
5 . 6 9 9
444 2 . 6 4 7
1 5 6 2 . 1 9 3
2 5 8 2 . 4 1 2
0 0 . 0 0 0
2 7 8 2 .444
2 4 5 2 . 3 8 9
8 9 2 2 . 9 5 0
2 7 1 . 4 3 1
0 0 . 0 0 0
1 6 9 2 . 2 2 8
0 0 . 0 0 0
3 2 1 . 5 0 5
8 6 7 2 . 9 3 8
0 0 . 0 0 0
0 0 . 0 0 0
377 2 . 5 7 6
0 0 . 0 0 0
5TH
3 0 1 . 4 7 7
1 6 2 2 . 2 1 0
0 0 . 0 0 0
1 3 1 . 1 1 4
9 3 6 2 . 9 7 1
9 3 3 2 . 9 7 0
9 5 1 . 9 7 8
0 0 . 0 0 0
8 0 1 . 9 0 3
1 0 2 6 3 . 0 1 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 3 6 2 . 1 3 4
0 0 . 0 0 0
0 0 . 0 0 0
1 2 9 2 . 1 1 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
6TH
207 2 . 3 1 6
2 3 1 . 3 6 2
0 0 . 0 0 0
6 . 7 7 8
3 9 1 . 5 9 1
664 2 . 8 2 2
6 2 7 2 . 7 9 7
0 0 . 0 0 0
0 0 . 0 0 0
6 2 9 2 .799
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 4 1
SUM
6 9 4 2 . 8 4 1
1 8 4 5 3 . 2 6 6
1 3 1 . 1 1 4
4 24 2 . 6 2 7
2 9 2 9 3 . 4 6 7
2898 3 . 4 6 2
1 6 7 8 3 . 2 2 5
29 1 . 4 6 2
8 6 7 2 . 9 3 8
3184 3 . 5 0 3
1 7 1 5 3 . 2 3 4
2 57 2 . 4 1 0
4 . 6 0 2
9 2 4 2 . 9 6 6
1 0 1 . 0 0 0
4 3 1 . 6 3 3
2 1 6 3 3 . 3 3 5
1 0 1 . 0 0 0
4 7 5 2 . 6 7 7
1 4 3 8 3 . 1 5 8
11 1 . 0 4 1
242 CHAPTER 5
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
BIGRAM POSITION 1 S T
WL 0 0 .000
WM 0 0 .000
WN 0 0 .000
WO 3 8 9 2 . 5 9 0
WP 0 0 . 0 0 0
WR 370 2 .568
ws 0 0 . 0 0 0
WY 9 . 9 5 4
X A 0 0 . 0 0 0
xc 0 0 . 0 0 0
X E 0 0 . 0 0 0
XH 0 0 . 0 0 0
X I 0 0 . 0 0 0
XP 0 0 . 0 0 0
XT 0 0 . 0 0 0
xw 0 0 . 0 0 0
YA 2 8 1 . 4 4 7
YB 0 0 .000
YC 0 0 . 0 0 0
Y E 9 . 9 5 4
YF 0 0 .000
2ND
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
2 1 1 . 3 2 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
4 3 5 2 . 6 3 8
4 9 1 . 6 9 0
20 1 . 3 0 1
3 2 1 . 5 0 5
40 1 . 6 0 2
298 2 . 4 7 4
8 0 1 . 9 0 3
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
11 1 . 0 4 1
0 0 . 0 0 0
3RD
3 . 4 7 7
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
27 1 . 4 3 1
4 . 6 0 2
4 . 6 0 2
2 3 1 . 3 6 2
8 . 9 0 3
0 0 . 0 0 0
0 0.00(1
0 0 .000
177 2 .248
0 0 .000
1 1 8 2 .072
11 1 . 0 4 1
3 2 1 . 5 0 5
81 1 . 9 0 8
11 1 . 0 4 1
4 . 6 0 2
0 0 . 0 0 0
4TH
3 1 1 . 4 9 1
3 . 4 7 7
2 1 1 . 3 2 2
44 1 . 6 4 3
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 .000
0 0 .000
0 0 .000
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
5 . 6 9 9
6 4 1 . 8 0 6
3 . 4 7 7
5TH
0 0 .000
0 0 . 0 0 0
4 . 6 0 2
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 1 1 . 4 9 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
9 9 1 . 9 9 6
0 0 . 0 0 0
6TH
0 0 . 0 0 0
0 0 . 0 0 0
5 6 1 . 7 4 8
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
1 9 8 2 . 2 9 7
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
3 8 1 . 5 8 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
6 . 7 7 8
0 0 . 0 0 0
SUM
3 4 1 . 5 3 1
3 . 4 7 7
81 1 . 9 0 8
4 54 2 . 6 5 7
27 1 . 4 3 1
374 2 . 5 7 3
2 0 2 2 . 3 0 5
3 2 1 . 5 0 5
4 4 3 2 . 6 4 6
4 9 1 . 6 9 0
5 1 1 . 7 0 8
32 1 . 5 0 5
2 1 7 2 . 3 3 6
298 2 . 4 7 4
2 36 2 . 3 7 3
11 1 . 0 4 1
6 0 1 . 7 7 8
8 1 1 . 9 0 8
1 6 1 . 2 0 4
1 9 3 2 . 2 8 6
3 . 4 7 7
APPENDIX 5 . 2
BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7
B I G R A M POSITION 1 S T
YG 0 0 . 0 0 0
Y H 0 0 .000
Y I 1 2 1 . 0 7 9
Y L 0 0 . 0 0 0
YM 0 0 . 0 0 0
Y N 0 0 . 0 0 0
Y O 44 1 . 6 4 3
YP 0 0 . 0 0 0
YR 0 0 . 0 0 0
YS 0 0 . 0 0 0
YT 0 0 . 0 0 0
YW 0 0 . 0 0 0
Y Z 0 0 . 0 0 0
Z A 0 0 . 0 0 0
Z E 7 .84 5
Z I 0 0 . 0 0 0
Z L 0 0 . 0 0 0
z o 0 0 . 0 0 0
z u 0 0 . 0 0 0
Z Y 0 0 . 0 0 0
z z 0 0 . 0 0 0
2ND
3 . 4 1 7
0 0 .000
0 0 .000
0 0 . 0 0 0
4 1 1 . 6 1 3
3 3 1 . 5 1 9
9 . 9 5 4
7 2 1 . 8 5 7
1 8 1 . 2 5 5
1 7 9 2 . 2 5 3
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . Q 0 0
0 0 . 0 0 0
3RD
0 0 . 0 0 0
8 . 9 0 3
0 0 . 0 0 0
1 2 1 . 0 7 9
8 1 1 . 9 0 8
1 3 1 . 1 1 4
0 0 .000
3 .477
54 1 . 7 3 2
4 5 1 . 6 5 3
3 1 1 . 4 9 1
1 7 1 . 2 3 0
0 0 .000
32 1 . 5 0 5
1 0 1 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
0 0 . 0 0 0
11 1 . 0 4 1
29 1 . 4 6 2
4TH
0 0 . 0 0 0
0 0 . 0 0 0
1 9 4 2 .288
0 0 . 0 0 0
11 1 . 0 4 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
27 1 . 4 3 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 9 1 . 5 9 1
2 3 1 . 3 6 2
9 - 9 5 4
6 . I 7 8
0 0 .000
0 0 . 0 0 0
5TH
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
7 . 8 4 5
0 0 . 0 0 0
0 0 . 0 0 0
1 0 1 . 0 0 0
0 0 .000
3 3 1 . 5 1 9
0 0 .000
0 0 . 0 0 0
27 1 . 4 3 1
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
6TH
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
3 . 4 7 7
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
57 1 . 7 5 6
0 0 . 0 0 0
0 0 . 0 0 0
0 0 .000
3 . 4 7 7
1 0 0 2 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
0 0 . 0 0 0
2 4 3
SUM
3 . 4 7 7
8 . 9 0 3
2 0 6 2 . 3 1 4
1 2 1 . 0 7 9
1 3 6 2 . 1 3 4
46 1 . 6 6 3
5 3 1 . 7 2 4
7 5 1 . 8 7 5
7 2 1 . 8 5 7
2 8 8 2 . 4 5 9
5 8 1 . 7 6 3
1 7 1 . 2 3 0
1 0 1 . 0 0 0
3 5 1 . 5 4 4
1 5 0 2 . 1 7 6
3 9 1 . 5 9 1
2 3 1 . 3 6 2
36 1 . 5 5 6
6 . I 1 8
11 1 . 0 4 1
29 1 . 4 6 2
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6 Summary and Conclusion
The g o a l o f t h i s r e s e a r c h p r o j e c t was t o e v a l u a t e how t h e r e a d e r ' s h i g h e r - o r d e r knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e i n t e r a c t s w i t h f e a t u r a l i n f o r m a t i o n d u r i n g t h e p r o c e s s i n g o f l e t t e r s and w o r d s . The r e s e a r c h was c a r r i e d o u t u t i l i z i n g a g e n e r a l i n f o r m a t i o n p r o c e s s i n g mode l , which p r o v i d e d a f o r m a l f ramework f rom which h y p o t h e s e s c o u l d b e d e r i v e d and t e s t e d . The model a l o n g w i t h s u p p o r t i n g e v i d e n c e was d e s c r i b e d i n C h a p t e r 1. S i n c e t h e s t u d y o f v i s u a l p r o c e s s i n g i n r e a d i n g r e q u i r e s a n e x a m i n a t i o n o f t h e v i s u a l f e a t u r e s t h a t a r e f u n c t i o n a l d u r i n g r e a d i n g , t h e d i s c u s s i o n i n C h a p t e r 2 d e s c r i b e d t h o s e f e a t u r e s u t i l i z e d i n t h e r e c o g n i t i o n o f l o w e r c a s e l e t t e r s . U n d e r s t a n d i n g f e a t u r e d e t e c t i o n p r o v e d u s e f u l i n a c c o u n t i n g f o r some o f t h e f i n d i n g s i n t h e p e r c e p t u a l r e c o g n i t i o n t a s k s d e s c r i b e d i n C h a p t e r 4 . The s i g n i f i c a n t f i n d i n g was t h a t t h e s e a r c h f o r a t a r g e t l e t t e r was c r i t i c a l l y d e p e n d e n t o n t h e f e a t u r a l s i m i l a r i t y b e t w e e n t h e t a r g e t l e t t e r and t h e l e t t e r s i n t h e t e s t s t r i n g .
The f u n d a m e n t a l p r o p e r t i e s o f t h e o r t h o g r a p h i c s t r u c t u r e o f E n g l i s h were d e s c r i b e d i n C h a p t e r 3. We d i s t i n g u i s h e d two b r o a d c a t e g o r i e s o f d e s c r i p t i o n s . The f i r s t was d e r i v e d f rom s t a t i s t i c a l - r e d u n d a n c y m e a s u r e s b a s e d o n t h e f r e q u e n c y w i t h wh ich l e t t e r s , l e t t e r s e q u e n c e s , and words o c c u r i n n a t u r a l t e x t s . The s e c o n d c a t e g o r y , r u l e - g o v e r n e d r e g u l a r i t y , was b a s e d o n p h o n o l o g i c a l c o n s t r a i n t s o f E n g l i s h and s c r i b a l c o n v e n t i o n s g o v e r n i n g t h e s p e l l i n g o f E n g l i s h . A l s o i n c l u d e d i n C h a p t e r 3 was a b r i e f r e v i e w o f p r e v i o u s s t u d i e s o f o r t h o g r a p h y .
I n C h a p t e r 4 , w e examined t h e p s y c h o l o g i c a l r e a l i t y o f v a r i o u s d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n t a s k s and o v e r t j u d g m e n t t a s k s . The r e c o g n i t i o n
2 4 6 CHAPTER 6
t a s k s a s s e s s e d t h e d e g r e e t o which knowledge o f o r t h o g r a p h i c s t r u c t u r e is u t i l i z e d i n word p e r c e p t i o n , and t h e o v e r t j udgmen t t a s k s a s s e s s e d t h e d e g r e e - t o wh ich t h i s knowledge is c o n s c i o u s l y a v a i l a b l e .
G i v e n o u r p r e v i o u s r e s u l t s (Massa ro e t a l . , 1 9 7 9 ) , we had r e a s o n t o s u s p e c t d i f f e r e n c e s be tween r e a c t i o n time t a s k s and a c c u r a c y t a s k s i n terms o f t h e i r s e n s i t i v i t i e s t o t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e . We b e g a n w i t h a d i r e c t c o m p a r i s o n be tween t h e s e two t a s k s , w h i l e s i m u l t a n e o u s l y c o n t r a s t i n g a r u l e - g o v e r n e d m e a s u r e and a s t a t i s t i c a l - r e d u n d a n - c y m e a s u r e o f o r t h o g r a p h i c s t r u c t u r e . Rep1 i c a t i n g o u r p r e v i o u s work, w e found h i g h l y s i g n i f i c a n t e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e i n t h e a c c u r a c y t a s k and r e l a t i v e l y s m a l l , a n d somet imes n o n s i g n i f i c a n t , e f f e c t s i n t h e r e a c t i o n time t a s k . The n e x t s i x e x p e r i m e n t s a s s e s s e d wha t a s p e c t s o f t h e two t a s k s a c c o u n t e d f o r t h e d i f f e r e n c e s t h a t were o b s e r v e d . We e v a l u a t e d t h e i n f l u e n c e s o f p r e s e n t i n g t h e t a r g e t l e t t e r b e f o r e o r a f t e r t h e t e s t d i s p l a y , t h e c o n t r i b u t i o n o f a f e a t u r e d e t e c t i o n s t r a t e g y , t h e r o l e o f l i m i t e d s t i m u l u s i n f o r m a t i o n , and t h e s e n s i t i v i t y o f s p e e d e d r e a c t i o n - t i m e e x p e r i m e n t s . The r e a s o n t h a t t h e m a g n i t u d e o f t h e e f f e c t a p p e a r s s m a l l e r f o r a h i g h a c c u r a c y r e a c t i o n - t i m e m e a s u r e is t h a t t h e d i f f e r e n c e s i n v i s u a l p r o c e s s i n g time a r e s m a l l r e l a t i v e t o t h e o v e r a l l r e a c t i o n time t o c o m p l e t e t h e t a s k . I n c o n t r a s t , t h e s t i m u l u s p a r a m e t e r s a r e m o d i f i e d i n t h e a c c u r a c y t a s k t o k e e p a v e r a g e p e r f o r m a n c e a t 7 5 % c o r r e c t ; a n y d i f f e r e n c e s i n a c c u r a c y a r e t h e n i n f l u e n c e d a l m o s t c o m p l e t e l y by v i s u a l p r o c e s s i n g . S u p p o r t i n g t h i s i n t e r p r e t a t i o n , t h e p o s t hoc e v a l u a t i o n o f v a r i o u s m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e r e v e a l e d r e a s o n a b l y good c o r r e l a t i o n s w i t h r e a c t i o n t ime b u t much h i g h e r c o r r e l a t i o n s w i t h a c c u r a c y .
To p r o v i d e a q u a n t i t a t i v e d e s c r i p t i o n o f t a s k a c c u r a c y , we f o r m a l i z e d t h e i n f o r m a t i o n p r o c e s s i n g model d e v e l o p e d i n C h a p t e r 1. T h i s model a l l o w s a f o r m a l d e s c r i p t i o n o f t h e f a c i l i t a t i v e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e o n b o t h r e a c t i o n time and t a s k a c c u r a c y . The b a s i c a s s u m p t i o n o f t h e model i s t h a t knowledge o f o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s a n i n d e p e n d e n t s o u r c e o f i n f o r m a t i o n a b o u t t h e l e t t e r s t r i n g . C o n s e q u e n t l y , f e w e r v i s u a l f e a t u r e s a r e n e c e s s a r y t o r e s o l v e w e l l - s t r u c t u r e d s t r i n g s t h a n t o r e s o l v e p o o r l y - s t r u c t u r e d s t r i n g s . The model was a p p l i e d t o t h e t a r g e t s e a r c h t a s k by f o r m a l i z i n g a d e c i s i o n a l g o r i t h m assumed t o b e used by t h e s u b j e c t when f a c e d w i t h p a r t i a l i n f o r m a t i o n . The model p r o v i d e d a good q u a n t i t a t i v e d e s c r i p t i o n o f t h e r e s u l t s from t h e a c c u r a c y t a s k . The p a r a m e t e r s o f t h e model were
SUMMARY AND CONCLUSION 247
p s y c h o l o g i c a l l y m e a n i n g f u l and t h e p a r a m e t e r v a l u e s c o r r e s p o n d i n g t o t h e number o f l e t t e r s s e e n i n t h e test s t r i n g s p r o v i d e d a q u a n t i t a t i v e measure o f t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e . A c c o r d i n g t o t h e m o d e l , o u r r e a d e r s were a b l e t o r e c o g n i z e two a d d i t i o n a l l e t t e r s i n we 1 1-st r uc t u r ed s t r i n g s compared t o poo r l y - s t r uc t u r e d s t r i n g s . T h i s i s a s u b s t a n t i a l e f f e c t c o n s i d e r i n g t h a t two l e t t e r s r e p r e s e n t o n e - t h i r d o f t h e s i x - l e t t e r t e s t s t r i n g .
We a l s o c a r r i e d o u t a s e r i e s o f o v e r t j u d g m e n t e x p e r i m e n t s t o assess which d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e a r e c o n s c i o u s l y a v a i l a b l e . We a s k e d w h e t h e r s u b j e c t s c o u l d r e l i a b l y a s s i g n r a t i n g s o f how much a l e t t e r s t r i n g r e s e m b l e s w r i t t e n E n g l i s h o n t h e b a s i s o f t h e t y p i c a l i t y o f t h e l e t t e r s e q u e n c i n g i n t h e t e s t s t r i n g s . I n a d d i t i o n , o t h e r s u b j e c t s were a s k e d t o d i s c r i m i n a t e t h e i tems o n t h e b a s i s o f r u l e - g o v e r n e d r e g u l a r i t y o r o n t h e b a s i s o f s t a t i s t i c a l r e d u n d a n c y . S u b j e c t s ' j u d g m e n t s were more a c c u r a t e l y d e s c r i b e d b y r u l e - g o v e r n e d r e g u l a r i t y t h a n by s t a t i s t i c a l r edun- d a n c y . F i n a l l y , t h e r a t i n g s o f t h e i n d i v i d u a l items c o r r e l a t e d q u i t e s t r o n g l y w i t h t h e i r a c c u r a c i e s and r e a c t i o n t imes i n t h e t a r g e t s e a r c h t a s k .
The f a c t o r i a l d e s i g n o f our e x p e r i m e n t s c o n t r a s t e d j u s t o n e m e a s u r e o f r u l e - g o v e r n e d r e g u l a r i t y w i t h o n e m e a s u r e o f s t a t i s t i c a l r e d u n d a n c y . T h e r e f o r e , w e c o n d u c t e d a l a r g e number o f p o s t h o c c o r r e l a t i o n a l a n a l y s e s t o e v a l u a t e a w i d e r a n g e o f m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . The d e p e n d e n t m e a s u r e s were t h e r e a c t i o n t imes , a c c u r a c y , and r a t i n g r e s p o n s e s t o e a c h o f 200 t e s t i tems . p o s i t i o n - s e n s i t i v e l o g b ig ram f r e q u e n c y p r o v i d e d t h e b e s t d e s c r i p t i o n o f p e r f o r m a n c e on t h e i n d i v i d u a l t e s t i tems . However, o u r r u l e - b a s e d r e g u l a r i t y m e a s u r e a l s o p r o v i d e d a v e r y good d e s c r i p t i o n . I n f a c t , o u r r e g u l a r i t y m e a s u r e c o r r e l a t e d v e r y h i g h l y w i t h t h e b e s t f r e q u e n c y - b a s e d m e a s u r e . T h e r e f o r e , we w e r e n o t s u c c e s s f u l i n c h o o s i n g b e t w e e n r u l e - g o v e r n e d r e g u l a r i t y and s t a t i s t i c a l r e d u n d a n c y i n t h e s e e x p e r i m e n t s .
We were a l s o a b l e t o e v a l u a t e t h e m o s t a p p r o p r i a t e m e a s u r e s f o r a s t a t i s t i c a l - r e d u n d a n c y d e s c r i p t i o n . We o b t a i n e d i n f o r m a t i o n a b o u t t h e u t i l i t y o f t y p e v e r s u s t o k e n c o u n t s , t h e a p p r o p r i a t e s c a l e f o r d e s c r i b i n g f r e q u e n c y o f o c c u r r e n c e , p o s i t i o n - s e n s i t i v e v e r s u s p o s i t i o n - i n s e n s i t i v e c o u n t s o f l e t t e r o c c u r r e n c e s , t h e r o l e o f word f r e q u e n c y , and t h e r e l a t i v e c o n t r i b u t i o n s o f v a r i o u s s e r i a l p o s i t i o n s i n d e t e r m i n i n g t h e o r t h o g r a p h i c s t r u c t u r e o f a n item.
What c o n c l u s i o n s c a n b e r e a c h e d and wha t a r e t h e i m p l i c a t i o n s f o r f u t u r e r e s e a r c h and c l a s s r o o m
2 4 8 CHAPTER 6
p r a c t i c e ? A l t h o u g h we were n o t s u c c e s s f u l i n c h o o s i n g be tween r u l e - g o v e r n e d r e g u l a r i t y and s t a t i s t i c a l r e d u n d a n c y i n t h e s e e x p e r i m e n t s , a d d i t i o n a l e x p e r i m e n t s m i g h t b e s u c c e s s f u l . G i v e n t h e b e s t s t a t i s t i c a l - r e d u n d a n c y m e a s u r e , i t s h o u l d b e p o s s i b l e t o d e v e l o p a new se t o f t e s t i tems t o c o n t r a s t t h i s m e a s u r e w i t h a r u l e - g o v e r n e d r e g u l a r i t y m e a s u r e . We p l a n t o f o l l o w t h e l o g i c o f t h e p r e s e n t s t u d i e s by c o n t r a s t i n g l o g b ig ram f r e q u e n c y and r e g u l a r i t y m e a s u r e s i n t a r g e t s e a r c h and o v e r t j udgmen t t a s k s . A l t h o u g h t h e s e two m e a s u r e s a r e h i g h l y c o r r e l a t e d , i t s h o u l d b e p o s s i b l e t o d i s t i n g u i s h be tween them. G i v e n t h e r e s u l t s , i t w i l l s t i l l b e n e c e s s a r y t o c a r r y o u t p o s t hoc c o r r e l a t i o n s t o d e t e r m i n e i f some o t h e r m e a s u r e m i g h t p r o v i d e e v e n a b e t t e r d e s c r i p t i o n . T h i s r e s e a r c h h a s t h e p r o m i s e o f l e a d i n g t o t h e d e s c r i p t i o n t h a t b e s t r e f l e c t s t h e knowledge o f o r t h o g r a p h i c s t r u c t u r e used i n t h e c o u r s e o f no rma l r e a d i n g .
A r r i v i n g a t a good d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e s h o u l d b e b e n e f i c i a l i n t h e d e v e l o p m e n t o f r e a d i n g i n s t r u c t i o n . G i v e n t h a t t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e i s a n i m p o r t a n t component i n l e t t e r and word r e c o g n i t i o n , i n s t r u c t i o n a l m a t e r i a l s s h o u l d b e d e s i g n e d t o f a c i l i t a t e c h i l d r e n ' s u n d e r s t a n d i n g o f t h i s s t r u c t u r e . C u r r e n t p h o n i c s p rograms a d d r e s s o n l y t h e c o r r e s p o n d e n c e s be tween s p e l l i n g and s o u n d , n o t t h e c o n s t r a i n t s i n E n g l i s h o r t h o g r a p h y . Y a s s a r o and T a y l o r ( 1 9 7 9 ) s k e t c h a s e r i e s o f c l a s s r o o m games t h a t m i g h t b e employed t o t e a c h c h i l d r e n common l e t t e r p a t t e r n s and t h e l o c a t i o n s i n words t h e s e l e t t e r p a t t e r n s a r e m o s t l i k e l y t o b e found . D e l i n e a t i n g t h e b e s t d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e m i g h t f a c i l i t a t e t h e t e a c h i n g and l e a r n i n g o f t h i s s t r u c t u r e .
A l l p o r t , A . Word r e c o g n i t i o n i n r e a d i n g ( T u t o r i a l p a p e r ) . I n P. A. K o l e r s , M . W r o l s t a d , & H . Bouma ( E d s . ) , P r o c e s s i n g -~ o f v i s i b l e l a n g u a g e r. N e w York: Plenum, 1979.
A n d e r s o n , I . H . , & D e a r b o r n , W . F. The p s y c h o l o g y of t e a c h i n g r e a d i n g . N e w York: Ronald P r e s s , 1952.
A n i s f e l d , M. A. A comment on "The r o l e o f grapheme-phoneme c o r r e s p o n d e n c e i n t h e p e r c e p t i o n o f words." American ~- J o u r n a l o f P s y c h o l o g y , 1 9 6 4 , 11, 320-326.
A t k i n s o n , R . C . , & J u o l a , J . F. S e a r c h and d e c i s i o n p r o c e s s e s i n r e c o g n i t i o n memory. I n D. H . K r a n t z , R . C. A t k i n s o n , R . D. L u c e , & P. S u p p e s ( E d s . ) , Con tempora ry d e v e l o p m e n t s - i n m a t h e m a t i c a l p s y c h o l o g y . San F r a n c i s c o : Freeman, 1974 .
B a d d e l e y , A. D . I m m e d i a t e memory and t h e " p e r c e p t i o n " o f l e t t e r s e q u e n c e s . Q u a r t e r l y J o u r n a l o f E x p e r i m e n t a l P s y c h o l o g y , 1 9 6 4 , 16, 364-367.
Ba ron , J . The word s u p e r i o r i t y e f f e c t . I n W . K . E s t e s ( E d . ) , Handbook of l e a r n i n g and c o g n i t i v e p r o c e s s e s ( V o l . 6 ) . H i l l s d a l e , N . J . : E r lbaum, 1978 .
B a r o n , J . , & T h u r s t o n , I . An a n a l y s i s o f t h e w o r d - s u p e r i o r i t y e f f e c t . C o g n i t i v e P s y c h o l o g y , 1 9 7 3 , 4, 207-228.
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Glossary
a c c u r a c y t a s k : a t a s k i n wh ich a c c u r a c y i s t h e p r i m a r y d e p e n d e n t m e a s u r e ; i n t h e t a r g e t s e a r c h t a s k , a v e r a g e p e r f o r m a n c e i s m a i n t a i n e d a t 7 5 % c o r r e c t by a d j u s t i n g t h e d u r a t i o n o f t h e t e s t s t r i n g a n d / o r t h e p r o c e s s i n g t ime a v a i l a b l e .
anagram: a p e r m u t a t i o n o f t h e l e t t e r s c o m p r i s i n g a word.
b ig ram: a t w o - l e t t e r c l u s t e r .
c a t c h t r i a l : a t r i a l d u r i n g which t h e t a r g e t l e t t e r d o e s n o t -- a p p e a r i n t h e t e s t s t r i n g .
f e a t u r e d e t e c t i o n : a p r o c e s s wh ich a n s w e r s t h e q u e s t i o n o f w h e t h e r o r n o t a p a r t i c u l a r f e a t u r e is p r e s e n t a n d / o r p r o v i d e s i n f o r m a t i o n a b o u t t h e d e g r e e t o wh ich t h e f e a t u r e i s p r e s e n t .
f o u r i e r a n a l y s i s : t h e d e s c r i p t i o n o f a v i s u a l d i s p l a y i n t e rms o f i n t e n s i t y and f r e q u e n c y o f component s i n e waves.
f u l l r e p o r t : g i v e n a d i s p l a y o f i t ems , s u b j e c t s a r e a s k e d t o r e p o r t a l l o f t h e i tems i n t h e d i s p l a y .
g e n e r a t e d a b s t r a c t memory: m o d a l i t y - f r e e ( a b s t r a c t ) s t o r a g e , a n a l o g o u s t o s h o r t - t e r m memory.
g r a p h e m i c c o n s t r a i n t s : s ee s c r i b a l c o n s t r a i n t s .
2 6 3
264 G L O S S A R Y
high s p a t i a l f r e q u e n c i e s : t h e h i g h f r e q u e n c i e s o f a f o u r i e r a n a l y s e s o f a v i s u a l d i s p l a y .
homophones: d i f f e r e n t words t h a t a r e p ronounced i d e n t i c a l l y , s u c h a s r i g h t / w r i t e .
i n f o r m a t i o n : s o u r c e o f knowledge a v a i l a b l e t o t h e r e a d e r ; f o r e x a m p l e , t h e f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l s t o r a g e o r t h e r e a d e r ' s memory o f l e t t e r p a t t e r n s i n t h e l a n g u a g e .
l e x i c o n : s t o r a g e o f p e r c e p t u a l and c o n c e p t u a l c o d e s o f w o r d s i n l o n g - t e r m memory; e a c h word h a s p e r c e p t u a l c o d e s s u c h a s t h e sound and v i s u a l p a t t e r n o f t h e word and c o n c e p t u a l c o d e s s u c h a s i t s mean ing .
l ong- t e rm memory: r e l a t i v e l y pe rmanen t s t o r e o f knowledge i n t e r m o f c o d e s , r u l e s , and p r o c e d u r e s ( s c h e m a t a ) .
- l o w s p a t i a l f r e q u e n c i e s : t h e low f r e q u e n c i e s o f a f o u r i e r a n a l y s i s o f a v i s u a l d i s p l a y .
morpheme i d e n t i t y : r e t e n t i o n o f s p e l l i n g s i m i l a r i t y o f s e m a n t i c a l l y - r e l a t e d w o r d s , s u c h a s c o n e / c o n i c .
nonword: a l e t t e r s t r i n g t h a t d o e s n o t s p e l l a word; s o m e t i m e s used t o mean t h a t t h e l e t t e r s t r i n g a l s o d o e s not confo rm t o s t a n d a r d E n g l i s h s p e l l i n g , i . e . , i t v i o l a t e s E n g l i s h o r t h o g r a p h y .
o r t h o g r a p h i c r e g u l a r i t y : d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e b a s e d upon r u l e s and g e n e r a l i z a t i o n s a b o u t t h e o b s e r v e d p a t t e r n s o f E n g l i s h o r t h o g r a p h y ; a l s o r e f e r r e d t o a s r u l e - b a s e d d e s c r i p t i o n .
o r t h o g r a p h i c s t r u c t u r e : t h e s p e l l i n g c o n s t r a i n t s i n a w r i t t e n l a n g u a g e ; i n E n g l i s h , f o r example , g i v e n i n a n i n i t i a l p o s i t i o n , r is more l i k e l y t o f o l l o w t h a n 2.
o v e r t j u d g m e n t s : j u d g m e n t s a b o u t t h e s p e l l i n g o f l e t t e r s t r i n g s ; s t u d i e d t o a s s e s s what knowledge o f o r t h o g r a p h y is c o n s c i o u s l y a v a i l a b l e and c a p a b l e o f r e p o r t .
p a r a l l e l p r o c e s s i n g : when i n f o r m a t i o n a b o u t two o r more i tems is p r o c e s s e d s i m u l t a n e o u s l y .
GLOSSARY 2 6 5
perceptual recognition: see primary recognition.
phonological constraints: the constraints on English orthography that derive from the allowable sequences of sounds in English words.
positional frequency: see position-sensitive measure.
position-dependent measure: see position-sensitive measure.
position-independent measure: see position-insensitive measure.
position-insensitive measure: a statistical-redundancy description of orthographic structure which counts letter sequences on the bases of occurrence in words of specific lengths without regard to position of occurrence; also referred to as position-independent measure.
position-sensitive measure: a statistical-redundancy descrip- tion of orthographic structure which counts letter sequences on the basis of occurrence in specific positions in words of specific lengths; also referred to as position-dependent measure or positional-frequency.
postcue: when a target letter follows a test string.
precue: when a target letter precedes a test string.
preperceptual visual storage: holds features passed on by feature detection for roughly one quarter of a second.
primary recognition: joint evaluation and integration of the features in preperceptual storage and knowledge of orthographic structure in long-term memory; the outcome is a synthesized percept; also referred to as perceptual recog n i t ion.
probabilistic description: see statistical redundancy.
pseudoword: a nonword that conforms to English spelling.
reaction time (RT) task: task in which reaction time is the primary dependent measure; in the high-accuracy target search task, for example, accuracy is kept near perfect by
266 GLOSSARY
k e e p i n g t h e t e s t s t r i n g p r e s e n t d u r i n g t h e r e s p o n s e i n t e r v a l .
r e g u l a r i t y : see o r t h o g r a p h i c r e g u l a r i t y . r u l e -based d e s c r i p t i o n : see o r t h o g r a p h i c r e g u l a r i t y . s c r i b a l c o n s t r a i n t s : t h e c o n s t r a i n t s i n t h e s e l e c t i o n o f
l e t t e r s f o r e i t h e r r e p r e s e n t i n g s o u n d s o r m a r k i n g g r a p h e m i c , g r a p h o t a c t i c , o r m o r p h o l o g i c a l f u n c t i o n s ; a l s o r e f e r r e d t o a s g r a p h e m i c c o n s t r a i n t s .
s e c o n d a r y r e c o g n i t i o n : t r a n s f o r m s v i s u a l p e r c e p t h e l d i n s y n t h e s i z e d memory i n t o meaning h e l d i n g e n e r a t e d a b s t r a c t memory.
s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y : t h e f r e q u e n c y w i t h wh ich a l e t t e r o c c u r s i n a s p e c i f i c p o s i t i o n i n words o f a s p e c i f i c l e n g t h i n a s a m p l e o f t e x t .
s p e e d e d fl task: s u b j e c t s a r e i n s t r u c t e d t o r e s p o n d more q u i c k l y t h a n t h e time needed f o r h i g h a c c u r a c y ; i n t h e t a r g e t s e a r c h t a s k , s u b j e c t s l e a r n t o r e s p o n d i n s y n c h r o n y w i t h a n e x t e r n a l s i g n a l whose r e l a t i v e o n s e t i s a d j u s t e d t o k e e p p e r f o r m a n c e a t 7 5 % c o r r e c t ; b o t h a c c u r a c y and RT a r e e v a l u a t e d a s d e p e n d e n t m e a s u r e s .
s t a t i s t i c a l r edundancy : c a t e g o r y o f d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e d e r i v e d from c o u n t s o f l e t t e r s o r l e t t e r s e q u e n c e s o c c u r r i n g i n t h e w r i t t e n l a n g u a g e ; a l s o c a l l e d p r o b a b i l i s t i c d e s c r i p t i o n .
~ _ _ _ summed c o u n t s : t h e sum o f i n d i v i d u a l f r e q u e n c i e s o f t h e l e t t e r s o r l e t t e r c l u s t e r s i n a l e t t e r s t r i n g .
s y n t h e s i z e d v i s u a l memory: h o l d s p e r c e p t u a l o u t c o m e s o f p r i m a r y r e c o g n i t i o n p r o c e s s .
t a r g e t l e t t e r : i n t h e t a r g e t s e a r c h t a s k , t h e l e t t e r whose p r e s e n c e o r a b s e n c e i n t h e t e s t s t r i n g o f l e t t e r s m u s t b e r e p o r t e d .
t a r g e t s e a r c h t a s k : t h e s u b j e c t i s g i v e n a t a r g e t l e t t e r and t h e t a s k i s t o i n d i c a t e w h e t h e r o r n o t t h e t a r g e t l e t t e r
- ~ -
is c o n t a i n e d i n a t e s t s t r i n g o f l e t t e r s .
GLOSSARY 267
- t e s t s t r i n g : i n t h e t a r g e t s e a r c h t a s k , t h e l e t t e r s t h a t m u s t be e v a l u a t e d i n te rms of p r e s e n c e o r a b s e n c e of t h e t a r g e t l e t t e r .
t o k e n c o u n t : a c o u n t based on t h e number of t o t a l o c c u r r e n c e s of an i tem; f o r example, t h e t o t a l number o f o c c u r r e n c e s of a l l words c o n t a i n i n g a p a r t i c u l a r l e t t e r .
--
t r i g r a m : a t h r e e - l e t t e r c l u s t e r .
*e count : a c o u n t based on t h e number o f un ique o c c u r r e n c e s o f an i tem; f o r example, t h e number of un ique words c o n t a i n i n g a p a r t i c u l a r l e t t e r .
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Author Index A
Adams, N., 5 8 , 67 A l l p o r t , A., viii A n d e r s o n , I . H., 1 1 - 1 2 A n i s f e l d , M . A . , 25 A t k i n s o n , R. C . , 56
B
B a d d e l e y , A . D . , 7 , 64 B a r b u t o , P . F . , 27 B a r o n , J , , viii, 6 2 B e a l , A. L . , 2 4 B j o r k , E . L . , 62
Bouwhuis , D . , G . 26 B r e i t m e y e r , B . G., 1 9 B r o a d b e n t , D. E . , 1 9 , 1 4 1 , B r o w n e l l , H . , 5 8 , 67 B r u n e r , J. S., 6 , 2 4 B y r n e s , J . , 2 4
Bouma, H., 1 2 , 15-16 , 43-45, 52-53
C
C a r r , T. H . , ix
C h a n d l e r , J . P . , 59 Chomsky, N . , 35 C l a r k , H . H . , 51
C a t t e l l , J . M., 1 1 - 1 2
269
270 AUTHOR I N D E X
Conger , B. , 132 C r e e l m a n , C . D . , 93
D
D e a r b o r n , W. F. , 11-12
E
E g e t h , H . E . , 25 Es t e s , W. R . , v i i i , 5 , 6 2
F
F a n t , C. G . M . , 1 4 F r a n c i s , W. N., 26-27, 126-127, 149
G
Ganz , L . , 1 9 G e o f f r i o n , L. D . , 5 G i b s o n , E . J . , v i i i , 1, 15 , 25 , 29-38, 32 G i l m o r e , G . C . , 25 Green, D. M . , 1 7
H
H a l l e , M . , 1 4 Hammond, M., 25 , 29-30 H a v i l a n d , S . E . , 58 , 67 H e n d e r s o n , L . , v i i i Huey, E . B . , 1, 1 3 Hung, D. L . , 29
J
J a k o b s o n , ' R. , 1 4 J o h n s o n , N . F. , v i i i J o h n s t o n , J. C . , 26 , 1 0 1 , 132 J o n e s , R. D . , 7 4 , 77-18
J u o l a , J. F. , 56, 68 J u e l , C. L.r 27
AUTHOR INDEX
K
2 7 1
Kallrnan, H. J . , 5 8 K a u s l e r , D. H., 3 3
King, J. F . , 2 7 K l i t z k e , D . , 1 0 5 Kleiman, G. M . , 2 9 K o l e r s , P . A., 1 0 8 Krueger , L. E . , v i i i , 7, 4 7 Kucera, H., 2 6 - 2 7 , 1 2 6 - 1 2 7 , 1 4 9 Kurath , H., 3 5
L
Landauer , T. K . , 2 7 - 2 8 L e f t o n , L. A., 24
Levin , H., viii, 1 Levy, B. A . , 2 9
Lewis, S. S., 2 9 - 3 0 Lipscomb, c . , 7 4 , 7 7 - 7 8 Lorge, I . , 2 5
M
Macey, W. H., 2 7 Mason, M . , 2 6 , 3 7 - 3 8 , 1 3 2 Massaro, D. W.,ix, 2, 5-8, 1 7 , 19, 21, 2 6 , 2 9 ,
3 8 - 4 7 , 4 3 , 56 -58 , 6 2 , 7 4 , 7 7 - 7 8 , 9 6 , 1 0 5 ,
2 4 6 , 2 4 8 Mayzner, M . S . , 26, 4 8 , 9 1 McClel land, J . L . , 2 6 , 1 0 1 , 1 3 2
Meyer, D. E . , 7 4 , M i l l e r , G. A., 6 , 2 4 M i l l e r , T. J . , 6 8
Newhort, D, J . , 24
N
N e i s s e r , U . , 1 4 , 4 3
0
Oden, G . C . , 2 1 , O l i v i e r , D. G . , 1 2 7 - 1 2 8 , 1 3 1 O l s e n , G. A . , 3 3
272 AUTHOR INDEX
Osser, H . , 1 5 , 2 5 , 29-30
P
P i c k , A . , 25 , 29-30 P o d g o r n y , P., 1 3 1 P o l l a t s e k , A . , ix P o s t m a n , L . , 6 , 24 , 27-28, 131-132 P y l e s , T. , 32
R
R e d e r , L. M . , 5 8 , 67 Reed , A. V., 7 5 , 1 0 5 R e i c h e r , G. M., 6 , 6 2 R u b e n s t e i n , H . , 29-30 R u b e n s t e i n , M . A . , 29-30 Ruddy, M . G., 74
S
S a v i n , H. B . , 27-28 S c h i f f , W., 15 S c h m u l l e r , J., 7 , 1 7 , 1 9 , 43 S c h o l z , R. , 7 4 , 77-78 S c h u l z , R. W., 25-26 S c h v a n d e v e l d t , R. W . , 74 S e l f r i d g e , 0. G., 1 4 Shannon , C. E., 6 , 24 S h a p i r o , R . G., 7, 47 S h e b i l s k e , W. , 3 S h e p a r d , R. N., 1 3 1 S h u r c l i f f , A . , 25-26, 29-30, 132 S idman , M., 47 S k a a r , E., 6 2 S m i t h , E. E., 4 , 29-30, 5 8 , 6 7 , 132 S m i t h , J., 15 Solomon, R. L . , 27-28, 1 3 1 S o l s o , R. L., 27 S p e n c e r , H . , 11-13 S p o e h r , R. T., 132 S p r a g i n s , A. B., 2 4 S p r e e n , O., 26 S t r e e t e r , L. A . , 27-28 S w e t s , J. A . , 1 7
AUTHOR I N D E X
T
27 3
T a y l o r , G . A . , 26, 38-47 , 57-58, 68 , 9 3 , 1 0 5 , 1 3 1 , 2 4 8
T h o m p s o n , M . C . , 6, 57-58 , 6 2 T h o r n d i k e , L. L . , 2 5 T h u r s t o n , I . , 6 2 T i n k e r , M. A . , 11 T o w n s e n d , J. T . , 15 T o p p e r , G . E . , 27 T r a v e r s , J . R . , 1 2 7 - 1 2 8 , 1 3 1 T r e s s e l t , M. E . , 26, 48, 9 1 T u l v i n g , E . , 6 T u r v e y , M . T . , 56 T z e n g , 0. J . L . , 2 9
U
U n d e r w o o d , 8. J . , 25-26
V
V a c h e k , J . , 3 3 V e n e z k y , R . L . , 26, 29, 31, 33 , 35 , 38-47, 57-58, 9 6
W
W a l l a c h , M . A . , 24 Wang, W. S-Y., 2 9 W h e e l e r , D. D . , 6, 6 2 W h o r f , B . L . , 35 Wol in , B. R . , 26 W o o d w o r t h , R. S., 3
Y
Yonas, A . , 25-26, 29-30, 1 3 2
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Subject Index
A
a c c u r a c y t a s k , 40 ,47 -48 , 56-61, 246-247 a n a g r a m , 3 8 a w a r e n e s s , 81
B
b i g r a m , 25-29 b i g r a m c o u n t s ,
c
c a t c h t r i a l , 39 c l a s s r o o m p r a c t
60-244
c e , 779 c o n f u s i o n m a t r i c e s , 14-15 c o n s o n a n t s p e l l i n g , 31-32
D
d e c i s i o n , 17-18 , 5 6 , 57 d ' m e a s u r e , 17-18
E
E n g l i s h n e s s , 127-128 e n v e l o p e , 15-16, 1 9
275
276 S U B J E C T I N D E X
F
f e a t u r e a n a l y s i s , 2 , 13-14 f e a t u r e d e t e c t i o n , 3-4 , 19-21 f e a t u r e d e t e c t i o n s t r a t e g y , 43-46, 6 8 , 71-73 f e a t u r e s , 3 , 5 , 1 4 , 14 -21 f o u r i e r a n a l y s i s , 1 9 f r e q u e n c y s c a l e , 130-132 f u l l r e p o r t , 6 , 24-25
G
g e n e r a t e d a b s t r a c t memory, 8
H
h i g h s p a t i a l f r e q u e n c i e s , 1 9 homophones , 3 3
i n f o r m a t i o n , 2 , 73-74 i n f o r m a t i o n p r o c e s s i n g m o d e l , 1-8, 55-62, 66-67
K
knowledge , 2 , 74
L
l e g i b i l i t y of t e x t , 11-13 l e t t e r - s o u n d c o r r e s p o n d e n c e s , 29-30 l e x i c o n , 8 l i n g i u s t , 34 long- t e rm memory, 3 , 8 low s p a t i a l f r e q u e n c i e s , 1 9
M
mask ing s t i m u l u s , 6 , 1 5 , 1 7 , 40 memory, 2-3 morpheme i d e n t i t y , 32 morphemic f e a t u r e s , 32-33
SUBJECT INDEX
N
nonword , 25
277
o r d e r e d a p p r o x i m a t i o n s t o E n g l i s h , 24-25 o r t h o g r a p h i c r e g u l a r i t y , 38 o r t h o g r a p h i c s t r u c t u r e , 2 , 4-9, 23-36 , 245 o v e r t j u d g m e n t s , 81 -90 , 247
P
p a r a l l e l p r o c e s s i n g , 5 , 56 p a i r e d j u d g m e n t s , 81, 87 -89 , 120-123 p e r c e p t u a l r e c o g n i t i o n , 8 p e r c e p t u a l u n i t , 5 p e r i p h e r a l v i s i o n , 1 3 , 1 5 , 1 9 p h o n o l o g i c a l c o n s t r a i n t s , 30-31 p h o n o l o g i c a l l y - b a s e d d e s c r i p t i o n s , 29-30 p o s i t i o n - i n s e n s i t i v e m e a s u r e , 1 3 2 p o s i t i o n - s e n s i t i v e m e a s u r e , 132 p o s t c u e , 47-48, 62-66 p r e c u e , 47-48 , 62-66 p r e p e r c e p t u a l v i s u a l s t o r a g e , 3-4, 56 p r i m a r y r e c o g n i t i o n , 4-5, 7 -8 , 56 p r i m i n g , 74 p r o c e s s , 2-3 p r o c e s s i n g t ime, 1 4 p s e u d o w o r d s , 24 , 82-85 , 115 p s y c h o l o g i s t s , 34
R
r a t i n g s , 81, 81 -87 , 113-119 r e a c t i o n - t i m e t a s k , 37-38 , 47-48 , 68-61 , 246-247 r e a d i n g , 1-2 r e a d i n g i n s t r u c t i o n , 1 - 2 , 247-248 r e c o d i n g , 8 r e d u n d a n c y , 6 r e h e a r s a l , 8 R e i c h e r - W h e e l e r p a r a d i g m , 6-7 , 40 r u l e - b a s e d d e s c r i p t i o n , 23-24 , 30-36, 3 8 , 9 6 , 1 2 9 , 247 r u l e - g o v e r n e d r e g u l a r i t y , 23-24, 30-36, 38 , 9 6 , 1 2 9 , 247
278 SUBJECT INDEX
S
s a c c a d e s , 3 s c r i b a l c o n s t r a i n t s , 31-32 s e c o n d a r y r e c o g n i t i o n , 4 , 8 s h o r t- t e rm memo r y , 7-8 s i m i l a r i t y , 43-46 , 51-54 , 64-65, 72-73 s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y , 3 7 , 48 s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y c o u n t s , 149-159 s p e e d - a c c u r a c y p a r a d i g m , 7 5 s p e e d e d RT t a s k , 75-82 s t a g e o f p r o c e s s i n g , 2-3 s t a t i s t i c a l r e d u n d a n c y , 23-29, 247 s t i m u l u s items, 97-98, 143-148 summed c o u n t s , 37 s y n t h e s i z e d v i s u a l memory, 8 , 56
T
t a r g e t l e t t e r , 37-39 t a r g e t s e a r c h t a s k , 3 7 , 37-81 t a r g e t t r i a l , 39 t e m p l a t e , 1 4 t e s t s t r i n g , 37-39 t o k e n c o u n t , 27-28, 128-130 t r i g ram , 27 t y p e c o u n t , 27-28, 128-130
V
vowel s p e l l i n g s , 31-32
w
word f r e q u e n c y , 1 4 1 word r e c o g n i t i o n , 1 -2 , 4