ATTENTION: SELECTIVITY AND RESOURCE ALLOCATION

• SELECTIVITY– what events “capture” attention?– how complete is selectivity?

• AROUSAL AND ALERTNESS– does capacity change over time?– how is it affected by arousal,task

demands or intention?

• DIVIDED ATTENTION– how well can we do two things at once?– can we improve our skill in dividing

attention?

MEASURING WHERE ATTENTION IS FOCUSSED

tracking eye fixations

tracking ear fixations (“shadowing”)

this is thefirst day of therest of yourlife in the.

“when in thecourse of …..”

“and anotherscore for theGators ……”

“.. another score, uh …”

EYE TRACKING TECHNOLOGY

Seven records of eye movements by the same subject. Each record lasted 3 minutes. 1) Free examination. Before subsequent recordings, the subject was asked to: 2) estimate the material circumstances of the family; 3) give the ages of the people; 4) surmise what the family had been doing before the arrival of the "unexpected visitor;" 5) remember the clothes worn by the people; 6) remember the position of the people and objects in the room; 7) estimate how long the "unexpected visitor" had been away from the family (from Yarbus (1967).

Fig. 4-18, p. 122

DYNAMICS OFVISUAL ATTENTION

“COVERT” SHIFTS OFSPATIAL ATTENTION

(Posner & Cohen, 1984)

fixate centerthroughout trial:

@

respond totarget figure:

X @

cue for likelyside of test:(p. = .8)

100 to1000msec

300

350

400

450

500

550

600

De

cis

ion

Tim

e

100 300 500 700 900

Cue-Target Delay

valid

invalid

Fig. 4-22, p. 126

ATTENTION TO OBJECTS vs. LOCATIONS (Egly 1994)

UNILATERAL NEGLECT:Impaired shifting of

spatial attention

Left hemisphere: focus on right sideof space

Right Hemisphere: focus on left and right side

Damage to Right Hemisphere:

• Evidence for “early” selection:– poor detection and memory for

unattended input channel(s)– tendency to report concurrent inputs

“by channel”

SELECTIVE ATTENTION AS A SENSORY FILTER(Broadbent, 1958)

input“channels”

sensoryanalysis

patternrecogn

“early” filter

left ear: 2 . .4 . .9right ear: 6 . .1 . .8

report:2,4 ,9 . .6, 1

•Evidence against “early” selection:–shadowing disrupted by S’s name–context can force switch to ignored ear–meaning of “ignored” words can affect behavior

EFFECTS OF AN “UNATTENDED” WORD

(MacKay, 1972)

“ . . the boy threw a rock at the bank and..”

“ . .scissor . . ladder . . money . . finger . .”

“Ignored” words not remembered, but still bias interpretation of sentence

• Evidence for “activation without awareness”

• Such “automatic” effects are small, and depend on special conditions

ATTENTION AS ALLOCATION OF LIMITED CAPACITY(Kahneman, 1972)

AROUSAL, ATTENTION AND PERFORMANCE

For many tasks, performance suffers if arousal is too low or too high (Yerkes & Dodson, 1903)

+

-Arousallow high

Per

form

ance

capacity too low

focus toonarrow

Easterbrook, ‘59: Cue Utilization Theory

task: decide if two successive letters are the same or different

+ R J ?presskey

200

300

400

500

600

RT

to

TO

NE

(m

se

c)

-1 -0.5 0 0.5 1 1.5 2 2.5

MEASURING ATTENTIONAL ALLOCATION

(Posner & Boies, 1971)

• decision and response selection as attentional “bottlenecks”

THE ATTENTIONAL DEMANDS OF SHADOWING

(Johnston & Heinz, 1978)

ShadowedList:

deskcouchchairsofaetc...

ignoredList:

NONE

voice classDIFF DIFF

SAME DIFF

DIFF SAME

or

RT toTONE

RT to tone alone: 320 msec

PRACTICE AND EXPERTISEStaszewski, 1988

task: mental multiplication

300 hours (!) of practice on simple (1 by 1) and complex (2 by 5) problems using left-to-right procedures

e.g. 267 x 97: “. . nine times two is eighteen hundred; nine time six is 540, that’s 2340 . .”

0

20

40

60

80

100

120

So

lutio

n t

ime

(se

c)

1x1 1x3 1x5 2x3 2x5Problem Size

first block

last bock

PRACTICE AND DIVIDED ATTENTION

• Practice in shadowing (Underwood, 1976)– Task: shadow prose in left ear– and detect occasional digits in right ear

• Oxford Undergrads: 13% hits• Neville Moray: 71% hits

• Practice in dictation (Spelke, Hirst & Neisser, 1976)– Task: read text for meaning, and

write down spoken words– after months of practice, no “cost” of

dictation on reading speed or comprehension

Is attention skill domain-specific?

ATTENTION AND CELL PHONESStrayer, Drew & Johnston, 2003

• About 150 million cell phones• 85% use them while driving• Inattention a leading cause of

crashes• So: simulated driving task (track

pace car), with/out hands-free chat

Drive Drive & ChatAccidents 0 3Brake onset 933 ms 1112 msFollowing distance 25.8 ft 29.3 ftBillboard recognition 6.9 3.9Billboard fixation 0.66 0.62

Date: 2003-03-27New Study Shows Drivers Using Cell Phones Twice As Likely To Cause Rear-end Collisions

CHAPEL HILL -- Drivers talking on cell phones are nearly twice as likely as other drivers involved in crashes to have rear-end collisions, according to a new University of North Carolina at Chapel Hill study. Crashes involving cell phone use, however, are less likely to result in fatalities or serious injuries than crashes not involving the devices.

LAPSES OF ATTENTION:THE “COGNITIVE FAILURES

QUESTIONNAIRE (CFQ)• How often do you . . .

– read something and realize you haven’t been thinking about it?

– forget why you went from one room to another?

– bump into people?– forget if you’ve locked the door?– forget to keep appointments?– drop things?– fail to hear people speaking when

you’re doing something else?

• Ratings correlate with performance in tasks of selective and divided attention (e.g., stroop interference; Tipper & Baylis, 1987)