MEMORY AND ATTENTION: THE EFFECT OF ATTENTIONAL CUEING MANIPULATIONS ON VISUAL AND AUDITORY WORKING MEMORY

by

NICOLE JESSICA BIES-HERNANDEZ

A Thesis submitted to the Graduate Faculty ofFayetteville State Universityin partial fulfillment of the

requirements for the Degree ofMaster of Arts in Psychology

DEPARTMENT OF PSYCHOLOGY

Fayetteville, North Carolina

May, 2008

APPROVED BY:

__________________________________Daniel Montoya, Ph.D.

Chair of Thesis Advisory Committee

__________________________________ __________________________________ Thomas Van Cantfort, Ph.D. Stephen Salek, Ph.D.

ABSTRACT

BIES-HERNANDEZ, NICOLE JESSICA. Memory and attention: The effect of

attentional cueing manipulations on visual and auditory working memory (Under the

direction of Daniel Montoya, Ph.D.).

Four experiments were conducted to compare the effect of exogenous-

endogenous attentional cueing manipulations on visual working memory versus auditory

working memory as measured through direct and indirect memory tests. Experiment 1

demonstrated that, on a direct test of visual memory, cued words were better remembered

than the uncued words, and recognition of cued words were more likely than ‘Yes’

responses to new words (false alarms). In Experiments 2 & 4, these attentional

manipulations had no significant effect on visual or auditory memory when measured

with an indirect memory test. Experiment 3 showed that, when using a direct test of

auditory memory, cueing produced a beneficial effect on memory—recognition of

studied words was more likely than false alarms. These results suggest that attentional

manipulations have a beneficial effect on subsequent visual and auditory working

memory when measured directly, but do not influence visual or auditory working

memory when measured indirectly.

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DEDICATION

I wish to dedicate this document to my beloved husband, Esidro Hernandez.

Without his love, understanding, and encouragement I would not have persevered in

accomplishing this ambition. I would also like to dedicate this document to my parents,

David and Susan Bies, and my brother, David M. Bies, who consistently support me.

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ACKNOWLEDGEMENT

I want to express my sincere gratitude and appreciation to everyone who

contributed to the study undertaken for this thesis. In particular, I would like to

acknowledge the assistance and encouragement of my advisor, Dr. Daniel Montoya, as

well as the significant support and scholarly advice provided by Drs. Thomas Van

Cantfort and Stephen Salek. In addition, I want to acknowledge Jacques Arrieux for his

significant assistance in recording and editing the auditory stimuli used in this study. I

would also like to thank Dr. Akbar Aghjanian and the Research Center for Health

Disparities for their support and resources provided in the completion of this study.

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TABLE OF CONTENTS

List of Tables ……………………………………………………………... vii

List of Figures ……………………………………………………………... viii

List of Abbreviations ……………………………………………………………... ix

Chapter I Introduction ………………………………………………... 1

Attention …………………………………………………... 2

Working Memory …………………………………………..

5

Direct and Indirect Memory Tests ………………………… 8

Interaction between Memory and Attention ………………. 11

Chapter II Theoretical Framework ……………………………………. 13

Review of Literature ………………………………………. 13

Objective …………………………………………………... 16

Hypothesis ………………………………………………… 17

Chapter III Experiment 1 ………………………………………............. 18

Participants…………………………………………………. 19

Materials …………………………………………………… 19

Apparatus ………………………………………………….. 20

Procedure ………………………………………………….. 21

Results ……………………………………………………... 24

Discussion …………………………………………………. 25

Chapter IV Experiment 2 ………………………………………............. 27

Participants…………………………………………………. 27

v

Materials …………………………………………………… 28

Apparatus ………………………………………………….. 28

Procedure ………………………………………………….. 28

Results ……………………………………………………... 28

Discussion …………………………………………………. 29

Chapter V Experiment 3 ………………………………………............. 31

Participants…………………………………………………. 32

Materials …………………………………………………… 32

Apparatus ………………………………………………….. 33

Procedure ………………………………………………….. 34

Results ……………………………………………………... 36

Discussion …………………………………………………. 37

Chapter VI Experiment 4 ………………………………………............. 40

Participants…………………………………………………. 40

Materials …………………………………………………… 40

Apparatus ………………………………………………….. 41

Procedure ………………………………………………….. 41

Results ……………………………………………………... 41

Discussion …………………………………………………. 42

Chapter VII Comparing across Experiments …………………………… 44

Chapter VIII Conclusion ………………………………………………… 45

References ……………………………………………………………... 47

Appendix A ……………………………………………………………... 50

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vii

LIST OF TABLES

Table 1 Experiment 1:

Recognition Test Phase (Visual) …………………………. 25

Table 2 Experiment 2:

Word-stem Completion Test Phase (Visual) …………….. 29

Table 3 Experiment 3:

Recognition Test Phase (Auditory) ………………………. 37

Table 4 Experiment 4:

Word-stem Completion Test Phase (Auditory) ………….... 42

viii

LIST OF FIGURES

Figure 1 Model of working memory ……………………………...... 7

Figure 2 Sequence and timing of a visual acquisition trial ................ 23

ix

LIST OF ABBREVATIONS

LSD Least significant difference

MS Milliseconds

RT Reaction time

x

CHAPTER I

INTRODUCTION

Our sensory systems are continuously bombarded by various stimuli from our

environment, most of which is unimportant to us (Kellogg, 2007; Johnson & Proctor,

2004). Fortunately, due to the cognitive process of attention, only very few of the various

stimuli bombarding our sensory systems reach our conscious awareness. Attention refers

to a person’s unconscious and conscious ability to focus or direct our cognitive capacities

on what is important to us while ignoring the rest (Kellogg, 2007; Johnson & Proctor,

2004; Jensen, Kaiser, & Lachaux, 2007). Additionally, attention influences the choices a

person makes by playing a fundamental role in all aspects of perception, cognition and

action (Jensen, Kaiser, & Lachaux, 2007; Johnson & Proctor, 2004; Lyon & Krasnegor,

1996). It is particularly important to all aspects of human functioning because the human

sensory systems have a limited processing capacity (Johnson & Proctor, 2004; Jensen,

Kaiser, & Lachaux, 2007). Without attention, a person would not be able to accomplish

any desired task because he or she would be constantly distracted not only by all the

stimuli in the environment but also by what is going on in his or her head (e.g., thoughts;

memories; desires) (Kellogg, 2007; Johnson & Proctor, 2004). Additionally, attention is

essential to the acquisition and subsequent remembering of information, and is sometimes

even thought of as the beginning of memory.

The ability to recall information, such as someone’s birthday or a math equation

needed for a test, are something most people take for granted. Imagine going through life

being completely naïve, constantly experiencing everything for the first time. Formal

language would not exist, progressing through simple tasks would be a struggle, and

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meaningful connections with other people would not be possible. These are examples of

what life would be like without memory, which emphasizes how valuable memory is.

Memory is what allows us to recognize sounds, smells and objects; it connects the past to

the present, and is what gives a person identity (Johnson & Proctor, 2004; Barmeier,

1996; Radvansky, 2006). Moreover, memory is vital to a person’s cognitive functioning,

particularly the cognitive processes of perception, reasoning, problem solving, and

learning (Bjork & Bjork, 1996). However, memory is not the only cognitive capacity that

is essential to cognitive functioning; the conscious and unconscious abilities of memory

and attention, as well as their interaction, all play fundamental roles in cognitive

functioning. A person’s behavior, especially the capacity to learn, depends on one’s

ability to pay attention to and store important information. A person must be capable of

focusing on relevant cues from the environment as well as have the ability to retain and

retrieve information in order to learn, remember and think (Lyon & Krasnegor, 1996;

Johnson & Proctor, 2004; Radvansky, 2006). Additionally, it is arguable that a person

can remember more information or remember information longer if he or she consciously

attends to that information.

Attention

The construct of attention can be described in numerous ways, from the

concentration of mental activity to an agent that directs cognitive resources. While

attention is multi-faceted playing numerous roles, it is more generally explained through

two major models—capacity and filter models. These models describe attention through

the two central facets of cognitive functioning, capacity limitation and selectivity,

respectively (Matlin, 2005; Johnson & Proctor, 2004; Hunt & Ellis, 2004). Based on the

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notion that attention is a limited-capacity resource, capacity models define attention in

terms of the allocation of cognitive resources. According to these models, attention is a

limited pool of resources that must be allocated, in differing amounts, to the various tasks

we engage in at any given time (Hunt & Ellis, 2004; Kellogg, 2007; Johnson & Proctor,

2004). The capacity limitation of attention influences both how many tasks we can focus

on simultaneously and how well we accomplish these tasks (Hunt & Ellis, 2004). On the

other hand, filter models describe attention as a selective agent. Selectivity (or selective

attention) refers to the unconscious and conscious ability of attention to selectively attend

to only a few stimuli from our environment while ignoring other competing stimuli (Hunt

& Ellis, 2004; Johnson & Proctor, 2004; Jensen, Kaiser, & Lachaux, 2007). The selective

nature of attention has been shown to be important for both generating coherent behavior

and performing simple and complex tasks (Johnson & Proctor, 2004). The notion of

attention as a selective agent was implemented in this study, specifically participants

engaged in a selective attention task requiring them to focus on one stimulus while

ignoring another competing stimulus.

A vast amount of research that has been conducted related to selective attention.

Two prominent paradigms used to investigate visual and auditory selective attention are

the Stroop task and the dichotic listening task, respectively. The Stroop task is a classical

psychological test from 1935 that examines interference through a task that requires the

cognitive mechanism of visual selective attention (Stroop, 1935). This task involves the

name of a word (e.g., blue, green, red, yellow) to be printed in a color differing from the

color expressed by the word’s semantic meaning (e.g., the word “blue” being printed in

green ink). For this task, what is referred to as the Stroop effect occurs when one is more

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readily capable of reading the word than naming the color in which the word is displayed.

The Stroop effect shows the interference that occurs between the automatic process of

reading the word itself and our ability to selectively attend to the ink color of the word

(Stroop, 1935). This effect demonstrates that irrelevant stimulus information can affect a

person’s performance on a task (Stroop, 1935; Johnson & Proctor, 2004).

Analogous to the Stroop task is the dichotic listening task, which is a paradigm

commonly used to examine selective attention in the auditory system. The dichotic

listening task was created by researchers to enable them to obtain more control of the

presentation of stimuli when studying auditory attention (Johnson & Proctor, 2004). This

paradigm involves two separate sources of auditory information being presented at the

same time, one to each ear. This task has been used to study both divided and selective

attention. When this task is used to study selective attention, the participant is required to

selectively attend to only one of the messages while ignoring the other, and then typically

is asked to shadow (or repeat aloud) the content from the attended ear (Johnson &

Proctor, 2004; Wood & Cowan, 1995). Commonly, following this task, the participants

are asked what they remember about the content of the attended channel, unattended

channel or both. This paradigm has been used extensively, and generally, the findings

have indicated the limits on attention (Johnson & Proctor, 2004; Ellis & Hunt, 2004).

Since the development of these selective attention tasks, attention has remained a

major area of interest within the fields of psychology, neuroscience and education. Over

the years, researchers have used these two selective attention paradigms and other

techniques to study attention. A popular technique that has been employed is the

manipulation of attention through cues, specifically through two distinctive methods of

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cueing—exogenously and endogenously (Hauer & MacLeod, 2006; Johnson & Proctor,

2004). Exogenous attentional cueing involves cues that attract attention towards a

stimulus; this type of manipulation is thought to be externally controlled and

automatically processed (Johnson & Proctor, 2004; Hauer & MacLeod, 2006;

McCormick, 1997; Theeuwes, 1991). On the other hand, endogenous attentional cueing

directs attention towards the target location of a stimulus. With endogenous cueing

manipulations, attention must be voluntarily shifted towards the stimulus, thus these

manipulations are internally controlled and thought to involve conscious control (Hauer

& MacLeod, 2006; McCormick, 1997; Johnson & Proctor, 2004). These exogenous-

endogenous attentional cueing manipulations have been used to examine the mechanism

of attention as well as the relationship between attention and cognitive processing.

However, this technique of orienting attention has only been employed to study the

relationship between visual attention and other cognitive processes, particularly memory.

In this study, exogenous-endogenous attentional cueing manipulations were used to

investigate the potential benefit on visual and auditory memory of directing and attracting

a person’s attention.

Working Memory

Receiving, storing, organizing, altering, and retrieving information is

accomplished through the cognitive process of memory. For over a century, researchers

have been trying to describe the construct of memory through various models and

theories. A common approach has been to divide memory into different parts or types of

memory. A popular general model of memory, proposed by Atkinson and Shiffrin

(1968), involves a distinction between two primary memory storage systems: short-term

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memory and long-term memory (Terry, 2006; Hunt & Ellis, 2004). The basic differences

between short-term and long-term memory lies in the amount of information each system

can store and the duration of memory retention. Short-term memory is a memory storage

system that holds a limited amount of information for a brief period, while long-term

memory is thought to be a memory storage system of virtually limitless capacity and

duration (Terry, 2006). Atkinson and Shiffrin’s model of memory has led to a vast

amount of research examining these two memory systems. The evidence from this

research has not supported the notion that short-term memory is purely a temporary

storage system (Hunt & Ellis, 2004; Terry, 2006). To emphasize that short-term memory

is not a passive storage system, the working memory model was proposed to enhance and

expand on the earlier concept of short-term memory (Terry, 2006; Johnson & Proctor,

2004; Hunt & Ellis, 2004).

Often viewed as an alternative to short-term memory, working memory is a

limited memory system that is responsible for the temporary storage, maintenance and

manipulation of information relevant to active or current undertakings, particularly

complex tasks and thoughts (Baddeley, 2000; King, 2007; Johnson & Proctor, 2004;

Morrison, 2005). The most widely accepted model of working memory is the model

developed by Baddeley & Hitch (1974; 2000). Baddeley & Hitch (1974) originally

proposed their model of working memory as a three-component model, but revised it in

2000 to a four-component model of working memory. The four components are the

visuo-spatial sketchpad, phonological loop, central executive and episodic buffer. Figure

1 illustrates Baddeley & Hitch’s (2000) revised model of working memory.

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Figure 1: Model of working memory Baddeley & Hitch’s current model of working memory (Baddeley, 2000).

The visuo-spatial sketchpad and phonological loop are modality-specific slave systems

that are responsible for the short-term storage, manipulation and rehearsal of information

(Baddeley, 2000; Morrison, 2005). The visuo-spatial sketchpad is responsible for visual

information, while the phonological loop responsible for is auditory information

(Baddeley, 2000; Johnson & Proctor, 2004; Morrison, 2005). These modality-specific

systems are managed and directed by the central executive (Baddeley, 2000; Johnson &

Proctor, 2004). Coordination of the visuo-spatial sketchpad and phonological loop is not

the only responsibility of the central executive; the central executive, more generally, is

thought of as an all-purpose attentional controller with the capacity for switching

attention between competing tasks or stimuli, to focus attention on relevant stimuli, and

to divide attention between tasks or stimuli (Baddeley, 2000; Baddeley, 2002). The fourth

component of this model, the episodic buffer, was added to Baddeley and Hitch’s original

model of working memory to account for some of the functions that had been implicitly

allocated to the central executive in the original model (Baddeley, 2000 Baddeley, 2002).

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Specifically, it was added to account for the integration of information from the modality-

specific systems and long-term memory in a manner that permits active maintenance and

manipulation (Baddeley, 2002). The episodic buffer is thought to be a limited capacity

system that temporarily stores information in a multimodal code. This multimodal code

allows for the binding of information from the visuo-spatial sketchpad, phonological loop

and long-term memory into a unitary episodic representation (Baddeley, 2000). The

central executive is presumed to control the episodic buffer, and have the ability to

retrieve information from the episodic buffer through conscious awareness, contemplate

that information and, if needed, manipulate and modify it (Baddeley, 2000). All of these

components just described work together to make up the active short-term memory

system of working memory proposed by Baddeley & Hitch (1974; 2000). As a whole,

working memory can be thought of as a mental “work bench” that allows for the

temporary storage, maintenance and manipulation of information relevant to active tasks,

particularly complex tasks involving learning, reasoning, language comprehension,

problem solving, and decision making (King, 2007; Baddeley, 2000; Morrison, 2005).

Direct and Indirect Memory Tests

Memory has been studied extensively in the past century by many different

researchers in numerous ways. Over the years, the study of memory has lead to the

classification of two main categories of memory tests: direct and indirect tests of

memory. The difference between direct (or explicit) and indirect (or implicit) memory

tests is in the way a person’s memory is assessed. The major distinction between these

categories of memory tests is that an explicit test of memory involves a procedure that

instructs participants to reference previously studied material, whereas implicit memory

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tests involve measuring knowledge indirectly without reference to previously studied

information (Terry, 2006; MacDonald & MacLeod, 1998; Johnson & Proctor, 2004).

Direct tests of memory require a person to intentionally retrieve information from

memory. There are two basic types of direct memory tests, which are tests of recall and

recognition. The difference between these two categories of explicit memory tests lies in

the way a person is required to remember studied information. Recall tests require a

person to retrieve (or recall) previously studied information (Terry, 2006; Hauer &

MacLeod, 2006; Johnson & Proctor, 2004). There are three types of recall tests: free

recall, serial recall, and cued recall. Free recall and serial recall tests are similar, but

differ in the order a person must recall the information; with free recall tests the person

merely is instructed to recall the studied information in any order, while with serial recall

tests the person is instructed to recall the studied information in the order it was presented

(Terry, 2006; Kellogg, 2007). Whereas, on cued recall tests people are given some type

of cue to help facilitate recall of studied information (Terry, 2006). In contrast, with

recognition memory tests a person must simply identify studied information (Terry, 2006;

Hauer & MacLeod, 2006; Johnson & Proctor, 2004). Typically, recognition tests present

a person with a list of items and ask the person to identify the previously studied items.

This type of direct test of memory is associated with a feeling of familiarity because

people may be able to recognize previous information but not be capable of reproducing

that information. In this study, when memory was assessed explicitly, a yes/no

recognition test was used. Specifically, the recognition test presented the participants

with both previously studied items and unstudied or distractor items to assess how

accurately and quickly they could identify previously studied information.

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In contrast to direct tests of memory, all types of indirect memory tests are

thought to reflect unintentional memory retrieval. The enhancement of performance on

implicit memory tests due to unintentional memory retrieval is reflected through priming

or when responding to a test item is facilitated by memory of previously presented

information (Hauer & MacLeod, 2006; Mulligan & Hartman, 1996; Hunt & Ellis, 2004;

MacDonald & MacLeod, 1998). There are also two general categories of indirect

memory tests, conceptual and perceptual, each encompassing a variety of different

implicit memory tests. The distinction between conceptual and perceptual implicit

memory tests stems from the type of information (conceptual or perceptual) that

influences priming. Conceptual implicit memory tests are driven by conceptual

information, particularly the meaning of the presented stimuli (Mulligan & Hartman,

1996; Hunt & Ellis, 2004). Specifically, these types of indirect tests are thought to

indicate the degree of conceptual processing taking place during the initial acquisition

and processing of information into memory (Mulligan, 2003; Mulligan & Hartman,

1996). Examples of conceptual implicit memory tests are general knowledge tests, free

association tests, and category-exemplar production tests. On the other hand, perceptual

implicit memory tests are data-driven or driven by stimuli information, such as perceptual

or surface-level features of the stimuli (Hunt & Ellis, 2004; Mulligan & Hartman, 1996).

In particular, this type of indirect memory tests are thought to be associated with the level

of perceptual processing occurring during the study or learning of information as well as

the resemblance in perceptual processing between study or acquisition and the test

(Mulligan & Hartman, 1996). Commonly used perceptual implicit memory tests, such as

the perceptual identification task, the speeded reading test, and word-stem completion

10

tests, are comprised of ambiguous perceptual cues (e.g., fragmented words or pictures)

(Mulligan & Hartman, 1996). In this study, when assessing memory implicitly, a word-

stem completion test was used. The word-stem completion test consisted of presenting

the participants with a series word stems and instructing them to complete the word stem

with the first thing that comes to mind. With word-stem completion tests, priming is

demonstrated when participants more accurately and quickly give correct completions to

a word stem when the solution was previously studied.

Research has shown that a person’s ability to remember past information may

depend on the way his or her memory is tested. Specifically, studies have found that

performance on direct memory tests can be independent of performance on indirect

memory tests. This has caused most researchers to conclude that there is a dissociation

between direct and indirect tests of memory. Depending on how memory is assessed,

prior information can affect memory differently. Recollection of previous information

may be evident when measured with a direct memory test but not an indirect memory

test, and vice versa (Hunt & Ellis, 2004; Terry, 2006).

Interaction between Memory and Attention

While attention and memory have often been treated as separate domains, a

complex relation exists between memory and attention (Hauer & MacLeod, 2006; Matlin,

2005). In fact, most of the research findings related to attention are either directly or

indirectly dependent on memory, often making it difficult for the researcher to determine

whether attention or memory is responsible for a particular effect (Johnson & Proctor,

2004). Attention can be thought of a gatekeeper for memory because of the role attention

plays in memory as a selective agent regulating information as well as restricting memory

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processes (Szymanski & MacLeod, 1996; Matlin, 2005; Johnson & Proctor, 2004;

MacDonald & MacLeod, 1998). Furthermore, the capacity of working memory is often

defined as the capability of a person to manage the allocation of attention (Johnson &

Proctor, 2004). However, the relation between memory and attention is not completely

straightforward.

Research has shown that when measuring subsequent memory, using both direct

and indirect tests of memory, attention during encoding is an essential component for

successful remembering (Hauer & MacLeod, 2006; Johnson & Proctor, 2004;

MacDonald & MacLeod, 1998). However, the role of attention in memory is

complicated with attention playing a different role depending on whether memory is

assessed directly or indirectly (MacDonald & MacLeod, 1998; Matlin, 2005). Some

researchers argue that attention can only be considered a crucial gatekeeper for memory

when discussing memory measured directly (Szymanski & MacLeod, 1996; Parkin, Reid

& Russo, 1990); others take this argument one-step further suggesting that performance

on an indirect memory test is independent of attention during encoding (Hayman &

Tulving, 1989; Roediger, 1990). Most of the research does not support this latter notion,

instead research has shown that attention is necessary for both explicit and implicit

remembering (MacDonald & MacLeod, 1998; Hauer & MacLeod, 2006; Parkin, Reid &

Russo, 1990). Nevertheless, attention does influence memory differently depending on

how it is tested; attention is much more crucial for explicit remembering than it is for

implicit remembering (MacDonald & MacLeod, 1998; Wood & Cowan, 1995; Hauer &

MacLeod, 2006; Parkin, Reid & Russo, 1990).

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CHAPTER II

THEORETICAL FRAMEWORK

Review of Literature

A vast amount of research has been conducted to examine the influence of

attentional manipulations at encoding on subsequent memory as measured through both

direct and indirect memory tests. The most common finding has been that attentional

manipulations have an effect on direct tests of memory, but have little or no effect on

indirect tests of memory (Eich, 1984; Parkin & Russo, 1990; Szymanski & MacLeod,

1996; Parkin, Reid & Russo, 1990; Hauer & MacLeod, 2006). Szymanski & MacLeod

(1996) demonstrated this notion with a modified Stroop task using non-color words (e.g.,

‘turtle’) printed in colors (red, green, blue, or yellow) (Szymanski & MacLeod, 1996). In

fashion with any Stroop task, participants were required to read aloud the non-color word

ignoring the printed color and vice versa depending on the trial block. Szymanski &

MacLeod (1996) tested memory using either a direct recognition test or an indirect

lexical decision test. Their results showed a different effect depending on how memory

was assessed—the attentional manipulations influenced the direct recognition test but did

not affect the indirect lexical decision test—leading to the conclusion that focused

attention at encoding is critical for memory when measured directly but not when

assessing memory indirectly (Szymanski & MacLeod, 1996).

To provide further support for the notion that there is a dissociation between

explicit memory tests and implicit memory tests, MacDonald & MacLeod (1998)

investigated the sensitivity of these tests to attentional manipulations during encoding.

Specifically, MacDonald & MacLeod (1998) reduced attention during study by

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instructing participants to read words presented in red while ignoring trials where words

were printed in white. In a similar manner to other studies, later memory was then

measured using both a direct recognition test and an indirect speeded reading test. As

expected, these experiments demonstrated that direct remembering depends on attention

at encoding while indirect remembering does not (MacDonald & MacLeod, 1998). This

study and other similar studies have provided support for the notion that attentional

manipulations affect direct tests of memory but to not influence performance when

measuring memory indirectly. However, recent research has indicated that the effect of

these attentional manipulations on subsequent memory may not be as straightforward as

previously described, and that attention at encoding is required for both direct and

indirect remembering (MacDonald & MacLeod, 1998; Wood & Cowan, 1995).

Not satisfied with the assumption that indirect remembering is completely

independent of attention at encoding, MacDonald & MacLeod (1996) conducted a third

experiment with a stronger attentional manipulation in order to examine whether

performance on indirect tests of memory could be impacted by reductions in attention at

study (MacDonald & MacLeod, 1996). They increased the reduction of attention during

encoding by presenting two words simultaneously—one word printed in red and the other

word printed in white, and required the participants to attend to one of the words while

ignoring the other (MacDonald & MacLeod, 1996). This type of attentional manipulation

now had an impact on both the direct recognition test and indirect speeded reading test.

There results demonstrated that mere exposure to stimuli is not adequate for indirect

remembering, but instead attention during encoding is necessary for both direct and

indirect remembering.

14

Through a series of selective listening experiments, Wood & Cowan (1995)

demonstrated a similar finding to MacDonald & MacLeod (1996) in the auditory system.

Wood & Cowan (1995) investigated the effect of attentional manipulations on auditory

memory using a dichotic listening paradigm, requiring participants to ignore information

heard in one ear while shadowing passages heard in the other ear (Wood & Cowan,

1995). To examine how well participants could recollect the information from the

unattended messages, Wood & Cowan (1995) embedded backward speech into the

passages of the unattended channel. When measuring memory with both direct and

indirect memory tests, they found that neither test revealed recollection for the content of

the unattended channel. These results provide further support that attention during

encoding is necessary for both direct and indirect tests of memory. The findings from

these or other similar studies has lead to the notion that the dissociation between explicit

and implicit memory tests occurs not because attentional manipulations affect one type of

remembering and not the other, but since explicit memory tests are more sensitive to

attentional manipulations than implicit memory tests (MacDonald & MacLeod, 1998;

Hauer & MacLeod, 2006).

Taking into consideration exogenous and endogenous attentional cueing

manipulations is a valuable step in the examination of the relation between attention and

memory (Hauer & MacLeod, 2006). Arguably, these manipulations are important to the

interplay between attention and memory because memory experiments commonly

involve studying information that must be attended, and the participant’s first contact

with the information to be studied and remembered is either by directing (endogenous) or

attracting (exogenous) attention (Hauer & MacLeod, 2006). Hauer & MacLeod (2006)

15

recently examined the potential benefit of exogenous-endogenous attentional cueing

manipulations on subsequent visual working memory through three experiments. During

the study phase, which was the same for all three experiments, a cue (either endogenous

or exogenous) preceded two simultaneously displayed four-letter words. The endogenous

cue used was a row of four arrows, which pointed either up or down towards one of the

trial words, and was presented at the center of the screen. The exogenous cue used was a

row of six asterisks, which appeared in the same location as one of the two words. The

trial cue indicated which word the participant was to read aloud. This was followed by a

test phase measuring memory for the cued and uncued words from the study phase. In the

study and test phases, reaction time and accuracy were measured. In their first

experiment, they measured the effect of these attentional manipulations through an

implicit memory test, specifically using a speeded reading (naming) test. They found that

the attentional cueing manipulations had no significant effect on later memory when

measured using an indirect memory test. In their second and third experiments, they

examined the effect of these attentional cueing manipulations using a direct test of

memory, a yes/no recognition test. These experiments demonstrated that attentional

cueing manipulations effect later memory when measured using an explicit memory test.

Specifically, they found that words from the endogenous condition were better

recognized on the recognition test then those from the exogenous condition. Overall,

Hauer & MacLeod (2006) showed that endogenous cueing manipulations have a

beneficial effect on memory when measured through a direct memory test but not when

measured with an indirect memory test; whereas, exogenous attentional cueing

16

manipulations did not influence later memory when measured with neither a direct nor

indirect memory test.

Objective

To date, the effects of exogenous-endogenous attentional cueing manipulations

have not been examined in the auditory memory system. The goal of this study was to

investigate the effect of these manipulations on subsequent auditory working memory.

The following key questions were addressed in this study: Will auditory attentional

cueing manipulations affect auditory memory when measured through a direct and/or

indirect memory test? Furthermore, will these attentional cueing manipulations have the

same effect on auditory memory as they do on visual memory when measured through

direct and indirect memory tests? Specifically, the aim of this study was to examine the

effect of early attentional cueing manipulations, using endogenous and exogenous cues,

on the visual and auditory working memory systems as measured through direct and

indirect tests of memory.

Hypothesis

It was hypothesized that auditory attentional manipulations at encoding, using

endogenous and exogenous cueing, would have a similar effect to the principal finding in

the visual memory system—attentional manipulations have a significant effect on direct

but not on indirect tests of memory (Hauer & MacLeod, 2006; Szymanski & MacLeod,

1996; Parkin & Russo, 1990; Eich, 1984; Parkin, Reid & Russo, 1990). Specifically,

endogenous attentional cueing manipulations were hypothesized to have a beneficial

effect on subsequent auditory memory as measured through a direct memory test, but not

17

when measured with an indirect memory test. In contrast, exogenous attentional

manipulations were not hypothesized to affect auditory memory as measured through

neither an explicit nor implicit memory test (Hauer & MacLeod, 2006).

18

CHAPTER III

EXPERIMENT 1

Experiment 1 investigated the influence of exogenous-endogenous attentional

cueing manipulations on later visual memory as measured through a direct memory test.

As described earlier, previous studies have shown that attentional manipulations can

affect subsequent memory as measured through a direct memory test. The aim of this

experiment was to reproduce the previous findings in order to obtain a basis of

comparison for Experiment 3, which investigated the effect of the attentional cueing

manipulations in the auditory memory system using a direct memory test. The procedure

for this experiment was based on the experiments by Hauer & MacLeod (2006) described

earlier. The acquisition phase consisted of participants being presented two words at the

same time, and the words being preceded by an exogenous or endogenous cue for either

the top or the bottom word. To ensure that the cue was processed, participants had to

identity whether the top or bottom word was cued using a response pad. In the test phase,

visual working memory was tested for both cued and uncued words from the acquisition

phase using a yes/no recognition test.

It was predicted that a measurable effect of these attentional cueing manipulations

would be observed through performance (accuracy and reaction time) on the direct

memory test. Specifically, it was predicted that endogenous cueing manipulations would

have a beneficial effect over exogenous cueing manipulations with words in the

endogenous condition being remembered better than those in the exogenous condition

are. However, it was not anticipated that an effect based on whether a word was cued or

uncued for either type of attentional cue would be found. On the other hand, reaction time

19

was predicted not to have a differential effect based on the type of cue, or based on

whether or not the studied word was cued. Instead, only a significant difference in

reaction time between studied words and new words was expected to be observed on the

recognition test.

Participants

Forty-four participants (33 females, 11 males) ranging in age from 19 to 44 years

old participated in this experiment. Participants were recruited from psychology courses

at Fayetteville State University, and they received course credit for their participation.

The data from 21 participants were deleted from analysis—nine participants (8 females, 1

male) because they made greater than 20% errors during the acquisition phase, and 12

participants (7 females, 5 males) due to technical problems (e.g., equipment failure;

misunderstanding the instructions)—leaving 23 participants (18 females, 5 males) in the

final sample used for analysis.

Materials

A pool of stimuli was created using the Brown Corpus, which is available at

http://www.edict.com.hk/lexiconindex/. The Brown Corpus is a word list comprised of

over a million words that reflect general non-academic English (i.e., words that are

commonly used in newspapers, magazines, and books). The stimuli pool consisted of 200

six-letter concrete nouns of medium frequency. The stimuli word pool was used to create

eight sub-lists for the acquisition phase as well as a new items list for the test phase. First,

64 words were randomly taken from the word pool to create a test list of new items; this

new words test list was used for all participants. The remaining 136 words of the stimuli

pool were used to create eight sub-lists of 64 words for the acquisition phase. For each

20

sub-list, these 64 words as well as one of the four cues (exogenous cue for the top word,

exogenous cue for the bottom word, endogenous cue for the top word, and endogenous

cue for the bottom word) were arbitrarily paired to create 32 acquisition phase trials. The

test phase consisted of 128 words, 64 old and 64 new words. The 32 acquisition pairs

were tested as the 64 old word items of the test phase—32 from the endogenously cued

trials (16 cued and 16 uncued words) and 32 from the exogenously cued trials (16 cued

and 16 uncued words). Words on the test phase were considered “old” whether they were

cued or uncued. In order to familiarize the participants with the cues and using the

response pad, 16 practice trials were also constructed; for these practice trials, the words

used were six-letter countries. These practice trials showed the participants the four

different types of attentional cues that could appear. Specifically, the practice trials

consisted of four trials for each of the four different attentional cues.

Apparatus

The experiment was written and presented using SuperLab 4.0.5 (Cedrus)

presentation software. Participants gave their responses to stimuli using a response pad

(Cedrus; Model RB-730). This study was carried out using a Zenith 27” television (model

# C27H26B); a laptop running the SuperLab software was connected to the TV with an

S-video cable in order for the experiment to be displayed through the TV. Stimuli

responses were recorded, with millisecond accuracy, using the SuperLab 4.0.5 software.

Accuracy, the proportion of correct responses, was measured. Response time, the interval

between the onset of the stimulus on the screen and the participant’s response through the

response pad, was also measured.

21

The display specifications used for this experiment were taken from the study

conducted by Hauer & MacLeod (2006). The background color of the screen was black

with the stimulus words presented in lower case white letters. The exogenous cue was a

series of six red asterisks presented at the location of one of the words (top or bottom) on

any given trial. The endogenous cue was a series of six arrows presented at the center of

the screen. The arrows either pointed up (in yellow) towards the top word, or pointed

down (in green) towards the bottom word; this color distinction was used to make it

easier for the participants to identify the cue. Six white dashes presented at the center of

the screen were used as an orienting stimulus. The stimulus words, cues and orienting

stimulus appeared in 72-point Times New Roman font.

Procedure

After the participants completed reading and signing the consent form, they

completed a short questionnaire (see Appendix A). The questionnaire consisted of

questions, among others, about basic demographic information (e.g., age; race; gender),

use of medications, alcohol use in the last 24 hours, and hours of sleep. The following

procedure was based on the procedure used by Hauer & MacLeod (2006). Accuracy and

response time were recorded during all of the trials of all phases of the study: the practice

phase, acquisition phase and test phase. The experiment began by presenting the four

cues (the exogenous cue for the top and bottom word, and the endogenous cue for the top

and bottom word) one at time for 1500 ms each to show the participant the attentional

cues. Following this presentation of the cues, the instructions for the acquisition phase

were shown. Next, the participant was asked to describe what he or she would have to do

during the acquisition phase; if the participant could not do this, the instructions were

22

repeated. Once the participant indicated that he or she understands the procedure, the 16

practice trials began. Before beginning the acquisition phase, the participants were

reminded that they are to pay attention to the cued word in each trial while ignoring the

uncued word, and that they must indicate which word was cued (the top or bottom word)

using the response pad at the end of each trial.

During the acquisition phase, the participants went through 32 trials (16

exogenously cued and 16 endogenously cued). Figure 2 is a diagram presenting the

sequencing and timing of an acquisition trial. Each trial consisted of two words, one

presented a single line above and one presented a single line below the centerline of the

screen. Before each trial appeared, the orienting stimulus, a row of six white dashes

(‘- - - - - -’), was presented for 250 ms at the center of the screen. For each trial, one of

the two words was cued either with an exogenous or endogenous cue; the type of cue was

randomized across the 32 trials. The presentation of either the exogenous or the

endogenous cue immediately followed the presentation of the orienting stimulus. The

exogenous cue of six red asterisks (‘******’) appeared for 100 ms at the same location as

one of the two words (either the top or bottom). The endogenous cue was a series of six

arrows (‘↑↑↑↑↑↑’ or ‘↓↓↓↓↓↓’), which was presented for 100 ms at the center of the

screen; the arrows either pointed up (in yellow) towards the top word or pointed down (in

green) towards the bottom word. The offset of the cue occurred simultaneously with the

onset of the pair of words for the trial. The words were presented for 100 ms and were

followed by the presentation of the orienting stimulus once again. The offset of the

orienting stimulus occurred simultaneously with the onset of a black screen where the

23

participants then needed to indicate which word was cued, the top or bottom word, using

the response pad.

Figure 2: Sequence and timing of a visual acquisition trial. In the endogenous condition, “animal” is the cued word and “dishes” is the uncued word; in the exogenous condition, “mirror” is the cued word and “powder” is the uncued word.

Immediately following the completion of the acquisition phase, the test phase

instructions were displayed on the screen. The instructions informed the participants that

they would now go through a series of screens where they would have to indicate, using

the yes or no button on the response pad, whether or not they saw the word during the

acquisition phase. The test phase consisted of a yes/no recognition test containing 128

trials/words. The words were presented one at a time at the center of screen in white 72-

24

point Times Roman font until the participant responded. The test phase contained 64 new

words and 64 old words (both the cued and uncued words from the 32 acquisition trials);

words were considered “old” regardless of the type of cue, and regardless of whether they

were cued or uncued.

Results

The dependent measures were accuracy (the proportion of correct responses) and

response time (RT), which were recorded during both the acquisition and test phases.

First, examining the data from the acquisition phase. The accuracy data showed that no

significant cueing effect occurred during study between the exogenously cued trials (M

= .97, SE = 0.009) and the endogenously cued trials (M = .986, SE = 0.008), t(22) = -

1.447. The RT data showed that there was no significant difference in the time to respond

to the exogenously cued trials (M = 628.75 ms, SE = 67.43) versus the endogenously

cued trials (M = 722.63 ms, SE = 94.36), t(22) = -.922. These results show that neither

response times nor errors varied during encoding as a function of the type of cue.

Next, looking at the crucial data from the test phase. The test phase had five

within-subject conditions: a 2 (Type: exogenous versus endogenous) x 2 (Cue: cued

versus uncued) factorial design for studied words plus the unstudied (or distractor) words

condition. A summary of the means and standard errors for these five test conditions is

presented in Table 1. All analyses reported in all experiments are repeated measures one-

way analyses of variance (ANOVAs). LSD comparisons were also conducted to examine

whether the four studied words conditions (exogenous cued, exogenous uncued,

endogenous cued, and endogenous uncued) differed from the unstudied words condition,

and to make comparisons corresponding to a standard 2 x 2 ANOVA.

25

Table 1Experiment 1—Recognition Test Phase (Visual): Means (and standard errors) for “Yes” responses and correct response time as function of cue type and whether a word was cued.

Exogenous _____Endogenous____ Unstudied Cued Uncued Cued Uncued

“Yes” .4969 .3545 .4918 .375 .3383(.049) (.044) (.035) (.037) (.029)

RT 1264.66 1394.5 1246.96 1399.27 1385.15(92.14) (102.79) (103.53) (117.48) (98.27)

Note: “Yes” responses are hits except for the unstudied condition, for which they are false alarms.

For the accuracy data from the test phase, the repeated measures one-way

ANOVA demonstrated an overall significant effect of condition, F(2.44, 53.69) = 6.875,

p < .05, though there was a relatively small effect size (eta-squared = .238). Mauchly’s

test indicated that the assumption of sphericity had been violated (χ2(9) = 24.686,

p< .05); therefore degrees of freedom were corrected using Greenhouse-Geisser estimates

of sphericity ( = .61). LSD comparisons were conducted and revealed significant

differences between the five conditions. The cued conditions, regardless of type of cue,

differed significantly compared to both the uncued conditions (regardless of Type) and

the unstudied words. No significant difference was found between the uncued conditions

and the unstudied words, nor was there a difference based on Type. In contrast, for the

RT data from the test phase, the repeated measures one-way ANOVA was not significant,

F(4, 84) = 1.366, p > .05.

Discussion

These results are consistent with previous findings showing that attentional cueing

manipulations have a reliable affect on memory when measured with a direct memory

26

test. A cueing effect was observed with cued words begin better remembered than uncued

words; this effect possibly occurred because attention was focused towards the cued

words. This effect conflicted with the hypothesis that an effect of cue type would be

observed, with words from the endogenous trials, whether or not the words were cued,

being better remembered than words from the exogenous trials. As discussed earlier, the

hypothesis for this experiment was based on previous findings from Hauer & MacLeod

(2006). While, this experiment was based on their study, it was not a replication, and thus

two slight changes were made to the procedure: the way participants gave their responses

to acquisition trials and the length of the word stimuli. The experiments conducted by

Hauer & MacLeod (2006) required participants to respond to stimuli during the

acquisition trials by reading aloud the cued word. In contrast, in this study, participants

had to identify which word was cued, the top or bottom word, using a response pad. It is

believed that this procedural difference could account for the findings of a cueing effect

but not an effect of cue type. Specifically, it is hypothesized that, in the studies by Hauer

& MacLeod (2006), requiring the participants to read the cued word aloud may have

actually interfered with processing during the exogenous trials. Since exogenous cues are

externally controlled, they are passively and more automatically processed (McCormick,

1997; Theeuwes, 1991). On the other hand, the process of reading the cued word aloud

demands active involvement from the participants. Therefore, the more active processing

required by this type of response may hinder the processing of the exogenously cued

trials. This hypothesis is something that would need to be investigated further.

27

CHAPTER IV

EXPERIMENT 2

The effect of exogenous-endogenous attentional cueing manipulations on

subsequent visual memory was investigated in Experiment 2 using an indirect memory

test. As was the case with Experiment 1, the aim of this experiment was to reproduce

similar findings to previous studies in order to have a basis for comparison to Experiment

4, which examined the effect of these manipulations in the auditory memory system using

an indirect test of memory. The procedure for Experiment 2 was the same as Experiment

1, except for a change in the test phase. In this experiment, memory was now tested with

an indirect memory test, specifically a word-stem completion test. The results of this

experiment were also anticipated to be similar to the results found by Hauer & MacLeod

(2006); early attentional cues were predicted not to have a reliably influence later visual

memory when measured with an indirect memory test. Specifically, it was predicted that

neither reaction times nor accuracy would differ as a function of type of cue (endogenous

versus exogenous) or whether a word was cued (cued versus uncued).

Participants

Thirty-eight participants (32 females, 6 males) ranging in age from 18 to 57 years

old participated in this experiment. Participants were recruited from psychology courses

at Fayetteville State University, and they received course credit for their participation.

The data from 18 participants were deleted from analysis—11 participants (10 females, 1

male) because they made greater than 20% errors during the acquisition phase, and 7

female participants due to technical problems (e.g., equipment failure)—leaving 20

participants (15 females, 5 males) in the final sample used for analysis.

28

Materials

The exact same materials as those used in Experiment 1 were used.

Apparatus

In addition to the apparatus described in Experiment 1, participants used a

standard computer keyboard to give their responses during the test phase. Consequently,

in this experiment, response time was measured as the interval between the onset of the

stimulus on the screen and the participant’s response through the response pad or

computer keyboard.

Procedure

The procedure was the same as described in Experiment 1 apart from a change in

the test phase. A word-stem completion test was substituted for the yes/no recognition

test. Participants went through a series of screens where they were presented with the first

3 letters of a six-letter word (e.g., ‘ani_ _ _’), and then had to complete the word by using

the keyboard to type in the last 3 letters needed to make it the first six-letter word they

could come up with.

Results

The data from the acquisition phase produced similar results to those found in

Experiment 1. A significant cueing effect was not found between the exogenously cued

trials (M = .972, SE = 0.016) and the endogenously cued trials (M = .994, SE = 0.004),

t(19) = -1.595 when examining the accuracy data from the acquisition phase. In a similar

manner, the reaction time data did not produce a significant difference between the time

to respond to exogenously cued trials (M = 746.29 ms, SE = 180.01) versus the

endogenously cued trials (M = 526.15 ms, SE = 77.24), t(19) = 1.24. As Experiment 1

29

did, the results demonstrate that no significant difference occurred for accuracy or

reaction time as a function of the type of cue during the acquisition phase.

Table 2Experiment 2—Word-stem Completion Test Phase (Visual): Means (and standard errors) for accuracy and correct response time as function of cue type and whether a word was cued.

Exogenous _____Endogenous____ Unstudied Cued Uncued Cued Uncued

Accuracy .4417 .4727 .4183 .4531 .4086(.033) (.032) (.026) (.032) (.012)

RT 3810.66 5077.86 4664.18 4871.19 4643.93(410.55) (552.46) (1110.79) (535.88) (420.88)

Now, examining the data from the test phase, where the memory test used was

now an indirect test of memory. The accuracy and RT means and stand errors for the five

test phase conditions are presented in Table 2. There was no significant main effect on

the repeated measures one-way ANVOA for neither accuracy, F(2.688, 51.069) = 1.128,

p > .05, nor reaction time, F(1.904, 36.181) = .688, p > .05. These results reveal that

when measured with an indirect memory test neither accuracy nor reaction times differed

as a function of type (exogenous versus exogenous) or cue (cued versus uncued).

Discussion

As expected, the results are consistent with previous studies showing that the

exogenous-endogenous attentional cueing manipulations do not reliably influence visual

memory when measured indirectly. These findings support the current notion that early

attentional manipulations seem to have little or no effect on indirect tests of memory.

However, previous findings, and those presented here, examined the influence of

30

attentional cueing manipulations on indirect memory tests using a perceptual implicit test.

This is important to note because in studies examining the relationship between implicit

memory tests and divided attention, conceptual implicit memory tests have been found to

be more sensitive to the effects of dividing attention than perceptual implicit memory

tests are (Mulligan, 2003; Mulligan & Hartman, 1996). Therefore, it may be worthwhile

to investigate further the relationship between attentional cueing manipulations and

memory using a conceptual implicit memory test (e.g., a general knowledge test).

31

CHAPTER V

EXPERIMENT 3

Examining the effect of exogenous-endogenous attentional cueing manipulations

on subsequent auditory memory as measured through a direct memory test was the

purpose of Experiment 3, and the primary focus of this study since these manipulations

have been shown to influence visual memory when measured directly and have not

previously be investigated in the auditory memory system. In addition, the intention of

this experiment was to show that the technique of manipulating attention using

exogenous and endogenous cueing during encoding can have a beneficial effect on

auditory working memory when measured directly. Consequently, the procedure of this

experiment was based on the procedure described for the visual experiments, but

participants were presented auditory stimuli through noise cancelling headphones. The

acquisition phase consisted of participants simultaneously hearing two words, one in ear

each, and either the word heard in the left or right ear was randomly cued on each trial.

For exogenously cued trials, the cue was simultaneously paired with the cued word. In

contrast, for endogenously cued trials, the word stimuli were preceded by the endogenous

cue in either the left or the right ear. To ensure that the cue was processed, participants

had to identity whether the word heard in the left or right ear was cued using a response

pad. In the test phase, auditory working memory was tested for both cued and uncued

words from the acquisition phase using an auditory yes/no recognition test.

Since there is currently no research examining the effect of exogenous-

endogenous attentional cueing manipulations on the auditory memory system it was

difficult to predict the specific relationship that the results would show for this

32

experiment. Given that working auditory memory has been found to be similar to visual

working memory (Visscher, Kaplan, Kahana & Sekuler, 2007), it was assumed that the

results of this experiment would be similar to those predicted for Experiment 1. It was

predicted that endogenous cueing manipulations would have a beneficial effect on

subsequent auditory memory with exogenous attentional cueing manipulations having

little or no effect on later auditory memory. Again, similar to Experiment 1, a significant

difference in reaction time was expected between old words and new words on the yes/no

recognition test.

Participants

Thirty-six participants (24 females and 12 males) ranging in age from 16 to 42

years old participated in this experiment. Participants were recruited from psychology

courses at Fayetteville State University, and they received course credit for their

participation. The data from 14 participants were deleted from analysis—nine

participants (6 females and 3 males) because they made greater than 20% errors during

the acquisition phase, and 5 participants (3 females and 2 males) due to technical

problems (e.g., equipment failure)—leaving 22 participants (15 females and 7 males) in

the final sample used for analysis.

Materials

The same stimuli word pool, practice trial words, new words test list, and eight

sub-lists as those described in Experiment 1 were used. The same practice, acquisition

and test phase trials that were arbitrarily created in Experiment 1 were also used;

however, the four attentional cues paired with each trial differed. The endogenous cue

was a beep, either to the left or right ear, prior to the two words of the trial. The

33

exogenous cue was an ocean wave sound used as background noise that was

simultaneously presented with the cued word. Similar to Experiments 1 & 2, there were

four attentional cues that were used: the exogenous cue for the left word, exogenous cue

for the right word, endogenous cue for the left word, and the endogenous cue for the right

word.

Apparatus

The 200 words from the stimuli list were recorded using a condenser microphone

(Applied Research & Technology MXL990 Professional Tub Microphone) and the Sonic

Foundry Sound Forge 8.0 recording software. The letters of the alphabet were also

recorded, which were used to create the stimuli word stems for the word-stem completion

memory test. All the files were checked for clipping (distortion) using studio monitors

that provided a flat response. The words from the stimuli list were then formatted with a

1 s pause at the beginning of the files to ensure the files would start at the same time

when they were mixed into trials. The audio files were mixed into trials using the

Steinberg Cubase LE software version 1.0.8 as a digital audio workstation. For each trial,

the words were mixed at a gain of 0 dB and the cues at a gain of -10 dB.

The experiment was written and presented using SuperLab 4.0.5 (Cedrus)

presentation software. All instructions for the experiment were displayed using a Zenith

27” television (model # C27H26B); a laptop running the SuperLab software was

connected to the TV with an S-video cable in order for the experiment to be displayed

through the TV. The display specifications for the instructions were white lettering in 72-

point Times New Roman font displayed on a screen with a black background; a black

screen was displayed throughout the remainder of the experiment. The trials from all

34

phases (practice, acquisition and test) were presented to the participants through

headphones (Bose QuietComfort 2 Acoustic Noise Cancelling Headphones). Participants

gave their responses to stimuli using a response pad (Cedrus; Model RB-730). Responses

were recorded, with millisecond accuracy, using the SuperLab 4.0.5 software. Accuracy,

the proportion of correct responses, was measured. Response time, the interval between

the presentation of the stimuli through the headphones and the participant’s response

through the response pad, was also measured. These dependent measures were recorded

during all of the trials during all phases of the study: the practice phase, acquisition phase

and test phase.

Procedure

After the participants completed reading and signing the consent form and the

short questionnaire discussed in Experiment 1. The experiment began by presenting the

four cues (the exogenous cue for the left and right word, and the endogenous cue for the

left and right word) one at time through the headphones in order for the participant to

hear the attentional cues that would be used. Following this presentation of the cues, the

instructions for the study phase were shown. Next, the participant was asked to describe

what he or she would have to do during the acquisition phase; if the participant could not

do this, the instructions were repeated. Once the participant indicated that he or she

understands the procedure, the 16 practice trials began. Before beginning the acquisition

phase, the participants were reminded that they are to pay attention to the cued word in

each trial while ignoring the uncued word, and that they must indicate which word was

cued (the left or right word) using the response pad at the end of each trial.

35

During the acquisition phase, the participants went through 32 trials (16

exogenously cued and 16 endogenously cued). Each trial consisted of two words, one

presented to the left ear and one presented to the right ear; both words were presented to

the respective ear at the same time. For each trial, one of the two words was cued with

either an exogenous or an endogenous cue; the type of cue was randomized across the 32

trials. The endogenous cue was a beep, either to the left or right ear, prior to the two

words of the trial. The exogenous cue was an ocean wave sound used as a background

noise that was simultaneously presented with the cued word. For the endogenously cued

trials, the onset of the pair of words for the trial occurred 1s after the offset of the cue.

With the exogenously cued trials, the cue and pair of words were presented

simultaneously. Regardless of whether the trial was endogenously or exogenously cued,

the trial ended with the participant’s response; the participants needed to indicate which

word was cued, the word heard in the left or right ear, using the left or right button on the

response pad.

Immediately following the completion of the acquisition phase, the test phase

instructions were displayed on the screen. The instructions informed the participants that

they would now go through a series of trials where they would have to indicate, using the

yes or no button on the response pad, whether or not they heard the word during the

acquisition phase. The test phase consisted of a yes/no recognition test containing 128

trials/words. The words were presented through the headphones one at time; the exact

audio files as those used in the acquisition phase were used during the test phase. The test

phase contained 64 new words and 64 old words (both the cued and uncued words from

36

the 32 acquisition trials); words were considered “old” regardless of the type of cue, and

regardless of whether they were cued or uncued.

Results

First, discussing the results from the acquisition phase. When analyzing the

accuracy data, no significant difference as observed between the exogenously cued trials

(M = .986, SE = 0.008) and the endogenously cued trials (M = .977, SE = 0.015), t(21)

= .485. Similarly, no significant effect occurred for reaction time between the

exogenously cued trials (M = 821.27 ms, SE = 58.27) versus the endogenously cued trials

(M = 778.26 ms, SE = 63.11), t(21) = .797. As was found in both visual experiments,

these results show that no significant cueing effect for accuracy or reaction time occurred

during the acquisition phase.

Turning to the critical test phase data, where auditory memory was assessed

directly. Table 3 presents the relevant accuracy and RT means and standard errors for the

five test phase conditions. As in Experiments 1 & 2, LSD comparisons were also

conducted. The repeated measures one-way ANOVA for the accuracy data demonstrated

an overall significant effect of condition, F(3.054, 64.137) = 22.153, p < .05, with a

medium effect size (eta-squared = .513). Mauchly’s test indicated that the assumption of

sphericity had been violated (χ2(9) = 18.103, p< .05); therefore degrees of freedom were

corrected using Greenhouse-Geisser estimates of sphericity ( = .764). LSD comparisons

revealed significant differences between the five conditions. ‘Yes’ responses to studied

words, regardless of cue type or whether the word was cued, were much more likely than

false alarms (‘Yes responses to unstudied words). Endogenously cued words were

37

reliably better recognized than both the endogenously uncued words and the exogenously

cued words. In contrast, for the words from the exogenously cued trials, the uncued

words were better remembered than the cued words. For the RT data, the repeated

measures one-way ANOVA was not significant, F(2.196, 46.125) = .668, p > .05.

Table 3Experiment 3—Recognition Test Phase (Auditory): Means (and standard errors) for “Yes” responses and correct response time as function of cue type and whether a word was cued.

Exogenous _____Endogenous____ Unstudied Cued Uncued Cued Uncued

“Yes” .4091 .554 .5938 .4744 .2536(.052) (.047) (.037) (.034) (.029)

RT 1048.94 978.32 941.16 946.98 950.38(88.53) (98.34) (124.45) (106.11) (74.96)

Note: “Yes” responses are hits except for the unstudied condition, for which they are false alarms.

Discussion

These results reveal that exogenous-endogenous attentional cueing manipulations

have a reliable effect on the accuracy of auditory working memory when assessed

directly. Furthermore, the findings are of particular importance because they offer the

first evidence of the relationship between these attentional manipulations and auditory

working memory. As anticipated, the results are consistent with the general finding in the

visual memory system of attentional manipulations influencing memory when assessed

using direct tests of memory. Thus, the findings demonstrate that the technique of

38

manipulating attention using exogenous and endogenous cueing during encoding can

have a beneficial effect on auditory working memory when measured directly.

Examining the specific findings from this experiment, an overall effect of the

cueing manipulations was observed; an advantage of exogenous and endogenous cues

was seen for both the cued and uncued words. These results conflicted with the

hypothesis that an effect of cue type would be observed, with words from the endogenous

trials, whether or not the words were cued, being better remembered than words from the

exogenous trials. However, the hypothesis was based on past findings in the visual

system thus the difference between visual and auditory processing may account for the

overall cueing effect that was observed. Auditory processing differs from visual

processing in numerous ways; the most important difference in relation to this study is

the difference in the spatial aspects of auditory versus visual processing. For visual

processing, each stimulus from the environment stimulates distinct, particular areas on

the retina; on the other hand, with auditory processing, processing occurs after auditory

stimuli from the environment have been combined (Johnson & Proctor, 2004).

The other specific finding that needs to be discussed is the difference in the

relationship between cued and uncued words that was observed in the endogenous

condition versus the exogenous condition. For the endogenous condition, cued words

were better remembered than uncued words, whereas the opposite effect occurred for the

exogenous condition with uncued words being better recognized than cued words. This

pattern is difficult to explain because participants mastered the acquisition phase for both

endogenously and exogenously cued trials with nearly perfect accuracy and without a

significant variation in reaction time. It is hypothesized that the pattern observed for the

39

exogenous condition occurred because of interference between the exogenous cue

(background sound) and the cued word. The background sound possibly muffled the cued

word causing the participant’s attention to be directed towards the clear uncued word.

This would need to be investigated further to confirm this assumption; one way this

hypothesis could be examined is by lowering the volume of the background sound. If

lowering the volume of the exogenous cue reversed the pattern observed, then it could be

concluded that the volume of the cue was muffling the cued word.

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CHAPTER VI

EXPERIMENT 4

Experiment 4 investigated the effect of exogenous-endogenous attentional cueing

manipulations on subsequent auditory memory as measured through an indirect memory

test. The procedure for Experiment 4 was the same as Experiment 3, except for a change

in the test phase. In this experiment, memory was now tested with an indirect memory

test, specifically a word-stem completion test. Following the assumption that was

presented in Experiment 3 that similar results will be found to those found in the visual

memory system, it was predicted that these attentional cueing manipulations would have

little or no effect on later auditory memory when measured indirectly. As was predicted

in Experiment 2, it was expected that neither reaction times nor accuracy would differ as

a function of type of cue (endogenous versus exogenous) or whether a word was cued

(cued versus uncued).

Participants

Twenty-six participants (22 females and 4 males) ranging in age from 16 to 35

years old participated in this experiment. Participants were recruited from psychology

courses at Fayetteville State University, and they received course credit for their

participation. The data from 7 participants were deleted from analysis—three participants

(2 females and 1 male) because they made greater than 20% errors during the acquisition

phase, and 4 female participants due to technical problems (e.g., equipment failure)—

leaving 19 participants (16 females and 3 males) in the final sample used for analysis.

Materials

The exact same materials as those used in Experiment 3 were used.

41

Apparatus

In addition to the apparatus described in Experiment 3, participants used a

standard computer keyboard to give their responses during the test phase.

Procedure

The procedure used was the same as that described in Experiment 3 apart from a

change in the test phase. A word-stem completion test was substituted for the yes/no

recognition test. The auditory word stems (the first 3 letters of the test word) were

presented to the participants through the headphones. The participants responded using

the keyboard to type in the last three letters needed to complete the six-letter test word.

Accuracy and reaction time were recorded during all trials of the test.

Results

The data from the acquisition phase produced similar results to those found in

Experiment 3. A significant cueing effect was not found between the exogenously cued

trials (M = .997, SE = 0.003) and the endogenously cued trials (M = .997, SE = 0.003),

t(18) = 0 when examining the accuracy from the acquisition phase. In a similar manner,

the reaction time data did not produce a significant difference between the time to

respond to exogenously cued trials ((M = 823.83 ms, SE = 71.43) versus the

endogenously cued trials ((M = 743.52 ms, SE = 84.6), t(18) = 2.032. As the previous

experiments showed, the results demonstrate that no significant difference occurred for

accuracy or reaction time as a function of the type of cue during the acquisition phase.

Now, examining the data from the test phase, where the memory test used was

now an indirect test of memory. The accuracy and RT means and standard errors for the

five test phase conditions are presented in Table 2. There was no significant main effect

42

on the repeated measures one-way ANVOA for neither accuracy, F(2.688, 51.069) =

1.128, p > .05, nor reaction time, F(1.904, 36.181) = .688, p > .05. These results reveal

that when measured with an indirect memory test neither accuracy nor reaction times

differed as a function of type (exogenous versus exogenous) or cue (cued versus uncued).

Next, examining the data from the test phase, where auditory memory was now

tested using an indirect test of memory. The accuracy and RT means and standard errors

for the five test phase conditions are presented in Table 4. For the test phase, there was no

significant main effect on the repeated measures one-way ANVOA for neither accuracy,

F(2.334, 42.008) = 1.559, p > .05, nor reaction time, F(2.471, 42.014) = .176, p > .05.

These results reveal that neither accuracy nor reaction times differed as a function of type

(exogenous versus exogenous) or cue (cued versus uncued) when measured with an

indirect memory test.

Table 4Experiment 4: Word-Stem Completion Test Phase (Auditory): Means (and standard errors) for accuracy and correct response time as function of cue type and whether a word was cued.

Exogenous _____Endogenous____ Unstudied Cued Uncued Cued Uncued

Accuracy .2993 .3289 .2495 .2914 .2796(.03) (.036) (.019) (.024) (.016)

RT 5355.26 5749.17 5262.24 5110.55 5003.53(915.27) (877.6) (1191.52) (1252.71) (626.56)

Discussion

As predicted, these results show that attentional cueing manipulations do not have

a reliable affect on auditory working memory when measured with an indirect test of

43

memory. This finding is consistent with studies that have examined the effect of

attentional manipulations on subsequent visual memory when measured indirectly—

attentional manipulations have little or no effect on indirect tests of memory. Therefore,

this finding provides further support for the notion described in Experiment 3 that the

technique of manipulating attention using exogenous and endogenous cueing can be

employed to assess the relationship between selective attention and auditory working

memory. However, as mentioned when discussing Experiment 2, it seems necessary to

investigate further the relationship between attentional cueing manipulations and

measuring memory indirectly, specifically by looking at the relationship between these

attentional manipulations and conceptual implicit memory tests.

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CHAPTER VII

COMPARING ACROSS EXPERIMENTS

Recognizing the hazards of such comparisons, statistical comparisons across

experiments were not conducted. Instead, the purpose of conducting these experiments

was to investigate if attentional cueing manipulations have an effect on auditory working

memory, and if so, is the effect similar to the effect observed on visual working memory

when measured through direct and indirect memory tests. The results of the experiments

conducted demonstrate that the effect of attentional cueing manipulations on auditory

working memory is similar to those observed when examining their effect on visual

working memory. Whether assessing visual or auditory working memory, the general

finding is consistent: exogenous and endogenous cueing manipulations have a beneficial

effect on memory when measured using a direct memory test, but have little or no effect

on memory when assessed with an indirect test of memory. The similarity reveals that the

technique of manipulating attention with endogenous and exogenous cues can be used in

examining the relationship between selective attention and auditory working memory.

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CHAPTER VIII

CONCLUSION

The results of the four experiments conducted in this study clearly demonstrate

that attentional cueing manipulations at encoding can have a measurable effect on visual

and auditory memory when assessed directly. Specifically, Experiments 1 & 3

demonstrated the benefit of directing and attracting a person’s attention on direct tests of

visual and auditory working memory. In contrast, Experiments 2 & 4 showed that

directing and attracting a person’s attention does not affect visual and auditory working

memory when measured indirectly. Experiments 3 & 4 are of particular importance and

were the focus of this study because this technique of orienting attention had not been

employed in the auditory system. It is obvious when looking at the history of attention

research that attention is usually studied in the visual system, and consequently we do not

know as much about auditory attention and its relation with other cognitive processes.

Furthermore, when orienting attention is discussed in the literature it is discussed in terms

of the visual orientation of attention. The findings from this study show that orienting

attention can also be described and studied in the auditory system. Moreover, the

findings, once further investigated to establish the relation between attentional cueing

manipulations and auditory working memory, could provide the foundation to examine

further the effect of attentional manipulations and working memory. For example, an

applicable investigation would be to examine the influence study-to-test modality

changes (i.e., auditory presentation at study and visual presentation at test, and vice

versa) have on the effect of early attentional manipulations on visual and auditory

working memory. Another potentially beneficial investigation would be to examine the

46

relation between attentional cueing manipulations and working memory with the

presentation of both visual and auditory stimuli simultaneously during acquisition. The

results of such investigations may be of particular importance because it is highly

unlikely for information processing and memory to be isolated to one sensory system in

natural settings (e.g., educational settings).

47

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APPENDIX A

Questionnaire

Name: _________________________________________________________________

Age: _____ Gender: Male or Female (circle one) Race: ____________

1. Are you currently taking any medication(s)? Yes or No (circle one)

If yes, which medication(s)? _______________________________________

2. Did you consume alcohol in the last 24 hours? Yes or No (circle one)

3. How many hours of sleep did you get last night? (circle one)

Less than 4 hours 5-6 hours 7-8 hours More than 8 hours

4. Do you suffer from any of the following?

Yes No

Impaired Vision

Impaired Hearing

Dizziness

Headache

51