Download do simultaneously presented visual and auditory

DO SIMULTANEOUSLY PRESENTED VISUAL AND AUDITORY
STIMULI ATTRACT OUR ATTENTION? THE EFFECT OF
DIVIDED ATTENTION ON MEMORY
by
Hisako Sakuraba
An Abstract
of a thesis submitted in partial fulfillment
of the requirements for the degree of
Master of Science
in the Department of Psychological Science
University of Central Missouri
February, 2012
ABSTRACT
by
Hisako Sakuraba
Attending to multiple stimuli is something that we do every day, but if the stimuli are presented
simultaneously, how is our attention directed and how much information can we comprehend?
We investigated how comprehension of information was affected when auditory and visual
stimuli were presented simultaneously and when attention was directed to one stimulus.
Participants were required to attend to either auditory or visual stimuli (Required Attention) with
either consistent or inconsistent information (Consistency), and the participants’ test scores were
measured. The comprehension of information was significantly lower when the information was
inconsistent, but there was no difference between auditory and visual required attention
conditions on test scores. Also, no significant interaction was found between Required Attention
and Consistency. The results suggest that when delivering inconsistent multiple stimuli,
attention is divided and information is less likely to be processed effectively. Possible practices
are proposed to improve comprehension and attention.
DO SIMULTANEOUSLY PRESENTED VISUAL AND AUDITORY
STIMULI ATTRACT OUR ATTENTION? THE EFFECT OF
DIVIDED ATTENTION ON MEMORY
by
Hisako Sakuraba
A Thesis
presented in partial fulfillment
of the requirements for the degree of
Master of Science
in the Department of Psychological Science
University of Central Missouri
February, 2012
C 2012
○
Hisako Sakuraba
ALL RIGHTS RESERVED
DO SIMULTANEOUSLY PRESENTED VISUAL AND AUDITORY
STIMULI ATTRACT OUR ATTENTION? THE EFFECT OF
DIVIDED ATTENTION ON MEMORY
by
Hisako Sakuraba
February, 2012
APPROVED:
Thesis Chair: Dr. David S. Kreiner
Thesis Committee Member: Dr. Jonathan W. Smith
Thesis Committee Member: Dr. Kimberly Stark-Wroblewski
ACCEPTED
Chair, Department of Psychological Science: Dr. David S. Kreiner
UNIVERSITY OF CENTRAL MISSOURI
WARRENSBURG, MISSOURI
ACKNOWLEDGMENTS
First of all, I am heartily thankful to my thesis committee members, Dr. David Kreiner, Dr. Jon
Smith, and Dr. Kim Stark-Wroblewski for their great help in every respect. I would like to offer
my sincerest gratitude and deepest appreciation to my thesis committee chair and also my
graduate adviser, Dr. David Kreiner, who has supported and encouraged me throughout my
thesis with his patience and knowledge while allowing me to complete my project at my own
pace. I also would like to thank Ms. Davie Davis and Mr. Tony Shaffer at Writing Center for
their assistance with my writing. Thanks to my friend, Charlene Atkins for good friendship with
me, and lastly, your unconditional support and understanding fill me with grateful thanks, my
husband, Toru. This thesis would not have been possible without the help and the guidance of
all those who supported me in the preparation and completion of this study. I truly appreciate
that I am able to reach this final stage of my graduate study with all of their help and support.
TABLE OF CONTENTS
Page
LIST OF TABLES...........................................................................................................................x
LIST OF FIGURES........................................................................................................................xi
CHAPTER 1: NATURE AND SCOPE OF THESTUDY...............................................................1
Background of the Study.....................................................................................................1
Overview of Method............................................................................................................1
Purpose of the Study............................................................................................................2
Rationale..............................................................................................................................3
Hypotheses...........................................................................................................................5
CHAPTER 2: REVIEW OF LITERATURE...................................................................................8
Overview..............................................................................................................................8
Structure and Function of Working Memory.......................................................................9
Memory Distortion and Capacity.......................................................................................13
The Attention System and Divided Attention....................................................................15
Conclusion.........................................................................................................................16
CHAPTER 3: METHODOLOGY.................................................................................................18
Participants.........................................................................................................................18
Materials............................................................................................................................18
Auditory Stimuli....................................................................................................18
Visual Stimuli........................................................................................................20
Questionnaire for Auditory and Visual Information..............................................21
Task Condition...................................................................................................................22
vii
Procedure...........................................................................................................................27
CHAPTER 4: RESULTS...............................................................................................................30
CHAPTER 5: DISCUSSION.........................................................................................................34
Discussion of Hypothesis...................................................................................................34
Discussion of Additional Results.......................................................................................42
Limitations and Weaknesses..............................................................................................43
Methodology and Data Collection.........................................................................44
Auditory and Visual Stimuli..................................................................................46
Future Directions...............................................................................................................48
REFERENCES..............................................................................................................................52
APPENDICES...............................................................................................................................56
A. Lectures........................................................................................................................56
Story A: Philosophy...............................................................................................56
Story B: Botany.....................................................................................................59
Story C: Psychology..............................................................................................62
Story D: Astronomy...............................................................................................65
B. PowerPoint slides.........................................................................................................67
Story A: Philosophy...............................................................................................67
Story B: Botany.....................................................................................................69
Story C: Psychology..............................................................................................71
Story D: Astronomy...............................................................................................74
C. Questionnaires..............................................................................................................76
Questions for Lecture A: Philosophy.....................................................................76
viii
Questions for Lecture B: Botany...........................................................................78
D. Demographic Survey....................................................................................................80
ix
LIST OF TABLES
Table
Page
1. Task Conditions.........................................................................................................................23
2. Mean Test Scores of Consistency and Required Attention Condition......................................30
x
LIST OF FIGURES
Figure
Page
1. Story B: Example of Botany PowerPoint slide..........................................................................21
2. Example of Auditory-Visual-Same; Auditory Attention Condition..........................................25
3. Example of Auditory-Visual-Different; Auditory Attention Condition....................................26
4. Mean Test Scores on Consistency with Required Attention Condition....................................31
xi
EFFECT OF DIVIDED ATTENTION ON MEMORY
1
CHAPTER 1
NATURE AND SCOPE OF
THE STUDY
Background of the Study
It is now common that news on TV is conveyed by presenting the most possible
information simultaneously in a complex format. An example is the anchor’s verbal news
presentation with visual insertions on the TV screen such as other news scrolling on the bottom
of the screen. Of course, the purpose is not to confuse the consumer; instead, there is a reason
for presenting information in such a way. However, if we focus on the scrolling news on the
bottom of the screen (visual) rather than the anchor’s presentation of the news (auditory), we
might miss what the anchor has presented, whereas focusing on the anchor’s presentation might
make us miss the scrolling news. When our attention is divided by more than one attractive
stimulus, our focus on any one object will be interrupted, and our memory of the information
may be reduced. Such situations might result in diminished and fragmented comprehension and
recall of the information. This assumption leads to the possibility that when auditory and visual
stimuli are presented simultaneously, our attention will be divided to focus on either one of those
stimuli. In order to utilize the retrieved information effectively, we need to avoid being
distracted by the stimulus that is not the focus of attention.
Overview of Method
To examine the effects of attention on memory, the degree of comprehension of material
from a PowerPoint-based recorded lecture was measured in the present study. Participants were
exposed to four different conditions based on the type of information presented and the focus of
EFFECT OF DIVIDED ATTENTION ON MEMORY
2
attention. In two conditions, participants were presented with auditory and visual stimuli that
conveyed the same information (consistent), but they were instructed to attend to either the
auditory or the visual stimulus. In the other two conditions, the auditory and visual stimuli
conveyed different information (inconsistent), and participants were instructed to attend either to
the auditory or the visual stimulus.
Purpose of the Study
The purpose of this study was to investigate how comprehension of information was
affected when auditory and visual stimuli were presented simultaneously and when attention was
directed to one stimulus. Our environment is full of auditory and visual stimuli, and
simultaneous presentations of auditory and visual stimuli are prevalent in many settings, such as
in education, business, and media. Although the context of the study is based on a recent TV
concept (i.e., auditory and visual stimuli presented at the same time), if we know that
presentation of both auditory and visual stimuli in a specific condition causes more interference
with attention, we could prevent inefficient memory recall caused by bimodal presentation of
stimuli, and we could attend effectively to appropriate stimuli.
As a method of conveying information, in general, both auditory visual stimuli were used
in many situations, such as educational or business settings. In those settings, the stimuli might
be presented in a lecture, presentation, or meeting using PowerPoint, overhead projector, poster,
or other techniques as tools to enhance and to share knowledge and skills. The current study
focused on the effects of divided attention in a situation involving simultaneous presentation of
PowerPoint slides and the instructor’s lecture. Investigating divided attention in such
environments might help us understand and improve learning in those situations.
EFFECT OF DIVIDED ATTENTION ON MEMORY
3
Rationale
How do the quality and quantity of recalled memory and comprehension differ when
auditory and visual stimuli convey the same or different types of information? Does auditory or
visual stimuli tend to attract more of our attention while, for example, watching TV, or attending
a meeting or class? Could it be possible to process both auditory and visual information when
those stimuli are presented at the same time? According to communication research done by
Drew and Grimes (1987), auditory information tends to command our attention when we are
watching TV news. However, Drew and Grimes (1987) pointed out that the direction of
attention can be altered by means of the complexity of visual and auditory stimuli. Also relevant
to the current study was research on memory processing capacity in the conditions of either
unimodal or bimodal stimuli. For example, Saults and Cowan (2007) report that memory
capacity was significantly lower in the bimodal conditions (i.e., auditory and visual stimuli were
presented) than in the unimodal conditions (i.e., either auditory or visual stimulus was presented).
With these considerations in mind, it would be difficult to comprehend both auditory and visual
information at the same time. Research on the nature of the relationship between attention to the
stimuli and comprehension and memory could be applied to our real lives in learning situations,
such as attending a meeting or class.
A previous study (Mowbray, 1953) found that we have more ability to comprehend
information when the same information is presented in two different modalities (i.e., visual and
auditory) simultaneously than when information was presented in either modality alone.
However, when different information is presented at the same time in different modalities, the
functioning of one modality would be diminished because simultaneous presentation of different
EFFECT OF DIVIDED ATTENTION ON MEMORY
4
stimuli incapacitates our ability to attend to both stimuli (i.e., attention is unitary; Mowbray,
1953). Interestingly, the deterioration of comprehension was greater with simultaneous
presentations of stimuli when the information had different levels of difficulty. In other words,
information with low difficulty tends to deteriorate more than difficult levels of stimuli in
simultaneous presentations of stimuli. In Mowbray’s (1953) study, alternation of attention
occurred as multiple stimuli were presented. When attention repeatedly changed from one
modality to the other, comprehension of information deteriorated. In addition, when the
individual finds it difficult to switch attention from one task to another, adequate performance of
memory (comprehension) would not be expected from both modalities (Mowbray, 1953).
According to Mowbray (1953), although we could not attend to simultaneously presented stimuli,
auditory stimuli tend to result in a greater disruption of comprehension than visual stimuli in
simultaneous presentation conditions.
Bergen, Grimes, and Potter (2005) also found that we were unable to attend to multiple
stimuli at the same time; the comprehension of information deteriorated when multiple stimuli
were presented at the same time. Although Mowbray (1953) and Bergen et al. (2005) both
indicate that there was deterioration of comprehension in the presence of multiple stimuli, their
conclusions about the two modalities were inconsistent with each other. Bergen et al. (2005)
found that attention was more likely to be directed to the auditory modality than to the visual
modality with simultaneously presented stimuli. Especially when complex stimuli were
presented in the visual modality, attention tended to shift to the auditory modality. Contrary to
their findings, Mowbray’s study (1953) indicates that attention tends to be directed more
to the visual stimuli than to the auditory stimuli when visual and auditory stimuli are presented
EFFECT OF DIVIDED ATTENTION ON MEMORY
5
simultaneously. These conflicting findings about whether attention is more likely to be directed
to the auditory or visual modality lead to the purpose of the present study. Even if we cannot
comprehend the information and store memories effectively when auditory and visual
information are presented simultaneously while watching TV, the consequences may not be
serious. However, if we are exposed to multiple stimuli (information) in different modalities
while attending important meetings, conferences, or classes, we might try to attend to both
auditory and visual stimuli in order to acquire necessary information. In order to help
individuals better comprehend the information effectively with simultaneous presentation of
stimuli, it would be valuable to understand what conditions could cause memory distortion.
Even though the majority of the previous research has involved the presentation of
stimuli such as numbers (for auditory) and short words, pictures, or visual array (for visual), not
much research has been conducted with passages and stories for both auditory and visual
presentation. The present study used materials that were more closely related to a realistic
setting; therefore, the research would be expected to generalize better than previous research to
education and business settings. With those considerations in mind, using lecture as auditory
stimuli and PowerPoint presentation as visual stimuli, relationships between attention and
memory (comprehension) were investigated in this study.
Hypotheses
Several hypotheses were tested in this research. The first hypothesis was that
comprehension would be lower when the auditory and visual stimuli were inconsistent (different
information presented at the same time) compared with consistent (same information) conditions,
because attention would be divided in the inconsistent conditions.
EFFECT OF DIVIDED ATTENTION ON MEMORY
6
Second, it was hypothesized that comprehension would be lower when people were
instructed to pay attention to auditory stimuli rather than visual stimuli due to the fact that visual
stimuli could interfere with attending to auditory stimuli because visual stimuli (information)
were subvocally rehearsed in our mind covertly. Therefore, visual stimuli would be more likely
to interrupt attention for auditory stimuli than auditory stimuli would interrupt attention for
visual stimuli when people were required to attend to inconsistent information conditions. This
notion is based on Baddeley’s previous research.
Baddeley (1995) claims that if a covert rehearsal process in the mind is not engaged,
memory (information) would decay. Although his statement does not suggest directly that visual
stimuli could interfere with paying attention to auditory stimuli, it could imply that if we rehearse
information in our minds covertly, the information would be retained. This means that
rehearsing visual information covertly makes us attend more to the visual stimuli because we
would concentrate on mentally reciting the visual stimuli. On the other hand, covert rehearsal
would not apply to the auditory stimuli because auditory information would be directly stored to
memory (i.e., working memory) without subvocal rehearsal (Baddeley, 1995). As such, it was
hypothesized that visual stimuli could distract people from processing auditory stimuli more than
auditory stimuli would distract them from processing visual stimuli.
However, there was a possibility of having an opposite scenario occur in the results of
this study. It was possible being instructed to pay attention to visual stimuli would result in
lower comprehension of visual information than being instructed to pay attention to
auditory stimuli because auditory stimuli could draw our attention more than visual stimuli.
Therefore, auditory stimuli might interrupt visual attention more so than visual stimuli interrupts
EFFECT OF DIVIDED ATTENTION ON MEMORY
auditory attention in inconsistent information conditions. The results of the present study may
provide information about which of these two scenarios was more likely to happen.
The interaction between Consistency (same vs. different) and Required Attention
(auditory vs. visual) on comprehension scores was analyzed to test the third hypothesis, that the
effect of Consistency (same vs. different) on the comprehension scores was greater when
participants were instructed to attend to visual stimuli than it would be when participants were
instructed to attend to auditory stimuli.
7
EFFECT OF DIVIDED ATTENTION ON MEMORY
8
CHAPTER 2
REVIEW OF LITERATURE
Overview
When we are watching news on TV, we may notice that the TV screen has a complex
format with a lot of information on it: the anchor’s news presentation (auditory stimuli) and
lexical insertions such as other news scrolling on the bottom of the screen (visual stimuli). If we
focus on the scrolling news (visually presented news) on the bottom of the screen rather than on
the anchor’s presentation of news, we might miss what the anchor presented, whereas focusing
on the anchor’s presentation might make us miss the scrolling news. In that divided attention
situation, our quality and quantity of recall of the information could be diminished. That is, it
might be hard to recall the scrolling news or the anchor’s news if we focus on either one or the
other.
The purpose of this study was to investigate the hypothesis that when auditory and visual
stimuli were presented simultaneously (bimodal condition), attention would be focused on either
one of those stimuli, and retrieval of information from memory would be diminished. As a result
of divided attention, memory might be fragmented or distorted. As such, the hypothesis was
based on the assumption that divided attention causes memory fragmentation and low quality
and quantity of memory compared with undivided attention (unimodal condition). Even though
simultaneous presentation of both visual and auditory stimuli might draw our attention, memory
for the information would be distorted, and comprehension of the information would be degraded,
and thus information would be remembered less. If those assumptions are reasonable notions for
divided attention, how large are the differences between bimodal conditions (divided attention to
EFFECT OF DIVIDED ATTENTION ON MEMORY
9
stimuli; i.e., auditory and visual stimuli) and unimodal conditions (single attention to stimuli; i.e.,
auditory or visual stimuli) with respect to the quality and quantity of recalled memory and
comprehension? Regarding auditory or visual stimuli, which tends to attract more of our
attention while, for example, watching TV, or attending a meeting or class? The following
literature review provided an overview of several topics related to the questions: the structure
and function of working memory, memory distortion and capacity, attention systems, and
divided attention.
Structure and Function of Working Memory
Working memory is derived from the concept of short-term memory, but these two
conceptual memory systems are distinct. Short-term memory is a hypothetical storage system of
information, while working memory is a hypothetical active temporary storage system of
information (Baddeley, 1986, 1995). Cowan (2005) describes that working memory refers to
“the retention of information in a temporarily accessible form, through all available mental
processing mechanisms” (p. 155), and the information stored in one’s mind could be
manipulated by working memory (Cowan, 2005).
According to Baddeley (1995), working memory’s temporary storage of information
could be activated for retrieving cognitive skills, such as “comprehension, learning, and
reasoning” (p. 755), and Cowan (2005) suggests calculations and problem-solving. For example,
when we understand someone’s speech, we have to comprehend the words’ meanings and
remember the words that are spoken until whole concepts are integrated together (Cowan, 2005).
Baddeley (1995) and Baddeley and Hitch (1974) assumed that short-term memory was
not a simple system and not just a single unit because it was unlikely to maintain and process the
EFFECT OF DIVIDED ATTENTION ON MEMORY
10
information in such a short time. They then proposed a model of working memory, which is
composed of three components commonly described in the memory literature as the central
executive, the phonological loop, and the visuospatial sketchpad. The central executive is a
center for those subsystems (e.g., the phonological loop and the visuospatial sketchpad), which
controls and manipulates processing in working memory and temporary storage; it has a limited
capacity which is connected to long-term memory. The visuospatial sketchpad is visually coded
and is also one component of short-term storage, which parallels the phonological loop, and
visual (e.g., color and shape) and visuospatial (e.g., location) information are stored. However,
the visual and visuospatial information interfere with each other in working memory. For
example, when visual information is processed, other spatial information could disturb
performance. These processing activities have been confirmed by studies examining some
regions of the brain (Baddeley, 1995). The phonological loop is coded acoustically for verbal
information.
Similar to Baddeley and Hitch’s (1974) findings of memory systems, Penny (1989)
proposed a separate processing modality model. Verbal information was processed separately
when it was presented to the auditory and visual modalities, and that separate route has “different
properties and capabilities” (p. 399). According to Penny (1989), auditory stimuli are coded to
an acoustic code and a phonological code without any attention. Also, visually presented stimuli
(other than coded to visuospatial) are coded to phonological code (transferred to the auditory
stimuli, the phonological code) but needed attention because of covert rehearsing of the visual
stimuli. Both auditory and visual stimuli are coded to the phonological code, but only stimuli
that people can hear could be coded to the acoustic. As a result, auditory presentation is recalled
EFFECT OF DIVIDED ATTENTION ON MEMORY
11
at a much higher rate than visual information in short-term memory because processing auditory
stimuli includes more extra work (i.e., acoustic and phonological coding) than processing visual
stimuli. Penny (1989) mentioned that using different modalities (i.e., visual and auditory)
improved performance if the information from each modality is processed separately, such as a
situation including auditory instructions with graphical diagrams (Mayer & Moreno, 1998;
Mayer, 2008). As such, it was assumed that the two subsystems, the visuospatial sketchpad and
the phonological loop, would convey different information independently, so working memory
could process information in two ways (Mousavi, Low, & Sweller, 1995).
Baddeley (1995) has mentioned that short-term storage, which is a hypothetical short-term
storage in working memory, was verbally (acoustically) based, while long-term storage tends to
be coded semantically. For instance, acoustically similar word sounds (i.e., “man, mat, cap,
map,” p. 756) are more likely to be difficult to process; however, words of dissimilar sounds (i.e.,
“pit, day, cow,” p. 756) and semantically similar words (i.e., “huge, big, large,” p. 756) are
processed easily (Baddeley, 1995). This finding suggests that an acoustic code is used in working
memory (not a semantic code) because acoustically similar words interfere with each other,
whereas semantically similar words do not interfere (semantically similar words are processed to
long-term memory).
Contrary to Cowan’s (1995, 2005, 2008) central capacity limited attentional system (i.e.,
short-term memory capacity limitations), Baddeley and Logie (1999), and Cocchini, Logie, Sala,
Mac Pherson, and Baddeley (2002) presented an alternative, multiple-component working
memory model. Cowan’s model indicated that memory system is composed of activated
components of focus of attention (part of short-term memory) in long-term memory. This part of
EFFECT OF DIVIDED ATTENTION ON MEMORY
12
short-term memory activates long-term memory in order to retrieve temporary information from
long-term memory. This activated information in the focus of attention is decreased quickly
unless it is rehearsed, thus attentional capacity in the focus of attention appears to be limited.
The focus of attention plays a central role for the memory system. On the other hand, Baddeley
and Logie (1999) and Cocchini et al. (2002) claimed that separated specific components, as
mentioned earlier, such as the visuospatial sketchpad and the phonological loop, as subsystems
of the central executive are working together to process working memory. Specific information
would be processed to the relevant storage (i.e., domain specific) in a subsystem, so this
indicates that storage resources play a key role.
Bergen, Grimes, and Potter (2005) claimed that visual working memory is more important
for processing in a dual task situation than is verbal memory. This notion is based on
observations of persons with a genetic disorder, Williams Syndrome, a condition in which the
individual has restricted visual working memory and cannot encode auditory spatially described
words such as above and inside into long-term memory (Bergen et al., 2005; Jarrold, Baddeley,
& Hewes, 1999). Because spatially described words appear to be related to the visual memory,
the visual working memory is important to help processing to go further. Thus, as Bergen et al.
(2005) mentioned, information was less likely to be processed in a parallel way. They also
suggested that when cognitive overload occurred because visual working memory was
encumbered by irrelevant and semantically unrelated information, visual and auditory long-term
memory would be diminished as well.
EFFECT OF DIVIDED ATTENTION ON MEMORY
13
Memory Distortion and Capacity
According to MacLeod and Saunders (2008), memory is updated continually. In addition,
older, useful memories are processed at the same time as we are retaining new information.
Sometimes memory distortions may occur because of misleading information about the event.
Lindsay and Johnson (1989), and MacLeod and Saunders (2008) mentioned that when sources of
information in memory are insufficient and vague, misleading information might come into play;
the newer information then overrides and erases older memories (Grimes, 1990; Loftus, Miller,
& Burns, 1978; Macleod & Saunders, 2008), which results in memory distortion. Suppose, in a
situation in which information is retrieved in a bimodal condition, memory processing would not
work optimally because the sources of information in memory are low. This notion is supported
by Saults and Cowan (2007), who found that memory capacity was significantly lower in
bimodal conditions (i.e., auditory and visual stimuli are presented) than in unimodal conditions
(i.e., auditory or visual stimuli).
Saults and Cowan (2007) also mentioned that memory capacity seemed to be limited
mainly by how much information could be simultaneously maintained in storage. Capacity
limitations are related to attention because information can be “simultaneously maintained by
conscious attention” (Saults & Cowan, 2007, p. 673). Moreover, Forlano (1988; as cited in
Armstrong & Chung, 2000) demonstrated that reading comprehension was easily distracted by
talk and speech. Armstrong and Chung (2000) showed in their research that background
television caused interference with processes of comprehension. Incomplete comprehension by
such distracters could result in capacity interference, causing less organized memory and a
weaker path of information into long-term memory.
EFFECT OF DIVIDED ATTENTION ON MEMORY
14
Cowan (1995) mentioned that the word-length effect in recall could be important
evidence of memory span in short-term storage. Participants had better recall of words for short
duration under specific conditions (i.e., when matching the number of syllables and phonemes)
than words for longer duration (Baddeley, Thomson, & Buchanan, 1975), for example, two
syllables and five phonemes for long duration words, “Coerce and Zygote” (Baddeley et al.,
1975, p. 580); two syllables and five phonemes for shorter duration words, “Wicket and Bishop”
(Baddeley et al., 1975, p. 580). According to Baddeley et al., (1975), this indicates that “the
articulatory loop” (p. 587) in short-term memory is “time-based” (p.587) and has a storage
capacity limitatation. The memory span people can hold at one time in memory is the same as
the number of words they can read within two seconds (Baddeley, et al., 1975). If a covert
rehearsal in the mind (the articulatory loop) is not engaged, the memory trace would be decayed
(Baddeley, 1995; Baddeley et al., 1975). Thus, if information capacity has a limitation, or
information is decayed without rehearsal, either or both auditory or/and visual stimuli
(information) could be diminished when engaging in dual tasks such as hearing the news and
watching a complex TV format simultaneously.
Also, Baddeley (1995) mentioned that there were individual differences in working
memory, and working memory could be a good predictor for better performance on standardized
tests of reading comprehension and intelligence (e.g., IQ). Additionally, Herlitz and Rehnman
(2008) found gender differences in memory. According to them, women tended to have an
episodic memory which required verbal processing, whereas men tended to have an episodic
memory which required visuospatial processing. This might suggest that men are more likely to
attend to stimuli that have visuospatial content such as TV news than are women.
EFFECT OF DIVIDED ATTENTION ON MEMORY
15
The Attention System and Divided Attention
According to Posner (1990), the attention system is composed of three processes: “1.
Orienting to sensory events; 2. Detecting signals for focal (conscious) processing; and 3.
Maintaining a vigilant or alert state” (p. 26). Each of those processes refers to “visual attention
system, relationship to networks that subserve semantic associations, and arousal systems in
relationship to the selective aspects of attention” (p.27), respectively. Those three components
play an important role in human attention. Attention level and function may differ among
healthy people and in people with disorders (Posner, 1990). Posner (1995) also suggested that
the capacity of attention at one time is limited. When we have to find two targets which occur at
the same time, we experience interference. Attention systems are greatly important in human
cognitive science (Posner, 1990). According to Posner (1990), the attention system is related to
sensory and motor systems, so specific brain regions and functions are engaged to facilitate
attention such as orienting, detecting, and alerting. Furthermore, higher levels of cognitive
disorder are likely to be related to deficits of attention. Thus, if the attention system in the brain
does not work properly, it might suggest that some regions of the brain could be impaired. As
such, it seems that because the attention system composes a hierarchical structure to be
processed, information might be less likely to be processed in a parallel way.
Keele (1972) investigated at what point information in the memory would be interfered
with (attention would be more drawn) in his study using simultaneous presentation of forms,
words, and colors. When memory was being retrieved (e.g., discriminating of the form and
color), multiple pieces of information could activate the memory at the same time without
interference, but the next process, the “selecting and operating” (p. 247) phase of memory (e.g.,
EFFECT OF DIVIDED ATTENTION ON MEMORY
16
discriminating of meaning), tended to cause delayed response, indicating interference of
information (Keele, 1972). Therefore, it is assumed that specific conditions (e.g., discriminating
sensory stimuli and meaning of stimuli) with multiple stimuli could result in poor memory
retrieval and memory distortion.
Conclusion
Numerous studies have been conducted about attention and memory, and there are
conflicting ideas about short-term memory (working memory), such as the central capacity
limited attentional system (i.e., single processing) and multiple-component working memory (i.e.,
multiple, parallel processing). When visual and auditory stimuli are presented simultaneously
(bimodal condition), we could predict that attention would be divided to either one of those
stimuli, and comprehension of information would be diminished. As a result, divided attention
may cause memory fragmentation and low quality and quantity of memory compared with
undivided attention (unimodal conditions). However, it has been unclear whether bimodal
conditions always cause our attention to be divided, causing poor memory function compared
with unimodal conditions. Cocchini et al. (2002) showed that bimodal conditions did not always
affect memory recall under certain condition; Bergen et al. (2005) demonstrated that divided
attention could occur depending on the presented stimuli.
A bimodal condition might occur in other situations outside typical laboratory settings;
for example, an oral presentation with lexical insertion by using some tools such as PowerPoint
at a business, meeting, or educational setting could cause divided attention. It might be difficult
to comprehend the presenter’s speech when we focus more on lexical insertion or opposite
results could be expected. Recent memory research is still debatable, so an understanding of the
EFFECT OF DIVIDED ATTENTION ON MEMORY
association among modality, attention, memory, and factors such as age, race, and situations
could be indispensable. The present study investigated how people use their attention and
comprehend stimuli presented at the same time to explore how attention and memory
mechanisms may be practiced in real life.
17
EFFECT OF DIVIDED ATTENTION ON MEMORY
18
CHAPTER 3
METHODOLOGY
Participants
A total of 102 students from the University of Central Missouri participated in this study.
Participants were between 18 and 34 years old (55 women, 36 men; gender of other participants
was not reported), were all undergraduates with English as their first language, and had normal
or corrected to normal vision and hearing. Participants were recruited through the online
psychology research participation system (SONA) on which this study was posted. Participants
were able to obtain research participation credit for psychology classes for participating.
Materials
Materials were presented using PowerPoint on Windows Vista, with a 20-in. monitor and
a headset. PowerPoint was utilized for presenting visual stimuli on the computer screen, and the
headset was utilized for presenting auditory stimuli. All instructions for the study were
presented on PowerPoint as well.
Auditory stimuli.
Four short lectures were presented as auditory stimuli. These lectures were taken from the
TOEFL test (Test of English as a Foreign Language) preparation book created by ETS
(Educational Testing Service) as the “official guide to the test” (ETS, 2007, p. 2). The auditory
versions of the stories were provided on the CD-ROM which comes with the book. Technically,
the TOEFL test is used for measuring “the ability of the test taker to use and understand English
as it is spoken, written, and heard in college and university settings” (ETS, 2008, p.1). The
TOEFL test is composed of four sections, which include reading, listening, speaking, and writing.
EFFECT OF DIVIDED ATTENTION ON MEMORY
19
The two lectures were provided from the listening section. The listening section in the TOEFL
test has a variety of topic areas such as academics, life sciences, humanities and arts, and
physical sciences (Bejar, Douglas, Jamieson, Nissan, & Turner, 2000). Each lecture for this
study was approximately four to six minutes in length. Lecture A was about philosophy, Lecture
B was about botany, Lecture C was about psychology, and Lecture D was about astronomy (see
Appendix A). The number of words was 691 for Lecture A and 786 for Lecture B, and 733 and
538 for Lecture C and D, respectively. Auditory volume was set at a relevant level in advance,
speaking rate was approximately three to four words per second, and recorded voices in the CDROM were both female and male.
Materials from the TOEFL test are valid because it is said that the “TOEFL examination
is representative of the knowledge and skills required to demonstrate English proficiency in
undergraduate and graduate programs in the United States and Canada” (Rosenfeld, Oltman, &
Sheppard, 2004, p. 2). In fact, the TOEFL test is “recognized by more than 8,000 destinations in
more than 130 countries” (ETS, 2012, TOEFL Test section, para. 2). The procedure for
evaluating the validity of items, administered by ETS test specialists and other external experts,
is “designed to evaluate and document the relationship between TOEFL test items and the
reading, writing, speaking, and listening tasks judged to be important for competent academic
performance at both the undergraduate and graduate levels” (Rosenfeld et al., 2004, p. 2). The
reliability coefficients for the listening part range from .48 to .91. Internal consistency is very
high at .98 (Rosenfeld et al., 2004). ETS (2008) mentions that “test tasks and content are likely
to be simulations, but not exact replications, of academic tasks,” and the test design focuses on
the “knowledge, abilities, and skills needed to succeed in academic situations as well as the tasks
EFFECT OF DIVIDED ATTENTION ON MEMORY
20
and materials typically encountered in colleges and universities” (p. 3). Thus, the validity of the
TOEFL test listening section is well established.
Visual stimuli.
A PowerPoint file was constructed in which the lectures were presented in black text with
a font size of 28-36 on a plain, light blue background screen. The lecture was presented in
sentences with bullets on the screen while auditory stimuli were also presented through the
headset at the same time. In two conditions, the visual information was the same lecture as the
auditory stimuli (information); in the other two conditions, the visual information was different
from the auditory stimuli (information). Visual and auditory stimuli were always presented at
the same time. The slide duration on the screen was set according to the duration of the auditory
stimulus. As for the timing of the movement from one slide to the next, when the auditory
stimulus (information) was reached at a specific point (i.e., meaning or story line is changed), the
next slide with the information of the sequenced lecture appeared automatically. The lecture
slides were made up of four or five slides. Visual and auditory stimuli (information) were
moving ahead together. After the lecture (PowerPoint slides) started, participants were not
allowed to stop or back up the lecture. Figure 1 shows an example of visual stimuli on the
PowerPoint slides (See Appendix B for PowerPoint slides).
EFFECT OF DIVIDED ATTENTION ON MEMORY
21
 “Manila hemp” –plant (cotton) fibers
-- useful fibers in the textile and chemical
industry
e.g. plastics, paper, explosives
-- a member of the banana family
(even bears little banana-shaped fruits)
--produced in the Philippine island
(Manila is the capital city of the
Philippines)
Figure 1. Story B – Example of Botany PowerPoint Slide
Questionnaire for auditory and visual information.
The questionnaires for each lecture taken from the TOEFL are shown in Appendix C.
Participants were provided seven multiple-choice questions for each lecture, in which each
question had four choices. Questions were employed to measure what auditory and visual
stimuli were remembered and comprehended and how well. The questionnaire was provided as
a paper and pencil quiz, and administered after one lecture was completed, and participants were
asked to answer each question with no time limitations. The next lecture was presented
following the completion of the questionnaire. The method for answering questions about the
second lecture was the same as for the first one.
EFFECT OF DIVIDED ATTENTION ON MEMORY
22
Task Conditions
The 102 participants were assigned to one of four conditions with 25 or 26 participants in
each condition, according to two independent variables. One independent variable was whether
the auditory and visual stimuli were the same or different (i.e., Consistency), and the other
independent variable was participant’s Required Attention (i.e., auditory or the visual stimuli).
Those four conditions were counterbalanced by Required Attention (i.e., auditory or visual
attention requirement condition) under the Consistency condition (i.e., auditory and visual
information are the same or different condition). The four conditions are as follows:
 auditory-visual-same information; auditory required attention
 auditory-visual-same information; visual required attention
 auditory-visual-different information; auditory required attention
 auditory-visual-different information; visual required attention
For the first condition, auditory and visual stimuli were the same information, and
participants were instructed to attend to auditory stimuli. For the second condition, auditory and
visual stimuli were the same information, but participants were instructed to attend to visual
stimuli. For the third condition, auditory and visual stimuli were different information, and
participants were instructed to attend to auditory stimuli. The last one was the same as the third
condition, but participants were instructed to attend to visual information. These task conditions
are shown in Table 1.
EFFECT OF DIVIDED ATTENTION ON MEMORY
23
Table 1
Task conditions
Conditions
Auditory – Visual
Auditory – Visual
(Consistency)
Same
Different
Groups
1
2
3
4
Required
Attention
Auditory
Visual
Auditory
Visual
Stimuli
Lecture
Auditory
Visual
Auditory
Visual
Auditory
Visual
Auditory
Visual
Story A
Story A
Story A
Story A
Story A
Story C
Story C
Story A
(Philosophy)
(Philosophy)
(Philosophy)
(Philosophy)
(Philosophy)
(Psychology)
(Psychology)
(Philosophy)
1
Quiz
Lecture
Story A
Story A
Story A
Story A
(Philosophy)
(Philosophy)
(Philosophy)
(Philosophy)
Story B
Story B
Story B
Story B
Story B
Story D
Story D
Story B
(Botany)
(Botany)
(Botany)
(Botany)
(Botany)
(Astronomy)
(Astronomy)
(Botany)
2
Quiz
Story B
Story B
Story B
Story B
(Botany)
(Botany)
(Botany)
(Botany)
Note. Shaded words indicate each group’s required attention (follow the shading words
vertically). For example, if a participant is in the “same” condition and group 1, his/her required
attention is “auditory.” Then, his/her Lecture 1, story A (philosophy) is presented followed by
quiz 1 with story A (philosophy). Next, Lecture 2, story B (botany) is presented followed by
quiz 2 with story B (botany). When required attention is auditory, visual stimuli are also
presented simultaneously, or vice versa.
EFFECT OF DIVIDED ATTENTION ON MEMORY
24
In the same information condition, participants in each group were given two pairs of the
same lecture as auditory or visual stimuli (philosophy-philosophy, or botany-botany); on the
other hand, each group in the different information condition was given two pairs of different
kinds of lectures (i.e., philosophy-psychology, botany-astronomy, psychology-philosophy, or
astronomy-botany) as auditory or visual stimuli. Examples of how the same and different
conditions were administered are shown in Figures 2 and 3.
EFFECT OF DIVIDED ATTENTION ON MEMORY
25
Auditory Stimulus (philosophy lecture)
OK. Another ancient Greek philosopher we need to discuss is Aristotle –
Aristotle’s ethical theory. What Aristotle’s ethical theory is all about is
this: he’s trying to show you how to be happy – what true happiness is….
Visual Stimulus (philosophy) Slide 1
 Aristotle’s ethical theory – how to be
happy, what true happiness is
 Extrinsic Value & Intrinsic Value
 Extrinsic Value – some things we aim for &
value, not for themselves but for what
they bring about in addition to
themselves (value something as a
means to something else)
 Intrinsic Value – other things we desire &
hold to be valuable for themselves
alone (value something not as a means
to something else, but for its own sake)
Figure 2. Example of auditory-visual-same; auditory attention condition. These two stimuli are
presented at the same time. In this condition, participants are required to attend to the auditory
stimulus.
EFFECT OF DIVIDED ATTENTION ON MEMORY
26
Auditory Stimulus (philosophy lecture)
OK. Another ancient Greek philosopher we need to discuss is Aristotle –
Aristotle’s ethical theory. What Aristotle’s ethical theory is all about is
this: he’s trying to show you how to be happy – what true happiness is….
Visual Stimulus (psychology) Slide 1
 John Watson – the founder of behaviorism
He believed…psychologists should study only
the behaviors they can observe and measure
(not interested in mental processes).
i.e., a person could describe his thoughts, but
no one else can observe them to verify the
accuracy of his report.
However, one thing you can observe….
 muscular habits
 Watson observed them as a manifestation of thinking
 One kind of habit that he studied
 laryngeal habits
Figure 3. Example of auditory-visual-different; auditory attention condition. These two stimuli
are presented at the same time. In this condition, participants are required to attend to the
auditory stimulus.
EFFECT OF DIVIDED ATTENTION ON MEMORY
27
Procedure
The study was conducted in a quiet, small computer room where the four computers were
set. Because all participants were seated in a partitioned area, they were neither disturbed by
other participants nor capable of seeing one another. The number of participants tested at one
time was no more than four. So as not to disturb other participants, delayed participants were not
allowed to attend a given session. Participants were given an informed consent form and were
able to withdraw without any penalty. After participants were seated in front of the computer
wearing headsets, instructions were presented with PowerPoint slides on the computer screen
according to the condition to which the participants had been randomly assigned. During the
experiment, participants were not allowed to take notes. Participants were also asked to focus on
their Required Attention (i.e., auditory or visual stimuli) as much as they could.
After the completion of the first part of auditory and visual stimuli (i.e., the first lecture),
participants responded to the questions for that lecture. The second set of auditory and visual
stimuli was presented followed by the second set of questions. After the second set of questions
was completed, the experiment was over. The brief instructions were as follows:
In the following experiment, you will be asked to watch two
PowerPoint lectures that include simultaneous presentation of
auditory and visual stimuli. Then, you will be asked to answer the
questions associated with the lectures.
You will see the
instructions before going on to each section. Please follow the
instructions carefully. Then, you will be assigned a task, so please
pay attention to the instructions. During the experiment, note-
EFFECT OF DIVIDED ATTENTION ON MEMORY
taking is not allowed. Please focus on and accomplish the task that
you will be given. After one lecture is completed, please answer
the multiple choice questions (paper and pencil) as best as you can.
No time limitation for answering the questions is set. Then, you
will be asked to move on to the next lecture. The procedure for the
second lecture and answering the multiple choice questions will be
the same as for the first one you completed. When you have
finished, please turn all the papers over to let the experimenter
know you have completed them all. Please remain seated and
follow the instructions on the Power Point slide. You will receive
further instructions from the experimenter afterward.
After participants were provided the above instructions, the task was presented on the
next slide:
Your Task:
Please attend to visual stimuli (PowerPoint
presentation on the screen) as much as possible while you are
listening. If you have any questions, please ask the experimenter
now. Otherwise, you may start now.
Then, the first lecture was started. When auditory tasks were assigned, the instruction
was changed to the following:
Your Task: Please attend to auditory stimuli from the headset as
much as possible while you are reading the PowerPoint lecture
(The PowerPoint lecture will appear on the screen as well).
28
EFFECT OF DIVIDED ATTENTION ON MEMORY
29
After participants completed all lectures and quizzes, they were instructed to complete
demographic questions about a general matter such as gender, age, year of study, and ethnicity,
and participants’ tiredness and familiarity with lecture (see Appendix D). Finally, they were
debriefed about the purpose of the study and dismissed.
EFFECT OF DIVIDED ATTENTION ON MEMORY
30
CHAPTER 4
RESULTS
The comprehension test score was calculated as the total number correct on both quizzes.
The data of 15 out of 102 participants were eliminated from the final analysis because the
demographic survey revealed that those participants had various kinds of learning disabilities and
other problems, such as head injuries, spinal cord injuries, injuries caused by drugs/medication,
or medical conditions in the past. The difference on number correct between participants who
had no learning disabilities or medical problems (M = 11.02, SE = 0.28) and who had problems
(M = 9.00, SE = 0.73) was significant, t(100) = 2.78, p = .01. A two-way analysis of variance
(ANOVA) with Consistency (same or different conditions) and Required Attention (visual or
auditory) was performed. The mean comprehension test scores for each condition are shown in
Table 2.
Table 2
Mean Test Scores of Consistency and Required Attention Condition
Required Attention
Consistency
Auditory
Visual
Total
M
SD
M
SD
M
SD
Consistent (same)
12.17
1.63
11.72
2.34
11.94
2.02
Inconsistent (different)
10.05
1.65
9.80
3.52
9.92
2.74
Total
11.23
1.94
10.87
3.04
11.05
2.56
EFFECT OF DIVIDED ATTENTION ON MEMORY
31
Also, Figure 4 shows the effect of Consistency and Required Attention and the
interaction between them on test scores.
Figure 4. Mean test scores on Consistency (same or different) with Required Attention
condition (auditory or visual). For consistent + auditory condition, N = 24; for consistent +
visual condition, N = 25; for inconsistent + auditory condition, N = 19; for inconsistent + visual
condition, N = 20. The error bar in each column represents standard errors.
First, there was a significant main effect of Consistency (same or different) on the
comprehension test score, F(1, 84) = 15.57, p = .001, indicating a medium effect,
suggesting that the comprehension of information was substantially affected by whether the
presentation of information was inconsistent (different) or consistent (same). The
comprehension score was lower in the inconsistent information conditions than in the consistent
EFFECT OF DIVIDED ATTENTION ON MEMORY
32
information conditions.
For the second main effect, Required Attention (auditory or visual), there was no
significant effect on the comprehension of information, F(1, 84) = 0.47, p = .50, . In
other words, the comprehension of information was not significantly affected depending on
whether the attention was directed to the auditory or visual stimuli.
Third, the interaction between Consistency (same vs. different) and Required Attention
(auditory vs. visual) was nonsignificant, F(1, 84) = 0.20, p = .85. The effect of Required
Attention (auditory vs. visual) on the comprehension test score was not different depending on
whether information was consistent or inconsistent. This suggests that information was
comprehended almost equally in both auditory and visual attention when information was
consistent and when the information was inconsistent. As shown in Figure 4, comprehension of
information tended to be lower in the inconsistent information conditions. Although the
comprehension scores in the auditory attention conditions appeared to be more affected than in
the visual attention conditions by the inconsistency of the information, the interaction was not
significant. Levene’s Test showed that homogeneity of variance was violated, indicating that
variances are significantly different. However, because the sample sizes for this study were
fairly similar in each condition, it was not a major concern for data analysis. Further, the results
showed the same pattern when the entire sample was included in the analysis, with equal cell
sizes; therefore, the results can be considered to be robust, and the violation of homogeneity of
variance appeared not to affect the analysis.
In addition, a three-way ANOVA was carried out including gender as an additional factor.
It revealed that there was no significant interaction between gender and Consistency,
EFFECT OF DIVIDED ATTENTION ON MEMORY
33
F(1, 71) = 0.53, p = .47, no significant interaction between gender and Required Attention,
F(1, 71) = 2.46, p = .12, and no significant three-way interaction, F(1, 71) = 1.24, p = .27. This
analysis suggested that gender differences did not interact with the other factors to affect test
performance.
Furthermore, the correlations between test scores and tiredness and familiarity with the
lecture of philosophy and botany were measured. There was not a significant correlation
between tiredness and test performance, r(84) = -.06, p = .61, indicating that there was no
significant relationship between comprehension of information and the degree to which
participants were tired. Likewise, neither familiarity with philosophy, r(85) = .04, p = .73, nor
botany, r(85) = -.05, p = .63 was significantly correlated with test performance. It follows that
whether or not participants were familiar with the information was not significantly related to
comprehension of information.
EFFECT OF DIVIDED ATTENTION ON MEMORY
34
CHAPTER 5
DISCUSSION
The purpose of this study was to investigate how comprehension of information is
affected when consistent or inconsistent auditory and visual stimuli are presented simultaneously
(i.e., Consistency) and when attention is directed to one stimulus (i.e., Required Attention;
auditory or visual condition). To investigate those questions, the effects of Consistency and
Required Attention and the interaction of both on the comprehension scores were tested in a
factorial design. Participants were instructed to attend to either auditory or visual stimuli which
were presented at the same time with consistent or inconsistent information. After experiencing
two lectures, participants were given two quizzes based on the information to which they had
been asked to attend (i.e., auditory or visual stimuli). The results did not fully support the
hypotheses about the effects of divided attention and Consistency.
Discussion of Hypotheses
The significant main effect of Consistency supported the hypothesis that comprehension
would be lower when concurrent auditory and visual information were inconsistent compared
with consistent information. Specifically, comprehension scores dramatically dropped when
concurrent presentation of auditory and visual information was inconsistent. This finding is
similar to that of Mowbray (1953), who found that comprehension of information was better
when the same information was presented in two different modalities. For instance, people
learned better when graphics (visual) with narration (auditory) were presented in two different
modalities at the same time rather than when graphics with text (also visual) were presented in
the same modalities at the same time (Mayer & Moreno, 1998; Mayer, 2008). Bergen et al.
EFFECT OF DIVIDED ATTENTION ON MEMORY
35
(2005) also claimed that we can attend to multiple stimuli when information is consistent.
Moreover, Grimes (1990) demonstrated that the contents of both auditory and visual information
were blended when the information was semantically related. Auditory and visual stimuli
included the same information in the consistent conditions in the present study. Thus, it is
assumed that even if people are attending to both auditory and visual stimuli under consistent
conditions, processing of information from both stimuli is less likely to be compromised because
both stimuli are semantically consistent with one another.
How do the theories of working memory explain why inconsistent information detracts
from the comprehension of information in the present study? The dual-processing theory of
working memory and domain specific working memory mechanisms may play important roles.
Cocchini et al. (2002) and Mayer and Moreno (1998) described the dual-processing theory,
claiming that auditory information is processed in auditory working memory, whereas visual
information is processed in visual working memory. When we are reading visually presented
material such as text, the words are conveyed in visual working memory first, and later the
material is processed in auditory working memory because it is changed into sounds (Mayer &
Moreno, 1998). Because visually presented stimuli such as text or words are silently rehearsed
(covert articulation) to process the information, visual stimuli are transferred to auditory working
memory, the phonological store (Baddeley, 1995; Baddeley & Logie, 1999). This suggests that
auditory and visual information are processed into subsystems in working memory such as the
visuospatial sketchpad for visual stimuli or the phonological store for auditory stimuli,
respectively (Cocchini et al., 2002; Baddeley, 1995; Baddeley & Logie, 1999). Cocchini et al.
(2002) also stated that the auditory and visual memory subsystems are domain specific.
EFFECT OF DIVIDED ATTENTION ON MEMORY
36
Cocchini et al. (2002) showed that when stimuli were presented in the same domain,
more interference occurred than when presented in different domains. For example, when
visually presented stimuli are processed in the visual working memory (the visuospatial
sketchpad), other visually presented stimuli are less likely to be processed as a result of using the
same domain. Information processing for working memory is domain specific and limited
capacity (Baddeley, 1995; Baddeley & Logie, 1999). Therefore, it seems that multiple sets of
information could not be handled in the same domain. In fact, Cocchini et al. (2002) found
supporting evidence in an experiment in which participants saw a visual pattern on the computer
screen and attempted to recall the pattern later. After the patterns disappeared from the screen,
participants tracked a moving object on the screen. After the tracking task was completed,
participants attempted to recall the pattern. After that, an auditorily presented digit sequence was
inserted instead of tracking, and participants attempted to recall the digits after the pattern was
recalled. The experiment revealed that visual pattern recall was impaired when the tracking task
was inserted, but not when the digit sequence was implemented. This result could be because the
visual pattern and the tracking required access to the same domain (visuospatial), but the visual
pattern and the digits were processed in different domains (visuospatial and phonological,
respectively).
In summary, it is assumed that after visually presented stimuli such as text are processed
into auditory working memory (based on dual-processing theory) because of covert rehearsal of
visual stimuli, the phonological store is activated (domain specific). However, because the
phonological store in working memory is thought to have limited capacity, attention processing
in the phonological store is limited, resulting in information conflict when inconsistent
EFFECT OF DIVIDED ATTENTION ON MEMORY
37
information is presented in the same domain. This is a possible reason that comprehension of
information is lower in the inconsistent information conditions when concurrent stimuli are
presented in different sensory modalities (auditory and visual). Mowbray (1953) also mentioned
that alternation of attention occurred when multiple stimuli were presented because attention is
unitary, so auditory and visual stimuli are not adequately processed simultaneously.
Other researchers, such as Baddeley (1999), Bergen et al. (2005), and Cocchini et al.
(2002), have claimed that attention shifting and divided attention would occur because of the
work of multiple components of working memory (e.g., the central executive and subsystems)
which are domain specific (Baddeley, 1999). Bergen et al. (2005) studied how participants
recognized the news facts of anchors’ stories under different conditions, such as the news anchor
broadcasting a news story (auditory stimuli) with a display containing multiple types of
information (visual stimuli: news crawls on the bottom of a screen and images with the news
anchor) or displaying simple information (i.e., no news crawls, and no other information on the
screen). Also, participants were able to attend to either auditory or visual stimuli by their own
decisions. The facts of news story were retained less when displaying multiple pieces of
information on the screen than when displaying simple information. These results were similar
to the significant effect of Consistency (consistent vs. inconsistent information) in the present
research.
The second result regarding the effect of Required Attention (auditory or visual) did not
support the hypothesis. Comprehension of information was not significantly affected depending
on whether the attention was directed to the auditory or visual stimuli. It was hypothesized that
comprehension would be lower when participants were required to pay attention to auditory
EFFECT OF DIVIDED ATTENTION ON MEMORY
38
stimuli rather than required to pay attention to visual stimuli. The primary assumption was that
visual stimuli could interfere with auditory stimuli because visual stimuli would require covert
subvocal rehearsing activity; as a result, participants might attend more to visual stimuli,
producing inefficient comprehension of auditory information. In addition, auditory memory is
directly stored in working memory without subvocal rehearsal, whereas visual memory (when
presented in the form of text or digits) decays if subvocal rehearsal is not engaged (Baddeley,
1995; Baddeley & Logie, 1999). Even if participants are required to attend to auditory stimuli,
because visual information is also concurrently conveyed, their attention could be substantially
engaged in subvocal rehearsal of visual information. Therefore, given such a premise, visual
stimuli might have interfered with auditory stimuli. Although previous research demonstrated
that attention tended to be directed to the visual stimuli more than to the auditory stimuli when
visual and auditory stimuli were presented simultaneously (Mowbray, 1953), the present findings
were not consistent with this conclusion. Also, Bergen et al. (2005) mentioned that visual
working memory is more important for processing in a dual task condition than verbal (auditory)
memory under certain conditions, suggesting that visual attention is processed prior to the verbal
attention; thus, it might be possible that comprehension of auditory information could be reduced
because visual information interferes with auditory information. However, the results in the
present study did not indicate a significant difference between auditory and visual attention
conditions.
There are several possibilities why the present results failed to show a significant
difference between auditory and visual attention conditions on comprehension of information.
First, Bergen et al. (2005) demonstrated how attention would be drawn to the complex or simple
EFFECT OF DIVIDED ATTENTION ON MEMORY
39
stimuli, and the comprehension of news was affected. In their study, before the presentation of
main auditory (a news anchor’s news story) and visual stimuli (complex or simple TV format as
described in Consistency condition section above), auditory (alpha-numeric strings such as
PG84R1 presented aloud) or visual stimuli (visual patterns) were presented to determine the
tendency of the direction of attention. In the visually complex condition conducted with visual
patterns, comprehension of the news story was lower than in the visually simple condition, but
visual pattern recall was higher than in the visually simple condition. This indicates that
attention is drawn more to the auditory stimuli when visual stimuli are complicated, and
participants try to spend more effort to focus on the recall of the visual pattern instead of
focusing on the visually presented complex stimuli. As a result, visual information capacity
could be more available because attention is not fully engaged in the visually complex stimuli.
On the other hand, visual attention was consistently preserved under the visually simple
condition, and recall of alpha-numeric strings presented aloud was better than recall in the
visually complex condition. Because, in the visually simple condition, participants could be
capable of attending to both auditory and visual stimuli, auditory presented alpha-numeric strings
would not fully occupy the auditory capacity. It is assumed that the auditorily alpha-numeric
strings could be rehearsed more efficiently in the visual simple condition. Bergen et al. (2005)
suggested that participants’ visual attention was overloaded because of complicated multiple
messages in the visual stimuli; consequently it appeared that the visual channel relied more on
the auditory channel to obtain the information because the auditory channel contained no
complex messages. As such, auditory information is likely to be processed when the visual
stimuli convey complex messages.
EFFECT OF DIVIDED ATTENTION ON MEMORY
40
Compared with their experiment, the present study’s visual stimuli did not carry any
visually complex information such as multiple messages with graphics. The visual stimuli were
displayed in a list of simple, straightforward pieces of information (sentences) with bullets (see
Figure 1). Thus, the visual attention would not shift to the auditory stimuli because the visual
stimuli did not carry complicated information in the present study. Therefore, the results were
consistent with the possibility that as long as the visual information is not complicated, the visual
attention can stay focused on the visual stimuli even if auditory stimuli are presented at the same
time.
A second possible explanation for the lack of difference between auditory and visual
conditions relates to Morey and Cowan’s (2005) suggestion that attention might be engaged
more in a maintenance period of working memory during which the processing of visual stimuli
could be interrupted more easily. In our study, visual information maintenance would occur
when participants were engaging in subvocal rehearsal of visual stimuli. However, in contrast
with Morey and Cowan’s (2005) idea, visual attention was not interrupted in the present study
regardless of processing maintenance period of visual stimuli. The assumption is that when
participants’ Required Attention was visual, they engaged in subvocal rehearsing to maintain the
information as Baddeley (1995) and Baddeley and Logie (1999) described. Because participants’
attention was more focused on visual stimuli rather than auditory stimuli, visual attention tended
not to be interrupted readily by the auditory stimuli; whereas when Required Attention was
auditory, participants did not constantly attend to the visual stimuli (i.e., rehearsing visual stimuli
covertly) because they were trying to focus on the auditory stimuli. Also, because participants
did not constantly rehearse the visual stimuli, that stimuli were not processed into the
EFFECT OF DIVIDED ATTENTION ON MEMORY
41
phonological storage, and the auditory stimuli were still intact; therefore, the auditory stimuli
were less likely to be interrupted by the visual stimuli in the present study. Thus, auditory and
visual stimuli did not interfere with one another because both stimuli were not sharing the
resources (i.e., the phonological loop or the visuospatial sketchpad; Cowan & Morey, 2005). It
may have been that the focus of attention on modalities canceled each other out. This might be a
reason for why the comprehension of information was not significantly affected depending on
whether the attention was directed to the auditory or visual stimuli.
Third, it is possible that participants did not follow the instructions, particularly when
they were asked to attend to the auditory stimuli in the present study. Those who were instructed
to attend to auditory stimuli might have simply closed their eyes or tried not to see the concurrent
visual stimuli, allowing them to focus on the auditory stimuli without distraction. Because
participants in the auditory stimuli conditions were only instructed to “please attend to auditory
stimuli from the headset as much as possible while you are reading the PowerPoint lecture,”
participants might have ignored the visual stimuli. This might be another reason for the lack of a
significant difference between the Required Attention conditions.
The results failed to support the hypothesis that the effect of Consistency (same vs.
different) on the comprehension scores would be greater when participants were instructed to
attend to auditory stimuli than when they were instructed to attend to visual stimuli (Required
Attention). Although the interaction was not significant, the comprehension scores in the
auditory attention conditions tended to be more affected than in the visual attention conditions by
the inconsistency of the information (see Figure 4). Previous studies suggested a possible
explanation for such an interaction. Mowbray (1953) claimed that auditory stimuli tended to be
EFFECT OF DIVIDED ATTENTION ON MEMORY
42
disturbed by visual stimuli when inconsistent information was presented simultaneously. In
contrast, some studies demonstrated that attention was more likely to be directed to the auditory
modality than to the visual modality with simultaneously presented stimuli (Bargen et al., 2005;
Penny, 1989), but the present study did not yield either result. As mentioned above, although
there was no interaction effect in the present study, participants’ comprehension scores for
requiring auditory attention tended to be more affected by inconsistent information. This
suggests that auditory attention could be interrupted by visual stimuli.
A reasonable explanation for this tendency could relate to subvocal rehearsing for visual
stimuli. Mayer and Moreno (1998) stated that our cognitive processing would be decreased when
our working memory was overloaded. Also, subvocally rehearsed information is likely to be
transferred into auditory working memory (the phonological loop), so that the already loaded
auditory working memory would be overloaded with newly transferred auditory stimuli. As a
result, an attention conflict is imposed, causing a deficiency of comprehension of targeted
information. Under the Required Attention conditions in our study, participants would attempt to
comply with the instructions, and because auditory and visual attention would cancel out each
other’s incoming inconsistent information, memory overload would not occur. This might be
another reason why there was not a clear interaction effect between Required Attention and
Consistency on the comprehension scores in the present study.
Discussion of Additional Results
Additional analyses in the present study examined gender differences, familiarity of
presented stories, and tiredness in relation to the comprehension scores. Although the results
showed that there were no gender differences and no relation of the familiarity with the
EFFECT OF DIVIDED ATTENTION ON MEMORY
43
presented stories or tiredness with the comprehension scores, previous studies have found
individual and gender differences in working memory (Baddeley, 1995; Herlitz & Rehnman,
2008). For example, episodic memory, which is related to verbal processing memory, tends to
be higher in women, and visuospatial memory, which is associated with spatial ability, tends to
be higher in men. It might be suggested that if the study had been implemented with visual
stimuli such as pictures, diagrams, and graphs that were related to spatial components in visual
memory, the results might have been different. In the present study, gender differences may not
have appeared because auditory and visual stimuli did not represent this specific property (i.e.,
visuospatial).
Also, familiarity with presented stories was not related to the comprehension scores.
This result did not support the idea that if participants were familiar with the presented stories,
they could guess the contents of the story. Mowbray (1953) investigated the degree of
familiarity with prose passages in his study, and very few people turned out to be familiar with
the passages; however, those who were familiar with the prose disclosed that the degree of
familiarity did not help to answer the questions.
It was expected that fatigue might be related to low test scores in the present study
because, if participants felt tired, it could affect their concentration on the stimuli. However,
fatigue was not significantly correlated with participants’ attention, suggesting that it did not
affect their test scores.
Limitations and weaknesses
There are several limitations of the present study. These limitations will be described in
two categories: methodology and data collection, and auditory and visual stimuli.
EFFECT OF DIVIDED ATTENTION ON MEMORY
44
Methodology and data collection.
The situations in the present study of presenting inconsistent information simultaneously
in auditory and visual modalities might not have been realistic. Originally, the idea of this study
came from a TV news format which conveys different kinds of messages or news at the same
time on the screen along with news anchors’ delivering the news. Such a complex format has
been used in media productions (Bergen et al., 2005). Even though the media have been using
this strategy, Bergen et al. (2005) suggested that comprehension of a news story is reduced under
such conditions. However, in other settings such as education or business communication, using
inconsistent information may be more rare when we need to present something to an audience;
rather the presenter tries to convey consistent and relevant information for the audience both to
see and hear. Although our study revealed that less comprehension of information was observed
when information was inconsistent, the situation was probably more extreme than would be
typical of education or business settings because auditory and visual stimuli were completely
different in inconsistent conditions (see Figure 3).
Also, it could have been helpful for intepreting the results to ask participants if they
complied when they were instructed to attend to the stimuli (i.e., auditory). The study was
conducted in a small room where the four computers were equipped and each of the desks was
partitioned. After the study begun, it was difficult for the researcher to observe exactly what
participants were doing because the researcher’s activity could disturb participants’ attention in
such a small room. So, in order to determine whether the Required Attention conditions were
successfully manipulated, manipulation check questions could have been added to the
demographic survey.
EFFECT OF DIVIDED ATTENTION ON MEMORY
45
Moreover, if participants were given no instructions to attend to either auditory or visual
stimuli, we might have observed the tendencies of how participants’ attention could rely more on
either auditory or visual stimuli. Although the present study’s visual stimuli were in only text
format rather than a more complicated format (i.e., with graphics and pictures), the results of
participants’ “free will” attention to either stimuli might have affected the comprehension of
information as Bergen et al. (2005) found in their study. Adding a free will condition would
allow us to study participants’ tendencies in reacting to the stimuli. Also, there would be no need
to be concerned with keeping participants from closing their eyes if a free will condition was
implemented because when Required Attention was auditory, there was a risk that participants
might close their eyes to accomplish their task. In a free will condition, test scores would be
measured with questionnaires which would be mixed with auditory and visual information
selected from lectures the participants would be given. If participants attended more to visual
stimuli than to auditory stimuli when their condition was free will, and also if their test scores
were higher on the questions related to visual stimuli than on the questions related to auditory
stimuli, it might indicate that similar tendencies of direction of attention could be seen as in the
Required Attention conditions. If participants have a visual attention tendency in such a
naturalistic condition, it could provide more valid information about the effect of the direction of
attention. In addition, gender differences could be observed in how attention would be directed
if the free will conditions were included.
Participants’ average age was 20.5 years, and most participants were freshmen and
sophomores. If the sample had included more older participants, the effects of Consistency and
Required Attention on test scores might have been larger. Younger people might be more able to
EFFECT OF DIVIDED ATTENTION ON MEMORY
46
perform multiple tasks at the same time than older people, but when degree of comprehension of
information was measured, Bergen et al. (2005) found that those who seemed to be multi-tasking
actually retained less information, indicating that their attention was not directed to every stimuli.
So, although the present study did not show differences between Required Attention conditions
on test scores, it would be interesting to examine how the results might vary with age.
Obtaining participants’ GPAs would have been useful. We might hypothesize that there
would be a correlation between participants’ degrees of attention and their GPAs because
students with higher GPAs might have more capacity for attention.
Familiarity with the lecture (i.e., philosophy, botany, psychology, and astronomy) was
asked because prior knowledge could have influenced the test scores. Even though the
familiarity with those stories was not correlated with their test scores, the format of the survey
question (see Appendix D) could have been made more clear with certain techniques, such as
using a scale of 1 to 5.
Auditory and visual stimuli.
In the present study, lectures were presented in a visual format using text on a computer
screen (see Figure 1), and spatial components such as pictures, diagrams, and graphs were not
included in the visual stimuli. If spatial components were used in the visual stimuli, the results
might have been different. As visual information gets more complicated, attention could shift to
auditory stimuli (causing visual overload), causing decreased comprehension of visual
information (Bergen et al., 2005; Mayer & Moreno, 1998). In addition, the visual stimuli in the
PowerPoint presentations were itemized with several bullets on the computer screen (see Figure
1). If the visual stimuli were presented as a whole lecture without being itemized, the effects of
EFFECT OF DIVIDED ATTENTION ON MEMORY
47
Required Attention and Consistency on comprehension score could be different. However, as
mentioned above, in real educational or business settings, we would not show the irrelevant,
inconsistent information to the audience. So, presenting a whole lecture without being itemized
could be an inefficient way to test the hypothesis.
Even though Cocchini et al. (2002) did not find the effect of dual-task interference as in
the present study, their study was conducted with different materials for the auditory and visual
stimuli. In fact, most previous research did not use a story (or lecture) as stimuli for both
auditory and visual information as in the present study. Most memory studies presented stimuli
acoustically with a short word, a letter, or a digit sequence, such as Map, A, or 27815,
respectively, as auditory stimuli (Baddeley, 1995; Baddeley & Logie, 1999; Cocchini et al.,
2002), whereas visual stimuli included visual patterns, visual tracking, graphs, pictures, or
animations (Bergen et al., 2005; Cocchini et al., 2002; Mayer & Moreno, 1998; Saults & Cowan,
2007). As such, the present study’s visual stimuli might be simpler (because of using only text)
than those used in previous studies. As mentioned earlier, when the visual stimuli were more
complex, visual attention was more likely to shift to auditory stimuli, resulting in less
comprehension of visual information. However, because our study’s visual stimuli were just a
simple text only format, participants’ attention may have not been drawn enough to the auditory
stimuli. If the present study had used more visually complex stimuli, the results might have
revealed that there could be a significant main effect of Required Attention and an effect of
interaction of Required Attention and Consistency on the test scores. That might account for the
possibility that some findings in the present study did not support the hypotheses.
EFFECT OF DIVIDED ATTENTION ON MEMORY
48
Future Directions
Our study did not show differences between auditory and visual required attention
conditions depending on whether the information was consistent or inconsistent, indicating that
attention could be directed to either auditory or visual stimuli; however, when auditory and
visual information were inconsistent, comprehension scores were significantly lower. The results
suggest that attention is not directed to one stimulus when different stimuli in the different
sensory modalities (i.e., auditory and visual) are presented at the same time. The debate of
whether auditory or visual stimuli tend to draw our attention more has not been resolved, but it
seems clear that attention is directed to either auditory or visual stimuli. If attention is divided, it
could be difficult to integrate the information, and that information would be less likely to be
processed in our memory, resulting in reduced comprehension of information. When auditory
and visual stimuli carry inconsistent information, attention is more likely to be divided, and
because multiple stimuli are not comprehended at the same time, information would not be
processed in working memory efficiently.
When we present information in situations such as educational settings or business
situations, we should consider how information could be effectively delivered. Some people
might only talk (only auditory stimuli) without any visual stimuli, or some might use both
auditory and visual materials. Previous research together with the results of the present study
suggest that the following practices would be helpful:
1. Consistent auditory and visual stimuli should be presented.
2. When only itemized sentences are presented in visual stimuli (without any images),
show one or two itemized sentences at a time along with corresponding auditory
EFFECT OF DIVIDED ATTENTION ON MEMORY
49
information (i.e., talk). When using visual materials such as pictures, graphs, and
animations, auditory information should correspond to the visual stimuli. However,
descriptive paragraphs (i.e., on-screen text) related to the visual images should be
avoided in the same frame of visual stimuli because they could cause working memory
overload. When multiple pieces of information are presented in the same domain (e.g.,
auditory), working memory is less likely to be processed efficiently because of
memory overload. Also, visually complex stimuli elicit semantic confusion; as a result,
such stimuli could cause attention to be divided between visual and auditory stimuli,
causing poor learning outcomes (Bergen et al., 2005). Mayer (2008), and Mayer and
Moreno (1998) demonstrated that participants learned better when auditory
information was delivered along with graphical visual stimuli at the same time;
however when graphical visual material had descriptive paragraphs (on-screen text) as
well as auditory information consistent with the visual stimuli at the same time,
participants learned less than those who were in the former condition.
3. Text and graphics should be presented in different modalities. When both text which
corresponds with graphics and the graphics are presented in the same modality
(i.e., in visual stimuli), visual working memory overload would occur because the
information would be processed visually first. That information should be presented in
different modalities, which could be processed separately. Presenting information in
different modalities is more likely to reduce visual working memory overload. So, it is
suggested that auditory information instead of text should be used to explain the
graphics or pictures.
EFFECT OF DIVIDED ATTENTION ON MEMORY
50
4. Try to avoid using multiple stimuli in the same domain (i.e., visuospatial or
phonological); the same kind of multiple stimuli in the same domain would result in
conflict and overload working memory, similar to the second point above. For
example, when text is presented as visual stimuli, the text is likely to be processed to
auditory working memory (the phonological loop). However, this might cause
information conflict or overload because visually presented stimuli (text) is being
processed to auditory information in the phonological domain, whereas concurrently
presented auditory stimuli are also activated in the same domain where the visual
stimuli (text) are activated. This could happen if such visually presented stimuli
were totally inconsistent with auditory stimuli.
5. Use visual stimuli such as graphics and pictures relevantly.
6. Make visual stimuli simple to reduce working memory load and attention shifting.
Also, how visual stimuli correspond to auditory information could be manipulated when
using presentation software such as PowerPoint. Two important issues would be timing of
advancing a slide and considering the amount of information to be put in one slide. It would also
be important to examine talking speed, articulation, and intervals between slides. When such
factors are integrated together, audience attention might be directed more effectively. A variety
of auditory and visual stimuli might attract people’s attention, but people may not be able to
obtain all the information from that attention. Even if people are capable of multi-tasking, it
could be difficult to comprehend all of the information.
For people who are attending to the stimuli, it could be helpful to realize how to attend to
the stimuli and how to organize the information based on that attention. By using effective
EFFECT OF DIVIDED ATTENTION ON MEMORY
51
strategies, learning skills could be improved. For presenters, it might be important to understand
attention mechanisms and memory storage systems because such understanding could lead to
more fruitful presentation of information. Continuing research on attention and memory could
help in identifying more efficient ways of employing the human attention and memory systems,
and the new findings could be applied practically in everyday life.
EFFECT OF DIVIDED ATTENTION ON MEMORY
52
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APPENDIX A
LECTURES
Story A – Philosophy
OK. Another ancient Greek philosopher we need to discuss is Aristotle—Aristotle’s
ethical theory. What Aristotle’s ethical theory is all about is this: he’s trying to show you how to
be happy—what true happiness is.
Now, why is he interested in human happiness? It’s not just because it’s something that
all people want or aim for. It’s more than that. But to get there we need to first make a very
important distinction. Let me introduce a couple of technical terms: extrinsic value and intrinsic
value.
To understand Aristotle’s interest in happiness, you need to understand this distinction.
Some things we aim for and value, not for themselves but for what they bring about in addition
to themselves. If I value something as a means to something else, then it has what we will call
“extrinsic value.” Other things we desire and hold to be valuable for themselves alone. If we
value something not as a means to something else, but for its own sake, let us say that it has
“intrinsic value.”
Exercise. There may be some people who value exercise for itself, but I don’t. I value
exercise because if I exercise, I tend to stay healthier than I would if I didn’t. So I desire to
engage in exercise and I value exercise extrinsically…not for its own sake, but as a means to
something beyond it. It brings me good health.
Health. Why do I value good health? Well, here it gets a little more complicated for me.
Um, health is important for me because I can’t…do other things I want to do—play music, teach
EFFECT OF DIVIDED ATTENTION ON MEMORY
57
philosophy—if I’m ill. So health is important to me—has value to me—as a means to a
productive life. But health is also important to me because I just kind of like to be healthy—it
feels good. It’s pleasant to be healthy, unpleasant not to be. So to some degree I value health
both for itself and as a means to something else: productivity. It’s got extrinsic and intrinsic
value for me.
Then there’s some things that are just valued for themselves. I’m a musician, not a
professional musician; I just play a musical instrument for fun. Why do I value playing music?
Well, like most amateur musicians, I only play because, well, I just enjoy it. It’s something
that’s an end in itself.
Now, something else I value is teaching. Why? Well, it brings in a modest income, but I
could make more money doing other things. I’d do it even if they didn’t pay me. I just enjoy
teaching. In that sense it’s an end to itself.
But teaching’s not something that has intrinsic value for all people—and that’s true
generally. Most things that are enjoyed in and of themselves vary from person to person. Some
people value teaching intrinsically, but others don’t.
So how does all this relate to human happiness? Well, Aristotle asks: is there something
that all human beings value…and value only intrinsically, for its own sake and only for its own
sake? If you could find such a thing, that would be the universal final good, or truly the ultimate
purpose or goal for all human beings. Aristotle thought the answer was yes. What is it?
Happiness. Everyone will agree, he argues, that happiness is the ultimate end to be valued for
itself and really only for itself. For what other purpose is there in being happy? What does it
yield? The attainment of happiness becomes the ultimate or highest good for Aristotle.
EFFECT OF DIVIDED ATTENTION ON MEMORY
58
The next question that Aristotle raises is: what is happiness? We all want it; we all desire it; we
all seek it. It’s the goal we have in life. But what is it? How do we find it? Here he notes, with
some frustration, people disagree.
But he does give us a couple of criteria, or features, to keep in mind as we look for what
true human happiness is. True human happiness should be, as he puts it, complete. Complete in
that it’s all we require. Well, true human happiness…if you had that, what else do you need?
Nothing.
And, second, true happiness should be something that I can obtain on my own. I
shouldn’t have to rely on other people for it. Many people value fame and seek fame. Fame for
them becomes the goal. But, according to Aristotle, this won’t work either, because fame
depends altogether too much on other people. I can’t get it on my own, without help from other
people.
In the end, Aristotle says that true happiness is the exercise of reason—a life of
intellectual contemplation…of thinking. So let’s see how he comes to that.
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59
Story B – Botany
Hi, everyone. Good to see you all today. Actually, I expected the population to be a lot
lower today. It typically runs between 50 and 60 percent on the day the research paper is due.
Um, I was hoping to have your exams back today, but, uh, the situation was that I went away for
the weekend, and I was supposed to get in yesterday at five, and I expected to fully complete all
the exams by midnight or so, which is the time that I usually go to bed, but my flight was
delayed, and I ended up not getting in until one o’clock in the morning. Anyway, I’ll do my best
to have them finished by the next time we meet.
OK. In the last class, we started talking about useful plant fibers. In particular, we talked
about cotton fibers, which we said were very useful, not only in the textile industry, but also in
the chemical industry, and in the production of many products, such as plastics, paper, explosives,
and so on. Today we’ll continue talking about useful fibers, and we’ll begin with a fiber that’s
commonly known as “Manila hemp.”
Now, for some strange reason, many people believe that Manila hemps is a hemp plant.
But Manila hemp is not really hemp. It’s actually a member of the banana family—it even bears
little banana-shaped fruits. The “Manila” part of the name makes sense, because Manila hemp is
produced chiefly in the Philippine Islands and, of course, the capital city of the Philippines is
Manila.
Now, as fibers go, Manila hemp fibers are very long. They can easily be several feet in
length and they’re also very strong, very flexible. They have one more characteristic that’s very
important, and that is that they are exceptionally resistant to salt water. And this combination of
characteristics—long, strong, flexible, resistant to salt water—makes Manila hemp a great
EFFECT OF DIVIDED ATTENTION ON MEMORY
60
material for ropes, especially for ropes that are gonna be used on ocean-going ships. In fact, by
the early 1940’s, even though steel cables were available, most ships in the United States Navy
were not moored with steel cables; they were moored with Manila hemp ropes.
Now, why was that? Well, the main reason was that steel cables degrade very, very
quickly in contact with salt water. If you’ve ever been to San Francisco, you know that the
Golden Gate Bridge is red. And it’s red because of the zinc paint that goes on those stainless
steel cables. That, if they start at one end of the bridge and they work to the other end, by the
time they finish, it’s already time to go back and start painting the beginning of the bridge again,
because the bridge was built with steel cables, and steel cables can’t take the salt air unless
they’re treated repeatedly with a zinc-based paint.
On the other hand, plant products like Manila hemp, you can drag through the ocean for
weeks on end. If you wanna tie your anchor to it and drop it right into the ocean, that’s no
problem, because plant fibers can stand up for months, even years, in direct contact with salt
water. OK. So how do you take plant fibers that individually you could break with your hands
and turn them into a rope that’s strong enough to moor a ship that weighs thousands of tons?
Well, what you do is you extract these long fibers from the Manila hemp plant, and then you take
several of these fibers, and you group them into a bundle, because by grouping the fibers you
greatly increase their breaking strength—that bundle of fibers is much stronger than any of the
individual fibers that compose it. And then you take that bundle of fibers and you twist it a little
bit, because by twisting it, you increase its breaking strength even more. And then you take
several of these little bundles, and you group and twist them into bigger bundles, which you then
EFFECT OF DIVIDED ATTENTION ON MEMORY
group and twist into even bigger bundles, and so on, until eventually, you end up with a very,
very strong rope.
61
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62
Story C – Psychology
Now, many people consider John Watson to be the founder of behaviorism. And like
other behaviorists, he believed that psychologists should study only the behaviors they can
observe and measure. They’re not interested in mental processes. While a person could describe
his thoughts, no one else can see or hear them to verify the accuracy of his report. But one thing
you can observe is muscular habits. What Watson did was to observe muscular habits because
he viewed them as a manifestation of thinking. One kind of habit that he studied are laryngeal
habits.
Watson thought laryngeal habits… you know, from larynx, in other words, related to the
voice box… he thought those habits were an expression of thinking, He argued that for very
young children, thinking is really talking out loud to oneself because they talk out loud even if
they’re not trying to communication with someone in particular. As the individual matures, that
overt talking to oneself becomes covert talking to oneself, but thinking still shows up as a
laryngeal habit. One of the bits of evidence that supports this is that when people are trying to
solve a problem, they um, typically have increased muscular activity in the throat region. That is,
if you put electrodes on the throat and measure muscle potential—muscle activity—you discover
that when people are thinking, like if they’re diligently trying to solve a problem, that there is
muscular activity in the throat region.
So, Watson made the argument that problem solving, or thinking, can be defined as a set
of behaviors—a set of responses—and in this case the response he observed was the throat
activity. That’s what he means when he calls it a laryngeal habit. Now, as I am thinking about
what I am going to be saying, my muscles in my throat are responding. So, thinking can be
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63
measured as muscle activity. Now, the motor theory…yes?
Professor Blake, um, did he happen to look at people who sign? I mean deaf people?
Uh, he did indeed, um, and to jump ahead, what one finds in deaf individuals who use sign
language when they’re given problems of various kinds, they have muscular changes in their
hands when they are trying to solve a problem…muscle changes in the hand, just like the
muscular changes going on in the throat region for speaking individuals.
So, for Watson, thinking is identical with the activity of muscles. A related concept of
thinking was developed by William James. It’s called ideomotor action.
Ideomotor action is an activity that occurs without our noticing it, without our being
aware of it. I’ll give you one simple example. If you think of locations, there tends to be eye
movement that occurs with your thinking about that location. In particular, from where we’re
sitting, imagine that you’re asked to think of our university library. Well, if you close your eyes
and think of the library, and if you’re sitting directly facing me, then according to this notion,
your eyeballs will move slightly to the left, to your left, ‘cause the library’s in that general
direction.
James and others said that this is an idea leading to a motor action, and that’s why it’s
called “ideomotor action”—an idea leads to motor activity. If you wish to impress your friends
and relatives, you can change this simple process into a magic trick. Ask people to do something
such as I’ve just described: think of something on their left; think of something on their right.
You get them to think about two things on either side with their eyes closed, and you watch their
eyes very carefully. And if you do that, you’ll discover that you can see rather clearly the eye
movement—that is, you can see the movement of the eyeballs. Now then you say, think of either
EFFECT OF DIVIDED ATTENTION ON MEMORY
64
one and I’ll tell which you’re thinking of.
OK. Well, Watson makes the assumption that muscular activity is equivalent to thinking.
But given everything we’ve been talking about here, one has to ask: are there alternatives to his
motor theory—this claim that muscular activities are equivalent to thinking? Is there anything
else that might account for this change in muscular activity, other than saying that it is thinking?
And the answer is clearly yes. Is there any way to answer the question definitively? I think the
answer is no.
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65
Story D – Astronomy
OK. Let’s get going. Today I’m going to talk about how the asteroid belt was
discovered. And..
I’m going to start by writing some numbers on the board. Here they are: We’ll start with zero,
then 3,..6..12. Uh, tell me what I’m doing.
Multiplying by 2?
Right. I’m doubling the numbers, so 2 times 12 is 24, and the next one I’m going to write after
24 would be…
48.
48. Then 96. We’ll stop there for now. Uh, now I’ll write another row of numbers under that.
Tell me what I’m doing. 4, 7, 10… How am I getting this second row?
Adding 4 to the numbers in the first row.
I’m adding 4 to each number in the first row to give you a second row. So the last two will be 52,
100, and now tell me what I’m doing.
Putting in a decimal?
Yes, I divided all those numbers by 10 by putting in a decimal point. Now I’m going to write the
names of the planets under the numbers. Mercury…Venus..Earth..Mars. So, what do the
numbers mean? Do you remember from the reading?
Is it the distance of the planets from the Sun?
Right. In astronomical units—not perfect, but tantalizingly close. The value for Mars is off
by… 6 or 7 percent or so. It’s…but it’s within 10 percent of the average distance to Mars from
the Sun. But I kind of have to skip the one after Mars for now. Then Jupiter’s right there at 5-
EFFECT OF DIVIDED ATTENTION ON MEMORY
66
point something, and then Saturn is about 10 astronomical units from the Sun. Um, well, this
pattern is known as Bode’s Law. Um, it isn’t really a scientific law, not in the sense of
predicting gravitation mathematically or something, but it’s attempting a pattern in the spacing of
the planets, and it was noticed by Bode hundreds of years ago. Well, you can imagine that there
was some interest in why the 2.8 spot in the pattern was skipped, and um…but there wasn’t
anything obvious there, in the early telescopes. Then what happened in the late 1700s? The
discovery of…?
Another planet?
The next planet out, Uranus—after Saturn. And look, Uranus fits in the next spot in the pattern
pretty nicely, um, not perfectly, but close. And so then people got really excited about the
validity of this thing and finding the missing object between Mars and Jupiter. And telescopes,
remember, were getting better. So people went to work on finding objects that would be at the
missing distance from the Sun, and then in 1801, the object Ceres was discovered. And Ceres
was in the right place—the missing spot. Uh, but it was way too faint to be a planet. It looked
like a little star. Uh, and because of its starlike appearance, un, it was called an “asteroid”.
OK? “Aster” is Greek for “star”, as in “astronomy.” Um, and so, Ceres was the first and is the
largest of what became many objects discovered at that same distance. Not just one thing, but all
the objects found at that distance form the asteroid belt. So the asteroid belt is the most famous
success of his Bode’s Law. That’s how the asteroid belt was discovered.
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67
APPENDIX B
POWERPOINT SLIDES
Story A – Philosophy
Slides 1

Aristotle’s ethical theory – how to be happy, what true happiness is

Extrinsic Value & Intrinsic Value

Extrinsic Value – some things we aim for & value, not for themselves but for what
they bring about in addition to themselves (value something as a
means to something else)

Intrinsic Value – other things we desire & hold to be valuable for themselves alone
(value something not as a means to something else, but for its own
sake)
Slides 2

For example: Extrinsic – exercise
Intrinsic – teaching, playing a musical instrument
Both extrinsic & intrinsic – health
(but, most things those are enjoyed in and of themselves vary from person
to person)
Slides 3

How does all this relate to human happiness?
- Aristotle: is there something that all human beings value & value only
EFFECT OF DIVIDED ATTENTION ON MEMORY
68
intrinsically, for its own sake & only for its own sake?
Happiness

Happiness – ultimate and to be valued for itself & really only for itself

The attainment of happiness becomes the ultimate or highest good for Aristotle
Slides 4

What is true human happiness?
– should be complete. Complete in that it’s all we require
– should be something that I can obtain on my own. I shouldn’t have to rely on
other people for it.

Fame – depends altogether too much on other people. I can’t get it on my own, without
help from other people.

Aristotle says: true happiness is the exercise of reason, a life of intellectual
contemplation of thinking
EFFECT OF DIVIDED ATTENTION ON MEMORY
Story B – Botany
Slides 1

“Manila hemp” –plant (cotton) fibers
– useful fibers in the textile and chemical Industry
e.g. plastics, paper, explosives
– a member of the banana family (even bears little banana-shaped fruits)
– produced in the Philippine island (Manila is the capital city of the Philippine)
Slides 2

Characteristics of Manila hemp fibers
– very long (easily be several feet in length)
– very strong and very flexible
– exceptionally resistant to salt water
– great material for ropes
e.g. on ocean going ships
* by the early 1940’s, steel cables are available, but most ships in the U. S. Navy
were moored with Manila hemp ropes.
Slides 3

“Manila hemp” vs. “steel cables”
Steel cables
– degrade very quickly (in contact with salt water)
e.g. Golden Gate Bridge (it’s red because of the zinc paint that goes on those
stainless steel cables)
69
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70
– steel cables can’t take the salt air (unless they’re treated repeatedly with a zinc
based paint)
Slides 4

“Manila hemp” vs. “steel cables”
Manila hemp
– no problem with salt water and air
– you can drag through the ocean for weeks on end
– plant fibers can stand up for months, even years, in direct contact with salt water

So, how do you take plant fibers?
(which is, individually you could break with your hands and turn them into a rope that’s
Strong enough to moor a ship)
Slides 5

How do you take plant fibers to make them stronger…?
1. Extract these long fibers from the Manila hemp plant
2. Take several of these fibers
3. Group them into a bundle – because by grouping the fibers you greatly increase
their breaking strength
4. Take that bundle of fibers and then twisting the bundles
– because by twisting it, you increase its breaking strength even more
5. Take several of these little bundles, and you group and twist them into bigger
bundles and so on
 become a very, very strong rope
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71
Story C – Psychology
Slides 1

John Watson – the founder of behaviorism. He believed…psychologists should study
only the behaviors they can observe and measure (not interested in mental processes).
i.e., a person could describe his thoughts, but no one else can observe them to verify
the accuracy of his report. However, one thing you can observe….
 muscular habits

Watson observed them as a manifestation of thinking

One kind of habit that he studied
 laryngeal habits
Slides 2

Laryngeal habits – related to the voice box (i.e., larynx). Thought to be an expression of
thinking.
* for young children – thinking is really talking out loud to oneself because they talk
out loud even if they’re not trying to communicate with
someone in particular.
* the individual matures – overt talking to oneself becomes covert talking to oneself,
but thinking still shows up as a laryngeal habit.

When people are thinking or trying to solve a problem, they typically have increased
Muscular activity in the throat region —muscle activity
EFFECT OF DIVIDED ATTENTION ON MEMORY
72
Slides 3

Watson’s argument – problem solving, or thinking, can be defined as a set of behaviors
(a set of responses) the throat activity (a laryngeal habit)
So, thinking can be measured as muscle activity the motor theory

Deaf individuals vs. speaking individuals
– Deaf individuals who use sign language have muscular changes in their hands when
They are trying to solve a problem muscular change in the hand
– Speaking individuals muscular changes in the throat region
Slides 4

William James – ideomotor action (a related concept of Watson’s: thinking is identical
with the activity of muscles)

Ideomotor action – an activity that occurs without our noticing it, without our being
aware of it. An idea leads to motor activity.
Ex: if you think of locations, there tends to be eye movement that occurs with your
thinking about that location. Let’s try “Magic trick”
Slides 5

“Magic trick”
- ask people to think of something on their left; think of something on their right. You
get them to think about two things on either side with their eyes closed, and you watch
their eyes very carefully. You can see rather clearly the eye movement – the
movement of the eyeballs.
- then, you say, think of either one and I’ll tell which you’re thinking of.
EFFECT OF DIVIDED ATTENTION ON MEMORY

73
There may be alternatives to this motor theory, but there is no way to answer the question
definitively.
EFFECT OF DIVIDED ATTENTION ON MEMORY
74
Story D – Astronomy
Slides 1

Asteroid belt and Bode’s law

Bode’s Law
-- a pattern in the spacing of the planets from the Sun (noticed by Bode in the late
1700s)
 multiplying each number by 2
0
3
6
x2
12
24
x2
48
96…
x2…
then..
 adding 4 to each number
0+4
3+4
6+4
12 + 4
4
7
10
16
24 +4 … 48, 96…
28 … 52, 100… then,
 dividing all those numbers by 10
4
7
10
16
28
52, 100…
0.4
0.7
1.0
1.6
2.8, 5.2, 10.0…
Slides 2

Bode’s Law – a pattern in the spacing of the planet from the Sun (in astronomical units)
0.4
0.7
Mercury Venus

1.0
Earth
1.6
Mars
2.8
5.2
(----- )
Jupiter
10.0
Saturn
19.6
Uranus
By late 1700s, those planets—Mercury through Saturn—were discovered by fitting into
the pattern. Then, in the late 1700s, there was a discovery of another planet, Uranus after
Saturn. Uranus fits in the next spot in the law’s pattern pretty nicely.
EFFECT OF DIVIDED ATTENTION ON MEMORY
0.4
0.7
Mercury Venus
1.0
Earth
1.6
Mars
2.8
(----- )
75
5.2
Jupiter
10.0
Saturn
19.6
Uranus
Slides 3

There was some interest in why the 2.8 spot in the pattern was skipped.
0.4
0.7
Mercury Venus
1.0
Earth
1.6
Mars
2.8
(----- )
5.2
10.0
19.6
Jupiter
Saturn
Uranus
 people got excited about the validity of this pattern and finding the missing object
between Mars and Jupiter. So, people went to work on finding objects that would be at
that missing distance from the Sun. Then…
 In 1801, the object Ceres was discovered (telescopes’ improvement is included).
Slides 4

Ceres was in the right place—the missing spot. But, it was way too faint to be a planet.
It looked like a little star. Because of its star like appearance, it was called an “asteroid.”

Ceres was the first and is the largest of what became many objects discovered at that
same distance.

Not just one thing, but all the objects found at that distance form the asteroid belt.

The asteroid belt – the most famous success of this Bode’s Law – that’s how the asteroid
belt was discovered.
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76
APPENDIX C
QUESTIONNAIRES
Questions for Lecture A: Philosophy
1. The professor gives examples of things that have value for her. She states that exercise
has
.
a. Only extrinsic value
b. Only intrinsic value
c. Both extrinsic and intrinsic value
d. Neither extrinsic nor intrinsic value
2. Why is happiness central to Aristotle’s theory?
a. Because it is so difficult for people to attain
b. Because it is valued for its own sake by all people
c. Because it is a means to a productive life
d. Because most people agree about what happiness is
3. According to the lecture, why does Aristotle think that fame cannot provide true happiness?
a. Fame cannot be obtained without help from other people
b. Fame cannot be obtained by all people
c. Fame does not last forever
d. People cannot share their fame with other people
4. What does the lecture say about teaching?
a. Teaching is not a highly valued profession in society
b. She may change professions in order to earn more money
EFFECT OF DIVIDED ATTENTION ON MEMORY
77
c. The reason she is a teacher has little to do with her salary
d. More people would become teachers if the salary were higher
5. What is the main purpose of the lecture?
a. To illustrate the importance of extrinsic values
b. To explain Aristotle’s views about the importance of teaching
c. To explain why people change what they value
d. To discuss Aristotle’s views about human happiness
6. According to the lecture, playing a musical instrument has
.
a. Only extrinsic value
b. Only intrinsic value
c. Both extrinsic and intrinsic value
d. Neither extrinsic nor intrinsic value
7. According to the lecture, health has
a. Only extrinsic value
b. Only intrinsic value
c. Both extrinsic and intrinsic value
d. Neither extrinsic nor intrinsic value
.
EFFECT OF DIVIDED ATTENTION ON MEMORY
Questions for Lecture B: Botany
1. What aspect of Manila hemp fibers does the lecture mainly discuss?
a. Similarities between cotton fibers and Manila hemp fibers
b. Various types of Manila hemp fibers
c. The economic importance of Manila hemp fibers
d. A use of Manila hemp fibers
2. What does the professor imply about the name “Manila hemp”?
a. It is a commercial brand name
b. Part of the name is inappropriate
c. The name has recently changed
d. The name was first used in the 1940’s
3. According to the lecture, cotton fibers are very useful. Those are used in the production of
many products, such as…
a. Paper
b. Plastics
c. Explosive
d. All of the above
4. Why does the professor mention the Golden Gate Bridge?
a. To demonstrate a disadvantage of steel cables
b. To give an example of the creative use of color
c. To show that steel cables are able to resist salt water
d. To give an example of a use of Manila hemp
78
EFFECT OF DIVIDED ATTENTION ON MEMORY
5. According to the professor, what was the main reason that many ships used Manila hemp
ropes instead of steel cables?
a. Manila hemp was cheaper
b. Manila hemp was easier to produce
c. Manila hemp is more resistant to salt water
d. Manila hemp is lighter in weight
6. According to the lecture, what is the one of two ways to increase the strength of rope made
from Manila hemp fibers?
a. Coat the fibers with zinc-based paint
b. Combine the fibers into bundles
c. Soak bundles of fibers in salt water
d. None of the above
7. According to the lecture, by the early 1940, what was used to moor the ships in the United
States Navy?
a. Steel cables
b. Silicone wire cables
c. Manila hemp ropes
d. None of the above
79
EFFECT OF DIVIDED ATTENTION ON MEMORY
80
APPENDIX D
DEMOGRAPHIC SURVEY
Today’s Date
Participant #
Age
Grade Level:
Gender:
Freshman
Sophomore
Female
Male
Junior
Senior
/
Graduate
/
Other
Your GPA
Racial/Ethnic Background:
Arab
Asian or Pacific Islanders
American Indian or Alaskan Native
Black
Hispanic
White
Latino
Other
Have you ever been diagnosed with a Learning Disability?
YES / NO
If yes, please explain when and where
Have you ever been diagnosed, believed to have had, or been told you have a reading problem or
reading speed problem caused by any of the following: a head injury, spinal cord injury, any
kind of injury caused by drugs/medication, or a medical condition?
Do you have any hearing problems?
YES / NO
If yes, has it been corrected to normal hearing?
Do you have any eyesight problems?
YES / NO
YES / NO
If yes, has it been corrected to normal vision?
Do you feel tired today?
YES / NO
YES / NO
YES / NO
If yes, what is your tiredness level from 1 to 5?
1. not tired ~ 5. very tired
Are you familiar with either one of stories you heard or read today’s study? If yes, please
circle where applicable and describe the familiarity of the subjects with a number.
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81
Philosophy / Botany / Psychology / Astronomy
Philosophy
1. somewhat familiar
2. more than somewhat familiar
3. very familiar
2. more than somewhat familiar
3. very familiar
2. more than somewhat familiar
3. very familiar
2. more than somewhat familiar
3. very familiar
Botany
1. somewhat familiar
Psychology
1. somewhat familiar
Astronomy
1. somewhat familiar