1. THE EFFECT OF PRESENTATION ON DEEPLY PROCESSED EXPLICIT MEMORY IN
OLDER ADULTS
Felicia Elena Luz Oropeza
B.A., Stanford University, 2004
THESIS
Submitted in partial satisfaction of
the requirements for the degree of
MASTER OF ARTS
in
GENERAL PSYCHOLOGY
at
CALIFORNIA STATE UNIVERSITY, SACRAMENTO
SPRING
2012

2. THE EFFECT OF PRESENTATION ON DEEPLY PROCESSED EXPLICIT MEMORY IN
OLDER ADULTS
A Thesis
by
Felicia Oropeza
Approved by:
__________________________________, Committee Chair
Dr. Kelly Cotter, Ph.D.
__________________________________, Second Reader
Dr. John Schaeuble, Ph.D.
__________________________________Third Reader
Dr. Emily Wickelgren, Ph.D.
ii

3. ____________________________
Date
Student: Felicia Oropeza
I certify that this student has met the requirements for format contained in the University format
manual, and that this thesis is suitable for shelving in the Library and credit is to be awarded for
the thesis.
__________________________, Graduate Coordinator ___________________
Dr. Qin, Ph. D. Date
Department of Psychology
iii

4. Abstract
of
THE EFFECT OF PRESENTATION ON DEEPLY PROCESSED EXPLICIT MEMORY IN
OLDER ADULTS
by
Felicia Oropeza
Statement of Problem
Is explicit memory test performance affected by thematically related and supraliminal
presentation conditions?
Sources of Data
Forty eight individuals over the age of 55 were sampled from two senior communities, Ethel
Hart MacLeod Senior Center and Swanston Community Center. Participants watched a series of
40 words on a computer monitor and then took a written exam that tested their explicit word
recall.
Conclusions Reached
Main effects for relatedness and presentation were found for hits, or number of words correctly
recalled. A higher number of words were correctly recalled in thematically related conditions
than in non thematic conditions independent of presentation. Also participants produced a higher
number of words in supraliminal presentation conditions, than in subliminal presentation
conditions across relatedness conditions. There was a significant interaction of presentation and
relatedness for hits where the number of words recalled in supraliminal thematic conditions was
higher than that of subliminal non thematic conditions. For false positives, or the number of
words written that were not presented in the word list, there was a main effect of presentation
where participants produced more false positives in supraliminal presentation conditions than in
subliminal presentation conditions. However, there was no main effect for relatedness showing
no difference in false positives produced in thematic and non thematic relatedness conditions.
Similarly, false positives did not show a significant interaction of presentation and relatedness.
_______________________, Committee Chair
Dr. Kelly Cotter, Ph.D.
_______________________
Date
iv

5. TABLE OF CONTENTS
Page
Dedication .................................................................................................................. vii
Acknowledgments...................................................................................................... viii
List of Tables ............................................................................................................... ix
List of Figures ............................................................................................................... x
Chapter
1. INTRODUCTION………………………………………………………………..1
Memory………………………………………………………………………..1
Explicit Memory………………………………………………………………2
Supraliminal and Subliminal Memory Processes……………………………..3
Levels of Processing………………………………………………………......4
Interaction of Levels of Processing and Timing of Presentation…………….5
The Present Study…………………………………………………………….6
2. METHOD………………………………………………………………………...8
Design...............................................................................................................8
Materials……………………………………………………………………...9
Word Generation……………………………………………………..9
Inter Rater Reliability………………………………………………...10
Final Word List Creation…………………………………………….10
v

6. Computer……………………………………………………………..12
Demographic Questionnaire………………………………………….12
Participants…………………………………………………………………..11
Procedure…………………………………………………………………….12
3. RESULTS………………………………………………………………………..14
Hits…………………………………………………………………………..14
False Positives………………………………………………………….........16
Covariates…………………………………………………………………...17
4. DISCUSSION…………………………………………………………………..18
Limitations and Strengths…………………………………………………...19
Further Directions…………….…………………………………………….20
References………………………………………………………………..................21
vi

7. Dedication
I would like to dedicate this thesis to my deceased maternal grandparents, Maria de la
Luz Razo and Salvador Gomez who raised me and served as the inspiration for my topic on
cognition and aging.
vii

8. ACKNOWLEDGMENTS
First and foremost, I would like to thank my parents for everything they have done for me. Since
preschool, my parents have impressed upon me the value of education and importance of using one’s
intellect to make a significant impact on the world; however small or big that may be. They gave me the
greatest gift that any parent could bestow on their child, individuation, by giving me the freedom to
explore my academic pursuits. My thesis topic availed me this golden opportunity to spread my wings
and fly. Special thanks to my mother’s extended family for their undying support of my educational
endeavors and contributions to my personal development throughout graduate school. During graduate
school, my grandmother passed away which was a major setback for our family, for she was the anchor
that held our family together. Amidst those trying times, my mom’s family taught me to rise above
hardships and to find my inner strength within to finish my degree. I would like to thank Dr. Kelly Cotter
for her patience, immense wisdom, alacrity, and generosity of time and effort towards helping me finish
my thesis. I would also like to thank Dr. John Schaeuble for helping me arrive at my thesis topic and for
assisting me with narrowing my thesis topic down to two variables. I would like to thank Dr. Wickelgren
for helping me with the Latin Square Experimental Design of my video presentations to eliminate bias. I
would like to thank Debbie Kircher for pacing me through the program and helping me see my own
beauty within. Finally, I would like to thank the two senior communities Swanston Community Center
and Ethel Hart MacLeod Senior Center, who graciously afforded me the opportunity to conduct my
experiment during their community events. For their patience and efforts to help me attain my degree, I
am grateful. My precious emblems, Belle, Lena, and Cha Cha have been my torches throughout the
entire writing process and they have seen it to completion providing constant companionship and support
when things seemed formidable and the end of the graduate school road seemed nowhere in sight.
viii

9. LIST OF TABLES
Page
1. Table 1 Descriptive Statistics for Hits and False Positives………………….16
ix

10. LIST OF FIGURES
Page
1. Figure 1 The Interaction of Presentation with Relatedness for Hits…………………… 15
2. Figure 2 The Main Effect of Presentation Time for False Positives…………………….17
x

11. 1
Chapter 1
INTRODUCTION
Dementia is a degenerative disease of the aging brain that impairs cognitive functioning
by attacking the central nervous system at the vascular and cellular levels (Whitehouse, Price,
Strubie, Clark, Coyle, & Delon, 1982). Although dementia impairs cognitive functioning in
many ways, profound and irreversible memory loss is its primary effect (Reed Group, 2009).
Because dementia is an increasingly prevalent age-related neural disease within senior
populations developing cognitive strategies for preventing memory loss is necessary for the
maintenance of quality of life and positive life orientations (Santacruz & Swagerty, 2001). I
focus on two potential memory-enhancing strategies in the present study: presentation of
information and processing of information. I examine these strategies as employed by older
adults who do not suffer from cognitive impairment, in hopes that what is learned in normal
aging populations can be beneficial for those at risk of developing dementia.
Memory
Memory, in its purest form, is the act of encoding, storing, and recalling a past event or
item of factual knowledge (The American Heritage Dictionary, 1985). Memory can be divided
into two forms: implicit and explicit (Graf & Schacter, 1985), both of which are affected by the
aging process (Light & Singh, 1987). Implicit memory is a memory task that depends on
cognitive processes occurring outside of one’s conscious awareness (Schacter, 1987). These
automatic processes can include stimuli-associate conditioning, social modeling, relearning and
practice effects, and priming (Schacter, 1987). Roediger and McDermott (1993) and Schacter
(1987) described implicit memory tasks as indirect or incidental, where there was no reference to
past exposure to information.
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12. 2
In contrast, explicit memory tasks require the conscious recollection of an item directly
referenced by past experience (Graf & Schacter, 1985). When one performs well on an explicit
memory test, he or she has brought factual knowledge into awareness (Challis, 1996; Joyce,
Paller, McIsaac, & Kutas, 1998). Roediger and McDermott (1993) and Schacter (1987)
characterized explicit memory tests as tasks performed with intention, where participants are
instructed to recall or recognize stimuli they had previously seen.
In cross-sectional and longitudinal studies examining age-related memory, older
participants tend to score lower than younger participants on explicit memory tasks (Anooshian,
1997; Carroll, Byrne, & Kirsner, 1985; Ellis, Ellis, & Hosey, 1993; Greenbaum & Graf, 1989;
Lorsbach & Morris, 1991; Lorsbach & Worman, 1990; Naito, 1990; Parkin & Streete, 1988).
However, older cohorts show equable performance to young adults on perceptual implicit tasks
(Light & Singh, 1987).
To understand potential compensatory mechanisms older adults can use to preserve
explicit memory, I analyzed the influence of two associative memory processes on explicit
memory test performance in aging adults: level of processing (shallow versus deep) and
awareness of presentation (subliminal versus supraliminal), described in detail below.
Explicit Memory
Explicit memory tests measure the conscious recollection of memory of previously
presented stimuli (Joyce et al., 1998). Explicit memory test stimuli can be presented visually,
pictorially, or aurally (Drury, Kinsella, & Ong, 2000). Recall and recognition are two main types
of explicit memory tests used by the research community. Free recall is a memory task that
depends on exerting cognitive resources to successfully retrieve a memory item. Performance on
a recall exam is a direct measurement of the conscious recollection of previously presented
2

13. 3
stimuli. This type of memory task relies on processing capacity, revealing the influence of
working memory and processing speed on retrieval (Craik, 1996; Whiting & Smith, 1997). Free
recall tests typically depend on effortful cognitive control and bottom up retrieval processes. I
chose to analyze free recall test performance as a measure of explicit memory processes in the
current study.
Recognition, on the other hand, is an explicit memory process that relies more on
automatic, top-down processes than processes required for recall tests. Performance on
recognition tests does not require the direct retrieval and generation of a memory trace, creating
less reliance on the use of cognitive strategies. Multiple-choice tests are one example of
recognition tests where performance is facilitated by the use of associative cues that assist
implicit retrieval of a memory trace. Thus, this type of test offers more environmental memory
support than is offered by free recall tests (Whiting & Smith, 1997). Recognition tests employ
different memory strategies from that of free recall tests, the measurement tool of the present
study.
A comparison of younger and older adults’ performance on implicit tests, such as word
stem completion, and explicit tests, such as word recognition, revealed lower test performance
for older adults on explicit memory tasks, but similar implicit memory performance across age
cohorts (Graf, 1992).
Supraliminal and Subliminal Memory Processes
As described above, explicit memory tests often involve asking participants to recall or
recognize information presented to them in a laboratory setting. The information can be
presented supraliminally (within one's conscious awareness) or subliminally (outside one's
ability to consciously perceive presented stimuli) in the study/encoding session. Supraliminal
3

14. 4
memory processes are driven by strong feelings of event recollection that enhance one’s ability
to visualize the scene (Aggleton & Brown, 1999; Gardiner, 1988; Gardiner & Java, 1990;
Gardiner & Java, 1991; Gardiner, Java & Richardson-Klavehn, 1996; Jacoby, 1991; Rajaram,
1993; Tulving, 1985; Wagner, Verfaeille, & Gabrieli, 1997; Yonelinas, 2002). Subliminal
processes depend upon feelings of familiarity that lack a concrete experience of an actual event
(Khilstrom, 1990; Khilstrom, 1996; Khilstrom, Barnhardt, & Tataryn, 1992a; Roediger &
McDermott, 1993; Szymanski & MacLeod, 1996; Toth, 1996).
The priming task is a classic methodology for studying subliminal processes. Age has
little effect on priming (Light & Singh, 1987). However, Englekamp and Wippich (1995)
demonstrate an age effect for conceptual priming, such that younger cohorts generally show
higher memory on implicit tests than older cohorts when presented with atypical stimuli at study.
Their study shows that younger cohorts tend to perform better than older cohorts in random
stimuli and subliminal presentation conditions while performing worse in moderate relatedness
conditions. Levels of processing may enhance performance in older cohorts on priming tests..
Levels of Processing
When presented stimuli within varying degrees of awareness, the brain can process
stimuli using deep or shallow processing. Deep encoding requires the utilization of meaning-
based encoding to activate associative memory network connections, while shallow processing
refers to the presentation of stimuli encoded at a rudimentary or physical level without the use of
semantic-level memory access (Craik & Lockhart, 1972). For example, deep processing is
applied during exposure to a word list consisting of items belonging to the same category, such
as Zoo Animals, because people form associations between the words. On the other hand,
shallow processing is utilized during exposure to randomly chosen words because there is no
4

15. 5
categorical link between the words. Craik and Lockhart (1972) showed that deep- or
semantically-processed stimuli had a higher chance of recall than shallow- or physically-
processed stimuli. This effect was found even when participants did not expect subsequent recall
or recognition tests.
Bradshaw and Anderson (1982) showed the effect of elaboration and thematic-
relatedness on memory processes. Their study demonstrated higher memory performance in the
thematic conditions requiring the elaborate integration of memory traces and lower memory
performance in the conditions with minimal thematic relatedness yielding the integration of poor
memory traces. Similarly, levels of processing theory stipulates that performance is facilitated by
elaborately encoded or “deeply” processed stimuli and degraded by low-level encoding or
“shallow” level processing of stimuli. Hence, their study draws parallels between thematic
relatedness and levels of processing theory shedding light on the role of neural networks in the
creation of interconnected explicit memory traces seen in the present study (Bradshaw &
Anderson, 1982). In the current study, I adapted the methodology that used thematic relatedness
to operationally define levels of processing to fit my experimental model for studying explicit
memory performance.
Interaction of Levels of Processing and Timing of Presentation
A careful examination of presentation and levels of processing effects on explicit
memory is necessary for developing a comprehensive network model of consciousness and
meaning-based concept maps. Among the memory tasks available to researchers, the category
exemplar test is one of the most effective tools for studying the interaction of levels of
processing and exposure to subliminal and supraliminal stimuli (Mitchell & Bruss, 2003).
5

16. 6
Presenting target exemplars from taxonomic groups of animals and vegetables to the participants
resembles the methodology used in the present study.
Because category exemplar tests utilize both explicit and implicit memory processes, the
distinction between the cognitive resources that drive each process begin to blur (Srinivas &
Roediger, 1990). Thus, category exemplar tasks capture conceptual subliminal processes as well
as perceptual subliminal processes revealing the overlapping effects of conscious and
unconscious processes on memory trace formation. Monti et al. (1996) investigated how
category exemplar tasks rely on relatedness conditions to create and consolidate meaning-based
or deeply processed memory traces. He theorized that cognitive networks accomplish this task
when processing semantic supraliminally presented content. Although category exemplar tasks
are classically referred to as “implicit” memory tasks, its conceptual properties are sensitive to
effects of levels of processing at the supraliminal level (Monti et al., 1996). Hence, regardless of
whether category exemplar tests contain implicit or explicit memory components, these tests
may have more conceptually-driven effects on memory if coupled with deep levels of processing
conditions. Therefore, research provides evidence for the possible interaction of presentation of
stimuli by levels of processing. There remains a paucity of research that examines the direct
effects of semantically processed stimuli on category exemplar task performance in older adults.
In contrast to recent studies which examined the relationship between relatedness,
elaboration, and explicit memory, the current study analyzed the effect of presentation and
thematic relatedness on explicit memory of older adults (Bradshaw & Anderson, 1982).
The Present Study
In the present study, I examined how levels of processing (deep versus shallow) affects
explicit memory task performance when moderated by presentation type (subliminal versus
6

17. 7
supraliminal). I operationally defined deep levels of processing as the presentation of
thematically-related words from two thematic categories (Zoo Animals and Vegetables). I
defined shallow levels of processing as the presentation of randomly generated, non-thematically
related words. I defined supraliminal presentation as seeing a series of words for 2 seconds each.
Subliminal presentation was defined as seeing a series of words for .4 seconds each.
I expected to find main effects for both presentation and processing of stimuli. For the
main effect of presentation, I expected to see a higher number of supraliminally-presented words
recalled than subliminally-presented words. For the main effect of relatedness, I proposed that
memory for thematically-related words would be higher than memory for non-thematically-
related words. Specifically, I expected that thematically-related words would provide a semantic
(deep) form of processing that would facilitate memory performance across both supraliminal
and subliminal presentation conditions.
I also hypothesized that participants would have higher memory performance in
supraliminal-deep levels of processing conditions and lower performance in supraliminal-
shallow levels of processing conditions. I expected to see this interaction because meaningful,
related words shown for a longer amount of time on a computer screen tend to produce more
durable memory traces than random words presented for a shorter amount of time. The focusing
of one’s mind on semantic content should yield a compound effect on explicit memory
performance because supraliminal processes require the effortful application of cognitive
resources that spark neural network activation and parallel processing stream distribution.
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18. 8
Chapter 2
METHOD
Design
With a 2x2x4 mixed repeated-measures factorial design, described in detail below, I
examined the nature of semantic facilitation on explicit memory for words presented at the
conscious and the unconscious perceptual level. I showed each participant a series of forty words
flashed on a computer screen and later asked participants to recall the words. The two within-
subjects independent variables were thematic association of words and presentation of stimuli.
The between-groups independent variable was order or presentation. Explicit memory recall test
performance was my dependent variable.
The first within-subjects independent variable was thematic association/level of
processing. Thematic association referred to how easily participants could form associations with
presented words (thus affecting their memory for those words), and was comprised of two levels:
a thematically-related word condition (deep processing) and a non-thematic word condition
(shallow processing). The thematically-related word condition was a list of ten words related to
the same category, either Zoo Animals (e.g., zebra) or Vegetables (e.g., broccoli). The non-
thematic word condition was a list of ten randomly generated words that had no relation to each
other (e.g., skirt, motorcycle).
The second within-subjects independent variable, presentation of stimuli, referred to how
long participants saw words flashed on the computer screen. This variable had two levels: the
supraliminal condition and the subliminal condition. In the supraliminal condition, participants
were exposed to words for 2 seconds each. This presentation time was long enough for
participants to read and understand the word, thus processing it completely (Moore, 1982;
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19. 9
Whiting, 1997). Words were presented for .4 seconds each in the subliminal condition. This
presentation time was long enough for participants to detect a word, but not long enough to
consciously process it (Moore, 1982; Khilstrom, 1987).
Video presentation was the only between-subjects variable used in this study. It consisted
of four levels in order to control for potential order effects. Each video started with a
supraliminal phase in order to prevent the participant from thinking that there were no words
presented in the video. To control for the order effect of presenting supraliminal conditions first
in all video presentations, I used a partial Latin-Square to counterbalance the sequence of phases
within each video presentation. This method of counterbalancing ensured that the thematic and
non-thematic words were presented in every possible order (first, second, third, fourth). For
example, order one consisted of supraliminal thematic words presented in phase 1, subliminal
non thematic words presented in phase 2, supraliminal non-thematic words presented in phase 3,
and subliminal thematic words presented in phase 4. In contrast, in order two supraliminal non
thematic words appeared in phase 1, subliminal thematic words appeared in phase 2,
supraliminal thematic words appeared in phase 3, and subliminal non thematic words appeared in
phase 4. Thus, the presentation conditions were counterbalanced across the four different videos.
A total of forty words were presented in each video.
Materials
Word Generation. To create the vegetable word list I randomly selected 41 Vegetable
words from the following website: http://www.gardenology.org/wiki/List_of_vegetables. To
create the zoo animal word list I randomly selected 26 Zoo Animal words from the following
website: http://www.catalandictionary.org/wordnets/eng/ZooAnimalList.htm. To create the non-
9

20. 10
thematic word list I randomly generated 24 words from the following website:
http://coyotecult.com/tools/randomwordgenerator.php.
Inter-rater Reliability. The relatedness of a word to a category could affect the speed
and accuracy by which a participant could retrieve the word from memory, thus assisting in the
formation of cognitive associations (Anderson, 1980). Therefore, I wanted to make sure that one
word list did not contain words that were more related to the theme than the other word list. To
check the equivalence of thematic-relatedness of the words in the two thematic word lists, I
collected inter-rater reliability data on the degree of relatedness of each word to its specific
category.
Ten friends and family members below the age of 55 participated as raters. They were
asked to rate how much each word from the vegetable list was related to the theme of vegetables,
and how much each word from the zoo animals list was related to the theme of zoo animals.
Relatedness ratings were collected only for thematic words.
I also collected inter-rater reliability data on the commonness of each word in everyday
usage because the commonness of a word could also increase the accuracy of recall (Deese,
1960; Gregg, Montgomery, & Castano, 1980; Hall, 1954; Matthews, 1966; May, Cuddy, &
Norton, 1979; May & Tryk, 1970; Postman, 1970; Sumby, 1963; Tulving & Patkau, 1962;
Whiting & Smith, 1997). The commonness inter-rater questionnaire asked raters to rate how
commonly words are used in everyday speech. Commonness ratings were collected for thematic
and non-thematic words. Upon completion of the word rating procedure, I rewarded the raters
with $5.00 Target gift cards.
Final Word List Creation. To create lists of equivalent length (10 words) for each
condition (thematically-related and non-thematically-related), I entered the participants’ ratings
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21. 11
into a spreadsheet. Next, I eliminated some words from the original lists by sorting the word lists
(Zoo Animals, Vegetables, non-thematic) from the highest to lowest mean commonness rating.
Then I chose every other two words descending from the highest to lowest mean commonness
rating until I obtained 10 words for each thematic list (Zoo Animals, Vegetables) and 20 words
for the non-thematic word lists. These 20 words were divided into two lists of ten words each
using the ABBA sorting sequence.
When the final word lists were created, I calculated the variability between the two
thematic word lists on relatedness and the variability between the two thematic and the two non-
thematic lists on commonness. T-tests revealed no significant differences between Zoo Animal
words (Μ = 4.09, SD = .54) and Vegetable words (M = 3.71, SD = .76) on relatedness to their
respective thematic category; t (38) = 1.73, p = .09. In other words, Zoo Animal words and
Vegetable words had the same degree of relatedness to their respective theme. T-tests also
showed no significant differences between thematic (M = 3.49, SD = .63) and non-thematic
words (M = 3.34, SD = 1.03) on commonness; t (38) = .70, p = .48. Thus, both thematic and non-
thematic words were considered equivalent on commonness.
Upon completion of the word list generation procedure I had four lists of 10 words. These
lists were capped at 10 words each because the average older adult has a working memory
capacity of 4 (+/- 2) items (Bo, Borza & Seidler, 2009). I chose to increase the size of the word
list from four words to ten words because I wanted to avoid any potential ceiling effects (Miller,
1956).
Finally, to randomly sort the words within the four lists for the video presentation
conditions, I used the following website: http://textmechanic.com/Sort-Text-Lines.html, which
generated random orders for each ten word list.
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Computer. Words were presented to participants on an ASUS gaming laptop computer
running Microsoft Movie Maker for Windows 7 Home Premium operating system.
Demographic Questionnaire. Before administering the computerized portion of the
procedure I collected the following demographic information: gender, educational status,
occupation ethnicity, and religion. Age information was not collected because my entire
participant pool consisted of older adults and I did not want the sensitivity of the age question to
deter them from participating in my study.
Participants
I sent letters to fourteen different agencies within the Sacramento Valley region and
called ten agencies. I recruited forty-eight older adults over the age of 55 from the following
agencies: Senior Center at Elk Grove, Mission Oaks/Swanston Community Center in
Carmichael, and Ethel Hart Senior Center. Of the twelve participants who gave a response to the
gender question on the demographic questionnaire, three participants were male and nine
participants were female. Four out of 48 participants “Completed High School,” 11 “Went to
college but did not finish,” 12 “Finished some graduate school or higher”, and 2 ”Earned a
doctorate degree.” Almost half of the participants were “Caucasian” (n = 23), 4 were “Hispanic,”
1 was of “Asian American” descent, 2 were “African American,” and 18 did not indicate their
ethnicity. Out of 45 participants who responded to the Religion question, 12 were “Catholic”, 13
were “Christian,” 5 were “Spiritual,” 1 was “Mormon,” 1 was “Episcopalian,” 3 were “Atheist,”
3 were “New Age,” 2 were “Baptist,” and 5 participants reported “Other” to signify that they
were of a religious affiliation other than what was presented. Three participants out of 48 did not
respond.
Procedure
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I received ethical approval to recruit participants from the Human Subjects Committee in
the Department of Psychology with minimal risk in Spring 2011. Next, I pilot-tested the
procedure with four individuals who did not meet the study’s criteria for participation to make
sure the testing protocols ran smoothly. There were no problems with the procedure.
To prepare for the experiment, I made arrangements with the activity coordinators from
each agency listed above to secure a room and a specific time to run my study. Before the day of
the experiment, I randomly assigned the participants to one of four video conditions. On test day,
I greeted each participant individually, showed the participant to his or her seat in front of the
laptop, and led the participant through the informed consent procedure. Next, I handed
participants an informed consent form to sign and return back to me. I then provided the
participants with a demographic questionnaire that asked participants to reveal their gender,
education status, occupation, religion, and ethnicity.
Before starting the video presentation, I instructed the participant to not touch any key on
the keyboard or touchpad because the screen ran by itself. Next, I started the video assigned to
the participant. Within each video, the supraliminal condition had one thematic phase and one
non-thematic phase. The subliminal condition also had one thematic phase and one non-thematic
phase. The order was counterbalanced, as described above.
The video presentation lasted for 3.99 minutes. After the video was complete, I
administered the free recall exam by giving the participant a pen and piece of lined 8.5 x11 white
printer paper with the following instructions at the top of the page: “Please write as many words
as you can remember from the presentation you just saw. You have as much time as you want to
complete this form.” Next, I told participants that they could take as much time as they needed to
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24. 14
complete the test while I was out of the room. After the exam was complete, I debriefed the
participant and gave the participant $5 gift card to Walmart.
Chapter 3
RESULTS
Using two mixed repeated measures ANOVAs, I examined differences between the
thematic and presentation conditions on recall (see Table 1). The first dependent variable, the
number of “hits,” represented the number of words the participant wrote down on the recall
task that were presented in the video presentation (i.e., correctly-recalled words). The second
dependent variable, number of false positives, was the number of words that the participant
wrote down on the recall task that were not presented in the video presentation.
Hits
The between subjects variable, order, did not show a significant main effect for hits, F (3,
44) = 2.18, p = .10, partial η2 = .13, indicating that order of presentation had no effect on
correct recall for presented words. The first within-subjects variable, timing of presentation,
showed a significant main effect for hits F (1, 44) = 220.90, p < .001, partial η2 = .83, such that
supraliminal presentation conditions yielded a higher number of hits than subliminal
presentation conditions, as predicted (see Table 1).
The second independent variable, thematic-relatedness, also showed a significant main
effect for hits, F (1, 44) = 100.37 p < .001, partial η2 = .70, such that thematic conditions
produced significantly more hits than non thematic conditions. However, this main effect was
qualified by a significant interaction where the number of hits in thematic conditions was
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25. 15
higher in supraliminal presentation conditions than in subliminal presentation conditions, F
(1,44) = 109.13, p < .001, partial η2 = .71, see Figure 1.
6
The Interaction of Presentation and Thematic
Relatedness
5
4 4.104
3
Presentation
Supraliminal
2
Subliminal
1.146
1
0.146
0
0
Thematic Non Thematic
Relatedness
-1
Figure 1. This graph shows the significant interaction of presentation and thematic relatedness
for number of hits. Thematic supraliminal conditions yielded higher performance than non
thematic subliminal conditions.
The pairwise comparisons for the number of hits for supraliminal presentation conditions
showed significant mean differences between thematic and non thematic conditions such that
the number of hits in thematic conditions was significantly higher than the number on hits in
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26. 16
non-thematic conditions during supraliminal presentation conditions. However, the pairwise
comparisons for the number of hits in subliminal presentation conditions did not show
significant differences between the two thematic variables.
Table 1.
Descriptive Statistics for Hits and False Positives
Hits False Positives
Independent Variable Effects M SD M SD
Thematic 2.13 .13 0.10 0.04
Non-thematic 0.57 0.11 0.13 0.05
Supraliminal 2.63 0.17 0.22 0.06
Subliminal 0.07 0.05 0.01 0.01
Relatedness*Presentation
Supraliminal Thematic 4.10 0.23 0.21 0.07
Subliminal Thematic .15 0.09 0.00 0.00
Supraliminal Nonthematic 1.15 0.2 0.23 0.09
Subliminal Nonthematic 0.00 0.00 0.02 0.02
Note: N=48 participants were randomly assigned to one of four presentation videos.
False Positives
The between subjects variable, order, did not show a significant main effect for false
positives F (3, 44) = .60, p = .62, partial η2 = .04, revealing no effect of video order
presentation on the number of written responses that were not on the word list. Presentation
showed a statistically significant main effect for false positives F (1, 44) = 10.05, p < .001,
partial η2 = .19 such that there were more false positives produced in supraliminal presentation
conditions than in subliminal presentation conditions (see Table 1).
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However, thematic relatedness did not show a main effect for false positives, F (1, 44) =
.19, p = .67, partial η2 = .00. Similarly, there was no statistically significant interaction of
presentation and thematic-relatedness, F (1, 44) = .00 p = 1.00, partial η2 = .00. See Figure 2
for the main effect of presentation time on false positives.
0.3
The Main Effect of Presentation for False
0.25
Positives
0.229
0.2
0.208
0.15
Presentation
Su;ralimina
l
0.1
0.05 0.021
0
0
Thematic Non Thematic
Relatedness
-0.05
Figure 2. Main effect of presentation time on false positives. This graph does not show a
significant interaction of thematic relatedness with presentation for number of false
positives.
Covariates
17

28. 18
Finally, I examined the covariates, “Gender” and “Highest Education Achieved”, because
they were categorical variables with ordinal levels. However, I found no significant
relationships among the covariates.
Chapter 4
DISCUSSION
The results confirmed my hypothesis that older adults would produce a higher number of
correctly recalled words in supraliminal presentation and thematically related conditions and a
lower number of correctly recalled words in supraliminal presentation and non thematically
related conditions. This main result was consistent with the previous literature on how levels of
processing strengthened the effect of supraliminally presented stimuli on category exemplar
test performance (Bradshaw & Anderson, 1982). Additionally, performance on the free recall
exam was higher in thematic relatedness conditions than in non thematic conditions. This
finding resembles the results of the Craik and Lockhart (1972) study which shows the positive
effect of deep levels of processing on explicit memory. Similarly, performance on the recall
test was higher in supraliminal conditions than in subliminal conditions coinciding with Monti
et al.’s (1996) study showing how conceptually-driven aspects of memory tasks could mediate
the engagement of supraliminal processes; thereby, enhancing explicit memory test
performance. Notably, older adults produced more words on the recall exam that were not
presented in the video supraliminal presentation conditions than in subliminal conditions but
there was no difference in thematic and non thematic conditions. Supraliminality and the
application of cognitive effort seemed to have more of an effect on incorrect guessing than
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29. 19
meaning-based memory processes such as levels of processing. Possibly, levels of processing
produces more accurate memory trace formations as a result of efficient neural network
activation whereas, conscious cognitive exertion of resources may be more useful in situations
that require the generation of ideas without the need for the accurate retrieval of exact memory
traces.
Limitations and Strengths
The elegance of this study’s design increases the strength of its internal validity. Because
the recall test was administered immediately after the study condition, the small time gap
between study and test increased the measurement’s accuracy for memory of the presented
words. The Latin-Square partial counterbalancing measure did not eliminate all bias; however,
it ensured that all relatedness and presentation conditions were viewed by each participant.
Equivalence of word lists’ variances also enhanced the strength of the present study.
The small sample size of forty-eight participants limited the power of my study by
increasing the risk of Type I error. Because I pooled my sample from a population within two
senior communities in the outlying areas of Sacramento, the sample was not representative of
the entire population of individuals over fifty-five years of age. I obtained the sample using a
convenience sample instead of using a random sample so I did not assume a normal
distribution of performance scores. Because I did not collect a random sample, the economic,
educational, and health characteristics unique to the senior communities sampled may have
biased the results in favor of individuals with high cognitive functioning and healthy lifestyles.
The sample also consisted of a disproportionate number of females compared to males.
Therefore, its limited generalizability to the universe of moderately healthy functioning older
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30. 20
adults decreased its external validity and application to real world situations that would include
older low functioning individuals as well. If I were to replicate this study, I would restrict the
number of words to twenty because the current forty word list intimidated many participants
when they realized that the next exercise was an exam of the words presented on the screen.
Additionally, I would also set a time limit for the exam to reduce the bias of some participants
remembering more words than others simply because they had more time to remember the
words. I would increase my sample size to 100 participants and would allot more time to
participant recruitment increasing the number of letters sent out to senior centers within the
Sacramento region. I would include a Telephone Interview Questionnaire for Cognitive Status
to obtain a more accurate picture of the cognitive functioning status of the participant pool. I
would include in the questionnaire a question on “Age.” With the information on cognitive
status and “Age”, I could analyze the relationship between Age, cognitive functioning, risk for
dementia, and the age group’s test performance.
Future Directions
To further analyze the relationship between relatedness and presentation, one might want
to incorporate elements from human-computer interface psychology literature to produce
websites that will facilitate the engagement of older adults. Websites designed with age-
relevant meaning-based contextual cues can assist the recall of older adults by activating
associative frameworks within their cognitive substrates. This may have important
applications in the design of educational curricula in senior centers. For example, teachers
could use computers to present seniors with supraliminally-timed reading exercises that consist
of related material sparking, consolidation of short term memories and association formations
within cognitive networks. The results from this study may assist those older adults with a
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31. 21
genetic history of Alzheimer’s disease because knowing how to facilitate recall could provide
older adults with a buffer against memory loss.
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