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The Effect of Words Versus Images on False Recall
Cameron C. McPherson
University of Oregon
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Abstract
The present study tests if the amount of false recall would be less when stimuli are presented as
images rather words. Frequencies of false memories were examined relative to modality and
relatedness of stimuli. 131 psychology 303 students at the University of Oregon completed an
online test of false recall. Participants ranged in age from 19 to 37 of which 69.5 percent were
female and 30.5 percent were male. This study found a main effect of both variables and an
interaction. Demonstrating how memory tasks such as eye witness testimonies may be
susceptible to false recall.
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The Effect of Words Versus Images on False Recall
Memories are complex functions of the brain that have always been of interest to
scientists and psychologists. Understanding what causes memories and how they work are
questions researchers are always trying to answer. Better comprehension of memory functions
can be of great aid in everyday life. The present study is focusing on false recall in memory,
which is when people report having seen a stimulus without ever having actually seen it. This
study attempts to test if modality has an effect on false recall in unrelated versus related study
items. The findings of this study are important because they could have practical and serious
implications. Showing that images produce less false recall than words can aid in everyday tasks
such as memorizing a shopping list by looking at images rather than reading words. A more
serious application of the findings could be in eyewitness testimony and how false recall can
affect that. Blair, Lenton & Hastie (2002) and Israel & Schacter (1997) are studies that used
similar methods to this study that also tested false recall.
In the study done by Blair et al. (2002) researchers wanted to know if the DRM paradigm
was reliable in assessing both global and specific tendencies for false memory and the reliability
of false memories relative to true memories. The Deese-Roediger-McDermott paradigm is a
procedure where participants are presented with a list of words, all associated with a particular
concept, and are then asked to perform a recall test. It is used in the study of false memories. The
researchers also wanted to know how stable the tendencies were. This is interesting as there is
not much research in this area and little evidence to show the DRM produces false memories that
reveal stable individual differences. Without the ability to reliably measure individual differences
in false memory the predictors, correlates, and consequences of individual differences cannot be
meaningfully studied. The researchers hypothesized that by using a test-retest method they
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would be able to show that the DRM is reliable in both global and specific tendencies for false
memories. Blair et al. (2002) used 59 male and female students from the University of Colorado
to conduct their study. They presented the students with five lists of 15 words each. Each list was
associated with a specific concept, four were taken from Rodger and McDermott (1995) and one
was a stereotype list. They were presented through an audiotape where each word was spoken to
the participant clearly and slowly. Participants were required to then work on simple arithmetic
problems for two minutes before moving on to the next list. After hearing all the lists participants
had to take a recognition test that consisted of two words that appeared on each of the initial lists.
It also had two lure words related to each list, three for the stereotype list, and 20 filler words
that were completely unrelated. This test was then repeated in the exact same manor two week
later. Researchers manipulated what words were shown to the participants in the recognition test
and measured the number of false memories produced by the tests. They found that both a global
and specific tendency to produce false memories was stable across the two-week testing period,
supporting the hypothesis that there is test-retest reliability. This shows that the DRM is a
reliable individual-difference measure and can be used to study the correlates and consequences
of false memory in future research. Blair et al. (2002) also stated that the findings of this study
have important practical implications. Such as the problem of using response stability as a
criterion for truth in eyewitness testimony. Which the present study suggests may be a serious
problem due specific false memories being more stable than specific true memories. This study
was limited in its ability to show why specific false memories were more stable than specific true
memories. They were unable to answer the question of whether presenting the words as images
would change the reliability of the DRM.
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Israel & Schacter (1997) studied whether using pictures corresponding to each word in an
associative list would reduce the number of false recalls compared to not having pictures
presented. They wanted to know if the modality in which the stimulus is presented has an effect.
This is intriguing research because if it is proven it shows that having distinctive perceptual
details of words allows for less false memories. Israel & Schacter (1997) hypothesized that
participants should have fewer false alarms due to lure words after studying semantic associates
presented with pictures as apposed to only words. The study involved 36 undergraduate
participants from Harvard University for each of the two experiments. Each experiment
presented the words through an auditory and visual component. Experiment one had participants
studying 14 lists of 12 items, completing a puzzle in between each list. Then they were given a
recognition test of 98 items consisting of 42 true targets, 18 true target controls, 28 false targets,
and 10 false target controls. Experiment 2 had the same number of lists however the two lists that
produced the lowest rates of false recognition in experiment 1 were replaced with two new study
lists. Participants were then given a recognition test with a few less items than in experiment one.
For both recognition tests, items were randomly assigned to be presented both visually and
audibly or simply audibly. Researchers manipulated what items were presented with pictures and
measured whether that influenced the number of false alarms. They found that in both
experiments false alarms due to related and unrelated lures are reduced when lists of semantic
associates are presented with pictures. These findings are significant and failed to reject their
hypothesis. These results are important because they can be applied practically in everyday life.
When a student is studying for a test he may be more inclined to study using images over words
since the findings show he will have less false memories when attempting to recall what he
studied. This study was limited in that it only studied between-subject groups and did not
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measure within subject groups. They were unable to answer the question of why lists of semantic
associates presented with pictures produce less false recall.
Based on the evidence from the aforementioned studies the present study will conduct an
experiment to test for a main effect of relatedness and modality in false recall. The study
conducted by Blair et al. (2002) did not use a control group when testing for false recall,
participants saw both related and unrelated words. In the current study participants are put into
either a related group or unrelated group. Blair et al. (2002) did however find the DRM to be
reliable. This helped inform hypothesis one, that there would be a main effect of relatedness,
with higher false recall in the related study item condition. While Israel & Schacter (1997) found
that images produce less false recall, they used over 10 lists’, which may have had an effect on
participant’s ability to remember what was on them. This study has participants only studying
two list, which reduces the chances of participants becoming fatigued with over testing. The
Israel & Schacter (1997) findings helped inform hypothesis two, that words will have a higher
number of false recall than images, specifically in the related study item condition.
Method
Participants
In this study we had 131 of the students in the psychology 303 classes at the University
of Oregon complete an online recall test (n=131). The mean age of the participants was 21.62
with a standard deviation of 3.014, indicating a small variation. The age of the participants
ranged from 19 to 37 (M=21.62, SD=3.014) and they were 69.5% female, 30.5% male.
Design
This study has two between-subjects independent variables each with two levels. It is a
two by two independent-group factorial design. The first independent variable is semantic
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relatedness. Its first level is related study items and its second is unrelated study items. The
second independent variable is the modality of how items are presented. Its first level is words
and its second is images. The dependent variable of the study is the number of falsely recalled
items ranging in scores from 0-2 since there were only 2 trials. The four conditions in the
experiment are as follows; condition one, related study items presented as words. Condition two,
related study items presented as images. Condition three, unrelated study items presented as
words. Condition four, unrelated study items presented as images.
Materials
The DRM paradigm was used in this study with four different study lists, two containing
words and two containing images. Each study list contained the same number of study items
whether they are words or images. Two lists contained items related to the test list (e.g. desk,
office, pencils, chairs). While the other two lists contained unrelated items (e.g. thread, yarn,
needle). Depending on which condition the participants were randomly assigned to they saw
these items either as images or written as words. Participants were randomly assigned to study
one of the four lists of words in order to maintain internal validity. Participants received the same
recall test across all four conditions. A list of 36 items (e.g. desk, office, pencils, chairs)
appearing only as words was shown with a key word that has a strong conceptual link to the
study items although it was never presented (e.g. books). The dependent variable was how many
participants falsely recalled the key word. It was scored on a scale from 0-2 because there were
two trials. A score of 0 meant no false recall, while 1 meant there was false recall during one trial
and 2 meant there was false recall during both.
Procedure
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Participants were asked to partake in an online experiment where, if they consented, they
were randomly assigned to one of the four conditions. Each condition showed different study
items but participants across all conditions were asked to memorize the items they were shown.
Next all participants were asked to read a paragraph that acted as a filler in-between the study
item presentation and the recall test. Finally the participants were given the recall test that was
identical across all conditions.
Results
In support of hypothesis one, a statistically significant main effect of relatedness was
found. Subjects in the related study item condition had higher levels of false recall (M=.73,
SD=.75) than subjects in the unrelated study item condition (M=.04, SD=.19; F(1,127)=43.82,
p<.01). Additionally, a statistically significant main effect of modality was found where words
had a higher level of false recall (M=.68, SD=.73) compared to images (M=.31, SD=.61;
F(1,127)=5.91, p<.05). In support of hypothesis two a statistically significant interaction
between relatedness and modality was found (F(1,127)=5.06, p<.05). Subjects in the unrelated
study item condition had almost identical values for modality with a mean of .03 (SD=.18) for
images and a mean of .05 (SD=.22) for words. However an independent samples t-test for
subjects in the related study item condition showed a statistically significant difference where
words were falsely recalled much more (M=1.0, SD=.69) than subjects who saw images (M=.50,
SD=.73; t(80)=-3.15, p<.01).
Discussion
A main effect of both variables and an interaction was found, supporting the two
hypotheses. The study replicated the findings of the Israel & Schacter (1997) paper and the
general findings of false memory with related items. False memories are more prominent with
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related items most likely due to the fact that people group related items together when
memorizing lists. This grouping of semantic similarities allows for us to memorize more items
however it allows for more false recall when items that have semantic similarities of the study
items are presented. The reason pictures cause less false recall is likely due to the fact that they
provide specific and varied perceptual information that words lack. The present study was
limited due to its unequal sample sizes. Only 40 of the participants were male while 91 were
female, meaning certain conditions could hypothetically only contain female participants. This
affects the external validity of the experiment because it may not be generalizable to a larger
male population. Another limitation was only having two lists from which participants studied
words compared to the Blair et al. (2002) study that used five lists. Having only two lists may
allow for easier memorization thus eliminating the possibility of false recall. The present study
lends support to the Israel & Schacter (1997) study because the findings are similar. The
implications are also similar to those of the Israel & Schacter (1997) study. The results of this
study have many practical implications. They can be applied when police are gathering
eyewitness testimonies by showing witnesses photo evidence instead of written evidence in an
attempt to produce less false recall. Students may also use the results to help with school by
studying images rather than words when preparing for tests. More experiments can be conducted
in the area of false recall to test different variables. One such study could involve changing the
independent variable of words and images to faces and bodies. So the experiment would be
testing the amount of false recall in related versus unrelated faces and bodies. This experiment
would have four conditions, similar to the present study. Participants would be studying images
of people’s bodies in one experiment and of faces in the other. The hypothesis that there would
be a main effect of relatedness would stay the same. However there would be a new hypothesis
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that bodies will have a higher number of false recall than faces, specifically in the related study
item condition. This is due to the fact that People with similar body types are common, while
people with similar faces are less common. Meaning faces have distinct perceptual differences
that allow for us to remember them easier. This experiment is important because it too could
have implications in eyewitness testimony. If the hypothesis was supported this experiment
would have important implications. It could be applied when police have suspects line up and
victims pick them out of a line up. Showing that similar bodies produce false recall may give
incentive to police to only show faces of potential suspects to witnesses and victims to reduce the
amount of false recall. Having found that images produce less false recall than words it is
exciting to see what different variables future research on false recall will test.
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References
Blair, I., Lenton, A., & Hastie, R. (2002). The reliability of the DRM paradigm as a measure of
individual differences in false memories. Psychonomic Bulletin & Review, 9, 590-596.
Israel, L., & Schacter, D. (1997). Pictorial encoding reduces false recognition of semantic
associates. Psychonomic Bulletin & Review, 4, 577-581.