ABSTRACT
Hypnotic Susceptibility, Not Suggestion, Influences False Memory Development
Michelle N. Dasse, B.A.
Advisor: Charles A. Weaver, III, Ph.D.
Hypnotic susceptibility is a measurable trait that influences the development of
false memories. In Experiment 1, participants heard a positive or negative suggestion
regarding hypnosis, then listened to eight DRM lists in hypnotic state. Neither hypnosis
nor suggestion affected memory. High susceptibility participants were significantly more
accurate in recall and recognition. In Experiment 2, suggestions were delivered in the
form of feedback. Participants heard a positive or negative suggestion about their
performance prior to either encoding or retrieval of eight DRM lists. Accurate and false
memory was not affected by the suggestion conditions. Those with high hypnotic
susceptibility recalled and recognized fewer critical lures if they received a negative
suggestion about their performance. These results highlight the importance of individual
differences to susceptibility of suggestion in the creation of false memories.
Copyright © 2013 by Michelle N. Dasse
All rights reserved
TABLE OF CONTENTS
List of Tables………………………………………………….…………………………..v
List of Figures…………………………………………………………………………….vi
Acknowledgments……………………………………………………………………….vii
Chapter One: Introduction…………………………...……………………………………1
False Memory Paradigms…………………………………………………………2
Theoretical Explanations of False Memory Production……...…………………...6
Susceptibility and False Memory Development…………………………………..9
Chapter Two: Experiment One…...…………...…………………………………………13
Methods and Materials…………………………………………………………...14
Participants…………………………………………………………….....14
Materials………………………………………………………………....14
Procedure…………………………………………………………..…….17
Design………………………………………………………………..…..19
Results…………………………………………………………………………….20
Discussion………………………………………………………………………...23
Chapter Three: Experiment Two……………………………………...…………………25
Methods and Materials……………………………………………………………27
Participants………………………………………………………………27
Procedure…………………………………………………………..…….27
Design………………………………………………………………..…..28
Results…...…………………………………………………………………..……29
Discussion………………………………………………………………….……..34
Chapter Four: General Discussion……………………………………………………...36
Appendices……………………………………………………………………………….39
References………………………………………………………………………………..44
iv
LIST OF TABLES
Table 1: Mean (SEM) values of individual differences scales………..............................20
Table 2: Mean proportion (SEM) of accurate recognition in Experiment One....……….21
Table 3: Mean proportion (SEM) of accurate recall in Experiment One..........................21
Table 4: Mean proportion (SEM) of false recognition in Experiment One...…………....22
Table 5: Mean proportion (SEM) of accurate recognition in Experiment Two………....29
Table 6: Mean proportion (SEM) of accurate recall in Experiment Two………………..31
Table 7: Mean proportion (SEM) of false recognition in Experiment Two…………......32
Table 8: Mean proportion (SEM) of false recall in Experiment Two…………………....34
v
LIST OF FIGURES
Figure 1: Mean proportion of accurate recognition as a function of susceptibility, type of
suggestion, and time of suggestion in Experiment Two…….………………………….30
Figure 2: Mean proportion of false recognition as a function of susceptibility and type of
suggestion in Experiment Two…...…………………………………………………..…33
vi
ACKNOWLEDGMENTS
This research was funded by the Baylor University Psychology Department. I
would like to thank Dr. Charles Weaver, Dr. Gary Elkins, and Dr. Jim Ellor for their
guidance and help throughout this research process. The quality of this study was
enhanced by their assistance in designing this study and their oversight. I am particularly
grateful for Dr. Weaver’s guidance and supervision in analyzing the data and formatting
this thesis. I would also like to express appreciation to the research assistants who
assisted with data collection, particularly Lynn Shafer, Devyn Lambell, Vianca Leon,
Howard Chang, and David Coalson.
vii
CHAPTER ONE
Introduction
Memory is a constructive process susceptible to many errors, including the belief
that we remembered events that were never experienced. For instance, the developmental
psychologist Piaget spent over a decade vividly recalling the details of an attempted
kidnapping as an infant, only to find out later that his childhood nurse lied to him (Piaget,
1962). False memories can be innocuous, such as misremembering spilling punch on
your mother when you were younger. False memories can also be serious. Falsely
remembering seeing someone at a crime scene can later imprison them for a crime they
did not commit.
How do these illusory memories form? The answer to that question depends, in
part, on the processes underlying recognition memory. Recognition memory is comprised
of both familiarity and recollection. Familiarity-based memory is characterized by a
nonspecific sense of prior occurrence, high confidence of memory strength, and an
increase in errors with repetition. Recollection memory involves retrieving specific
details of the encoding context of an event, and is characterized by a decrease in errors
with repetition. False memories were historically attributed to familiarity processes, as it
is conceptually implausible for an event that did not occur to involve retrieval of
encoding context that did not exist (Yonelinas, 2002). However, researchers employing
misinformation paradigms, imagination inflation paradigms, and list learning paradigms
to create such errors suggest that people experience memory errors in a way that mimics
recollecting a previous occurrence (Ardnt, 2010).
1
Susceptibility to false memories is greatly influenced by individual differences,
including dissociative tendencies, introversion, extroversion, intelligence, working
memory, and locus of control (Zhu, Chen, Loftus, et al., 2010). Hypnotic susceptibility is
one such trait. Susceptibility is often tied to hypnosis, because hypnosis is essentially a
series of suggestions. However, the role of hypnosis in the development of false
memories, both as a catalyst and a retrieval aid, is often overestimated (Lynn & Kirsch,
1996). Suggestibility underlies hypnotic beliefs, and this trait does influence false
memory development (Barnier & McConkey, 1992; Kirsch, 1990). In this paper, I
explore the phenomenon of suggestibility. In particular, I examine the degree to which
one’s susceptibility to suggestion influences the development of false memories in the
highly suggestible context of hypnosis. I then observe the influence of participant
susceptibility without the hypnotic context; specifically the effect of suggestions
regarding prior performance on false memory development in participants with high and
low susceptibility.
False Memory Paradigms
False memories occur when people recollect misinformation as part of an event
they witnessed, perform actions they only imagined, and remember events that never
occurred. Platt, Lacey, Iobst, and Finkelman (1998) organized false memory research into
three separate research paradigms. The misinformation paradigm, developed by Loftus
and her colleagues, examines the extent to which misinformation is incorporated into
memory. In her original misinformation study, participants were shown a series of slides,
one which featured a car stopped in front of a yield sign. After viewing the slides,
participants read a description of what they saw, and some participants were presented
2
with misinformation stating that the car stopped at a stop sign. Participants who
experienced the misinformation were more likely to report seeing a non-existent stop sign
than those who had not experienced the misinformation (Loftus, Miller, & Burns, 1978).
Participants are often asked to make source judgments about where misinformation was
experienced in the study (before, during, after). People routinely claim, with high
confidence, to have experienced the misinformation during the original event, even when
given prior warnings that misinformation may occur. In the misinformation paradigm,
people make subjective judgments about the context of their memories, but they are not
actually retrieving specific details from the originally experienced events. The more often
misinformation is presented, the more likely are participants to attribute it to the original
event, and the more confident they become in their attributions. Misinformation is the
result of a familiarity based process. In fact, there is little to no support for recollection
contributing to the effect (Ardnt, 2010).
A second false memory paradigm is imagination inflation (Goff & Roediger,
1998) and the creation of false autobiographical memories through imagination (Seamon,
Philbon, & Harrison, 2006). Imagination inflation involves participants listening to a
variety of action statements and being asked either to perform or to imagine performing
those actions. A popular example of imagination inflation involves proposing marriage to
a Pepsi machine. Seamon et al. (2006) gave their participants familiar or bizarre action
statements with instructions either to perform the actions or to imagine performing the
actions, or watch or imagine the experimenter perform the actions. Participants who
imagined themselves or the experimenter performing familiar or bizarre actions falsely
recalled themselves performing both types of actions when tested two weeks later. On a
3
later memory test, participants judged whether they heard the action, and if so, whether
the action was imagined or actually performed. Not only did participants typically believe
that they performed actions they only imagined, they also claimed to recollect vivid
perceptual and contextual details of executing both familiar and bizarre actions. This
demonstrates the powerful nature of imagination inflation, even in a natural real-life
setting.
In false autobiographical memory studies, participants are questioned about past
autobiographical events, including an event that did not occur. Researchers then examine
the extent to which the false memory has been adopted as authentic. One of the better
known false autobiographical experiments is that of Loftus and Pickrell (1995) who
enlisted relatives of their subjects to suggest and verify false autobiographical memories
about participants. Participants were given four short narratives describing childhood
events, all provided by family members, and instructed to try to remember as much as
possible about each of the four events. One of the narratives describing the participant
being lost in a shopping mall at the age of 5 was false, despite the incorporation of many
plausible details. The participants then reported what they remembered about each
narrative, and interviewed about the details of the events. Roughly 25% of the
participants reported remembering the false narrative.
While it could be argued that the recollection of an imagined or false
autobiographical event is merely familiarity-based guesswork, evidence suggests
otherwise. For example, the more perceptual or contextually rich details participants
imagined about an event they did not experience, the more likely they were to believe
they had performed it. Lyle and Johnson (2006) explored how feature information
4
(perceptual and contextual details) from memories of similar perceived events present
support for recollection based mechanisms behind false memories. Participants viewed
pairs of slides that were related visually or conceptually. One member of each pair was
seen in a perception trial, and the other was imagined in an imagination trial. Participants
falsely remembered the objects as appearing in locations previously occupied by visually
or conceptually similar objects. The color and shape of “seen” objects were misattributed
as false memories of imagined objects, and perceived details were misattributed as false
memories of objects that had not been explicitly imagined. Lyle and Johnson (2006)
concluded that any particular false memory may contain details that were previously
imagined or perceived, and therefore this type of false memory development employs
episodic and recollection based mechanisms.
The third and final paradigm, the Deese-Roediger-McDermott paradigm, focuses
on creating false memory intrusions in recall and recognition of word lists. Participants
are presented with a list of words (syringe, knitting, pin, thread) that are semantically
related to a non-presented critical lure (needle). On later memory tests, falsely recalling
or recognizing the critical lure is indicative of a false memory (Roediger & McDermott,
1995). While most recognition errors are familiarity based (misinformation), lure errors
show several characteristics that support the theory they are recollection based. For one,
lure error rates are much higher than other recognition memory errors, and are robust in
the face of manipulations meant to eradicate them. Participants are highly confident in
their judgments and willingly provide specific contextual and perceptual source
information of these lure items. In fact, participants make more errors to lure items when
they are required to scrutinize their memories for specific details of the items to make a
5
source memory judgment (rather than simple identifying whether the lure was old or
new). For example, recognition memory for studied items and lure errors increased when
tested in a context encountered during encoding (font type, etc.). This suggests that lure
items cue the retrieval of the context present when the associates were encoded. These
findings suggest participants retrieve highly detailed information about the context in
which a lure’s associates were encoded when a lure item is tested. This false belief
underlies the conviction with which they falsely recollect lures as having been studied
(Hicks & Hancock, 2002).
Theoretical Explanations of False Memory Production
In these experiments, I used the DRM paradigm to assess false memory
development. Theoretical explanations of this phenomenon vary. The fuzzy-trace theory
(Brainerd & Reyna, 2002) suggests that any event experienced produces the storage of
memory traces that vary on a continuum between gist traces (familiarity/commonalities
of events) and verbatim traces (recollection/perceptual details of experience). In the DRM
paradigm, the semantic commonalities among the studied associates represent gist
information. If the gist traces created are strong enough at retrieval, they can produce
phantom recollection. Phantom recollection occurs when participants confuse the strength
of a gist trace with the experience of recollecting or retrieving verbatim traces of studied
items (Brainerd, Wright, Reyna, & Morjardin, 2001). Therefore, people produce DRM
lures because lure items tend to match very strong gist traces in memory. Fuzzy trace
theory is limited in its capacity to explain false memories of the DRM paradigm.
Primarily, research examining fuzzy trace theory and the DRM paradigm has focused on
manipulating within-list effects, such as the placement of the words or the strength of the
6
word lists at encoding. Since this is primary a study of individual differences, rather than
differences between individuals who rely on gist or verbatim processing, fuzzy trace
theory is mentioned here out of thoroughness, rather than as a possible account of later
results.
The activation-monitoring theory (Roediger, Watson, McDermott, & Gallo, 2001)
provides an alternative explanation. Activation-monitoring theory proposes that two
processes, semantic activation and retrieval monitoring, account for false memory in
DRM lists. Semantic activation occurs when one studies a list containing the associates of
a critical lure. The associates activate the lure’s representation in semantic memory. This
leads to the formation of associations between representations for the lure and encoding
context of the associates, increasing the likelihood that the participant makes errors to
that lure on a subsequent memory test (Roediger et al., 2001). Once lures are activated,
they are likely to be recalled unless prevented by a retrieval monitoring strategy. Lures
associated with encoding context are accessed again at retrieval, when studied items of
the same encoding context are activated. Thus, the activation-monitoring theory suggests
that little can be done to suppress activation of the lure. Instead, to reduce the false
memory effect, a warning about the lures might be beneficial prior to encoding or
retrieval (Gallo, Roediger, & McDermott, 2001).
The common underlying theme of both the fuzzy trace theory and the activationmonitoring theory is that critical lure errors are the result of the retrieval of a specific
memory representation, such as the activated representation in a semantic network or the
gist trace of word. Global matching models focus instead on the lure errors being similar
to numerous traces of their encoded associates (Ardnt & Hirshman, 1998; Hintzman,
7
1988). Encoding in a DRM task involves the storage of memory traces for each study
word. More specifically, an event produces a memory trace that contains features
describing the semantic and perceptual characteristics. All of these traces of information,
as well as elements of the context in which they were experienced, are encoded. At
retrieval, test items are compared to all the event traces in memory, and an activation
value is produced based upon the similarity of each event trace to the tested item. The
similarity values are summed, reflecting how much memory is activated. If the test value
is sufficiently high, the test item will be judged to have been “studied”.
In the case of the DRM paradigm, lures somewhat match the memory traces of
their studied associates. Although lure items may not strongly resemble individual traces,
they can accrue substantial strength because they were activated by a number of memory
traces to a moderate degree. The summation of these moderate traces produces strong
activation of memory as a whole. More specifically, each lure consists of a test probe that
is constructed when participants make a source judgment. The test probe contains item
information from the lure item and source information from each of the sources a
participant is being asked to judge. If the lure test probe is constructed with a source not
used to study its associates, it will match item information in the traces corresponding to
its studied associates, but not source information. However, if all the associates are
evaluated in a single context, then the test probe representing the lure will match the item
and source information for all the memory traces of the studied associates and trigger
activation. Interactive cueing occurs when memory probes match both item and context
information in a single trace. This generates a larger activation signal than memory
probes that activate item information and context information in different memory traces.
8
The matches of a lure to both the item and context portions of its associates’ memory
traces provide the basis for the illusion (Arndt, 2012). Global matching models can
account for all the major findings in the DRM literature that support the notion that lures
produce retrieval of encoding context, and do so using the same basic principles used to
explain recognition and source memory for studied items.
Theoretical explanations for the DRM phenomenon are extensive and complex.
Multiple individual differences also influence how and why people are more likely to
falsely recognize a critical lure. One such trait is hypnotic susceptibility to suggestion.
Susceptibility and False Memory Development
Hypnosis can effectively reduce pain, lessen depression and anxiety, and improve
quality of life (Elkins, 2007). Although hypnosis is commonly believed to benefit
memory as well (Ready, Bothwell, & Brigham, 1997), the overwhelming majority of
studies suggest that hypnotic procedures do not significantly improve memory (Erdelyi,
1994; Steblay & Bothwell, 1994; Wagstaff, Cole, Wheatcroft, Anderton, & Madden,
2008). The evidence suggesting hypnosis distorts memory is equally weak. Furthermore,
the influence varies across differing paradigms (Sheehan, Grigg, & McCann, 1984).
Researchers have studied the role of hypnotic-induced suggestibility in the development
of false memories using the misinformation paradigm and the false autobiographical
memory paradigm (Kihlstrom, 1998; Lynn, Lock, Myers, & Payne, 1977; Orne, 1979).
Erdelyi (1994) reviewed more than 30 studies examining hypnosis and memory,
concluding that hypnosis increased neither recognition nor recall of nonmeaningful
stimuli. Whether hypnosis reduces inaccurate recall (e.g. intrusions of nonpresented
stimuli that never occurred) is a separate matter. Steblay and Bothwell (1994)
9
summarized 24 such studies (some included in Erdelyi’s review). Six studies reported
that hypnotized participants produced more false memories in response to misleading
questions or false information than non-hypnotized control subjects.
Curiously, few researchers have used the DRM paradigm, and the results are
mixed (Neuschatz, Lynn, Benoit, & Fite, 2002). Neuschatz et al. (2002) read two DRM
lists to forty students, half of whom were hypnotized. If hypnosis reduced false memories
under these conditions, participants’ would have avoided circling the critical lures on the
later recognition test. This was not the case. False recognition was equivalent (and
substantial) across both conditions. However, the hypnotic induction was comparatively
weak, as the majority of participants rated themselves, “somewhat hypnotized”
(Neuschatz et. al., 2002).
Barnier and McConkey (1992) found that hypnotic susceptibility, not hypnosis
itself, increased false memory reports in a misinformation study. Participants viewed a
series of slides of a purse snatching and then imagined seeing the slides in either hypnosis
or waking conditions. The experimenter suggested that the offender had a mustache (true),
wore a scarf (false) and picked up flowers (false). Memory was immediately tested by the
experimenter; another experimenter questioned the participant in a later inquiry session,
and again after the session ended. Hypnosis had no effect on memory performance.
Hypnotic susceptibility, on the other hand, was a major predictor of subjects’ false
memory. Highly susceptible subjects are more likely to accept suggestions and
cognitively elaborate in a way that gives it a greater degree of personal meaningfulness
(Barnier & McConkey, 1992; Winograd, Peluso, & Glover, 1998).
10
While hypnosis does not improve memory, neither does it appear to be a
“dangerous” procedure (Steblay et al., 1994). However, a number of factors might
complicate prior research on hypnosis, including situational context, instructions and
warnings, monetary rewards, and rapport between participants and researchers. In
particular, suggestion and expection (e.g., "You can and will recall everything") are
critical. Subtle instructional differences may increase compliance on the part of
participants, making them less vulnerable to reversing false memories in the face of
shifting demand characteristics (Green, Lynn, & Malinoski, 1998). Green et al. (1998)
found that prehypnotic warnings, such as “Hypnosis can create false memories” and
encouraging participants to distinguish reality from imagination both had an appreciable
effect on participant suggestibility during hypnosis. On those who accepted the
suggestion during hypnosis, the warning had no effect. Although the prehypnotic
warnings reduced suggestibility, they did not reduce the overall false memory rate. A
sizeable number of participants continued to report false memories even after a strong
warning about the potential of hypnosis to create false memories (Green et al., 1998;
Lynn et al., 1977).
Participant susceptibility to critical lures of the DRM paradigm is dependent not
only on the suggestions, but also the differences among participants. Certain traits such as
fantasy proneness, dissociation, and magical thinking are associated with false memory
development (Loftus, 1995; McNally & Clancy, 2005b). On the other hand, the
relationship between dissociative symptoms and false memories is mixed; some studies
find those high on dissociative experiences (as measured by the Dissociative Experiences
Scale; DES) produce more false memories (e.g. Dehon, Bastin, & Laroi, 2008; Geraerts,
11
Smeets, Jelicic, van Heerden, & Merckelbach, 2005; Hyman & Billings, 1998; Winograd
et al., 1998). Others did not find a relationship (Platt, Lacey, Iobst, & Finkelman, 1998).
Various metholodological details might explain these opposing findings, such as the
specific version of the DES scale used, the nature of the source monitoring task, or the
sample characteristics.
12
CHAPTER TWO
Experiment One
In this study, I examined the effects of contextual suggestions and expectations on
memory using a DRM task. In a typical DRM task, participants hear a list of words that
are semantically related to an unpresented critical word. On later memory tests, falsely
recalling or recognizing the critical word is indicative of a false memory. Given the
complex nature of hypnosis and suggestibility, I offer two predictions consistent with the
activation monitoring theory of false memory. Any lures activated in the study are likely
to be accessed again at retrieval unless suppressed by a monitoring strategy. I predict that
participants misinformed of the advantages of using hypnosis would show high rates of
false memories because they are less inclined to monitor their responses if they believe
hypnosis to be beneficial. Participants hearing a suggestion about the advantage of
hypnosis would show higher rates of false memory compared to participants hearing a
suggestion about the disadvantages of hypnosis on memory. Providing participants with a
suggestion about hypnosis being detrimental may encourage them to monitor their
memory better and therefore make fewer errors.
In addition, participant differences with respect to their susceptibility to
suggestions would also influence false memory creation. I measured hypnotic
susceptibility using the Creative Imagination Scale (Barber & Wilson, 1978). I also
examined whether individual differences in fantasy proneness and dissociation affect
false recall and recognition in the DRM task. People who exhibit heightened levels of
fantasy proneness and dissociative tendencies should be more susceptible to both
13
hypnotic induction and false memory. Those prone to dissociation may well have lower
confidence in their own memories. As a result, participants may rely more on the use of
external cues in deciding whether plausible apparent memories are real.
Materials and Methods
Participants
One hundred and twenty two undergraduates between the ages of 18 to 22
enrolled in psychology and neuroscience courses at Baylor University were recruited to
receive credit in partial fulfillment of a college course requirement. Each participant was
required to attend two individual sessions. All participants signed an informed consent
for research participation and received a copy of the form for their research participation
and a copy for their records. The study was approved by Baylor’s Instituional Review
Board and met the American Psychological Association’s and the American Clinical
Society of Hypnosis standards for minimal risk to the well-being of subjects.
Materials
The twenty minute induction in the experimental conditions was administered
using a prerecorded hypnosis induction tape from Gary Elkins (Elkins, 2012). In order to
determine participants’ hypnotic susceptibility, the thirty minutes Creative Imagination
Scale was administered to all participants via recording. The participants self-scored their
hypnotic susceptibility on a ten item follow up CIS questionnaire.
The eight word lists were selected from the 24 lists used by Roediger and
McDermott (1995), each consisting of 15 words. Four of the lists are considered “strong”
lists, as levels of false recall in normative studies are particularly high. The other four
14
lists are considered weak lists, as the probability of false recall of the critical lures is
more modest (McDermott & Watson, 2001). Each DRM list contains words related to the
critical non-presented item. Ordering of the words within each list was held constant; the
items were presented in order of decreasing association with the critical non-presented
item. For counterbalancing purposes, the order in which the lists were heard was
switched across participant. Participants heard all eight lists, with a 5 minutes pause in
between each set of four lists for participants to complete a word search distracter task.
Presenting of the study items involved a pre-recorded researcher reading the study words
at a rate of one word per two seconds. After all words are read, the researcher then
recorded participants’ recall with a tape recorder.
The 56 item recognition test included eight blocks of seven items for each DRM
list. Items within blocks were fixed, but the order of the blocks was randomized. Each
block of seven words contained two weak by association studied words, two strong by
association studied words, two distracter (non-studied) words, and the critical lure. All
blocks started with a weakly related word and ended with the critical word, but the order
of the words in between were random. Participants rated each word using a 4 point Likert
scale were 1 (certainly new), 2 (probably new, but not sure), 3 (probably old, but not
sure) to 4 (certainly old). In addition, participants completed a number of questionnaires.
The Australian Sheep-Goat Scale (ASGS; Thalbourne, 1995) is designed to
measure belief in, and alleged experience of, the paranormal. It consists of 16 items that
all relate specifically to the three core concepts of parapsychology: ESP (extrasensory
perception), PK (psychokinesis), and life after death. Example items are “I believe in the
existence of ESP”, “I believe I have personally exerted PK on at least one occasion” and
15
“I believe in life after death”. For all items, the response items are “True” and “False”
resulting in a score of 2, 1, or 0 points respectively. The scale has a range from 0 to 36,
with higher scores indicating higher levels of belief and experience. The ASG has been
widely used and has proven reliability and validity (Chronbach’s a= .94) (Thalbourne,
1995).
The Magical Ideation Scale (MIS; Eckblad & Chapman, 1983) is a 30-item self
report measure that evaluates participants’ level of magical ideation, or belief in forms of
causation that by conventional standards are invalid. Subjects respond “True” or “False”
questions that indicate magical thoughts, psychotic experiences, schizotypal experiences,
affective symptoms, and difficulties in concentrations, such as “I sometimes have a
feeling of gaining or losing energy when people look at me or touch me" (keyed "true")
and "Some people can make me aware of them just by thinking about me" (keyed
"true").” Respondents indicate whether the item is true or false regarding their personal
experience. Items 7, 12, 13, 16, 18, 22, 23 are scored 1 if answered false. All other items
are scored 1 if answered true. Total scores on the MI scale range from 0 to 30, with
higher scores indicating more pronounced magical thinking. The MIS has good internal
consistency and validity (Chronbach’s a= .85) (Eckblad & Chapman, 1983).
The Dissociative Experiences Scale (DES; Bernstein & Putnam, 1986) is a 28item self-report measure that asks respondents how often they experience dissociative
symptoms like derealization and depersonalization. Subjects respond to an 11-point scale,
ranging from 0% (Never) to 100% (Always) in 10% increments. Scores are summed to
obtain a total DES score (range 0-100), higher scores indicated higher dissociative
tendencies. The DES exhibits high internal consistency and test-retest correlations
16
ranging from .74 to .84. It has been shown that the DES has excellent psychometric
properties (Cronbach’s a= .92) (Van IJzendoorm & Schuengel, 1996).
The Creative Experiences Questionnaire (CEQ; Merckelbach, Muris, & Rassin,
1999) is a measure that is based on Wilson and Barber’s (1983) listing of fantasy
proneness characteristics. The CEQ includes 25 dichotomous (yes/no) items that cover
experiences related to daydreaming, imagining, and intense fantasizing. Yes answers to
CEQ items are summed to obtain a total score (range: 0-25) with higher scores indicating
higher levels of fantasy proneness. Psychometric research has shown that the CEQ
possesses adequate reliability in terms of internal consistency and test-retest stability
(Cronbach’s a= .79).
Procedure
Participants were tested individually. In the first session, participants were
randomly assigned into one of three groups: the control/waking condition, the lowsuggestion hypnosis condition, and the high suggestion hypnosis condition. Participants
in the positive suggestion condition heard a positive suggestion (“hypnosis will allow you
to remember everything”). Participants in the negative suggestion condition heard a
negative suggestion (“hypnosis will have little to no effect on your memory”). Finally,
participants in the control condition were read a set of instructions that makes no mention
of hypnosis having any effect on memory. All participants were then told that they would
hear an audio tape containing four lists of fifteen words each and they would be tested
immediately after each list by recalling the words aloud into a tape recorder. Participants
were encouraged to recall as many words as they could.
17
Participants in the experimental conditions listened to a twenty minute
prerecorded segment of a guided relaxation tape. The hypnotic induction took
approximately twenty minutes to complete. Immediately following the induction,
participants listened to a taped recording of two weak lists and two strong lists as
described earlier by the researcher. Following the presentation of all fifteen words,
subjects were cued by the saying, “Recall”. Participants were given two minutes to recall
each list out loud into the tape recorder. Following this recall session, the next list was
cued by the phrase, “Begin list”. The process repeated until all four lists were heard and
recalled.
Following the fourth list recall, participants were instructed to find the researcher
for their next task. Participants were then given five minutes to complete a word search.
Following this, the participants heard a different set of four lists and, as before told that
they would recall the words aloud following presentation. The lists were then played as
before.
At this point, participants were given another five minutes to complete a word
search. Fifty six words were read aloud and participants judged each word on a scale of
one to four, based on their confidence that the word occurred previously on one of the
lists they had just heard. The 4-point rating scale: 4 for sure that the item was old (or
studied), 3 for probably old, 2 for probably new, and 1 for sure it was new. Subjects
completed this at their own pace, indicating to the researcher when the researcher should
say the next word. Participants were then thanked and reminded to come back in a week
for their second session.
18
Those in the non-hypnosis group followed similar procedures, but read twenty
minutes of a Scientific American article entitled, “Brominated Battle: Soda Chemical Has
Cloudy Health History,” instead of listening to the hypnotic induction. Prior to listening
to the DRM lists, control participants were warned similar to those participants in the
experimental hypnosis condition.
Subjects returned a week later. During the second session, all participants
completed four surveys, the Australian Sheep-Goat Scale, the Magical Ideation Scale, the
Dissociative Experiences Scale, and the Creative Experiences Questionnaire. Then, they
listened to the thirty minute Creative Imagination Scale and completed the CIS
questionnaire regarding their ability to imagine the tasks they heard. Participants were
then debriefed and excused.
Design
All participants heard all 8 lists, though two thirds heard them in a state of
hypnosis and the other third during a non-treatment control session. The study consisted
of three independent conditions: 1) Positive suggestion hypnosis (N= 38), 2) negative
suggestion hypnosis (N=41) and 3) No suggestion control (N=43). Thus, the data were
analyzed using a 3 (condition, 3 levels, between-subjects) by 2 (hypnotic susceptibility, 2
levels between-subjects) MANOVA.
Results
Unless stated otherwise, an alpha level of .05 was adopted throughout data
analysis. Means and standard errors for all five individual differences measures are
19
presented below (Table 1). Selected analyses derived from the measures will be discussed
shortly.
Table 1:
Mean (SEM) values of individual differences scales
Scale
Mean
SEM
Australian Sheep/Goat Scale
6.16
0.60
Creative Experiences Scale
9.27
0.42
Magical Ideation Scale
9.54
0.34
Dissociative Experiences Scale
21.32
1.52
Creative Imagination Scale
14.35
0.88
Only minor differences were found between measures, with the exception of
scores on the Creative Imagination scale, the measure of hypnotic susceptibility. To
address susceptibility, our sample was filtered to include only participants with scores on
the bottom quartile of the CIS (n=35) and scores in the top quartile (n=28). Mean
accuracy and mean false memory were analyzed in 3 (condition; positive suggestion,
negative suggestion, no suggestion control) by 2 (hypnotic susceptibility; low and high)
MANOVA. Essentially, hypnotic susceptibility was treated as an independent variable
with two levels. Analyses for accurate and false memories were performed separately.
Mean accurate recognition is shown in Table 2, mean accurate recall is displayed in
Table 3, and mean false recognition is displayed in Table 4.
Accurate Recognition
The main effect of suggestion on accurate recognition was significant, F(2, 62) =
3.8, eta squared = .18. Participants who heard a positive suggestion were less accurate
20
than participants who heard a negative suggestion or no suggestion. The main effect of
susceptibility on accurate recognition was not significant, and neither was the interaction
between suggestion and hypnotic susceptibility.
Table 2
Mean proportion (SEM) of accurate recognition in Experiment 1
Accurate Recognition
Suggestion
Low susceptibility
High susceptibility
Positive Suggestion
0.70 (.03)
0.78(.03)
Negative Suggestion
0.79 (.03)
0.78(.03)
Control
0.80 (.03)
0.87(.03)
Accurate Recall
Table 3
Mean proportion (SEM) of accurate recall in Experiment 1
Accurate Recall
Low susceptibility
High susceptibility
Positive Suggestion
Suggestion
0.47 (.03)
0.62 (.03)
Negative Suggestion
0.63 (.03)
0.64 (.03)
Control
0.67 (.03)
0.66 (.03)
The main effect of suggestion on accurate recognition was significant, F(2, 62) =
6.3, eta squared = .12. Again, participants who heard a positive suggestion were less
accurate than participants who heard a negative suggestion or no suggestion. The main
effect of susceptibility on accurate recall was not significant. The interaction between
suggestion and hypnotic susceptibility was not significant. Participants in the control
condition were more accurate than participants in both experimental conditions.
False Recognition
21
Table 4
Mean proportion (SEM) of false recognition in Experiment 1
False Recognition
Suggestion
Low susceptibility
High susceptibility
Positive Suggestion
0.38 (.04)
0.27 (.04)
Negative Suggestion
0.31 (.04)
0.24 (.04)
Control
0.30 (.04)
0.25 (.04)
The main effect of suggestion on false recognition was not significant. However,
the main effect of hypnotic susceptibility was significant. False memory differed between
the two levels of susceptibility for recognition, F(2, 62) = 4.8, eta squared = .07.
Participants with low susceptibility were more likely to false recognize a critical lure. The
interaction between suggestion and hypnotic susceptibility did not significantly influence
false recognition. Neither suggestion nor hypnotic susceptibility significantly influenced
false recall, so false recall will not be discussed any further.
Both experimental conditions were combined, then analyzed with a (condition;
experimental and control) by 2 (hypnotic susceptibility; low and high) MANOVA.
Participants in the control condition remained more accurate in their responses, F(1, 62)
= 5.00, eta squared = .08. Finally, participants of high susceptibility also remained more
accurate in their responses, but this effect was trending on significant, F(1, 62) = 3.45, eta
squared = .05, p = .07.
Discussion
In Experiment One, I looked at the effects of contextual suggestions and
participant susceptibility on accurate and false memory for DRM lists. I predicted that
participants in the positive suggestion condition would show impaired memory accuracy
and reduced likelihood of false memory, while participants hearing a negative suggestion
22
would show the converse. However, participants receiving no suggestion about hypnosis
were more accurate than those receiving suggestions. Furthermore, suggestion produced
no differences on false memory tasks. These results are consistent with previous literature
assessing the use of suggestibility in false memory paradigms (Green et al., 1998;
Neuschatz et al., 2002). Receiving suggestions about the benefits or detriments of
hypnosis affected neither accurate nor false memory of critical items. No significant
interaction effects were found between hypnotic susceptibility and suggestion condition
for both accurate and false memory.
I also predicted that participants with high levels of hypnotic susceptibility would
be more responsive to suggestions regarding hypnosis. While highly susceptible
participants were no more responsive to the suggestions than their low susceptibility
peers, they were more accurate in both recall and recognition. The results regarding
hypnotic susceptibility as a trait are inconsistent with previous literature (Barnier et al.,
1992) but this might likely result from restricted range amongst participants score on the
CIS, weakening our ability to draw conclusions. The role of hypnotic susceptibility in the
production of false memories remains interesting, and this will be explored further in
Experiment Two.
23
CHAPTER THREE
Experiment Two
The most interesting finding in Experiment One was the lack of interaction
between suggestion and false memory development. Participants who received no
suggestion about memory before the DRM task were significantly more accurate and
falsely recognized less lures than participants who had received any kind of suggestion.
Our findings raised more questions. Would suggestion have a significant effect on false
memory if directed at participant performance, rather than the context of the experiment?
Are suggestions more effective if delivered before retrieval rather than before encoding?
Finally, is the significant influence of hypnotic susceptibility in Experiment One an
interesting fluke, or does hypnotic susceptibility play a more significant role in the
creation of false memories than previously thought?
To answer these questions, I manipulated the suggestions given to participants to
see how different types of feedback influence false recognition rates. More specifically, I
presented participants with a positive or negative suggestion about performance before or
after a DRM task, and examined how this influenced performance on the later recognition
test. This allowed us to measure not only the effect of feedback on accurate and false
memory rates, but also how these suggestions could potentially have different effects
based on time of delivery. I was also interested in examining the previously seen
influence of participant susceptibility in false memory development.
In Experiment Two, I followed the methodology of Experiment One, but
examined the effects of a type and time of suggestion on memory accuracy. Participants
24
heard one of two salient suggestions that had nothing to do with actual performance on
the task. Participants heard the affirming suggestion, “Your score on the online memory
test is at the top of the distribution” or the negative suggestion “Your score on the online
memory test is at the bottom of the distribution”. This message was heard at one of two
different times during the experiment, either at the onset of the study or directly after
encoding but prior to completing the recognition test for the 8 DRM lists used in
Experiment One.
From this, I offered two contradictory predictions, based on different
understandings of the source of the false memory. If false memories are the result from
inaccurate monitoring of retrieval, then manipulations designed to impair monitoring
should increase false memories (Roediger et al., 2001). Therefore, participants who
received a positive suggestion should be more susceptible to errors, as their monitoring
should be impaired by the belief that they are performing well. I predicted participants
receiving a negative suggestion should monitor their memory closer throughout the rest
of the session, and demonstrate more accuracy.
However, if false memories are the result of encoding processes, the valence of
the feedback participants are receiving should make no difference. If false memories
result from encoding errors, then the time at which suggestions are delivered will
influence participant accuracy more than the valence of the suggestion. If differences
arise in accuracy between participants receiving the suggestion at the beginning of the
session and participants who receive the suggestion before the recognition test, we can
determine whether or not false memories are an encoding error or a retrieval error. If
participants who receive the suggestion before encoding make more false memory errors,
25
this is consistent with the global matching models framework, which states that false
memories are the result of errors within encoding (Ardnt & Hintzman, 1998). If
participants receiving the suggestion prior to test make more errors, we can assume false
memories are a retrieval error. This is consistent with the activation-monitoring theory.
This theory views false memory as source judgment errors made at retrieval (Roediger et
al., 2001).
Materials and Methods
Participants
One hundred and eight undergraduates between 18 and 22 enrolled in psychology
and neuroscience courses at Baylor University were recruited to receive credit in partial
fulfillment of a college course requirement. Each participant completed an online
memory test and attended one session at the lab. All participants signed an informed
consent for research participation and received a copy of the form for their records.
Procedure
After signing up to participate in the study on our online database SONA,
participants were directed to complete a ten-minute memory test as a precursor to the
individual lab session. The online memory test consisted of fifteen words that participants
viewed for thirty seconds and then attempted to recall. After completing the online
memory test, participants came into the lab for their individual lab session. Participants
were consented, and then randomly assigned to one of six groups, the positive suggestion
group/pre-study, the positive suggestion group/pre-test, the negative suggestion
group/pre-study, the negative suggestion group/pre-test, or one of two control conditions
(no suggestion/pre-study and no suggestion/post-study). Those in one of the two the pre26
session suggestion condition heard either the positive or negative feedback regarding
their performance on the online memory test. Participants in the control condition did not
hear any suggestions about their performance on the online memory test.
Participants then listened to the eight DRM lists, completed the recall, and
completed the recognition test. These are the same word lists and the same instructions
and procedure from Experiment 1. After hearing all eight lists of words, participants in
the pre-test condition heard either the positive or negative suggestion. All participants
were then be given the recognition test. Participants then listened to thirty minutes of the
Creative Imagination Scale and completed the CIS questionnaire regarding their ability to
imagine the tasks they heard. Participants were then debriefed and excused. The session
took no longer than one hour.
Design
The study consisted of six independent conditions: Positive suggestion/pre-study
(N= 35), negative suggestion/pre-study (N=34), positive suggestion/pre-test (N=34),
negative suggestion/post-test (N=34), no suggestion/pre-study control (N=36), and no
suggestion/pre test control (N=34). The data were analyzed using a 3 (type of suggestion,
3 levels between-subjects) by 2 (time of suggestion, 2 levels between-subjects) by 2
(susceptibility, 2 levels between-subjects) MANOVA.
Results
Unless stated otherwise, an alpha level of .05 was adopted throughout data
analysis. To address susceptibility, our sample was filtered to include only participants
with scores in the bottom quartile of the Creative Imagination Scale (n=59) and scores in
27
the top quartile (n=49). Mean accuracy and mean false memory were analyzed in a 3
(type of suggestion; positive, negative, or none) by 2 (time of suggestion; pre or post
DRM) by 2 (hypnotic susceptibility; high vs. low susceptibility) MANOVA. Analyses for
accurate memories and false memories were performed separately. Mean accurate
recognition is shown in Table 1, mean accurate recall is displayed in Table 2, mean false
recognition in Table 3, and mean false recall is displayed in Table 4.
Accurate Recognition
Table 5
Mean proportion (SEM) of accurate recognition in Experiment Two
Accurate recognition
Low
High
Suggestion
Time of suggestion
susceptibility
susceptibility
Positive suggestion
Pre-DRM
0.85 (0.01)
0.88 (0.01)
Post-DRM
0.83 (0.01)
0.67 (0.01)
Pre-DRM
0.83 (0.01)
0.79 (0.01)
Post-DRM
0.82 (0.01)
0.88 (0.01)
Pre-DRM
0.83 (0.01)
0.79 (0.01)
Post-DRM
0.78 (0.01)
0.84 (0.01)
Negative suggestion
No suggestion
The main effects of type of suggestion, time of suggestion, and susceptibility on
accurate recognition were not significant. However, the interaction between the type of
suggestion and time of suggestion on accurate recognition was significant, F(2, 106) =
6.331, eta squared = .117. Participants who received a positive suggestion prior to
encoding were more accurate, but the reverse was true for those who received the
positive suggestion after encoding. Participants who heard the negative suggestion prior
28
to hearing the DRM lists were less accurate than the positive suggestion group, but the
pattern reversed for those who received a negative suggestion after encoding. All results
must be interpreted within the context of a three way interaction between type of
suggestion, time of suggestion, and susceptibility, F(2, 106) = 5.350, eta squared = .100.
The two way interaction between type of suggestion and time of suggestion was seen
only in participants who were receptive to the suggestion, or those with high
susceptibility. The three way interaction is shown in Figure 1.
Figure 1. Mean proportion of accurate recognition as a function of susceptibility, type of suggestion, and
time of suggestion in Experiment Two.
Accurate Recall
Accurate recall demonstrated the same pattern as accurate recognition, the three
way interaction between susceptibility, type of suggestion, and time of suggestion was
significant, F(2, 106) = 3.966, eta squared = .076. Because of this similarity, these results
will not be discussed further.
29
Table 6
Mean proportion (SEM) of accurate recall in Experiment Two
Accurate recall
Low
High
Suggestion
Time of suggestion
susceptibility
susceptibility
Positive suggestion
Pre-DRM
0.62 (0.01)
0.69 (0.01)
Post-DRM
0.65 (0.01)
0.57 (0.01)
Pre-DRM
0.65 (0.01)
0.57 (0.01)
Post-DRM
0.66 (0.01)
0.71 (0.01)
Pre-DRM
0.65 (0.01)
0.62 (0.01)
Post-DRM
0.61 (0.01)
0.60 (0.01)
Negative suggestion
No suggestion
False Recognition
Table 7
Mean proportion (SEM) of false recognition in Experiment Two
False recognition
Suggestion
Time of suggestion
Low susceptibility
High susceptibility
Positive suggestion
Pre-DRM
0.69 (0.01)
0.73 (0.02)
Post-DRM
0.69 (0.01)
0.68 (0.01)
Pre-DRM
0.83 (0.02)
0.71 (0.02)
Post-DRM
0.75 (0.02)
0.61 (0.02)
Pre-DRM
0.59 (0.02)
0.74 (0.02)
Post-DRM
0.63 (0.03)
0.72 (0.01)
Negative suggestion
No suggestion
In the case of false recognition, the two way interaction between type of
suggestion and susceptibility was significant, F(2,160) = 3.667, eta squared = .071.
Participants with high susceptibility made significantly fewer false recognition errors if
they received a negative suggestion about their performance, regardless of when they
30
heard the suggestion. Again, this reinforces the significance of suggestions in a
responsive population. This interaction is shown in Figure 2.
Figure 2. Mean proportion of false recognition as a function of susceptibility and type of suggestion in
Experiment Two.
False Recall
Table 8
Mean proportion (SEM) of false recall in Experiment Two
False recall
Low
High
Suggestion
Time of suggestion
susceptibility
susceptibility
Positive suggestion
Pre-DRM
0.27 (0.02)
0.43 (0.02)
Post-DRM
0.46 (0.02)
0.43 (0.02)
Pre-DRM
0.48 (0.03)
0.35 (0.02)
Post-DRM
0.47 (0.02)
0.23 (0.01)
Pre-DRM
0.33 (0.02)
0.48 (0.02)
Post-DRM
0.30 (0.02)
0.42 (0.02)
Negative suggestion
No suggestion
31
The two way interaction between type of suggestion and susceptibility on false
recall was also significant, F(2,160) = 5.509, eta squared = .103. Participants of high
susceptibility made significantly fewer false recall errors if they received a negative
suggestion about their performance, regardless of when they heard the suggestion.
Participants with low susceptibility who heard a positive suggestion were significantly
less likely to recall false critical lures.
Discussion
In Experiment Two, I investigated both the type and timing of suggestions on
accurate and false memory for DRM lists. I predicted that participants given the positive
feedback would be more susceptible to errors because increased confidence would impair
monitoring during recall and recognition. I anticipated that those given negative feedback
would show improved monitoring and better accuracy. Different types of suggestions did
not produce differences in accuracy or false memory. I also predicted differences in rates
of false memory between participants receiving the suggestion at the beginning of the
session and participants who received the suggestion before the recognition test. Time of
suggestion alone also failed to significantly influence false memory development.
The trait of hypnotic susceptibility was the key to interactions seen in both
accurate and false recognition (Barnier et al., 1992). Brunot and colleagues suggest the
obvious: highly susceptible people are more receptive to suggestions (Brunot, Huguet, &
Monteil, 2000). In the case of accurate memory, highly susceptible participants
responded to suggestions depending on the type and time of the suggestion. Broken down
across the four conditions, participants who heard positive suggestions before hearing
word lists recalled more words. Participants who heard a negative suggestion prior to
32
study recalled fewer words. However, participants who heard the positive suggestion
prior to retrieval were less accurate in their recognition. Participants in the negative
suggestion condition demonstrated the inverse. Positive feedback facilitated encoding,
and negative feedback facilitated monitoring. This is an interesting finding regarding
accurate memory, but it will not be discussed further.
Participant susceptibility and type of suggestion also interacted to influence false
memory, particularly recognition performance. Highly susceptible participants hearing a
negative suggestion falsely recognized fewer critical lures than those low in susceptibility.
Participants low in susceptibility showed little effect of negative suggestion. Indeed, they
had higher false memory rates.
33
CHAPTER FOUR
General Discussion
The present study examined the effect of contextual and performance suggestions
on the development of false memories. Although I report accurate memory results for
Experiment One and Two, we do not discuss it further. Overall, suggestion alone did not
produce effects. However, suggestion did produce effects when hypnotic susceptibility
was considered. In Experiment One, I found a significant influence of susceptibility to
suggestion on episodic false memory. The effect of hypnotic susceptibility was confirmed
in Experiment Two.
My findings regarding the importance of hypnotic susceptibility to memory are
consistent with findings from Barnier et al., (1992), McConkey et al., (1990), and
Sheehan et al., (1991, 1992). According to Sheehan and colleagues (1991), hypnotic
susceptibility is relevant to the creation of false memories, regardless of whether
participants are in a suggestible context. However, my findings regarding the direction of
the effect of participant susceptibility are not entirely consistent with prior findings. In
general, most researchers report a positive correlation between susceptibility and false
memory. The findings of the present study propose that increased susceptibility to
suggestion decreases false memory.
My findings regarding false memory creation are best explained by the activationmonitoring theory (Roediger et al., 2001). The activation-monitoring theory states that
false memories occur when the semantically related critical items are activated at study
through semantic networks. At recall or recognition, the critical lures can be rejected by
34
employing a monitoring strategy (McDermott & Watson, 2001; Neuschatz et al., 2003).
To prevent false memories, one can increase attention at encoding or adapt better
monitoring strategies during retrieval. Recall in Experiment 1, suggestions regarding
hypnosis had no effect on false memory rates. Hypnotic susceptibility was the key to
false memory development. Frost and colleagues (2006) demonstrated that people with
high hypnotic susceptibility have larger working memory spans. A larger working
memory capacity facilitates better encoding and retrieval, reducing false memories, thus
explaining the results of Experiment One. It is possible that participants of high
susceptibility monitored their recall and recognition better to prevent inaccuracies, in line
with the activation-monitoring theory.
In Experiment Two, hypnotic susceptibility interacted with the performance
suggestions to decrease false memory rates. Those with high hypnotic susceptibility who
heard a negative suggestion were less likely to identify critical lures as being studied. The
activation-monitoring theory argues that negative feedback may have encouraged
participants to redirect their attention towards the task at hand and attempt to improve
their performance (Brunot et al., 2000; Krenn et al., 2013). Further research is needed to
examine why participants of high hypnotic susceptibility were responsive to performance
suggestions of a negative valence, but not to contextual suggestions regarding hypnosis.
My results were generally inconsistent with predictions made by the fuzzy trace
theory or the global matching models of false memory development. However, fuzzy
trace theory derives predictions primarily from item-based differences in materials, our
studies do not provide strong test.
35
The common underlying theme of both the fuzzy trace theory and the activationmonitoring theory is that false recollection is a familiarity based process. Critical lure
errors are the result of the retrieval of a specific memory representation, such as the
activated representation in a semantic network or the gist trace of word. In contrast,
global matching models argue that false recollection involves the retrieval of specific
episodic details. Lure errors are numerous traces of their encoded associates (Ardnt &
Hirshman, 1998; Hintzman, 1988). In Experiment Two, I administered suggestions at two
different times to test the global matching models framework. If false memories were the
result of encoding processes, the suggestion delivered prior to encoding would have made
more errors. If false memories were the product of retrieval processes, participants
receiving the suggestion prior to test would have made more errors. The time of
suggestion did not significantly influence false memory development. Therefore, I am
unable to support the global matching models framework. False memories are no more
than errors involving familiarity occurring at retrieval.
The results of the present study highlight the importance of individual differences
in susceptibility to suggestion in the creation of false memories. Hypnotic susceptibility
is a measurable trait that influences the development of false memories. High levels of
hypnotic susceptibility alone are effective in reducing false memory rates. Highly
susceptible people also respond effectively to suggestions that encourage better
monitoring, such as negative performance suggestions. Both these findings are indicative
of better monitoring in people with high hypnotic susceptibility, and are consistent with
the activation-monitoring theory. Further research is needed to examine the most
effective suggestions for the highly susceptible population.
36
APPENDICES
37
APPENDIX A
DRM Word Lists
Window
door
glass
pane
shade
ledge
sill
house
open
curtain
frame
view
breeze
sash
screen
shutter
Fruit
apple
vegetable
orange
kiwi
citrus
ripe
pear
banana
berry
cherry
basket
juice
salad
bowl
cocktail
Sleep
bed
rest
awake
tired
dream
wake
snooze
blanket
doze
slumber
snore
nap
peace
yawn
drowsy
Smell
nose
breathe
sniff
aroma
hear
see
nostril
whiff
scent
reek
stench
fragrance
perfume
salts
rose
38
Thief
steal
robber
crook
burglar
money
cop
bad
rob
jail
gun
villain
crime
bank
bandit
criminal
Lion
tiger
circus
jungle
tamer
den
cub
Africa
mane
cage
feline
roar
fierce
bears
hunt
pride
Needle
thread
pin
eye
sewing
sharp
point
prick
thimble
haystack
thorn
hurt
injection
syringe
cloth
knitting
King
queen
England
crown
prince
George
dictator
palace
throne
chess
rule
subjects
monarch
royal
leader
reign
APPENDIX B
Recognition Test
Screen
Web
Glass
Shutter
Door
Insect
Window
Salts
Cross
Breathe
Rose
Nose
Trash
Smell
Yawn
Rest
Bed
Uneven
Course
Drowsy
Sleep
Criminal
Cap
Steal
Robber
Felt
Bandit
Thief
Bowl
Coffee
Cocktail
Sip
Vegetable
Apple
Fruit
Leader
Note
England
Queen
Reign
Happy
King
Cloth
Hard
Thread
Knitting
Light
Pin
Needle
Pride
Tiger
Hunt
Kitten
Circus
Fear
Lion
Scoring: 4 point scale (1 to 4)
1: NEW (participant is certain the word is new, has never heard it before
2: PROBABLY NEW (the word is probably new, but participant is not sure)
3: PROBABLY OLD (the word is probably old, but participant is not sure)
4: OLD (participant has heard the word before)
39
APPENDIX C
Suggestions
Experiment One
(A) Just a quick warning before we begin, as you may already know, memory is
imperfect, whether or not hypnosis is used. Memory is not like a tape recorder,
and rarely will all the details of any recollection be fully accurate. People are
capable of filling in gaps in their memory, of distorting information, and of being
influenced by what is “remember” by leading questions or suggestions. In fact,
researchers have discovered that hypnosis improves memory, especially for lists
of words. By listening to this guided relaxation tape, you will undergo hypnosis,
and be taken to a deep trance state that will allow you to remember everything
you hear during and after the induction. Do you have any questions?
(B) Just a quick warning before we begin, as you may already know, memory is
imperfect, whether or not hypnosis is used. Memory is not like a tape recorder,
and rarely will all the details of any recollection be fully accurate. People are
capable of filling in gaps in their memory, of distorting information, and of being
influenced by what is “remember” by leading questions or suggestions. In fact,
researchers have discovered that hypnosis is detrimental to memory, especially
for lists of words. By listening to this guided relaxation tape, you will undergo
hypnosis, and be taken to a deep trance state that will prevent you from
remembering anything you hear during and after the induction. Do you have any
questions?
(C) Just a quick warning before we begin, as you may already know, memory is
imperfect. Memory is not like a tape recorder, and rarely will all the details of
any recollection be fully accurate. People are capable of filling in gaps in their
memory, of distorting information, and of being influenced by what is
“remember” by leading questions or suggestions. Do you have any questions?
Experiment Two
Time 1 (A)
Positive: Wow! It looks like you did really well on the online memory test! Your score on
the prescreen test was at the top of the distribution of scores, definitely higher than the
typical average for college students. Good job! Are you ready to get started on your next
task?
Negative: Oh no! It looks like you did really poorly on the online memory test. Your
score on the prescreen test fell into the bottom of the distribution of scores that we’ve
40
received so far, definitely lower than the typical average for college students. That’s not
good. Are you ready to get started on your next task?
Time 2 (B)
Positive: I listened to a bit of your tape when you were working. It looks like you did
really well! Your recall was at the top of the distribution of scores, definitely higher than
the typical average for college students. Good job! Are you ready to get started on your
next task?
Negative: I listened to a bit of your tape when you were working. It looks like you did
really badly! Your recall was at the bottom of the distribution of scores, definitely lower
than the typical average for college students. That’s not good. Are you ready to get
started on your next task?
41
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