ABSTRACT
EVALUATING THE EFFECTS OF HIGH-PROBABILITY/LOWPROBABILITY SEQUENCES ON A MEASURE OF
INTERROGATIVE SUGGESTIBILITY
Interrogative suggestibility is characterized by factors present during
interrogations that make people more likely to accept inaccurate information and
change their responses accordingly. Research on interrogative suggestibility has
been vital in changing the way interrogations are conducted in court trials and
police interrogations, yet many different factors involved in interrogative
suggestibility, that are present during interrogations, have not been investigated.
Recent research has emphasized the importance of verbal feedback and the
interviewer’s behavior, yet no research has analyzed the possible effects if any, of
building momentum during interrogations by manipulating the order of questions
(suggestible vs. non-suggestible). High-probability and low-probability sequences
are one way to increase the likelihood of previously low-probability responses.
This procedure is commonly used to increase appropriate behaviors and reduce
problem behavior during instructional tasks, by presenting tasks that are more
likely to be completed first, then presenting tasks that are less likely to be
completed. The purpose of the current study was to examine the application of
high-probability/low-probability sequences on a measure of interrogative
suggestibility, and the effects, if any, on suggestibility scores.
Grecia Argelia Mendoza
May 2017
EVALUATING THE EFFECTS OF HIGH-PROBABILITY/LOWPROBABILITY SEQUENCES ON A MEASURE OF
INTERROGATIVE SUGGESTIBILITY
by
Grecia Argelia Mendoza
A thesis
submitted in partial
fulfillment of the requirements for the degree of
Master of Arts in Psychology
in the College of Science and Mathematics
California State University, Fresno
May 2017
APPROVED
For the Department of Psychology:
We, the undersigned, certify that the thesis of the following student
meets the required standards of scholarship, format, and style of the
university and the student's graduate degree program for the
awarding of the master's degree.
Grecia Argelia Mendoza
Thesis Author
Marianne Jackson (Chair)
Psychology
JP Moschella
Psychology
Steven Payne
Psychology
For the University Graduate Committee:
Dean, Division of Graduate Studies
AUTHORIZATION FOR REPRODUCTION
OF MASTER’S THESIS
X
I grant permission for the reproduction of this thesis in part or in
its entirety without further authorization from me, on the
condition that the person or agency requesting reproduction
absorbs the cost and provides proper acknowledgment of
authorship.
Permission to reproduce this thesis in part or in its entirety must
be obtained from me.
Signature of thesis author:
ACKNOWLEDGMENTS
I would like to express my sincere gratitude to my thesis chair and advisor,
Dr. Marianne Jackson, for her continuous support through the process of
developing my thesis, her commitment to this project, her guidance, and for this
learning opportunity. I am also grateful to the members of my committee, Dr.
Payne and JP Moschella, for their constant support and valuable comments on this
thesis. I would also like to express my gratitude to Dr. Price and Chelsea Wilhite
for their help and guidance with statistics. I would like to thank my research
assistants for their passionate participation, time, and for working together with
me to complete sessions by the set deadline.
I would also like to express my profound gratitude to the most important
people of my life. First, I would like to thank my mother Rosa, for her
unconditional love, continuous encouragement throughout the years, and for
always believing in me. I would also like to thank my father Longino, for teaching
me to never give up and to always pursue my dreams. I am forever grateful for
your support. I would also like to thank my husband for his patience, love, and for
being a constant source of support during the challenging times. I would also like
to express my gratitude to the rest of my family members and friends, for
constantly providing words of encouragement. All of you made this
accomplishment possible.
TABLE OF CONTENTS
Page
LIST OF TABLES ................................................................................................. vii
LIST OF FIGURES ............................................................................................... viii
CHAPTER 1: INTRODUCTION ............................................................................ 1
Eyewitness Testimony and Suggestibility ........................................................ 1
CHAPTER 2: LITERATURE REVIEW ................................................................. 7
Theoretical Approaches to Interrogative Suggestibility ................................... 7
Measuring Interrogative Suggestibility ............................................................. 9
Interrogative Suggestibility Components........................................................ 13
The Context ..................................................................................................... 13
The Suggestible Stimulus................................................................................ 17
The Questioning Procedure ............................................................................. 19
High-Probability and Low-Probability Sequences ......................................... 20
Purpose ............................................................................................................ 27
CHAPTER 3: METHODOLOGY.......................................................................... 29
Participants and Settings ................................................................................. 29
Materials .......................................................................................................... 29
Research Design .............................................................................................. 30
Independent Variable ...................................................................................... 31
Dependent Variable ......................................................................................... 31
Interobserver Agreement and Procedural Integrity ......................................... 32
Procedures ....................................................................................................... 33
CHAPTER 4: DATA ANALYSIS ......................................................................... 37
Graphical and Statistical Analyses .................................................................. 37
vi
Page
CHAPTER 5: RESULTS AND DISCUSSION ..................................................... 38
Discussion ....................................................................................................... 41
REFERENCES ....................................................................................................... 46
APPENDICES ........................................................................................................ 52
APPENDIX A: INFORMED CONSENT .............................................................. 53
APPENDIX B: PROCEDURES INTEGRITY ...................................................... 55
LIST OF TABLES
Page
Table 1 Means and Standard Deviations for Scores on the GSS Scales for
Baseline and HP/LP Sequence Conditions .................................................. 40
LIST OF FIGURES
Page
Figure 1. Differences in Yield 1 and Yield 2 scores between conditions.............. 40
Figure 2. Means for Yield 1 and Yield 2 for baseline and the HP/LP sequence. .. 41
CHAPTER 1: INTRODUCTION
Eyewitness Testimony and Suggestibility
In the most recent annual report released by the Federal Bureau of
Investigation (FBI), an estimated 1,197,704 violent crimes were reported by law
enforcement in the U.S in 2015 (The Federal Bureau of Investigation, 2016).
Estimates of 7,993,631 property crimes were also reported by law enforcement in
the U.S. for that same year. According to the Innocence Project (2016), a nonprofit legal clinic affiliated with the Benjamin N. Cardozo School of Law at
Yeshiva University, at least 1 in every 4 people wrongfully convicted in the U.S.
have provided incriminating statements and false confessions during
interrogations. In addition, there have been 330 known criminal cases in U.S.
history that have resulted in convictions of innocent people because the
eyewitnesses incorrectly identified them as the perpetrators (Innocence Project,
2016). Despite the large number of wrongful convictions in the U.S., eyewitness
testimony is still considered the most important evidence against a defendant in
criminal trials (Innocence Project, 2016). Although, the Innocence Project does
not discourage the incorporation of eyewitness testimony as part of the evidence in
a court trial, it does emphasize the importance of other relevant factors that must
be controlled in order to obtain accurate testimonies. In addition, the American
Psychological Association also supports the relevance of eyewitness testimony
and the importance of understanding the factors involved in eyewitness testimony
and how these can affect the accuracy of testimonies during interrogations (Azar,
2011).
For this reason, several studies (e.g., Eisen, Morgan, & Mickes, 2002;
Eisen, Quas, & Goodman, 2002; Gudjonsson, 1992; Gudjonsson & Sigurdsson,
2
2004; Pezdek & Roe, 1995) have investigated the factors that may affect the
outcomes of interrogations and have emphasized the importance of understanding
suggestibility, more specifically interrogative suggestibility. According to
Gudjonsson (2003), the term suggestibility was initially related to mental
processes that occurred in a person’s consciousness. In addition, he went on to say
that Eysenck’s (1947) work further expanded these processes by identifying two
types of suggestibility: primary and secondary suggestibility. According to
Eysenck’s work, primary suggestibility requires motor movements that occur
without the person’s awareness; secondary suggestibility is characterized by the
perception of an event that never happened. Eysenck further proposed that these
types of suggestibility occur after a direct or indirect suggestion is provided. These
types of suggestibility were assumed to occur inside the person’s mind, not
allowing for accurate measurement of these processes (Gudjonsson, 2003).
In 1986, Gudjonsson and Clark proposed yet another type of suggestibility
referred to as “interrogative suggestibility” that results from suggestions presented
during questioning: “The extent to which, within a social interaction, people come
to accept messages during formal questioning, as a result of which their
subsequent behavioral response is affected” (p. 84). Gudjonsson and Clark further
argued that interrogative suggestibility should be considered a unique and
important type of suggestibility because it involves the interaction of many factors
that are likely to co-occur during formal interviews. In addition, Gudjonsson and
Clark argued that interrogative suggestibility involved five components: a social
interaction, a questioning procedure, a suggestible stimulus, acceptance of the
stimulus, and a behavioral response. The researchers go on to say that these
components resemble the interactions that take place during questioning and can
3
be observed when the person makes a response to indicate the acceptance or denial
of a particular stimulus.
The first component of interrogative suggestibility is the social interaction
that takes place, often in a closed room, with other people asking questions about
an event, and with minimal interruptions (Gudjonsson, 2003). The second
component involves the questioning procedure, which involves the recollection of
information that the participants experienced in the past. The third component
involves the suggestive stimulus, which can range from question styles, to the type
of feedback given during interrogations. The fourth component is the acceptance
of the suggestive stimulus, and the last component requires the participants’
behavioral response, which allows the researchers to observe whether or not the
suggestion was accepted. This component is usually measured when the
participant makes a verbal or non-verbal response that conforms to the suggestive
stimulus given.
The definition provided by Gudjonsson and Clark (1986) allowed for the
development of a theoretical model to enhance the understanding and awareness
of these components during interrogations. Furthermore, these components can
vary during interrogations, and may alter the acceptance or rejection of a
suggestive stimulus. For this reason, research (e.g., Bain, Baxter, & Fellowes,
2004; Baxter & Boon, 2000; Baxter, Charles, Martin, & McGroarty, 2013;
Baxter, Jackson, & Bain, 2003; McGroarty & Baxter, 2007, 2009; Sparling,
Wilder, Kondash, Boyle, & Compton, 2011) has focused on investigating the
effects of changes in one or more of the components involved in interrogative
suggestibility. The components manipulated have involved interviewers’
behaviors that are classified as abrupt, firm, or friendly and the type of feedback
delivered, while others have looked into the individual differences between
4
participants, such as self-esteem, age differences, and intellectual capabilities
(Baxter & Boon 2000; Baxter et al., 2003, 2013; Doepke, Henderson, &
Critchfield, 2003; McGroarty & Baxter, 2007, 2009; Sparling et al., 2011). Other
research has focused on the types of questions asked, in relation to the delivery of
negative feedback, and has found increased susceptibility to inaccurate
information during interrogations when specific questions are presented in
combination with negative feedback (Baxter, Boon, & Marley, 2006; Baxter et al.,
2013; Doepke et al., 2003; Drake & Bull, 2011). The specific questions
investigated in past research have consisted of suggestible and non-suggestible
questions. Suggestible questions have been defined as questions that suggest an
answer (e.g., Was the woman’s name Anna Wilson?) and that cannot be answered
based on the information previously provided. Non-suggestible questions have
been defined as questions that do not suggest an answer (e.g., What was the
woman’s name?) and that could be answered correctly based on the information
previously provided.
Although research has emphasized the importance of the types of questions
and social feedback, no emphasis has been placed on the order of the questions
presented during interrogations. Past behavioral research has shown that
presenting high-probability tasks and low-probability tasks in a specific order can
increase compliance with low probability tasks (Austin & Agar, 2005; Axelrod &
Zank, 2012; Banda, Matuszny, & Therrien, 2009; Belfiore, Basile, & Lee, 2008;
Ducharme & Worling, 1994; Esch & Fryling, 2013; Hughes, 2009; Humm,
Blampied, & Liberty, 2005; Lee, 2006; Meier, Fryling, & Wallace, 2012; Riviere,
Becquet, Peltret, Facon, & Darcheville, 2011; Wehby & Hollahan, 2000). This is
often referred to as high-probability/low-probability (HP/LP) sequence (Pierce &
Cheney, 2013). These sequences are selected based on the level of difficulty of the
5
task, question, or instruction presented, with the difficult tasks assigned to the lowprobability condition, and the easier tasks assigned to the high-probability
condition. These tasks are then presented in the following manner: highprobability tasks first, followed by low-probability tasks. Research has shown that
when tasks, instructions, or questions are presented following the HP/LP
sequence, the probability, the response rate, and the fluency increase for the lowprobability tasks (Austin & Agar, 2005; Banda et al., 2009; Belfiore et al., 2008;
Ducharme & Worling, 1994; Esch & Fryling, 2013; Hughes, 2009; Humm et al.,
2005; Lee, 2006; Meier et al., 2012; Riviere et al., 2011; Wehby & Hollahan,
2000). This phenomenon is often discussed using the concept of behavioral
momentum: the continuation of behavioral responses in conditions in which these
responses were less likely to occur prior to the presentation of the HP/LP
sequences (Pierce & Cheney, 2013).
Although behavioral research has shown the effectiveness of HP/LP
sequences, these sequences have primarily been applied to interventions to
increase behaviors in the home and academic environment (Austin & Agar, 2005;
Axelrod & Zank, 2012; Banda et al., 2009; Belfiore et al., 2008; Ducharme &
Worling, 1994; Esch & Fryling, 2013; Humm et al., 2005; Hughes, 2009; Lee,
2006; Wehby & Hollahan, 2000; Meier et al., 2012; Riviere et al., 2011). An
exception to this is a study conducted by Hughes (2009), who investigated the
presence of HP/LP sequences during three real life audiotaped hostage
negotiations and found that compliance only occurred when the requests followed
the HP/LP sequence. These results not only showed that compliance increased
during negotiations when requests follow the HP/LP sequence, but also indicated
that these sequences can be applied to other context outside the academic
environment. In the study conducted by Hughes, increasing compliance with low-
6
probability request was beneficial; however, compliance with such a sequence
may also produce undesirable outcomes (i.e., inaccurate testimony). This study
allows for the possible application of these sequences to context where compliance
may not be beneficial or therapeutic.
During criminal trials, the eyewitness is often questioned multiple times
and thus compliance with inaccurate information can result in the conviction of
innocent people (Innocence Project, 2016). Given this, it may be important to
examine the effects of a HP/LP sequence on a measure of interrogative
suggestibility, by altering the order of questions presented in an analogue
interrogative context.
CHAPTER 2: LITERATURE REVIEW
Theoretical Approaches to Interrogative Suggestibility
Schooler, Gerhard, and Loftus (1986) identified two main approaches to
interrogative suggestibility: the experimental approach and the individual
differences approach. The experimental approach examines the conditions under
which the questions are presented and the effect this has on the responses of the
people interrogated (Gudjonsson, 2003, pp. 334-335). In addition, this approach
examines the cognitive and memory processes involved and how memories can be
modified or created. The individual-differences approach examines the
individuals’ personal history and their coping strategies during interrogations that
resemble the context in which interrogations are conducted. This approach
emphasizes the importance of the individual’s personal history as a factor that
alters interrogative suggestibility (Gudjonsson, 2003).
According to Gudjonsson (2003), the experimental approach is best
reflected by the work of Loftus and colleagues (Loftus 1979; Loftus, Miller &
Burns, 1978; Schooler & Loftus, 1993). Loftus’s (1979) research emphasizes the
creation of new memories after the introduction of incorrect information. In
addition, the emphasis is placed on how incorrect information transforms what the
participant recalls from a previously experienced event. For example, in the Loftus
et al. (1978) study, the researchers investigated the effects of providing incorrect
information during questioning and its effects on memory recall. In the study,
participants saw different slides containing visual information about an accident.
Immediately after seeing the different slides, participants were asked a series of
questions regarding the accident portrayed on the slides. One group was asked if
there was a stop sign on the slides, while the other group was asked if there was a
8
yield sign. The participants engaged in an unrelated activity for 20 minutes, and
were then presented with a series of 15 slides and instructed to select the slide that
they had seen earlier. The results showed that, when the question contained
information that matches the actual slide initially presented to the participants,
75% of the participants responded correctly and selected the correct slide. When
the question contained incorrect information, only 41% of the participants
responded correctly (Loftus et al., 1978). These results indicate that the
introduction of incorrect information can affect the accuracy of responses.
On the other hand, the individual-differences approach is best illustrated by
the work of Gudjonsson and colleagues (Gudjonsson, 1983, 1984; Gudjonsson &
Clark, 1986) because it focuses on the relationship between the procedures used
during interrogations and the participants’ coping strategies and personal life
events (Gudjonsson, 2003). The emphasis is on the individual’s personal history
and how this enhances or reduces their degree of suggestibility. For example,
Gudjonsson and Singh (1984) conducted a study in which they investigated the
relationship between the number of convictions of a group of delinquent boys and
a measure of their interrogative suggestibility. In the study, participants had an
average of 3.2 convictions and were tested individually. The participants were
required to listen to a short story, to engage in a 50-minute unrelated activity, and
to answer questions regarding the story. These questions consisted of suggestible
and non-suggestible questions. Suggestible questions were defined as questions
that suggested an answer that did not match the information provided in the story.
Non-suggestible questions were defined as questions that did not suggest an
answer but could be answered correctly based on the information provided in the
story. Participants were then given negative feedback about their performance and
were required to answer the same questions for a second time. The negative
9
feedback consisted of the researchers telling the participants that they made a lot
of errors, that the same questions were going to be presented, and were instructed
to try to be more accurate. This feedback was given regardless of the correctness
of their responses to the questions. The results showed that there was a direct
correlation between the number of convictions and the degree of interrogative
suggestibility, as measured by the participants’ total number of compliances with
the suggestion given during questioning. In addition, the negative feedback
increased the participants’ overall interrogative suggestibility scores. As
mentioned before, the emphasis is placed on the role of participant’s personal
history, and the individual’s suggestibility to interrogative pressure (Gudjonsson &
Clark, 1986).
Although the previously mentioned research has focused on interrogative
suggestibility using the “experimental approach” or the “individual differences
approach,” Gudjonsson (2003) has argued that both of these approaches cannot be
completely separated when testing for interrogative suggestibility. According to
Gudjonsson (2003), an individual’s personal history, and the modifications in the
type of information provided and procedures used during questioning, are both
present during interrogative situations. For this reason, Gudjonsson (2003)
suggests that these approaches can be investigated simultaneously and that the
emphasis must be placed on investigating alterations in the components of
interrogative suggestibility.
Measuring Interrogative Suggestibility
Most of the studies investigating interrogative suggestibility have used the
Gudjonsson Suggestibility Scales (Bain et al., 2004; Baxter & Boon, 2000; Baxter
el al., 2003; Drake & Bull, 2011; McGroarty & Baxter, 2007) The Gudjonsson’s
10
Suggestibility Scales (GSS) are one of the methods widely recognized to assess
and measure aspects of interrogative suggestibility (Merckelbach, Muris, Wessel,
& Koppen, 1998). The GSS were created and developed by Gisli Gudjonsson in
1984, and measure verbal memory recall and interrogative suggestibility using two
different components: Yield and Shift (Gudjonsson & Clark, 1986).
The GSS come with short stories and questions. The participants listen to a
short story and immediately recall all the information they can remember about the
story. After immediate recall, participants engage in a 50-minute unrelated
activity, and then answer a set of 20 questions. Their first answers are scored as
Yield 1, because they are the immediate answers the participants give after being
exposed to the short story and the unrelated activity. After the participants answer
this first set of 20 questions, they receive negative feedback, and are instructed to
answer the same set of questions for a second time. The negative feedback consists
of the researcher telling the participants that they made a lot of errors, and that the
questions will be repeated. The negative feedback provided is the same for all
participants regardless of the correctness of their responses to the set of questions.
Three scores are then calculated: Yield 2, Shift, and Total Suggestibility. Yield 2 is
defined as the number of suggestions that the participant accepted after the
negative feedback was given. Shift measures the number of responses changed
between Yield 1 and Yield 2. Total Suggestibility is obtained by adding Yield 1
and Shift scores (Gudjonsson, & Young, 2011).
Past research on these scales (Gudjonsson, 2003; Merckelbach et al., 1998)
supports their application and reliability for immediate and delayed measurement
of verbal memory recall, problems in memory processing, and interrogative
suggestibility. For example, Merckelbach et al. (1998) examined the reliability and
validity of the GSS by testing for internal consistency, test-retest stability, and
11
Yield scale, across different past experiences and identities. In the study,
participants were exposed to the same procedures as those indicated in the GSS
manual. Results indicated a significant internal consistency of the GSS subscales
as well as reliability of the Yield scale based on the test-retest stability. Together,
these results support the validity of the GSS as an instrument to assess
interrogative suggestibility and contain many of the features of the interrogative
context that people face when their testimony is necessary for police
investigations.
Past research on the GSS has allowed for variations to the procedures and
other aspects of the scales. For example, Gudjonsson developed two parallel
scales, GSS1 and GSS2. These scales are identical to each other in structure,
measure the same components, but differ in the information that their paragraphs
contain, as well as the content of the questions (Gudjonsson, 2003). The
paragraphs and questions in the GSS1 involve forensic information such as details
about a robbery, whereas the paragraphs and questions in the GSS2 contain nonforensic information such as a family enjoying an everyday activity. The type of
information the GSS1 and GSS2 require varies because the purpose of these scales
is to address not only information required during police interrogations, but also
everyday information. Other variations in the use of the scales have consisted of
changing the unrelated activity duration during interrogations. For example,
Smeets, Leppink, Jelicic, and Merckelbach (2009) conducted a study in which
they investigated the effects of shortened versions of the unrelated activity on the
GSS (GSS1 and GSS2), and found that these shortened versions produced results
similar to the original GSS procedures. In the study, the researchers tested for four
different conditions: the standard GSS procedure, a no delay/immediate recall, no
delay/no recall, and a short 20-minute delay/no recall. The standard GSS
12
procedure condition required participants to listen to a short story and to provide
immediate recall about the short story. After this immediate recall, participants
answered a set of 20 questions and then were instructed to engage in a 50-minute
unrelated activity. Once the 50-minute unrelated activity time elapsed, participants
were required to answer the same set of 20 questions.
The no delay/immediate recall condition consisted of the participants
providing an immediate recall about what they remembered about the short story,
and where then required to answer a set of 20 questions. After answering the set of
20 questions, participants were then instructed to answer the same set of 20
questions without giving them an unrelated activity between the first and the
second presentation of the 20 questions. The no delay/no recall condition consisted
of the participants answering the set of 20 questions twice, immediately after
listening to the short story, without immediate recall and without an unrelated
activity delay in between testing. The delay/no recall condition followed the
original procedures except that the participants engaged in a 20-minute unrelated
activity and answered the set of 20 questions after listening to the short story
without providing any immediate recall prior or after engaging in the unrelated
activity. Results showed that the shorter versions of the GSS (GSS1 and GSS2)
did produce similar results to the standard GSS procedure, in the presence and
absence of the unrelated activity interval and the immediate recall. These results
suggest that the GSS scores are relatively unaffected by the variation of the
retention interval, which can vary from 20 minutes to 50 minutes, as well as by the
presence or absence of free recall tests (Smeets et al., 2009). These results are
important because they indicate that the time between questioning does not
significantly affect interrogative suggestibility. This is relevant to current
13
interrogating procedures because the intervals in between interrogations often vary
during criminal trials (Police Executive Research Forum, 2013).
Interrogative Suggestibility Components
As previously mentioned, Gudjonsson (2003) has argued that the
experimental approach and the individual-differences approach are both useful and
complementary approaches to investigate interrogative suggestibility. However,
Gudjonsson (2003) has also argued that in order to further understand
interrogative suggestibility, research must focus on identifying and controlling
variations in the components present during interrogations. For this reason,
Gudjonsson (2003) proposed five components that are present during
interrogations and that could affect how suggestible a person is to interrogative
suggestibility. According to Gudjonsson (2003), the components involved in
interrogative suggestibility consist of: the context in which interrogations take
place, the questioning procedure that requires the participant to give an answer, the
suggestible stimulus, the covert verbal behavior, and a behavioral response. Thus,
a great deal of research on interrogative suggestibility has focused on the effects of
changing three of these components: the context, the suggestible stimulus given,
and the questioning procedure (Bain et al., 2004; Baxter & Boon, 2000; Baxter et
al., 2003; Doepke et al., 2003; McGroarty & Baxter, 2007; Sparling et al., 2011).
Changes in these three components are often investigated in order to understand
changes in the participants’ behavioral responses when exposed to interrogative
pressure.
The Context
Research investigating context focuses primarily on changes in the
interviewer’s behavior during questioning. For example, Baxter and Boon (2000)
14
assessed the effects of three interviewer styles: firm, friendly, and stern. In the
study, the researchers used the GSS2 to measure interrogative suggestibility. In
addition, the researchers compared the effects of negative feedback and no
feedback after an unrelated activity. Again negative feedback involved telling the
participants that they made a lot of errors, that the questions were going to be
repeated, and that this time they needed try to answer the questions more
accurately. Friendliness was defined as the interviewer having a positive attitude,
greeting the interviewee, smiling, and responding to the interviewee’s initiations.
Firmness was defined as the interviewer having a neutral and professional attitude
and only interacting with the participant to deliver instructions and to ask
questions. Sternness was defined as the interviewer having a forceful attitude
characterized by being confident and assertive. Results showed that the delivery of
the negative feedback on the GSS2 did affect the participants’ scores for Yield 2
and Shift, as the participants only changed their responses to the questions after
the negative feedback. In addition, there were no significant differences between
the three interviewer styles, indicating that changes in these scores were a result of
negative feedback and not the interviewer demeanor.
Past research has also investigated the relationship between the
interviewee’s self-esteem and suggestibility (Gudjonsson & Lister, 1984; Singh &
Gudjonsson, 1984). For example, Singh and Gudjonsson (1984) researched the
effects of differences in the interviewee’s self-esteem by comparing suggestibility
scores of individuals with high self-esteem to those with low self-esteem. In the
study, the participants were exposed to the GSS twice (e.g., each presentation of
the GSS one week apart from the next presentation) and were asked to rate
themselves during the experiment. Each presentation of the GSS was presented as
indicated in the GSS procedures. Results showed that individuals with low self-
15
esteem were more suggestible to the external cues presented during questioning as
indicated by the GSS manual. In addition, the results showed that individuals with
low self-esteem were more likely to agree with suggestions when exposed to
interrogative pressure. These results indicated that self-esteem did make a
difference in suggestibility scores when exposed to interrogative pressure.
Baxter et al. (2003) further investigated the effects of interviewee’s selfesteem and the interaction of this with interviewer demeanor, using the GSS1. In
the study, researchers gathered an equal number of participants with high and low
self-esteem scores on a standardized questionnaire and exposed the participants to
one of the two different interviewer styles: Abrupt or Friendly. Half of the
participants with low-self esteem were exposed to the Abrupt condition, and the
other half were exposed to the Friendly condition. Participants in the high-self
esteem group were assigned similarly, with half of them assigned to the Abrupt
condition, and the other half to the Friendly condition. In the Abrupt condition, the
interviewer leaned their body towards the participant, did not attempt to smile or
greet the participant, and delivered all required instructions with a facial
expression that indicated the interviewer was mildly annoyed. In the Friendly
condition, the interviewer maintained a body position of leaning back from the
participants, smiled frequently, responded to conversations initiated by the
participants, and maintained eye contact. Negative feedback was delivered after
the initial set of questions, as outlined in the GSS2 procedures.
Consistent with previous studies (Baxter & Boon, 2000), Baxter et al.
(2003), found no significant difference in the suggestibility scores across the
Friendly and Abrupt conditions; however, the results indicated an interaction
effect: those with low self-esteem had lower Yield 2 and Shift scores when they
were exposed to the Friendly condition and higher Yield 2 and Shift scores when
16
they were exposed to the Abrupt condition. Participants with high self-esteem
scored higher on Yield 2 and Shift in the Friendly condition, and lower in the
Abrupt condition. Thus, participants with low self-esteem scores were more
suggestible during the Abrupt condition, and participants with high self-esteem
were more suggestible during the Friendly condition.
Bain et al. (2004) also studied the interaction between the interviewer’s
behaviors and self-esteem, but examined the difference between a warning (e.g.,
that they would be given false information) or no warning condition. In this study,
the interviewer’s behavior consisted of Abrupt and Friendly interviewer styles, as
characterized by Baxter et al. (2003), and participants’ self- esteem was again
evaluated using a standardized self-esteem scale. Results suggested that all of the
factors tested could affect interrogative suggestibility. First, the researchers found
a significant difference between participants with low-self esteem and high-self
esteem, with those with low-self esteem scoring higher on Shift. This indicates
that participants with low-self esteem changed their answers more frequently than
those with high-self esteem. The researchers also found a significant difference in
Yield 2 and Total Suggestibility scores when participants received a warning
about the presence of misleading information, with those in the warning condition
scoring lower on these measures than those in the no warning condition. These
results indicated that the warning about the presence of misleading information
decreased participant’s suggestibility to interrogative pressure when compared to
the no warning condition. One interesting result of this study was that an increase
in the number of Shifts was observed when participants were exposed to the
Friendly interviewer and the warning condition, and a decrease was observed
when exposed to the Abrupt and warning condition. These results indicate that all
three variables affect how suggestible people are to interrogative suggestibility and
17
that further evaluations of the specific procedures of the GSS1 and GSS2 should
be conducted (Bain et al., 2004).
The results obtained in the studies described indicate that the interviewer’s
demeanor (e.g., firm, friendly, abrupt) did not significantly change the
participant’s interrogative scores when presented alone; however, when changes to
the interviewer’s demeanor were combined with negative feedback, warning or no
warning about misleading information, and interacted with individual differences
such as high or low self-esteem, the participant’s interrogative scores were
significantly affected (Bain et al., 2004; Baxter & Boon, 2000; Baxter et al., 2003;
Gudjonsson & Lister, 1984); Singh & Gudjonsson, 1984). These results have
allowed for the further investigations of other components of interrogative
suggestibility, such as changes in the suggestible stimulus given (e.g., negative
feedback) and in the questioning procedures.
The Suggestible Stimulus
As previously mentioned, Baxter and Boon (2000) compared the effect of
negative feedback and no feedback on interrogative suggestibility and found that
participants were more suggestible in the presence of the negative feedback. In
addition, other studies (Baxter & Boon, 2000; Baxter et al., 2013; Doepke et al.,
2003; McGroarty & Baxter, 2007; Sparling et al., 2011) have also found that
negative feedback can affect how suggestible a person is to interrogations. For
example, Doepke et al. (2003) compared the effects of social influence in the form
of negative and positive feedback regarding a person or event and found that the
negative feedback did affect accuracy during interrogations. In the study, children
were exposed to a simulated health check situation in which the doctor conducted
specific check-up procedures (e.g., measured the child, used a stethoscope, etc.).
18
After the event, participants were exposed to no feedback, positive feedback, and
negative feedback regarding the event and the doctor. In this study, the
participant’s parents delivered the positive and negative feedback. Results showed
a decline in the accuracy of the participants’ responses to questions regarding the
event they experienced when they received negative feedback but not when they
received positive feedback.
In addition, McGroarty and Baxter (2007) also researched the effects of
negative feedback and neutral feedback and found that the negative feedback did
affect interrogative suggestibility. In the study, the researchers exposed the
participants to neutral feedback or negative feedback. In addition, the researchers
tested the effects of a second interviewer during questioning. Negative feedback
was defined as the interviewer stating that other people performed better than the
participant, and that the consultant wanted to see if the participant could do better
when answering the same questions for the second time. Neutral feedback was
defined as the consultant saying thank you to the participant and proposing to go
through the questions for a second time to ensure the answers were correctly
recorded. The second interviewer was in charge of asking every fifth question
during the interrogation and sat next to the primary interviewer. Results showed
that the presence of a second interviewer had no significant effect on interrogative
suggestibility. However, the results also showed that the negative feedback
produced the highest change in responses to the initial answers, and thus, did have
a significant effect on interrogative suggestibility. These results support those
obtained by Baxter and Boon (2000) and Doepke et al. (2003), indicating that
negative feedback increases interrogative suggestibility.
19
The Questioning Procedure
Studies that have investigated the effects of types of feedback have also
focused on the types of questions presented during questioning (Baxter et al.,
2013; Doepke et al., 2003; Drake & Bull, 2011). The types of questions have
varied in the information they require, from simple yes or no answers, to
elaborated answers that require the participant to recall details (e.g., number of
children in the story, color of the item) of a previously experienced event.
Research suggests that the types of questions presented and the information they
require, can affect interrogative suggestibility. For example, Baxter et al. (2013)
studied the effects of suggestible and non-suggestible questions in the presence of
negative and neutral feedback. The four conditions were as follows: negative
feedback with suggestible questions, negative feedback with adapted nonsuggestible questions, neutral feedback with suggestible questions, and neutral
feedback with adapted non-suggestible questions. The results showed no major
impact on the participants’ susceptibility to interrogative suggestibility when
exposed to either suggestible or non-suggestible questions separately. However,
when presented in combination with negative feedback, the participants’
susceptibility to interrogative suggestibility increased.
This study (Baxter et al., 2013) places an emphasis on the effects of
specific things that reliably occur before and after the suggestible response and
may be functionally relevant variables (i.e. the contingencies of the suggestible
response). One such variable that may affect suggestible responses is the order of
questions presented. Research has shown that the presentation of high probability
(HP) responses (for our purposes, these are responses to non-suggestible
questions) followed by the presentation of low probability (LP) responses (here,
these are responses to suggestible questions), can result in the continuation and
20
increase in behavior that is less likely to be performed. HP/LP sequences involve
tasks that are more likely to be performed (high probability) since these involve
behaviors that are associated with a higher rate of reinforcement, before presenting
tasks that are less likely to be performed (low-probability) because they are
associated with less reinforcement (Pierce & Cheney, 2013). Since reinforcement
is characterized by an increase in the probability that a behavior will occur in the
future under similar circumstances, differences in the reinforcement schedule can
increase or decrease its probability of occurrence (Pierce & Cheney, 2013). Thus,
a behavior that is associated with a higher rate of reinforcement is more likely to
occur in the future compared to a behavior that has a thinner schedule of
reinforcement. Therefore, HP/LP sequences would be particularly concerning in
the area of interrogative suggestibility, because they can alter the behavior in
subsequent tasks that are otherwise less likely to be performed (i.e., individuals
would be more suggestible and responding to suggestible questions would be less
accurate).
High-Probability and Low-Probability Sequences
Applied researchers have utilized the HP/LP sequence to increase the
response rate of desired behavioral responses and to decrease the rate of undesired
responses. Research using HP/LP sequences have shown that these sequences can
be applied to different contexts and settings, from schools to households (Austin &
Agar, 2005; Banda et al., 2009; Belfiore et al., 2008; Belfiore, Lee, Vargas, &
Skinner, 1997; Ducharme & Worling, 1994; Esch & Fryling, 2013; Hughes, 2009;
Humm et al., 2005; Lee, 2006; Meier et al., 2012; Riviere et al., 2011; Wehby &
Hollahan, 2000). In addition, research has shown that these sequences can be
effective in a variety of different tasks, from academic tasks such as classroom
21
instructions, reading material, functional vocabulary, and math problems (Austin
& Agar, 2005; Banda et al., 2009; Belfiore et al., 2008; Esch & Fryling, 2013;
Lee, 2006; Wehby & Hollahan, 2000). Research has also shown that HP/LP
sequences can also be effective in increasing behaviors during everyday activities
such as social interactions, eating preferred and non-preferred food, and tolerating
medical examinations (Ducharme & Worling, 1994; Hughes, 2009; Humm et al.,
2005; Meier et al., 2012; Riviere et al., 2011).
Past researchers investigating the application of HP/LP sequences in the
academic environment have found these sequences to be effective in increasing
compliance with instructions (Belfiore et al., 2008; Esch & Fryling, 2013; Vostal
& Lee, 2011. For example, Belfiore et al. (2008) analyzed the effects of presenting
classroom instructions in a HP/LP sequence and found that compliance with lowprobability instructions increased from an average of 13% to 90%. The highprobability instructions consisted of instructions that the students complied with at
least 80% of the time (e.g., clap your hands, touch your toes, raise your hand).
Low-probability instructions were defined as instructions that the student
complied with 40% of the time or less (e.g., come here, sit down, go to your desk).
At least three high-probability instructions were presented before one lowprobability instruction. The results showed HP/LP sequences to be effective in
increasing compliance with low-probability instructions. Increasing compliance
with instructions in the classroom setting is important because not following
instructions can interfere with learning and academic performance (Austin &
Agar, 2005; Belfiore et al., 2008).
Vostal and Lee (2011) also examined the application of HP/LP sequences
to desirable behaviors in the academic environment and also found these
sequences to be effective. In the study, the researchers compared the effectiveness
22
of HP/LP sequences to increase reading fluency in adolescents with emotional and
behavioral disorders when reading low-probability paragraphs. The HP/LP
sequence condition consisted of third-grade reading tasks followed by fifth-grade
reading tasks. The LP/HP sequence condition consisted of fifth-grade reading
tasks followed by third-grade reading tasks. Participants in the study were required
to read the excerpts presented and the latency and fluency of their responses were
measured. The results showed an increase in fluency and a decrease in latency in
their responses when the reading tasks followed the HP/LP sequence (i.e. thirdgrade reading tasks followed by fifth-grade reading tasks). In addition, results
showed a decrease in fluency and an increase in latency of their responses when
the reading tasks followed the LP/HP sequence (Vostal & Lee, 2011).
Consequently, when the paragraphs moved from third-grade readability level to
fifth-grade readability level, participants initiated the oral reading at a faster rate
and the fluency of their responses carried over to the low-probability passages (i.e.
reading fluency stayed at the same level for both the high-probability and the lowprobability reading tasks). These results further support the use of HP/LP
sequences in academic tasks to increase desirable behaviors (Vostal & Lee, 2011).
A study by Esch & Fryling (2013) also explored the effectiveness of using
HP/LP sequences to increase compliance with low-probability instructions in
children, and compared two variations of the high-probability instructions. In the
study, high-probability maintenance instructions (i.e., previously mastered
instructions) and high-probability leisure instructions were compared. Highprobability maintenance instructions consisted of one-step instructions that the
participant complied 90% of the time or more based on the results obtained during
the assessment. High-probability leisure instructions consisted of instructions on
activities were previously identified as highly preferred leisure tasks. Low-
23
probability instructions consisted of instructions that the participants complied to
30% of the time or less. Results showed that both leisure and maintenance HP/LP
sequences increased compliance with low-probability instructions. These results
are particularly noteworthy because they support the effectiveness of using HP/LP
sequences to increase compliance with different instructions. In addition, these
instructions can require the participant to engage in a variety of responses (Esch &
Fryling, 2013).
Research applying HP/LP sequences has also shown that these sequences
can be applied to everyday contexts and tasks (Ducharme & Worling, 1994;
Hughes, 2009; Humm et al., 2005; Meier et al., 2012; Riviere et al., 2011). For
example, Ducharme & Worling (1994) used HP/LP sequences in the form of
requests to increase child compliance in the home and found that compliance with
low-probability requests only increased when these followed the high-probability
requests. The requests used in the study consisted of “do” and “don’t” requests.
“Do” requests consisted of requests that required the participant to perform a
particular behavior such as standing up. “Don’t,” requests consisted of requests
that required the participants to stop engaging in a behavior or instructed the
participant to not engage in a particular behavior (e.g., don’t lie on the floor). In
addition, the high-probability requests were requests to which the participant
complied at least 80% of the time and consisted of both “do” and “don’t” requests.
The low-probability requests consisted of “do” and “don’t” requests to which
compliance response was obtained for less than 40% of the time based on
opportunities presented. The researchers found that compliance to the “do” and
“don’t” low-probability requests significantly increased when these followed the
HP/LP sequence. The results of this study provide further evidence of the
24
effectiveness of HP/LP sequences and their applicability to other contexts outside
of the academic environment.
In a similar study, Humm et al. (2005) analyzed the use of HP/LP
sequences in increasing compliance to requests in the home, but reduced the
amount of assistance provided by providing a written manual and by training
parents to implement these sequences with a modest amount of therapist
assistance. In the study, parents were taught to implement HP/LP sequences at
home to increase compliance with low-probability requests. The HP/LP requests
were selected based on parental report regarding the likelihood of their child
complying with a series of requests. High-probability requests consisted of
requests rated between 76 to 100% of compliance. Low-probability requests
consisted of requests rated between 0 to 50% of compliance and were selected by
parents based on parental concern and relevance to the family. In addition, the
researchers also implemented a fading and maintenance condition to assess
compliance maintenance to the low-probability requests after the gradual
reduction of high-probability requests presented prior to low-probability requests.
The results showed that compliance with low-probability requests increased for all
the participants when these followed the HP/LP sequence. In addition, compliance
with low-probability requests minimally increased or decreased after the highprobability requests were gradually reduced from the HP/LP sequences (Humm et
al., 2005). These results further support Ducharme & Worling’s (1994) findings
regarding the effectiveness of using HP/LP sequences in increasing compliance in
the home. However, these results also support the effectiveness of HP/LP
sequences in increasing compliance in children with developmental disabilities.
In 2011, Riviere et al. conducted a study to examine the effectiveness of
HP/LP sequences in increasing compliance in children with developmental
25
disabilities. In the study, the researchers use HP/LP sequences to increase
compliance with medical examination tasks in children with autism (Riviere et al.,
2011). Compliance was defined as the participant completing the low-probability
request within 10 seconds of the request. The low-probability requests were those
for which the participant exhibited non-compliance and the high-probability
requests consisted of requests to which the participant complied at least 80% of
the time. In the study, participants were exposed to baseline, HP/LP sequences
presented by parents, HP/LP sequences presented by a medical professional, and
HP/LP sequences with low-reinforcement rate. Baseline consisted of only lowprobability requests. The HP/LP sequences presented by parents consisted of
presenting high-probability requests first, then low-probability requests. The
HP/LP sequences presented by a medical professional were the same as the ones
presented by parents, except that the professional delivered the requests. The
HP/LP sequences with low-reinforcement rate were identical to the HP/LP
sequences presented by parents and a medical professional, except that
reinforcement was delivered for every third correct response. The results showed
high levels of compliance with low-probability requests when these were
presented following the HP/LP sequence with both parents and the medical
professional (Riviere et al., 2011). These results provided further evidence
supporting the effectiveness and applicability of HP/LP sequences to everyday
activities such as medical examinations.
Although the primarily purpose of research on HP/LP sequences has been
to develop interventions to increase desirable behaviors, or response classes, that
are less likely to occur in a number of educational and treatment contexts (Belfiore
et al., 1997, 2008; Mace, Hock, Lalli, West, Belfiore, Pinter & Brown, 1988;
McComas, Wacker, Cooper, Peck, Golonka, Millard & Richman, 2000; Vostal &
26
Lee, 2011; Zuluaga & Normand, 2008), one study has found these sequences to be
correlated with an increase in compliance to requests in hostage negotiations
(Hughes, 2009). In 2009, Hughes examined the presence of naturally occurring
HP/LP sequences in hostage negotiations. The researcher used audiotapes of three
real-life situations and a trained observer identified the requests made in all three
events. Requests were defined as any demands that required the hostage-taker to
perform a behavior (e.g., Put Carol on the phone), to provide information (e.g.,
“How many people do you have with you?”), to stop performing a behavior (e.g.,
“Don’t put the phone down”) or not engage in a behavior (e.g., “Don’t shoot
anybody in the leg”). The requests were rated based on their probability of
compliance; however, the number of times the low-probability requests preceded
the high-probability requests varied between three, five, and nine high-probability
requests. Results showed that when the requests followed the HP/LP sequence,
compliance with low-probability requests increased by 100%. In addition, results
also showed that when the high-probability requests were presented after the lowprobability requests, compliance did not occur with any of the low-probability
requests made.
The study conducted by Hughes (2009) indicated that compliance only
occurred when the request presented during the hostage negotiations followed the
HP/LP sequences. It should be noted that the Hughes study was correlational and
did not manipulate the presentation of HP/LP instructions but simply analyzed
sequences from actual situations; however the study by Hughes does support the
effectiveness of HP/LP sequences in increasing compliance in this context. It is
therefore possible that these sequences can be applied to interrogations. As
previously mentioned, past research (Baxter et al., 2013; Doepke et al., 2003;
Drake & Bull, 2011) investigating changes in the questioning procedures during
27
interrogations have found that the presence of suggestible or non-suggestible
questions do not affect suggestibility scores when presented separately. However,
these studies did not examine the effects of presenting suggestible and nonsuggestible questions together, and following a specific sequence, the HP/LP
sequence. Past research on the effectiveness of HP/LP sequences to increase
behavior (e.g., compliance) suggests that this may be a relevant variable to
understand changes in interrogative suggestibility (Austin & Agar, 2005; Banda et
al., 2009; Belfiore et al., 2008; Ducharme & Worling, 1994; Esch & Fryling,
2013; Humm et al., 2005; Lee, 2006; Meier et al., 2012; Riviere et al., 2011;
Wehby & Hollahan, 2000).
Understanding the effects of HP/LP sequences during interrogations may
highlight the need for procedures to eliminate or reduce the likelihood of
suggestibility, and potentially increase the accuracy of responses. This is
particularly relevant to criminal trials, as witnesses are exposed to a number of
scenarios to gather information needed regarding the crime, and the exact
questioning procedures are not clearly outlined (Police Executive Research Forum,
2013). As previously mentioned, eyewitness testimony is still considered one of
the most important pieces of evidence against someone in a court trial, and thus,
understanding the factors that can affect testimonies can enhance the development
of specific control measures to reduce or eliminate them. It is therefore important
to investigate the possible effects of HP/LP sequences during interrogative
suggestions, to minimize suggestibility and maintain or increase accuracy.
Purpose
The purpose of this study was to examine the effects of HP/LP sequences
on a measure of interrogative suggestibility. It was hypothesized that presenting
28
questions following the HP/LP sequence would increase suggestibility on
standardized measures when compared to other sequence of questions.
CHAPTER 3: METHODOLOGY
Participants and Settings
Fifty-two undergraduate college students participated in this study. All
participants were at least 18 years old, had normal hearing, and no known memory
impairments, as assessed by self-report. Participants were recruited through
announcements in classes. The study took place in a small research room that
contained a table, chairs, and recording equipment. Each participant was
interviewed individually and all participants signed a video consent and informed
consent prior to beginning the study (see Appendix A).
Materials
Instruments
Two passages, with their respective questionnaires, from the GSS manual
(Gudjonsson, 1997) were used to assess the effects of HP/LP sequences on
interrogative suggestibility. The passages were read to participants at a standard
speed to ensure consistency across all passages. Standard speed was defined as
reading a paragraph without pausing after each sentence for more than 5 seconds.
Each passage came with its respective set of 20 questions containing 15
suggestible questions and five non-suggestible questions. The standard order of
the set of questions is the following: 1 suggestible question followed by 3 nonsuggestible questions. The order in which these questions were presented was
modified based on the condition (HP/LP sequence condition, or baseline
condition). Each set of questions was scored in accordance to the GSS Manual.
Answers were recorded on the respective questionnaire using paper and pencils.
30
All sessions were recorded using video cameras and this was used for further data
collection.
Research Design
The study conducted used an A-B design (or B-A design for half the
participants) and individual and group analyses were conducted. Two passages
from the GSS Manual were used; the GSS1 and the GSS2. The order of the
passages was randomly assigned for each participant, but no single passage was
repeated for any participant to prevent any effects of repeated exposure to
passages. There were two conditions: baseline condition and HP/LP sequence
condition. The baseline condition consisted of the presentation of questions in the
standard order as indicated in the GSS manual. Each subject was exposed to both
conditions during the experiment. To assess any order effects in the presentation
of the two conditions, the order of these conditions were randomly assigned such
that 50% of the participants received the baseline condition first, followed by the
HP/LP sequence condition, and 50% of the participants received the HP/LP
sequence condition first, followed by the baseline condition. In addition, the
presentation of the two passages was randomly assigned. Thirteen participants
received the following presentation of conditions: Baseline (GSS1) followed by
the HP/LP sequence (GSS2). Thirteen of the participants were exposed to baseline
(GSS2) followed by the HP/LP sequence (GSS1). Thirteen of the participants
received the HP/LP sequence (GSS1) first, followed by baseline (GSS2). Thirteen
of the participants received the HP/LP sequence (GSS2) first, followed by baseline
(GSS1) (see Figure 1, p. 40, for details). Each condition was presented one time to
each participant, for a total of two conditions.
31
Independent Variable
The independent variable was the order of the suggestible and nonsuggestible questions (e.g., baseline condition, HP/LP). The baseline condition
consisted of presenting a total of 20 questions following the standard order as
indicated in the GSS: 1 non-suggestible question followed by 3 suggestible
questions. The HP/LP sequence consisted of the presentation of 5 non-suggestible
questions first, before presenting 15 suggestible questions. Non-suggestible
questions were defined as questions that did not suggest an answer, that contained
information regarding the passage, and that required an answer that could be given
based on the passage previously presented. Suggestible questions were defined as
questions that suggested an answer that did not match the information previously
provided in the passages.
Dependent Variable
The dependent variable in this study was (a) the response to the suggestible
and non-suggestible questions (b) the change in responses as determined by the
Shift score, and (c) the overall suggestibility of the participant as determined by
the Total Suggestibility score. During the first round of questioning, answers that
indicated the acceptance of the suggestion for the 15 suggestible questions were
scored as one Yield 1 point Answers that did not indicate acceptance of the
suggestion provided in the suggestible questions were scored as zero points. Zero
points were given for the non-suggestible questions regardless of their correctness
as indicated in the GSS manual. The range of scores for Yield 1 was 0 to 15.
During the second round of questioning, answers to the same set of 20 questions
were scored as Yield 2 and were scored in the same way as Yield 1. The total
possible scores for Yield 2 also ranged from 0 to 15. Shift scores were obtained by
comparing all 20 answers for Yield 1 and all 20 answers for Yield 2. One point
32
was given for any changes in the responses between the 20 answers for Yield 1
and the 20 answers for Yield 2. Shift scores ranged from 0 to 20. The overall
suggestibility consisted of the total score obtained by adding the participants’ first
responses Yield 1 and Shift scores. The range of scores for Total Suggestibility
was 0 to 35 (see GSS Scoring section for more details). Data were collected
through direct observation for all participants.
Interobserver Agreement and Procedural Integrity
All research assistants received training prior to the study and served as the
interviewers in the study. During training, research assistants were taught to define
the dependent variables, to collect data using the GSS scoring sheet
questionnaires, and to act in a formal manner (firm) towards the participants at all
times during the study. A formal manner was defined as the interviewer delivering
instructions in a neutral tone, interacting with the participant only when indicated,
and only asking questions to the participants as indicated in the protocol or when
needing clarifications on the responses given by the participant. After the training,
all research assistants were evaluated to reach a criterion to be allowed to deliver
the conditions in the study. The criterion was defined as the interviewer delivering
the correct question sequences and maintaining a formal manner 100% of the time
on three consecutive training sessions. The percentage for each session was
calculated by adding the total number of questions required in the specific
sequence divided by the total number of questions presented in a formal manner
and in the correct sequence. Research assistants received feedback after each trial
and at the end of each training session. If performance fell below 80%, the
procedures were clarified and the research assistants were retrained as needed.
33
All sessions were recorded using a video camera to ensure the research
assistants’ facial expressions remain neutral throughout each session. The correct
implementation of the various procedures was assessed throughout the study
through the use of a procedural integrity checklist (see Appendix B). This
checklist was completed for 50% of the videotaped sessions for all participants.
Procedure integrity for all participants was 99.35% and ranged from 94% to 100%.
To assess interobserver agreement, a second research assistant watched the
videotaped sessions and completed the same GSS questionnaires. Both of these
questionnaires were compared on a question-by-question basis, and the number of
agreements was divided by the number of agreements plus disagreements, and
multiplied by 100. Interobserver agreement was conducted for 100% of sessions in
the study and agreement was 95.5%, ranging from 89% to 100%.
Procedures
Participants read and signed the video consent and informed consent form
prior to beginning the study and were asked to self-report any hearing difficulties
or any known memory impairments. Participants were informed that the
experiment was about memory recall. They listened to a short story read by the
experimenter and were asked to recall as much information about it as they could,
via open-ended recall. The immediate recall of information was scored with a 1 for
correct information, with ½ a point for partially correct information, and a 0 for
incorrect information as standardized on the GSS. After immediately recalling
information from the passage, participants were instructed to engage in an
unrelated activity for 20 minutes (i.e., “You can now take a 20 min break; here is a
tablet with some games for you to play during this time”). After this 20-min period
elapsed, participants were asked a set of 20 questions in the condition assigned:
34
the baseline condition and the HP/LP sequence condition. These procedures were
repeated for each passage. Each participant completed a total of two passages with
accompanying questionnaires. Each session lasted between 1 hour to 1.5 hours and
all participants completed both passages in one session. In addition, all
participants were debriefed immediately after completing the required session in
order to address any negative impact of the feedback used during session, and the
deception about the purpose of the study.
Baseline Condition
During the baseline condition, the questions were presented in the standard
order as indicated in the GSS manual: one non-suggestible question followed by
three suggestible questions. Research assistants collected data on the participants’
responses on the respective scoring sheet. After the participants had answered the
set of 20 questions, the research assistant delivered negative feedback, which
consisted of telling the participants that they made a lot of errors, and for this
reason, they were required to answer the same set of questions again. In addition,
the research assistants instructed the participants to try to be more accurate during
the second round questions. It is important to mention that the same negative
feedback was provided to all participants regardless of their performance. In
addition, the second round of questions was presented in the same order as the first
for that condition. The participants’ responses to the same set of 20 questions for a
second time were scored as indicated in the GSS manual. There was a total of one
presentation of the baseline condition for each participant and this condition was
approximately 30 minutes long.
35
Experimental Conditions
One experimental condition was evaluated in this study. The procedures
used in this condition were the same as those in baseline but the order in which the
questions were presented differed. In the HP/LP sequence condition, the questions
were presented in the following order: 5 non-suggestible questions followed by 15
suggestible questions. Research assistants recorded the responses to the questions
in the condition presented in the corresponding questionnaire. The sets of
questions addressed information provided in the passages and information not
provided in the passages. After the first answer to the set of questions, participants
received negative feedback regardless of the correctness of their responses. All 20
questions were presented for a second time following the same order in which they
were initially presented. There was a total of one presentation of the HP/LP
sequence condition per participant, and this condition was approximately 30
minutes long.
GSS Scoring
Scoring was based on the guidelines provided by GSS manual. The
participants were required to listen to a short story and then recall the story they
heard. A score of 1 was given for correct responses; a score of ½ was given for
partially correct responses, and a score of 0 for incorrect. The maximum score for
the free recall of ideas was 40. The first answer for each of the 20 questions was
recorded under Answers Yield 1, and a score of one Yield 1 point was given for
answers that indicated the acceptance of the suggestible questions (i.e., yes, two, I
think so, yeah). The total possible score for Yield 1 was 0 to 15. The same set of
20 questions and the same scoring system was used to obtain Yield 2 scores. The
second answer for each of the 20 questions was recorded under Answers Yield 2.
Change in responses to any of the 20 questions, during the second round of the
36
same set of 20 questions was scored as Shift. Shift scores ranged from 0 to 20. The
Total Suggestibility score was obtained by adding the sum of Yield 1 and Shift.
The range of scores for Total Suggestibility was 0 to 35 (0 to 15 for Yield 1, plus 0
to 20 for Shift). Once the experiment session was completed, all subjects were
thanked for participating in the study and instructed not to discuss the experiment
with other students. They were also debriefed immediately after the completion of
the study.
CHAPTER 4: DATA ANALYSIS
Graphical and Statistical Analyses
Graphic and statistical analyses were conducted for the study (see Figure 1,
p. 40, for graphic analyses). The data for each participant were analyzed
individually and as a group. Dependent sample t-tests were conducted to
determine if there was a statistical difference between baseline and the HP/LP
sequence condition for Yield 1, Yield 2, Shift, and Total Suggestibility scores for
all participants. Dependent sample t-tests were also conducted to compare
differences between Yield 1 and Yield 2 for baseline and for the HP/LP sequence
condition. A one-way ANOVA was conducted to determine if there was a
statistical differences between baseline and the HP/LP sequence condition
between those that received the HP/LP sequence condition first, and those that
received baseline first. A two-way ANOVA was also conducted to indicate if there
was a statistical difference between the following groups: baseline (GSS1)/HP/LP
Sequence (GSS2), baseline (GSS2)/ HP/LP sequence (GSS1), HP/LP sequence
(GSS1)/ baseline (GSS2), and HP/LP Sequence (GSS2)/ baseline (GSS1). An
alpha level of .05 was used for all statistical analyses conducted. The means and
standard deviations for responses to the suggestible and non-suggestible questions
as measured on the GSS manual can be seen in Table 1 (p. 40). A bar graph can be
seen in Figure 2 (p. 41), which indicates the mean scores for both baseline and the
HP/LP sequence conditions.
CHAPTER 5: RESULTS AND DISCUSSION
The purpose of this study was to examine the effects of HP/LP sequences
on a measure of interrogative suggestibility. It was hypothesized that presenting
questions following the HP/LP sequence would increase suggestibility on
standardized measures when compared to the standard sequence of questions. A
graphic analysis indicated that for 32 of the participants, Yield 1 scores were
higher in the HP/LP sequence condition when compared to the baseline condition.
Thus, 62% of the participants were more suggestible to the questioning procedures
during the first round of questioning (Yield 1) in the HP/LP sequence condition
than during baseline. Results also indicated that this effect differed across subjects
with 30% of the participants scoring lower in the HP/LP sequence condition for
Yield 1, and 8% of the participants scoring the same for Yield 1 in the HP/LP
sequence condition when compared to the baseline condition. These results
suggest that other individual variables may be responsible for these differences
(see Figure 1, p. 40). A graphic analysis also indicated that there was a small
difference in the participant’s first responses to the questions (Yield 1) between
the HP/LP sequence condition and baseline (see Figure 2, p. 41, for more details).
Thus, participants responded significantly higher to the suggestible questions in
the HP/LP sequence condition than in the baseline condition.
A t-test revealed a significant difference between the mean Yield 1 scores
for the HP/LP sequence condition (M = 7.02, SD = 4.12) and the baseline
condition (M = 6.21, SD = 3.32), t (51) = -2.07, p < .05, d = 0.29. It was also
hypothesized that presenting questions following the HP/LP sequence would
increase the participants’ total suggestibility scores, thus, affecting also Yield 2
and Shift; however, results show no statistical difference between the baseline
39
condition and the HP/LP sequence condition for Yield 2, Shift, or total
suggestibility scores. A t-test revealed a significant difference between the mean
scores of Yield 1 (M = 6.21, SD = 3.32) and Yield 2 (M = 8.06, SD = 3.99), t (51)
= -5.24, p < .05, d = 0.73 for the baseline condition. These results indicate that
participants’ scored significantly higher during the second presentation of the
questions, after the negative feedback was given, than in the first presentation of
the same questions during baseline. A t-test also revealed a significant difference
between the mean scores of Yield 1 (M = 7.02, SD = 4.12) and Yield 2 (M = 7.90,
SD = 4.31), t = (51) = -2.20, p < .05, d = 0.30 for the HP/LP sequence condition.
These results indicate that the participants’ response to the second presentation of
the same set of questions were also significantly higher than their responses on the
first presentation of the same set of questions for the HP/LP sequence condition.
A one-way ANOVA showed no significant differences between those that
received the baseline condition first, and those that received the HP/LP sequence
condition first, indicating that the order was not a relevant variable. In addition, a
two-way ANOVA was also conducted and found no significant differences
between those that received baseline (GSS1)/HP/LP sequence (GSS2), those that
received baseline (GSS2)/HP/LP sequence (GSS1), those that received the HP/LP
sequence (GSS1)/ baseline (GSS2), and those that received the HP/LP sequence
(GSS2)/ baseline (GSS1). These results suggest that the difference found between
the baseline condition and the HP/LP sequence condition was due to the sequence
in which the questions were presented and not to any other variables. In addition,
these results suggest that the scales are parallel to each other and that the
information they contain, is not a relevant factor in increasing suggestibility. No
other correlations between any of the other variables showed any statistical
significance.
40
Difference Between the HP/LP sequence and Baseline for
Participant's Yield 1 and Yield 2 Scores
8
Change From Baseline
6
4
2
0
Yield 1
-2
Yield 2
-4
-6
-8
11 14 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62
Participant Number
Figure 1. Differences in Yield 1 and Yield 2 scores between conditions.
Table 1
Means and Standard Deviations for Scores on the GSS Scales for Baseline and
HP/LP Sequence Conditions
Baseline
Measure
M
HP/LP Sequence
SD
M
SD
t-test
p-value
Yield 1
6.21
3.32
7.02
4.12
- 0.21
*0.04
Yield 2
8.06
3.99
7.90
4.31
0.44
0.67
Shift
4.62
3.48
4.19
3.27
1.20
0.24
Yield 1-Yield 2
1.85
2.54
- 5.24
*0.00
Yield 1- Yield 2
Total Suggestibility
10.87
5.66
* P-value < 0.05.
Note. M= Mean. SD= Standard Deviation.
0.89
2.90
- 2.20
*0.03
11.21
6.44
- 0.74
0.46
41
Means for Baseline and HP/LP Sequence for Participants'
Responses to the Questionnaires
9
8
7
Mean
6
5
4
Yield 1
Yield 2
3
2
1
0
Baseline
HP/LP Sequence
Baseline
Condition
HP/LP Sequence
Figure 2. Means for Yield 1 and Yield 2 for baseline and the HP/LP sequence.
Discussion
It was hypothesized that presenting questions following the HP/LP
sequence would increase the participants’ suggestibility on all measures of the
standardized test (Yield 1, Yield 2, Shift, and Total Suggestibility) when compared
to the baseline condition. Results indicated that presenting questions following the
HP/LP sequence did not significantly increase the participants’ suggestibility
scores on all of the standardized measures of the test when compared to baseline.
Participants’ total suggestibility scores did not differ significantly between the
HP/LP sequence condition and the baseline condition.
Results showed a significant difference in Yield 1 scores between the
HP/LP sequence condition and the baseline condition; however, there was no
significant difference between the HP/LP sequence and baseline for Yield 2 and
42
Shift respectably. Thus, participants seemed to be more suggestible to the
suggestible questions during the first presentation of the questions, and provided
an answer that indicated the acceptance of the suggestible stimulus when the
questions followed the HP/LP sequence condition. However, the delivery of the
negative feedback as indicated in the GSS manual resulted in a larger increase in
suggestibility for all participants in all conditions as assessed by Yield 2. Thus, the
increase in suggestibility as a result of the negative feedback was large enough for
both conditions to overpower the differences resulting from the HP/LP sequence
condition, affecting Yield 2, Shift, and Total Suggestibility scores. These results
support previous research about the effects of negative feedback on interrogative
suggestibility since the negative feedback increased all of the participants’
suggestibility scores regardless of the condition presented (Baxter & Boon, 2000;
Baxter et al., 2013; Doepke et al., 2003; McGroarty & Baxter, 2007; Sparling et
al., 2011).
The effects obtained in this study between the HP/LP sequence condition
and the baseline condition for the first responses to the questions (Yield 1) may be
of importance because they show that the ordering of questions may be important
for some individuals. High-probability tasks involve behaviors that are associated
with a higher rate of reinforcement, before presenting low-probability tasks that
are less likely to be performed because they are associated with less reinforcement
(Pierce & Cheney, 2013). Since reinforcement increases the probability that a
behavior will occur in the future under similar circumstances, it is possible that the
participants’ correct responses were reinforcing because of their extensive history
of reinforcement for correct responses to questions. This extensive history of
reinforcement for correct responses to questions increases the probability that
43
people will continue to respond to low-probability questions under similar
circumstances in order to contact similar reinforcement.
In addition, it is also possible that the delivery of the negative feedback
could have created an aversive condition that evoked responses to the questions. It
seems that the negative feedback functioned as a motiving operation to provide an
answer to the questions (regardless of the accuracy) in order to contact negative
reinforcement through the removal of the aversive stimulus, in this case, by
avoiding further negative feedback or having to answer the same question again.
In addition, after the participants received negative feedback indicating that they
made a number of errors, and that the questions were going to be represented, the
negative feedback and the presentation of the same questions may have reduced
the reinforcing effect of the responses to the non-suggestible questions observed in
the first presentation of the questions (i.e. participants were less sure that they
were giving correct responses). Thus, the aversive condition during the second
presentation of questions may have competed with the positively reinforced
responses of the first presentation of questions, affecting any differences between
baseline and the HP/LP sequence condition for Yield 2, Shift, and total
suggestibility scores.
The present study expands the application of HP/LP sequences to contexts
where compliance may not be beneficial, such as during interrogations. It also
demonstrates the effects of using HP/LP sequences during interrogations on the
participants’ responses to suggestible questions. However, there are some
limitations to the present study. First, since the order of the questions and the
presentation of the scales were randomly assigned to prevent any order effects, it
was not possible to compare the suggestible questions positioned following the
non-suggestible questions in the HP/LP sequence conditions and the same
44
questions in the baseline condition. Second, there were a large number of
variations in the participants’ responses and yield scores, and it was not possible to
assess this phenomenon on an individual level without repeated exposure to the
GSS scales. Third, since only two scales are available, it was not possible to test
for other sequences.
Future research should address these limitations by expanding the available
tools (i.e., number of standardized passages) in order to facilitate further research
on interrogative suggestibility while avoiding repeated exposure to the same
scales. This would allow for further examination of the variables that may
influence interrogative suggestibility at an individual level. Expanding the
available tools could also facilitate investigations on the effects of other sequences
on interrogative suggestibility. In addition, the present study did not investigate
the effects of providing other types of feedback and their effects in combination
with the sequences presented. Thus, future research could focus on the effects of
these sequences in the presence of different types of feedback, since HP/LP
sequences are often associated with a higher rate of reinforcement.
The results of this study highlight the importance of understanding the
order effects of questioning. In practice it may be necessary to standardize the
order of suggestible questions and limit the presence of HP/LP sequences during
questioning, in order to increase accurate responding in contexts where
compliance with suggestible questions may not be beneficial, such as during
criminal investigations. During criminal investigations, the eyewitnesses are often
questioned multiple times, but no specific questioning procedure is currently
available or standardized. This allows for the possibility of presenting questions
following the HP/LP sequence, if questions that can be answered based on the
information the eyewitness already possesses are presented first. Therefore, more
45
studies need to be conducted in order to develop an accurate method to prevent
these sequences from being used during interrogations.
REFERENCES
REFERENCES
Austin, J., & Agar, G. (2005). Helping young children follow their teachers’
directions: the utility of high probability command sequences in pre-k and
kindergarten classrooms. Educational and Treatment of Children, 28, 222236.
Axelrod, M., & Zank, A. (2012). Increasing classroom compliance: Using a highprobability command sequence with non-compliant students. Journal of
Behavior Education, 21, 119-133.
Azar, B. (2011). The limits of eyewitness testimony. American Psychological
Association. Retrieved from www.apa.org/monitor/2011/12/eyewitness/aspx
Banda, D., Matuszny, R., & Therrien, W. (2009). Enhancing motivation to
complete math tasks using the high-preference strategy. Intervention in
School and Clinic, 44, 146-150.
Bain, S. A., Baxter, J. S., & Fellowes, V. (2004). Interacting influences on
interrogative suggestibility. Legal and Criminological Psychology, 9, 239-752.
Baxter, J. S., & Boon, J. C. W. (2000). Interrogative suggestibility: the importance
of being earnest. Personality and Individual Differences, 28, 753-762.
Baxter, J. S., Boon, J. C. W., & Marley, C. (2006). Interrogative pressure and
responses to minimally leading questions. Personality and Individual
Differences, 40, 87-98.
Baxter, J., Charles, K., Martin, M., & McGroarty, A. (2013). The relative
influence of leading questions and negative feedback on response change on
the Gudjonsson’s Suggestibility Scale (2): Implications for forensic
interviewing. Psychology, Crime, and Law, 3, 277-285.
Baxter, J. S., Jackson, M., & Bain, S. A. (2003). Interrogative suggestibility:
Interactions between interviewees’ self-esteem and interviewer style.
Personality and Individual Differences, 35, 1285-1292.
Belfiore, P. J., Basile, S. P., & Lee, D. L. (2008). Using a high probability
command sequence to increase classroom compliance: The role of behavioral
momentum. Journal of Behavioral Education, 17, 160-171.
48
Belfiore, P. J., Lee, D. L., Vargas, A. U., & Skinner, C. H. (1997). Effects of highpreference single-digit mathematics problem completion on multiple-digit
mathematics problem performance. Journal of Applied Behavior Analysis,
30, 327-330.
Doepke, K., Henderson, A., & Critchfield, T. (2003). Social antecedents of
children's eyewitness testimony: A single-subject experimental analysis.
Journal of Applied Behavior Analysis, 36, 459-463.
Drake, K., & Bull, R. (2011). Individual differences in interrogative suggestibility:
Life adversity and field. Psychology, Crime, and Law, 17, 677-687, doi:
10.1080/10683160903511967
Ducharme, J., & Worling, D. (1994). Behavioral momentum and stimulus fading
in the acquisition and maintenance of child compliance in the home. Journal
of Applied Behavior Analysis, 27, 639-647.
Eisen, M. L., Quas, J. A., & Goodman, G. S. (2002). Memory and suggestibility in
the forensic interview. Mahwah, NJ: Lawrence Erlbaum
Eisen, M. L., Morgan, D. Y., & Mickes, L. (2002). Individual differences in
eyewitness memory and suggestibility: examining relations between
acquiescence, dissociation and resistance to misleading information.
Personality and Individual Differences, 33, 553-571.
Esch, K., & Fryling, M. (2013). A comparison of two variations of the highprobability instructional sequence with a child with autism. Education and
Treatment of Children, 36, 61-72.
Eysenck, H. (1947). Dimensions of personality. London, UK: Routhedge and
Kegan Paul.
The Federal Bureau of Investigation (2016). 2015 Crime in the United States
(2015). Retrieved from http://www.fbi.gov/news/stories/2015/september/
latest-crime-stats-released/latest-crime-stats-released
Gudjonsson, G. H. (1983). Suggestibility, intelligence, memory recall and
personality: An experimental study. British Journal of Psychiatry, 142, 3537.
Gudjonsson, G. H. (1984). A new scale of interrogative suggestibility. Personality
and Individual Differences, 5, 303-314.
49
Gudjonsson, G. H. (1992). Interrogation and false confessions: Vulnerability
factors. British Journal of Hospital Medicine, 47, 597-599.
Gudjonsson, G. H. (2003). The psychology of interrogations, confessions, and
testimony. Chichester, UK: Wiley.
Gudjonsson, G. H., & Clark, N. K. (1986). Suggestibility in police interrogation:
A social psychological model. Social Behavior, 1, 83-104.
Gudjonsson, G. H., & Lister, S. (1984). Interrogative suggestibility and its
relationship with self-esteem and control. Journal of the Forensic Science
Society, 24, 99- 110.
Gudjonsson, G. H., & Sigurdsson, J. F. (2004). The relationship of suggestibility
and compliance with self-deception and other-deception. Psychology, Crime
& Law, 10, 447-453.
Gudjonsson, G. H, & Singh, K. K. (1984). The relationship between criminal
conviction and interrogative suggestibility among delinquent boys. Journal
of Adolescence, 7, 29-34.
Gudjonsson, G. H., & Young, S. (2011). Personality and deception. Are
suggestibility, compliance, and acquiescence related to socially desirable
responding? Personality and Individual Differences, 50, 192-195.
Hughes, J. (2009). A pilot study of naturally occurring high-probability request
sequences in hostage negotiations. Journal of Applied Behavior Analysis, 42,
491-496.
Humm, S., Blampied, N., & Liberty, K. (2005). Effects of parent-administered,
home-based, high-probability request sequences on compliance by children
with developmental disabilities. Child and Family Behavior Therapy, 27, 2745.
Innocence Project. (2016a). Eyewitness Misidentification. Retrieved from
www.innocenceproject.org/about/Mission-Statement.php
Innocence Project. (2016b). False Confessions or Admissions. Retrieved from
www.innocenceproject.org/causes-wrongful-conviction/false-confessions-oradmissions.
Lee, D. L. (2006). Facilitating transitions between and within academic tasks: an
application of behavioral momentum. Remedial and Special Education, 27,
312-317.
50
Loftus, E. F. (1979). Eyewitness testimony. Cambridge, MA: Harvard University
Press.
Loftus, E., Miller, D., & Burns, H. (1978). Semantic integration of verbal
information into a visual memory. Journal of Experimental Psychology:
Human Learning and Memory, 4, 19-31.
Mace, F. C., Hock, M. L., Lalli, J. A., West, B. J., Belfiore, P., Pinter, E., &
Brown, D. K. (1988). Behavioral momentum in the treatment of
noncompliance. Journal of Applied Behavior Analysis, 21, 123-141.
McComas, J. J., Wacker, D. P., Cooper, L. J., Peck, S., Golonka, Z., Millard, T., &
Richman, D. (2000). Effects of the high-probability request procedure:
Patterns of responding to low-probability requests. Journal of Developmental
and Physical Disabilities, 12, 157-171.
McGroarty, A., & Baxter, J. S. (2007). Interrogative pressure in simulated forensic
interviews: The effects of negative feedback. British Journal of Psychology,
98, 455-465.
McGroarty, A., & Baxter, J. S. (2009). Interviewer behavior, interviewee selfesteem, and response change in simulated forensic interviews. Personality
and Individual Differences, 47, 642-646.
Meier, A., Fryling, M., & Wallace, M. (2012). Using high-probability foods to
increase the acceptance of low-probability foods to increase the acceptance
of low-probability foods. Journal of Applied Behavior Analysis, 45, 149-153.
Merckelbach, H., Muris, P., Wessel, I., & Koppen, P. J. V. (1998). The
Gudjonsson suggestibility scale (GSS): Further data on its reliability,
validity, and metacognition correlates. Social Behavior and Personality, 26,
203-210.
Pezdek, K., & Roe, C. (1995). The effect of memory trace strength on
suggestibility. Journal of Experimental Child Psychology, 60, 116-128.
Pierce, W. D., & Cheney, C. D. (2013). Behavior analysis and learning. New
York, NY: Taylor and Francis.
Police Executive Research Forum (2013). A national survey of eyewitness
identification procedures in law enforcement agencies. Retrieved from
www.policeforum.org/free-online-documents.
51
Riviere, V., Becquet, M., Peltret, E., Facon, B., & Darcheville, J. (2011).
Increasing compliance with medical examination requests directed to
children with autism: Effects of a high-probability request procedure. Journal
of Applied Behavior Analysis, 44, 193-197.
Schooler, J. W., & Loftus, E. F. (1993). Individual differences and
experimentation: Complementary approaches to interrogative suggestibility.
Social Behaviour, 1, 105-112.
Schooler, J. W., Gerhard, D., & Loftus, E. F. (1986). Qualities of the unreal.
Journal of Experimental Psychology: Learning, Memory, and Cognition, 12,
171-181.
Singh, K. K., & Gudjonsson, G. H. (1984). Interrogative suggestibility, delayed
memory and self-concept. Personality and Individual Differences, 5, 203209.
Smeets, T., Leppink, J., Jelicic, M., & Merckelbach, H. (2009). Shortened versions
of the Gudjonsson suggestibility scale meet the standards. Legal and
Criminological Psychology, 14, 149-155.
Sparling, J., Wilder, D., Kondash, J., Boyle, M., & Compton, M. (2011). Effects of
interviewer behavior on accuracy of children's responses. Journal of Applied
Behavior Analysis, 44, 587-592.
Vostal, B. R., & Lee, D. L. (2011). Behavioral momentum during a continuous
reading task: An exploratory study. Journal of Behavioral Education, 20,
163-181.
Wehby, J., & Hollahan, M. (2000). Effects of high-probability requests on the
latency to initiate academic tasks. Journal of Applied Behavior Analysis, 33,
259-262.
Zuluaga, C. A., & Normand, M. P. (2008). An evaluation of the high-probability
instruction sequence with and without programmed reinforcement for
compliance with high-probability instructions. Journal of Applied Behavior
Analysis, 41, 453-457.
APPENDICES
APPENDIX A: INFORMED CONSENT
54
VIDEO AND CONSENT FORM
You are invited to participate in a study conducted by Dr. Marianne Jackson and Grecia Argelia Mendoza
from California State University Fresno. We hope to learn more about memory processes in this study and
you were selected as a possible participant in this study because we are interested in understanding more
about these processes in typical adults.
If you decide to participate, we will require you to attend a total of one session. You will be read two short
stories and you will be asked to recall everything you can about them. You will then be given two 20minute breaks during the session, although you must stay in the research room. An I-pad will be available
for you to use during the two 20-minute breaks provided. You will then be asked to answer questions about
the stories. The study will take place over the course of one session for a maximum of two hours per
session. It is important to be aware that this session will be recorded. The risk of participation include: you
may not like being in a room for a complete period of two hours, you may not like being recorded, and may
be tired at the end of the session. If you decide to participate in the study, you will obtain up to 3 extra
credit points after you complete the required session for the study. We cannot guarantee, however that you
will receive any benefits from this study.
Any information that is obtained in connection with this study and that can identified you will remain
confidential and will be disclosed only with your permission or as required by law. All video recordings
will be deleted once the study is completed.
Your decision of participating or not in the study will not prejudice your future relations with California
State University, Fresno. If you decide to participate, you are free to withdraw your consent and to
discontinue participation at any time without penalty. The Committee on the Protection of Human Subjects
at California State University, Fresno has reviewed and approved the present research.
If you have any questions, please ask us. If you have any additional questions later, Dr. Marianne Jackson
([email protected]) will be happy to answer them. Questions regarding the rights of research
subjects may be directed to Constance Jones, Chair, CSUF Committee on the Protection of Human
Subjects, (559) 278-4468.
You will be given a copy of this form to keep.
YOU ARE MAKING THE DECISION OF WHETHER OR NOT TO PARTICIPATE IN THIS STUDY.
YOUR SIGNATURE INDICATES THAT YOU HAVE DECIDED TO PARTICIPATE AND THAT
YOU HAVE READ AND UNDERSTAND THE INFORMATION PROVIDED ABOVE.
_________________________________
_________________
Signature
Date
____________________________________________________
Name of Participant
APPENDIX B: PROCEDURES INTEGRITY
56
Procedures Integrity:
Primary RA: ______________________
2nd RA (IOA): ___________________________
Participant ID # _________________
Part 1


Script b
Read first assigned story at the correct standard speed
c. Defined as reading the assigned paragraph without pausing after
each sentence for more than 5 seconds.
 Only interacted with the participant to read the story
Part 2 (After reading the story)
 Asked for immediate recall after reading the story.
o Said Script d
o Recorded responses
 Informed the participant that he/she could now take a break but could not
leave the room during the break (script e.)
 Provided the participant with an I-pad and magazines to use during the 20minute break
 After the 20-minute break, removed the tablet and informed the participant
that he/she was going to ask some questions about the story. Said script f
 Asked the set of questions in the correct assigned order
 Only interacted with the participant to ask questions in the correct assigned
order, and to request clarifications
 Did not move to the next question until the participant responded to the
question asked
 Scored each answer in the correct scoring section
 After obtaining answers for the first set of questions, he/she told the
participant script g
 Represented the same set of questions
 Did not move to the next question until the participant responded to the
question asked
 Only interacted with the participant to ask questions in the correct assigned
order, and to request clarifications
 Scored each answer in the correct scoring section
 Repeated procedures for second story