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37014 CJBXXX10.1177/0093854812437014WALNITIVE DETECTIONOF DECEPTIONINWITNESSESCRIMINALJUSTICE ANDBEHAVIOR

AUTHORS NOTE:This material is based on work funded by National Science Foundation (NSF) Grant648375. Any opinions, findings, conclusions, or recommendations expressed in this material are those of theauthors, not NSF. The authors thank Alexandra Bellone, Melissa Bordelon, Victoria Gault, and Coleen

Maidlow for their assistance with data collection and coding. Correspondence may be addressed to Jeffrey J.Walczyk, Psychology & Behavioral Sciences, P.O. Box 10048, Louisiana Tech University, Ruston, LA 71272;

e-mail: [email protected].

CRIMINAL JUSTICE AND BEHAVIOR, Vol. 39, No. 7, July 2012, 887-909.

DOI: 10.1177/0093854812437014

2012 International Association for Correctional and Forensic Psychology

LIE DETECTION BY INDUCING COGNITIVE

LOAD

Eye Movements and Other Cues to the False Answers

of Witnesses to Crimes

JEFFREY J. WALCZYK

DIANA A. GRIFFITH

RACHEL YATES

SHELLEY R. VISCONTE

BYRON SIMONEAUX

LAURA L. HARRISLouisiana Tech University

Research on the accuracy of eyewitness testimony has expanded dramatically in recent years. Most of it concerns the issue

of mistaken identification, not the problem of uncovering deceptive accounts of witnesses, which is the focus of this research.

In the literature, a technique for lie detection has been proposed that induces cognitive load on liars by averting their rehearsal

of deception: Time Restricted Integrity-Confirmation. The current authors tested it by instructing witnesses of actual crime

videos to lie or tell the truth to related questions. Each of 145 adults was randomly assigned to a truth telling, an unrehearsed

lying, or a rehearsed lying condition. The cognitive cues were response time, answer consistency, eye movements, and pupil

dilation. Eye data were gathered with an infrared eye tracker. Truth tellers had the quickest response times and the fewest

inconsistencies. Moreover, they generally had more eye movements, suggesting low cognitive loads. Discriminant analyses

classified rehearsed liars, unrehearsed liars, and truth tellers up to 69% accurately, with few false positives. Further refine-

ment is warranted.

Keywords: lie detection; rehearsal; cognition and deception; eyewitness testimony

Eyewitness testimony is often the evidence most persuasive to juries despite its unreli-ability (Bond & DePaulo, 2006; Loftus, 2007). In some cases, such testimony wascrucial for conviction, even when there was compelling exculpatory evidence (Loftus,

1979). Advances in DNA testing applied to postconviction cases have led to the release of

more than 240 inmates wrongfully convicted partly by mistaken eyewitness testimony

(Garrett, 2010). Most validity concerns over eyewitness testimony involve mistaken iden-tification (Loftus, 2007; Wells & Olson, 2003), not the deceptive testimony of witnesses.

More research is needed on detecting it. The present study is relevant to eventually reduc-

ing false confessions, false alibis, and perjured testimony of witnesses through cognitive lie

detection.

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888 CRIMINAL JUSTICE AND BEHAVIOR

LIES DURING QUESTIONING, PERJURED TESTIMONY, AND THEIR DETECTION

A pernicious source of invalid testimony is witnesses giving deceptive accounts to inves-

tigators or perjuring themselves on the stand. If witnesses know the accused, they some-

times feel compelled to provide a false alibi or identification to shield him or her or toprotect themselves from reprisal from a disgruntled suspect (Lykken, 1998). Researchers

have identified a number of signs of deceptive testimony. Porter and Yuille (1996)

instructed participants to lie about their involvement in a mock crime and had some create

false alibis. Investigators observed that accounts of those in the false alibi condition had

fewer details, less coherence, and were less likely to admit they had forgotten a detail of an

event. Overconfidence when recounting details of events can thus signal deception.

Researchers have also compared the police with lay people in their ability to detect

deception. Garrido, Masip, and Herrero (2004) contrasted 121 officers with 146 college

students in the accuracy of judging deceptive and truthful videotaped statements. The accu-

racy of the officers was at chance level, whereas that of laypeople was slightly higher.

Police officers reported higher confidence in their lie detection abilities, though Garrido

et al. argued that officers overconfidence potentially hinders their learning of actual cues

to deceit. These findings, replicated by others (Hartwig, Granhag, Stromwall, & Vrij, 2004;

Vrij, 1993), run contrary to the stereotype of the public that police officers are superlative

lie detectors (Lykken, 1998). However, in a review of studies of the accuracy of police

officers, OSullivan, Frank, and Hurley (2009) found that police could detect deception

significantly beyond chance when the lies being witnessed involve high stakes for the liar,

such as when a perpetrator discloses a false alibi (see also Bond & DePaulo, 2006). Cues

to deception multiply as motivated liars monitor and try to control their behavior to appeartruthful (DePaulo et al., 2003).

Jurors often do no better as lie detectors. Landstrm, Granhag, and Hartwig (2005)

examined various cues to deception available to 122 mock jurors who evaluated the testi-

mony of 12 witnesses, half of whom lied when testifying about a staged accident that took

place 3 weeks prior. Jurors were asked to judge the truthfulness of witnesses, justify their

judgments, and rate witnesses on various behavioral dimensions. Analyses showed that

observers perceptions of truthfulness were influenced by the plausibility of statements,

how much detail they contained, and how confidently witnesses relayed them. Additionally,

the appearance of witnesses affected judgments, including how hard witnesses had to think,

how at ease they were, their eloquence in speech, and their pleasantness. Jurors performed

poorly at detecting deception. In fact, how hard the witness had to think (e.g., the time

needed to respond) was the only cue they used that correlated with deception, which is also

a basic cue of the cognitive lie detector tested in this research.

In conclusion, lies during questioning and deceptive testimony in courtrooms are serious

threats to procedural justice (Garrett, 2010). Moreover, deceptive and perjured testimony

(e.g., false alibis) can slip past investigators and jurors because of their weak abilities as lie

detectors. Regarding the latter, there has been much recent criticism of the validity of the

polygraph, the most common method of lie detection, and calls for alternatives technolo-

gies (DePaulo et al., 2003; Lykken, 1998; National Research Council [NRC], 2003). Thisresearch advances the development of a cognitive-based alternative to the polygraph with

potential to uncover deceptive testimony.



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Walczyk et al. / COGNITIVE DETECTION OF DECEPTION IN WITNESSES 889

LIE DETECTION BY INDUCING COGNITIVE LOAD: AVERTING REHEARSAL

Walczyk et al. (2005) introduced a novel approach to lie detection intended to maximize

cognitive load on liars and minimize it on truth tellers by averting the rehearsal of deceptive

answers: Time Restricted Integrity-Confirmation (TRI-Con). In essence, it surprises exam-inees with questions by following these guidelines during lie detection examinations: (a)

Examinees are prompted about the focus of the questions to follow (e.g., The next 15

questions concern your relationship with the suspect prior to the crime). By preactivating

relevant nodes of episodic memory,promptingreduces examinees need for explicit mem-

ory searching to answer truthfully and so should make cognitive cues to deception less

confounded. (b) The specific questions are not made known to examinees until the exami-

nation itself to discourage the rehearsal of lies. (c) Questions should be answerable in one

or two words (e.g., Did you see the shooting?), thereby making determination of the time

needed to fully answer a question clearer compared to questions evoking narratives (e.g.,

What happened during the crime?). (d) Examinees are instructed to answer quickly to

limit their opportunity to prepare lies. (e) Interrelated questions are asked to increase liars

cognitive load and provoke contradictions, found to be higher in liars (DePaulo et al.,

2003), especially without rehearsal (Vrij et al., 2009). We now add another guideline to

enhance cognitive load on liars. (f) When feasible, examinees should be instructed to main-

tain eye contact with the examiner (Vrij, Mann, Leal, & Fisher, 2010).

Requiring sustained eye contact should make gaze aversion and eye movements more

obvious. Glenberg, Schroeder, and Robertson (1998) asked participants moderately diffi-

cult general informational questions requiring memory searching and showed that averting

gaze away from environmental distraction facilitated the allocation of cognitive resourcesto internal processing that enhanced performance. Doherty-Sneddon and Phelps (2005) and

Doherty-Sneddon, Bruce, Bonner, Longbotham, and Doyle (2002) replicated these results

with children. If lying is more cognitively demanding than truth telling, we propose that a

corollary of Glenberg et al.s position is that less eye movement should be evident during

deception. Clearly, eye movements can increase visual stimulation that might be distracting

to someone who is focusing attention inwardly to generate a lie. This study is the first to

test this possibility.

LIE DETECTION BY INDUCING COGNITIVE LOAD: DUAL TASKING

Following TRI-Cons introduction, researchers have proposed other ways that lie detec-

tion procedures might induce cognitive load selectively on liars. Vrij, Fisher, Mann, and

Leal (2008) labeled two load-related approaches. The mere cognitive load approach is

based on the hypothesis that lying is inherently more cognitively demanding of limited

attention and working memory than truth telling (Sporer & Schwandt, 2007; Zuckerman,

DePaulo, & Rosenthal, 1981). Empirical support for this hypothesis is weak (DePaulo

et al., 2003; Walczyk et al., 2005). Vrij et al. named another the increase cognitive load

approach, which concerns methods for inducing cognitive load on liars. These authors

discussed what we now call dual tasking (performing two tasks concurrently). This is a

well-known experimental paradigm for determining the architecture of the mind (Pashler,

1994). As an example of a concurrent task in lie detection, Vrij et al. suggested that exam-

inees could answer an investigators questions while also engaging in a computerized

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driving simulation. If deception is more cognitively demanding than truthfulness, the

simulation should interfere more with liars than truth tellers and enhance cognitive cues. In

a milder form of what investigators argue is dual tasking, Vrij et al. (2010) found that liars

instructed to maintain eye contact during an interview about money taken from a wallet

showed more cues (fewer auditory and temporal details in a narrative, slower speech) than

liars not so instructed. Because making eye contact is a natural part of conversing, we are

not sure that requiring it rises to the level of dual tasking. However, we added it to TRI-Con

because it may increase cognitive load more on liars. Though the dual tasking approach is

promising, theoretical consideration should be given to what concurrent tasks will interfere

more with lying than truth telling and why (see Pashler, 1994).

To summarize, averting-rehearsal approaches induce cognitive load selectively on liars

by blindsiding examinees with questions and by having them answer quickly. Dual tasking

induces load by imposing split attention interference such that liars are more adversely

affected. Though theoretically distinct, the two approaches are practically compatible andcan be integrated by investigators.

REHEARSAL: AN ATTENUATOR OF COGNITIVE LOAD

Studies have examined the effects of planning a lie on its detection. In their meta-anal-

ysis of the accuracy of judgments of deception, Bond and DePaulo (2006) noted that lies

were easier to detect if baseline behaviors of individuals were available to observers and

the lies were unrehearsed. Likewise, Littlepage and Pineault (1985) found that observers

were less accurate at detecting planned deceptions than spontaneous ones. Littlepage, Tang,

and Pineault (1986) investigated why and found that planning allowed liars to controleffectively nonverbal cues to deception. OHair, Cody, and McLaughlin (1981) observed

that planned lies were briefer, took less time, and involved fewer illustrators. Although such

results are interesting, they do not advance understanding of the effects of rehearsal on

indices of cognitive load. Research on the cognition of deception has largely ignored the

effects of rehearsal on cognitive cues. In two recent meta-analyses of verbal and nonverbal

cues, Sporer and Schwandt (2006, 2007) sought to include rehearsal as a moderator but

were unable to locate sufficient studies that manipulated it. Still, to ensure its validity, any

cognitive-load-inducing lie detector must consider rehearsal to be a likely countermeasure.

Walczyk, Mahoney, Doverspike, and Griffith-Ross (2009) found that rehearsal decreased

lying response times and inconsistencies compared to unrehearsed lying. More research is

needed, however, on the effects of rehearsal on these and other cognitive cues.

CURRENT STUDY

In their influential meta-analysis of cues to deception, DePaulo et al. (2003) concluded

that there are no unequivocal signs of deception and recommended lie detection via con-

verging cues. Walczyk et al. (2005, 2009) helped validate TRI-Con but only with response

time and answer inconsistency, not using multiple cognitive cues or in a forensically rele-

vant context of eye witnessed crimes, limitations that are overcome in this research.Specifically, we showed 145 participants two videos of actual crimes and then instructed

them to play the role of witnesses and answer crime-related questions either (a) truthfully

or with (b) rehearsed or (c) unrehearsed lies. They also answered 18 general questions



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truthfully to provide ground-truth behavioral baselines. The four cues evaluated were

response time, the inconsistency of answers to interrelated questions, eye movements, and

pupil dilation. These cues were selected systematically, each accessing a distinct aspect of

cognitive load. Response time and pupil dilation are direct measures of the extent of pro-

cessing (Solso, 2001). Answer consistency is the output of processing (DePaulo et al.,

2003). Reducing eye movements is hypothesized to reflect attempts to lower cognitive

load. This is the first study to assess eye movements as a cognitive cue as individuals

answer questions.

Two types of questions were asked: those requiring yes or no responses and open-ended

questions evoking short responses besides yes or no. Because yesno and open-ended ques-

tions differ in the syntactic constraints that each puts on permissible responses, Walczyk et

al. (2005) urged analyzing the cues of each separately, which we do. Moreover, Walters

(1996) argued that the accuracy of deception detection increases if truth telling baseline

rates are established for each behavioral cue against which suspected deceptive respondingcan be compared. In effect, this controls for individual differences in baseline rates, which

confound strictly between-subjects comparisons. The polygraph, too, involves within-

subject comparison by establishing physiological base rates (Lykken, 1998). Similarly,

Walczyk et al. (2005) proposed controlling for such individual differences by subtracting

truthful base rates from base rates of questions suspected of deception, a suggestion we

follow. Finally, participants adopted the roles of witnesses to two different crime videos

to see if the pattern of cues observed with one could be replicated with the second. Four

hypotheses and their theoretical and empirical rationales follow.

H1: Unrehearsed liars will have longer response times than truth tellers, who will have

longer response times than rehearsed liars.Studies show that unrehearsed lying takes

longer than truth telling (DePaulo et al., 2003; Seymour, Seifert, Shafto, & Mosmann,

2000). Moreover, rehearsal can decrease the time required to lie (OHair et al., 1981;

Walczyk et al., 2009). The ample rehearsal of this study should lower response times

below that of truth tellers.

H2: Total inconsistencies across interrelated questions will be greatest for unrehearsed

liars, followed by rehearsed liars, and then truth tellers.Liars are often more incon-

sistent than truth tellers, likely due to not having generated sufficiently coherent and

detailed narratives before lying (Porter & Yuille, 1996; Vrij et al., 2009). We expected

rehearsal to reduce inconsistency below that of unrehearsed lying (Walczyk et al.,

2009).

H3: Truth tellers will move their eyes the most, followed by rehearsed liars; unrehearsed

liars will move their eyes the least.Unrehearsed liars should move their eyes little as

they focus on internal processes. Recall also that the instruction to maintain eye con-

tact increased the cognitive load of lying and cues to deception. Vrij et al. (2010)

videotaped participants and later coded tapes for the eye contact made during inter-

views, whereas we precisely measured eye movements with an infrared eye tracker

while participants answered.H4: Unrehearsed liars will have more pupil dilation than rehearsed liars, followed by

truth tellers.Studies demonstrate more pupil dilation in liars than truth tellers, likely



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due to a greater cognitive load accompanying deception (Bradley & Janisse, 1979;

Dionisio, Granholm, Hillix, & Perrine, 2001; Heilveil, 1976; Lubow & Fein, 1996;

Webb, Honts, Kircher, Bernhardt, & Cook, 2009). Although studies have not consid-

ered the effects of rehearsal on the pupil dilation of deceptive answers, it was expected

to be lower than that of unrehearsed liars.

METHOD

PARTICIPANTS

Recruited from psychology classes at a southern university, 145 adults received extra

credit. The racial composition was 105 White (72.4%), 31 Black (21.4%), 5 Asian (3.5%),

and 4 Latino (2.8%). The gender breakdown was 82 females (56.6%) and 63 males

(43.4%). The mean age was 22.23 years (SD= 5.92). All were American citizens and native

English speakers.

RESEARCH DESIGN

A multilevel, completely randomized, between-subjects design was used. The independ-

ent variable (IV), lie condition, involved the video-related questions and had three levels:

truth telling, unrehearsed lying, and rehearsed lying. The dependent variables were these

cognitive cues: response time, answer consistency, eye movements, and pupil dilation.

GENERAL PROCEDURE

Participants were tested individually, each session lasting about 30 min. Two experi-

menters were required: a greeter and an examiner. The greeter first obtained informed

consent, then handed a hardcopy of general instructions to participants and read them aloud

as they followed along. Participants were informed that they would witness two surveil-

lance videos of actual crimes and were instructed to watch and listen carefully because they

would only be shown each video once and would be questioned after each. Consistent with

TRI-Con, they were told to answer all questions as quickly as possible while constantly

maintaining eye contact with me as well as to answer in a clear, loud voice.All participants were directed to answer truthfully the 18 general questions asked first.

The instructions then diverged depending on the lie condition to which a participant was

randomly assigned. (a) Truth tellerswere instructed to adopt the role of a witness who

wants the perpetrators brought to justice and to answer all questions about the videos

truthfully to the best of your recollection. (b) Unrehearsed liarswere asked to assume

that the perpetrators were friends of theirs whom they did not want to see have criminal

records for a lapse of judgment, in effect, covering for them. They were instructed to

answer all video-related questions deceptively and to be sure that all answers were logically

consistent and plausible. However, they had no prior exposure to the questions, consistent

with TRI-Con. (c)Rehearsed liarshad the exact same instructions as unrehearsed liars but,after viewing each video, were also given a copy of questions and 5 min for preparing lies.

Afterward, participants were interviewed with these questions. Pilot testing on 11 college

students before the experiment, who were otherwise uninvolved, confirmed that 5 min was



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adequate time for all to prepare deceptive answers for each video question set. Such

rehearsal is ecologically valid in that allowing examinees to preview questions is a com-

mon practice with the polygraph (Lykken, 1998).

After receiving their instructions, all participants were ushered by the greeter into the

eye tracking lab. During all three question sets of the eye tracking interview, the greeter sat

directly in front of participants, making direct eye contact throughout and reminding par-

ticipants to do so as needed, which rarely was necessary. The 18 general questions were

asked first as eye data were collected. After that, participants were moved to a computer in

the same room and were shown the first of two crime videos. Video order was counterbal-

anced over participants. Rehearsed liars were given the opportunity to prepare lies after-

ward. Next, participants were interviewed about the video just seen as the cognitive cues

were assessed. Then this procedure was repeated for the second video. Even though neither

the greeter nor the examiner was blind to the experimental conditions of participants, given

that the eye tracking interview task was largely automated, there were minimal opportuni-ties for either to bias the results. Finally, the postexperiment questionnaire was adminis-

tered, followed by a debriefing.

MATERIALS

Crime videos.The local police department provided digital copies of two surveillance

training videos (with audio) of actual thefts, which were shown on a Dell desktop computer

in full-screen mode (13.5 11 in.).

Video 1.This video is 106 s in length and features a young, White male working as ajanitor. He enters an office to empty the garbage. While alone, he sees cash in an open purse

on the floor and steals it. Shortly after, the offices occupant, an elderly White female who

does not detect the pilferage, enters the office and exchanges pleasantries with the perpetra-

tor, who then nonchalantly leaves. The video features a 3-s close-up of the perpetrators

face.

Video 2.Lasting 75 s, this crime is set in a convenience store. Two individuals are visible

throughout: a salesclerk behind the counter, who is distracted while on the Internet rather

than minding the store, and a customer (perpetrator). Both are young, White males. The

perpetrator is clearly visible. Only the head of the salesclerk is visible but shows clearly his

race and dark hair. The two talk throughout mostly about their cars. When the salesclerk is

distracted, the perpetrator pilfers a box of some nondescript product from the lower shelf

of a counter and conceals it under a coat draped on his left shoulder. Next, he calmly leaves

the store.

Categories of questions (i.e., question set).Three categories of questions were written

general, Video 1, and Video 2each a mixture of yesno and open-ended questions. All 37

appear in the appendix. Per TRI-Con guidelines, most were answerable with a word or two.

The appendix specifies which question pairs were written to be logically interrelated. The18 general questions probed personal information and general knowledge to provide

ground truth behavioral baseline data (Walters, 1996). The boldfaced questions tested facts

that could be verified to ensure compliance with instructions to answer truthfully. The 19



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interview questions (10 Video 1, 9 Video 2) addressed what happened in the videos, includ-

ing characteristics of the perpetrators and the nature of the theft. They are of the kind often

asked by detectives (Inbau, Reid, Buckley, & Jayne, 2001).

Postexperiment questionnaire. A postexperimenter questionnaire was prepared thatlisted the 10 Video 1 questions and 9 Video 2 questions to assess whether the truth had been

encoded by participants. The instructions directed participants to answer them all truthfully.

AUDACITY DIGITAL RECORDING SOFTWARE

Audacity version 1.3.8 (http://audacity.sourceforge.net), an open source digital record-

ing and editing software, was used to record the instructions that preceded each set of ques-

tions (prompting the focus of the questions to follow) and each question as its own digital

file. A young woman read the instructions and questions in a clear, authoritative voice. A

JAVA program presented the instructions for a set of questions, followed by the appropriate

questions in their order of appearance in the appendix.

THE EYE TRACKING SYSTEM AND INTERVIEW TASK

The Eye Tracking Laboratory (ETL) 400 Infrared eye tracking system (manufactured by

ISCAN Inc., 21 Cabot Road, Woburn, MA 01801; website: http://iscaninc.com) assessed

pupil dilation and eye movements. A computer ran the JAVA program that controlled the

procedure. The time needed to answer was measured to the millisecond by a voice key. Any

noise following a question, usually the answer, caused the voice key to trip and an audiblebeep. Answers were also digitally recorded. When an irrelevant noise caused the voice key

to trip prematurely, response times were determined using the recordings.

Participants chins were positioned on a chinrest. The greeter sat 4 feet in front of them.

Before testing, the ETL 400 was calibrated using four numbered corners on a rectangle 29

in. wide and 23 in. tall on the wall behind the greeter. The eye tracker imposed a virtual

coordinate system of pixels corresponding to where participants were looking. The origin

was in the upper, left-hand corner (horizontal = 0, vertical = 0). The bottom right had

maximum coordinates (horizontal = 511, vertical = 511). The greeter sat such that her eyes

were about in the middle of the rectangle. Throughout the ETL 400 took 60 snapshots of

the right eye per second. In each, the pupil dilation and point of regard (i.e., virtual coordi-nates where the fovea was centered at any instant) were measured. Pupil dilation and eye

movements of Tables 3 through 6 are expressed in pixels. For each test question, the eye

data analyzed started with the beginning of a question and ended when the voice key

tripped, that is, for the full questionanswer event. The mean pupil dilation for this interval

was used. Also, the ETL 400 is designed to analyze eye movements into vertical and hori-

zontal components, which is why vertical and horizontal eye data were analyzed separately.

ISCAN recommended using the standard deviation of the vertical points of regard and the

standard deviation of the horizontal points of regard for each questionanswer event to

assess eye movement, which we did. Smaller mean standard deviations in Tables 3, 4, and6 indicate more stationary eyes. Readers interested in obtaining more details about this or

any other aspect of the procedure can contact the lead author.



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TRANSCRIBING AUDIO RECORDINGS AND CODING FOR INCONSISTENCIES

A graduate assistant (GA) transcribed audio recordings for all utterances following each

question. Rarely were answers inaudible. Transcriptions were later coded for the number

of inconsistencies within a question set. An inconsistency occurred when the secondanswer of an interrelated pair was implausible if the answer to the first question was

assumed true. For example, in Video 1, inconsistencies occurred when Question 22 (see the

appendix) was answered yes but the answer to Questions 23 began with He . . . For

Video 2, a common inconsistency was answering Question 29 with a violent crime and

later answering Question 33 with he hid the stolen item with his jacket.

To assess interrater reliability, copies of 47 transcriptions, randomly selected from the

145, were independently coded for inconsistencies by the GA and by another GA otherwise

unaffiliated with this project. Pearson correlations between inconsistency totals of the two

raters for the general, Video 1, and Video 2 questions were .92, .67, and .78, respectively,

all significant and large enough to justify having the first GA code the remaining transcripts

(Anastasi & Urbina, 1997). Her inconsistency totals are used in the analyses.

SUMMARIZING DATA FOR EACH CATEGORY OF QUESTION

For each questionanswer event, there was a mean for response time and pupil dilation,

as well as a vertical eye movement standard deviation and a horizontal eye movement

standard deviation. These data were summarized for hypothesis testing as follows. Within

each question category, the mean pupil dilation for yesno questions was determined, as

well as for open-ended questions. Also, within each question category, the mean horizontaland vertical eye movement standard deviations were determined by question type. Since

response times often were positively skewed, the median response time within each ques-

tion category and question type was used to control for outliers (Solso, 2001).

CHECKING TRANSCRIPTIONS FOR COMPLIANCE

The transcribed answers were checked for participant compliance with instructions to

answer general questions truthfully, which was possible with the boldfaced factual general

questions of the appendix. No one answered more than two of them incorrectly, and few

inconsistencies occurred. Compliance was good. Regarding the postexperimenter question-naire data, the mean number of questions correctly answered for Video 1 for all 145 was

9.81 (SD=.44, 98% correct). For Video 2, mean accuracy was 7.48 (SD=.65, 83% correct),

results showing that participants generally had encoded truths. Finally, comparing the post-

experiment surveys with the transcriptions, it was clear that participants assigned to truth

telling generally answered Video 1 and 2 questions truthfully or with an I dont know.

Liars, rehearsed and unrehearsed, overall answered


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was lie condition (truth telling, unrehearsed lying, rehearsed lying). To avoid overwhelming

readers with statistics, main effects for question type and Question Type Lie Condition

interactions are only reported when significant. Moreover, the F statistics of simple main

effects used to understand interactions are not reported. H2 was tested with a one-way

ANOVA. For a significant main effect or simple main effect for lie condition, the

Studentized-Newman-Keuls (S-N-K) procedure determined which means were significantly

different. ANOVAs on the cues for general questions were conducted to ensure equality of

the conditions that random assignment produces. Only if significant lie condition effects

occurred are these results reported.

RESULTS

Four hypotheses were tested, one for each cognitive cue evaluated. H1, regarding longerresponse times with lying, was well supported, as was H2, predicting more inconsistencies

with deception. H3 asserts greater eye movement with truth telling and was partially con-

firmed. H4, predicting greater pupil dilation with deception, was not supported.

H1: RESPONSE TIME

Descriptive statistics for response times are provided in Table 1. In all tables, condition

Ns are boldfaced. There were no missing data with this cue. In the case of Video 1, question

type made a difference, F(1, 142) = 260.89, p= .001, = .648, (yesno M= 574, open-

endedM= 1,007), with open-ended questions taking longer. Lie condition was significant,F(2, 142) = 32.42,p= .001, = .313. The Question Type Lie Condition interaction was

also significant,F(2, 142) = 14.34,p= .001, = .168. In the case of yesno questions, truth

tellers and rehearsed liars were significantly faster than unrehearsed liars. For open-ended

questions, rehearsed liars answered the fastest, followed by truth tellers. Unrehearsed liars

answered the slowest. For Video 2, open-ended questions took longer than yesno ques-

tions,F(1, 142) = 97.24,p= .001, = .406 (yesno M= 629, open-endedM= 878). Lie

condition made a difference, F(2, 142) = 22.74, p= .001, = .243. The interaction was

significant,F(2, 142) = 23.11,p= .001, = .246. For yesno questions, rehearsed liars and

truth tellers were significantly faster than unrehearsed liars. In the case of open-ended ques-

tions, all three conditions were significantly different, with rehearsed liars the fastest and

unrehearsed liars the slowest. A constant pattern of results occurred across videos that sup-

ports H1, especially with open-ended questions.

Consistent with Walters (1996) and Walczyk and colleagues (Walczyk et al. 2005;

Walczyk et al., 2009), truthful base rate means were used to adjust means of cues of ques-

tions suspected of deception. Specifically, adjusted Video 1 response timeswere computed

by subtracting the yesno and open-ended means of general questions from the correspond-

ing means of the Video 1 questions. These adjustments also occurred for Video 2 response

times. For adjusted means, see Table 1. For adjusted Video 1 means, a main effect was

found for question type,F(1, 142) = 79.60,p= .001, = .359 (yesnoM= 20, open-endedM= 306), and for lie condition,F(2, 142) = 36.49, p= .001, = .339. Because of a sig-

nificant interaction,F(2, 142) = 9.18,p= .001, = .115, simple main effects were exam-

ined. For yesno questions, unrehearsed liars took significantly longer than the other two

conditions. For open-ended questions, all three condition means differed significantly, with



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unrehearsed liars taking the most time, rehearsed liars the least. These results parallel those

of the unadjusted scores. Adjusted Video 2 means showed a main effect for question type,

F(1, 142) = 12.02,p= .001, = .078 (yesnoM= 74, open-endedM= 176); another for

lie condition,F(2, 142) = 19.36,p= .001, =. 214; and an interaction,F(2, 142) = 15.11,

p= .001, = .176. For yesno questions, unrehearsed liars took longer than truth tellers

and rehearsed liars. Rehearsed liars were faster than truth tellers and unrehearsed liars with

open-ended questions.

The pattern is that open-ended questions took longer to answer. Moreover, unrehearsed lying

took the longest for Videos 1 and 2. For open-ended questions, rehearsal often reduced responsetimes below those of truth tellers. Finally, adjusting for individual differences by subtracting

yesno or open-ended means produced a pattern of differences similar to those of the unad-

justed means while controlling for individual differences in base rates. H1 was supported.

H2: INCONSISTENCIES

Table 2 reports statistics for total inconsistencies by question set. Ns are occasionally

reduced due to at least one answer of an interrelated pair being inaudible such that total

inconsistency within a set could not be determined. Although infrequent, inconsistencies

occurred enough to discriminate among conditions for the videos. A significant main effectfor lie condition occurred for Video 1,F(2, 140) = 8.33,p= .001. Truth tellers had fewer

inconsistencies than the other two conditions. A significant lie condition main effect was

also observed for Video 2,F(2, 138) = 10.67,p= .001. Once again, truth tellers had fewer

inconsistencies than the other conditions. H2 was partially supported.

TABLE 1: Statistics for Response Times (in milliseconds) by Lie Condition, Question Type, and Question

Category

Lie Condition

Truth Telling Unrehearsed Lying Rehearsed Lying

Questions M SD M SD M SD

Means

Significantly

Different

Yesno questions

General 545 171 575 157 544 174 None

Video 1 498 214 758 366 475 237 1-2,2-3

Video 2 583 202 751 279 558 262 1-2,2-3

Adj. Video 1 47 165 183 323 69 229 1-2,2-3

Adj. Video 2 37 197 176 242 14 232 1-2,2-3

N 48 47 50

Mean no. 1 2 3

Open-ended questions

General 676 211 748 270 683 218 None

Video 1 1,028 340 1,304 372 708 332 1-2,1-3,2-3

Video 2 936 314 1,148 515 567 270 1-2,1-3,2-3

Adj. Video 1 352 304 556 430 25 276 1-2,1-3,2-3

Adj. Video 2 260 285 399 600 115 231 1-3,2-3

N 48 47 50

Mean no. 1 2 3



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H3: EYE MOVEMENT

Vertical eye movements.See Table 3 for statistics on vertical eye movements. Reduced

condition Ns were usually due to loss of calibration of point of regard caused by head

movements, which did not affect the assessment of pupil dilation. For Video 1, a main

effect occurred for type of question,F(1, 133) = 10.17,p= .002, = .071 (yesnoM= 50,

open-endedM= 57). Open-ended questions entailed slightly more eye movements. There

was also a lie condition main effect, F(2, 133) = 3.65, p= .028, = .071. A significant

Question Type Lie Condition interaction occurred as well, F(2, 133) = 5.99, p= .003,

= .083. For yesno questions, truth tellers had significantly more eye movements thanrehearsed or unrehearsed liars. Regarding Video 2, question type generated a main effect,

F(1, 128) = 4.61,p= .034, = .035, by which yesno questions elicited less eye movement

(yesnoM= 50, open-endedM= 57). A main effect for lie condition happened,F(2, 128)

= 3.52,p= .032, = .052. Truth tellers had significantly more eye movements than rehearsed

liars. These analyses partially support H3. Truth tellers generally had more eye movements,

especially for yesno questions.

Adjusted Video 1 eye movements were calculated by subtracting the general yesno

vertical eye movement means from the yesno Video 1 vertical eye movement means. The

same was done for the open-ended means as well as for Video 2. Corresponding adjust-

ments were also done for the horizontal eye movement data of both videos. Adjusted verti-cal means are reported in Table 3. Adjusted horizontal means appear in Table 4. For

adjusted vertical eye movements of Video 1, a significant interaction occurred,F(2, 131) =

6.39,p= .002, = .089. Also, lie condition mattered,F(2, 131) = 3.24,p= .042, = .047.

In the case of yesno questions, truth tellers had significantly more movement than

rehearsed liars. Regarding Video 2, lie condition had an impact,F(2, 126) = 3.88,p= .023,

= .058. Rehearsed liars had less eye movements the other two conditions.

Horizontal eye movements.Table 4 summarizes horizontal eye movements. As in Table

3, the largest means are observed with truth tellers. For Video 1, an effect for type of ques-tion occurred,F(1, 133) = 6.06,p= .015, = .044. Open-ended questions elicited more eye

movements (yesnoM= 52, open-endedM= 58). Lie condition had an impact,F(2, 133)

TABLE 2: Total Inconsistency

Lie Condition



Means Significantly

Different

General 0.00 0.00 0.00 0.00 0.04 0.20 None

Video 1 0.04 0.20 0.61 0.93 0.48 0.75 1-2,1-3

N 47 46 50

Video 2 0.14 0.49 0.80 0.78 0.69 0.91 1-2,1-3

N 47 45 49



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= 4.14,p= .018, = .059, with an interaction, F(2, 133) = 5.59,p= .005, = .078. Truth

tellers had more eye movements than either rehearsed or unrehearsed liars with yesno

questions only. For Video 2, there was a main effect for question type,F(1, 129) = 6.93,

p= .009, = .051. Open-ended questions elicited more eye movement (yesno M= 50,

open-endedM= 54). Lie condition was significant,F(1, 129) = 4.24, p= .016, = .062.

Truth tellers moved their eye more than rehearsed liars.

For the adjusted Video 1 horizontal eye movements, a significant interaction occurred,

F(2, 131) = 5.04, p= .008, = .071, but no effect of lie condition, F(2, 131) = 2.32, p=

.102. Truth tellers had significantly more eye movements than rehearsed liars with yesno

questions. Regarding adjusted Video 2 horizontal means, lie condition was significant,F(3,

95) = 3.95, p= .022, = .059. Rehearsed liars had less eye movement than unrehearsed

liars and truth tellers.

Importantly, the same pattern of significant differences was found for vertical (Table 3)and horizontal (Table 4) eye movements. For the videos, open-ended questions elicited the

most eye movements. Mixed support was obtained for H3. Whether or not means were

adjusted, truth tellers tended to have the most eye movements, and yesno question tended

to produce the best discrimination across conditions.

TABLE 3: Vertical Eye Movements (in pixels)

Lie Condition



Means

Significantly

Different

Yesno questions

General 53 40 44 36 54 45 None

N 45 47 45

Video 1 67 45 44 40 40 36 1-2,1-3

N 43 46 47

Video 2 60 46 46 43 37 34 1-3

N 42 42 47

Adj. Video 1 14 39 0 31 14 38 1-3

N 43 46 45

Adj. Video 2 5 36 2 28 18 41 1-3, 2-3

N 42 42 45

1 2 3


General 58 36 50 36 49 35 None

N 45 47 45

Video 1 64 38 58 43 49 36 None

N 43 46 47

Video 2 62 40 51 37 42 34 1-3

N 42 42 47

Adj. Video 1 5 36 8 27 0 30 None

N 43 46 45

Adj. Video 2 4 31 1 28 6 34 1-3, 2-3

N 42 42 45

1 2 3



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H4: PUPIL DILATION DURING DECEPTION

Table 5 summarizes pupil dilation. For Video 1, there was a main effect for question

type, F(1, 142) = 32.72, p= .001, = .187. Open-ended questions involved more pupil

dilation (yesnoM= 67, open-endedM= 69). Lie condition had no effect,F(2, 142) =.16,

p = .850. For Video 2, open-ended questions entailed more pupil dilation, F(1, 142) =

12.55, p= .001, = .081 (yesno M= 65, open-ended M= 67). Lie condition had no

impact,F(2, 142) =.67,p= .513. A significant interaction occurred, F(2, 142) = 3.62,p=

.029, = .049. The simple main effects across question type were not significant. However,

pair-sample t tests across lie conditions clarified the interaction. For truth tellers, open-ended questions involved more pupil dilation, which also occurred for unrehearsed liars,

but not for rehearsed liars. Rehearsing answers apparently equated the cognitive load of

answering across question types. H4 was not supported.

TABLE 4: Horizontal Eye Movements

Lie Condition



Means

Significantly

Different

Yesno questions

General 55 41 47 37 53 42 None

N 45 47 45

Video 1 70 40 45 39 43 43 1-2, 1-3

N 43 46 47

Video 2 63 41 49 46 38 36 1-3

N 42 43 47 Adj. Video 1 14 38 2 37 9 34 1-3

N 43 46 45

Adj. Video 2 6 32 1 34 16 33 1-3, 2-3

N 42 43 45

1 2 3


General 60 40 52 34 50 36 None

N 45 47 45

Video 1 67 42 60 43 48 36 None

N 43 46 47

Video 2 66 37 54 42 44 39 1-3N 42 43 47

Adj. Video 1 5 37 8 27 1 32 None

N 43 46 45

Adj. Video 2 5 28 3 29 5 33 1-3, 2-3

N 42 43 45

1 2 3



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DISCRIMINANT ANALYSES

Two exploratory discriminant analyses, one for each video, assessed the collectivepotential of the cognitive cues except pupil dilation. They served as the IVs. Only adjusted

IV means were used (Walters, 1996) and inconsistency totals. Lie condition was the

dependent (grouping) variable for both, with three levels: truth tellers, unrehearsed liars,

and rehearsed liars. Condition means are reported in Table 6, along with the results of one

way ANOVAs comparing them.Ns were reduced by only including observations that have

complete data for all the IVs. Rows of IVs with significant models are italicized. All but

the open-ended eye movement means were significant.

The discriminant model of Video 1 was significant, Wilkss Lambda =.77,p= .001; 67%

of the sample was accurately classified, 33% accuracy expected by chance. The false posi-

tive rate (truth tellers misclassified as liars) was 9%. The false negative rate (liars misclas-

sified as truth tellers) was 17%. Video 2s discriminant model was also significant, Wilkss

Lambda =.81, p= .001; 69% of the sample was classified accurately. The rate of false

positive was very close to that of Video 1 at 8%, as was the false negative rate at 14%.

Overall, these results show across videos that the adjusted cognitive cues of this research,

along with inconsistencies, perform well beyond chance and with low false positive rates.

DISCUSSION

Though highly valued by juries (Bond & DePaulo, 2006), the testimony of eyewitnesses

has several threats to its validity, especially misidentification (Loftus, 2007; Wells & Olson,

2003). Perjury is the most pernicious threat and an impediment to evenhanded justice. Given

recent concerns with the polygraphs validity (DePaulo et al., 2003; Lykken, 1998; NRC,

TABLE 5: Pupil Dilation (in pixels)

Lie Condition



Means

Significantly

Different

Yesno questions

General 67 19 67 14 70 20 None

Video 1 66 18 67 12 67 16 None

Video 2 64 18 68 16 66 16 None

N 48 47 50

1 2 3

Open-ended questionsGeneral 65 16 66 14 69 20 None

Video 1 67 18 70 14 70 17 None

Video 2 66 18 69 17 66 16 None

N 48 47 50

1 2 3



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2003), an effective alternative lie detector would benefit the criminal justice system byuncovering deception during interviews, thereby reducing perjury. We sought to help refine

TRI-Con, a method of lie detection designed to induce cognitive load selectively on liars

(Walczyk et al., 2005). Participants adopted the roles of eyewitnesses of videos of actual

thefts and then told the truth or lied, rehearsed or unrehearsed, when questioned. Moreover,

although others have considered the effects of rehearsal on deception detection (e.g.,

Littlepage et al., 1986; Littlepage & Pineault, 1985; OHair et al., 1981), this study is the

first to examine its effects on multiple cognitive cues: response time, answer consistency,

eye movements, and pupil dilation. The analyses suggest the individual and collective value

of most of these cues for lie detection.

RESPONSE TIME

The longer response times hypothesized to occur with deception, especially unrehearsed,

were confirmed. Response time, a valuable cue to deception (DePaulo et al., 2003;

TABLE 6: Lie Condition Means and ANOVA Results for Independent Variables of the Discriminant

Analyses

Lie Condition

Truth Telling

Unrehearsed

Lying

Rehearsed

Lying

M M M F p

Adjusted yesno response times

Video 1 43.90 192.71 78.54 15.15 .001

Video 2 37.10 204.80 16.40 8.47 .001

Adjusted open-ended response times

Video 1 356.66 569.57 31.05 26.73 .001

Video 2 247.24 446.59 110.95 23.09 .001

Total Video 1 inconsistency 0.05 0.62 0.51 7.62 .001Total Video 2 inconsistency 0.12 0.82 0.68 9.34 .001

Adjusted vertical eye movements

Yesno

Video 1 13.17 0.57 13.94 6.13 .003

Video 2 5.45 0.95 17.79 5.04 .008

Open-ended

Video 1 5.46 8.79 0.02 0.92 .401

Video 2 4.43 2.62 6.49 1.52 .221

Adjusted horizontal eye movements

Yesno

Video 1 12.93 0.96 9.00 4.03 .020 Video 2 5.79 2.49 15.51 5.06 .008

Open-ended

Video 1 4.02 8.49 1.27 1.05 .352

Video 2 4.40 4.51 5.28 1.45 .237

Nfor Video 1 42 45 45

Nfor Video 2 41 40 44

Note. ANOVAs in italicized rows have pvalues < .05 and were used in discriminant analyses.



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Seymour et al., 2000; Sporer & Schwandt, 2007), was the best one of those we evaluated.

Also, open-ended questions elicited longer response times than yesno questions, replicat-

ing previous studies (Walczyk et al., 2005; Walczyk et al., 2009). Importantly, the same

general pattern of group differences of Video 1 was replicated with Video 2 (see Table 1),

but not across question types. For yesno questions, unrehearsed liars took significantly

longer to answer than both truth tellers and rehearsed liars. That rehearsed liars did not dif-

fer significantly from truth tellers may partially reflect that answers to yesno questions are

syntactically constrained. The adjusted yesno scores showed the same pattern as the unad-

justed ones but also control for individual differences (Walters, 1996), making them most

appropriate for lie detection examinations.

For the unadjusted open-ended response times of both videos, rehearsed liars answered

the quickest, followed by truth tellers. Unrehearsed liars were the slowest. This pattern was

maintained with the adjusted open-ended scores, except for a nonsignificant difference

between truth tellers and unrehearsed liars for Video 2. For yesno and open-ended ques-tions, rehearsal is an effective cognitive load-attenuating countermeasure as assessed by

response time, replicating others findings (OHair et al., 1981; Walczyk et al., 2009). That

open-ended question response times were significantly below those of truth tellers implies

that the use of rehearsal is a detectable countermeasure for this question type.

These findings suggest that open-ended questions involving eyewitness accounts can

provide better cues than yesno questions. Why? Walczyk, Roper, Seemann, and Humphrey

(2003) observed that lying to yesno questions was less cognitively demanding in general

than lying to open-ended questions according to participant self-reports of lie construction.

For the yesno questions, they reported flipping an answer from yes to no or vice versa to

make it untrue. For open-ended questions, more thought was given to the plausibility of

answers due to their greater range of possible responses. Likewise, in this study, owing to

fewer syntactic and more plausibility constraints, open-ended questions may generally

have imposed greater cognitive loads, which can multiply the cues to deception (Vrij et al.,

2010). In short, the less constrained the response, the greater are the opportunities for cues

to deception to manifest (DePaulo et al., 2003). Still, open-ended questions will not always

impose greater cognitive load. For instance, if answering a yesno question truthfully

requires retrieval of a truth long-dormant but an open-ended question accesses a truth of a

recent event, the former should cause more load.

INCONSISTENCIES

This hypothesis was generally supported. Although the frequencies of inconsistencies

were low across question categories, truth tellers had significantly fewer than rehearsed or

unrehearsed liars across videos. The two lying conditions did not differ. Walczyk et al.

(2009) and Vrij et al. (2010) both found more inconsistencies in liars than truth tellers,

especially when deceptions are unrehearsed. Importantly, total inconsistency depends on

how many interrelated questions are asked and the depth of their logical interdependence.

Video 1 and Video 2 had only five and four interrelated question pairs, respectively, which

may not have been sufficiently cognitive load inducing to provoke many contradictions.Even so, they did help distinguish truth tellers from liars. Also, the present data showed that

the inconsistencies are often subtle, blurting he instead of she. Having to answer under

time restriction may maximize inconsistencies as question interrelatedness increases,

which future research can explore.



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EYE MOVEMENTS

The hypothesis that truth tellers would have the most eye movements was partially sup-

ported. Because of the ETL 400s design, eye movements were analyzed into vertical and

horizontal components. On examining the vertical eye movements of Table 3 and the hori-zontal movements of Table 4, it is evident that the largest unadjusted vertical eye movement

means occurred for truth tellers yesno and open-ended questions of both videos, although

the differences were not always significant. Importantly, the same pattern of significant dif-

ferences held across tables. For Video 1, yesno questions of truth tellers entailed greater

eye movements than unrehearsed and rehearsed liars. For Video 2, truth tellers moved their

eyes more than rehearsed liars for both question types. Truth tellers were expected to have

the most eye movements. The unadjusted means thus partially supported this hypothesis.

The adjusted yesno means retained the same general pattern of truth tellers having the most

eye movements and surprisingly showed that rehearsed liars had less eye movements than

unrehearsed liars. For Video 1, truth tellers had more eye movement than rehearsed liars

with yesno questions. For Video 2, rehearsed liars had less than truth tellers and unre-

hearsed liars for both question types. Adjusting means support this hypothesis in that the

largest means tend to be with truth tellers, but do not support it with the smallest means

tending to go with rehearsed liars, especially for yesno questions. Searching memory for

rehearsed lies may require less environmental distraction than unrehearsed lying.

Stimulation from the environment can be distracting and impair internal processing

(Doherty-Sneddon et al., 2002; Doherty-Sneddon & Phelps, 2005; Glenberg et al., 1998).

Expanding on this notion, we predicted less eye movements for liars because their high

cognitive loads focused on internal processing would have them reducing environmentaldistraction. In addition to having to generate or recall deceptive answers, liars loads were

presumed high due to having to maintain eye contact (Vrij et al., 2010). As noted above,

sometimes rehearsed liars had the least eye movements likely to minimize environmental

distraction, which we believe helped them recall their prepared lies. Future research should

try to replicate these results and assess the effects of extensive rehearsal of lies on eye

movements. We expect that well-rehearsed lies will have eye movement rates exceeding

those of truth tellers. The present data show that eye movements can distinguish truth tell-

ers from liars and run contrary to the stereotype that liars are shifty-eyed (Vrij, 2000). Out

of cognitive necessity, their eyes often must be stationary.

PUPIL DILATION

Surprisingly, the greater pupil dilation hypothesized with deception was not observed.

Researchers have nonetheless found more pupil dilation in lying (Bradley & Janisse, 1979;

Dionisio et al., 2001; Heilveil, 1976; Lubow & Fein, 1996; Webb et al., 2009). One prob-

lem in this study may have been that dilation reflected not only cognitive load but emo-

tional arousal as well (DePaulo et al., 2003). Of the cues of this research, it may be the most

confounded index of cognitive load. For instance, the novelty of the procedure and the

stress of having to maintain eye contact may have been sufficiently arousing, even for truthtellers, to have overshadowed small group differences due to lying. Given its utility in past

studies, though, researchers should continue to examine it. If cognitive lie detection exam-

ination procedures become standardized, it will likely become less ambiguous as an index

of the cognitive load of deception.



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EXPLORATORY DISCRIMINANT ANALYSES

The verbal skills of liars moderate the efficiency of lie generation (Walczyk et al., 2003), so

do social skills (Walczyk et al., 2005) and other individual differences (Vrij, 2000). We con-

trolled for them by following the recommendation of Walters (1996). Specifically, onlyresponse time and eye movement means adjusted by means of general questions were used to

estimate discriminant functions, along with inconsistency data. Collectively they discriminated

among truth tellers, rehearsed liars, and unrehearsed liars. Moreover, although Walczyk et al.

(2009) demonstrated the value of adjusted response times and inconsistency totals as dis-

criminators, our research contributes by also considering the effects of rehearsal on eye data.

Table 6 reveals an interesting contrast. The best discriminators for response times

involved open-ended questions, whereas for eye movements they were with yesno ques-

tions. Our explanation follows. Eye movements and response times both index cognitive

load, but differently. Measuring the amount of processing, response time is a direct conse-

quence of cognitive load (Solso, 2001), but gaze aversion and eye movements reflect

attempts to manage load (Doherty-Sneddon et al., 2002; Doherty-Sneddon & Phelps, 2005;

Glenberg et al., 1998). Minimal syntactic constraint on answers to open-ended questions

likely required extended memory search for plausible lies for unrehearsed liars, causing the

long responses times, but also dramatic reduction in processing below that of truth telling

when lies are rehearsed. The processing reduction caused by rehearsal could not be

matched with the constrained yesno questions. In contrast, Table 6 shows a much greater

range of adjusted eye movement means across lie conditions for yesno questions than for

open-ended questions. Adjusted yesno means for unrehearsed liars are close to those of

general questions (near zero). Truth tellers have the most eye movements, reflecting mini-mal need to reduce load. Rehearsed liars have eye movements dramatically below those of

general questions, suggestive of attempted load reduction. Reduced eye movements for

yesno questions may reflect rehearsed liars lessening of environmental distraction to

focus on overcoming the Stroop-like interference of giving mildly practiced responses that

were incompatible with a habitual behavior: answering truthfully syntactically constrained

yesno questions. Stated generally, rehearsing responses lightens cognitive load more for

unconstrained responding than for constrained responding, but rehearsal of atypical

responding (e.g., lying) produces the most interference and need for focused attention when

response options are highly constrained. This account must be verified by future research.

Admittedly, some polygraph validity studies have achieved higher classification accura-

cies than those of this research (Lykken, 1998; NRC, 2003). Even so, we caution readers

against dismissing prematurely TRI-Con and other cognitive load-inducing lie detection

techniques. The polygraph has been refined over many decades, whereas TRI-Con and

similar techniques (see Vrij, Fisher et al., 2008) are new. Only research aimed at refining

averting-rehearsal, dual tasking, and combined approaches will realize their potential.

Some encouraging findings for TRI-Con are the low rates of false positives we observed,

which are a problem with the polygraph and a major reason for its limited use in the

criminal justice system (Lykken, 1998).

USING TRI-CON WITHIN THE CRIMINAL JUSTICE SYSTEM

There are many legal and psychological obstacles to the adoption of new forensic tech-

nologies like cognitive-load-inducing lie detection techniques. Will judges, lawyers,



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victims, suspects, defendants, and witnesses accept TRI-Con and similar approaches, even

if they become well validated? Having to answers questions under the guidelines of TRI-

Con might not be accepted by professionals initially. However, to put this in a historical

perspective, the publics initial reaction to the invasiveness of the polygraph was negative.

Still, the device was eventually accepted (Lykken, 1998). If TRI-Con and other load-induc-

ing techniques can prove their worth, they likely will be accepted, too. TRI-Con has poten-

tial to assess truthfulness and deception wherever short answers can be given. For instance,

if a suspect provides an alibi that police believe is false, a series of yesno and open-ended

questions could be written based on the alibi-probing details the individual may not have

anticipated. Moreover, as in this research, prompting, the asking of questions, and the

assessment of cues can be largely automated. Also, determining whether an examinee is

answering honestly or lying rehearsed or unrehearsed can be done using statistical proce-

dures like logistical regression or discriminant analyses. Of course, more refinement of TRI-

Con is needed, especially on authentic samples and involving high stakes lies.

LIMITATIONS AND FUTURE RESEARCH DIRECTIONS

A few limitations are noteworthy. Unlike the polygraph, lie detection did not occur at the

level of the question. Rather, it occurred for question set. Walczyk et al. (2005) noted that

the cognitive cues to an individual question may be too unreliable at present to support such

precise lie detection. However, the present data suggest that response times, inconsistency,

and eye movements can discriminate truth tellers from rehearsed and unrehearsed liars.

Future refinement of load-inducing approaches that adds cognitive cues, tweaks the proce-

dures to prevent rehearsal further, and imposes concurrent tasks that interfere selectivelywith lying may make question-level detection a reality. Another limitation is the fact that

two factors were actually manipulated in this research under the IV lie condition: lie

instructions (lie, tell the truth) and level of rehearsal (rehearsed, unrehearsed). Moreover,

they were not fully crossed in a 2 2 factorial design. That is, there was no rehearsed, truth

teller condition. Had there been one, then interactions between these factors could have

been examined. However, readers can discern the effects of lie instructions by comparing

unrehearsed liars and truth tellers and can consider the effects of level of rehearsal by com-

paring rehearsed and unrehearsed liars. The rehearsal of truthful responses is rare in authen-

tic contexts but should be added as a condition in future research. Another limitation relates

to instructions to maintain eye contact; these might be ineffective with Japanese and other

non-Western cultures for whom such eye contact goes against a societal norm. These

instructions might induce inordinately high levels of anxiety and be distracting within these

cultures (McCarthy, Lee, Itakura, & Muir, 2006), even for truth tellers. Finally, the motiva-

tion of our participants to appear truthful was not as high as that of actual witnesses lying

to protect someone. Future research testing TRI-Con and similar approaches should

increase the incentive for lying by offering cash rewards to participants who can deceive

while appearing sincere, as well as test more authentic samples (e.g., prisoners). Still, the

promising results of this study justify more research on TRI-Con and other cognitive load-

inducing techniques with the hope of uncovering deception during interviews of witnessesand thereby reducing perjured testimony.



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APPENDIX

GENERAL AND VIDEO-RELATED QUESTIONS

General Questions Question pairs involving inconsistencies: 2-16, 3-15, 5-10, 7-171) What was president Washingtons first name?*

2) Is Independence Day celebrated during August?

3) Is it possible for a person to be burned when operating an oven?

4) What is your last name?

5) What is your age?

6) What is your biological mothers first name?

7) In what city is the White House located?

8) You received your GED or graduated from high school in what year?

9) What is your gender?

10) Were you born before the year 1979?

11) What is your race?

12) Are you a freshman?

13) Is our current presidents first name Leo?

14) Are you a student?

15) Can an oven get hot?

16) On what date does the United States celebrate Independence Day?

17) Is Los Angeles the location of the White House?

18) What is the name of city of the Louisiana state capital?

Video 1 Questions Question pairs involving inconsistencies: 19-20, 19-23, 19-28,

22-23, 22-25

19) What job did the perpetrator have?

20) Following the crime, who came into the office and talked with the perpetrator?

21) What was the perpetrators race?22) Was the perpetrator a woman?

23) What was the perpetrators job-related reason for being in the office?

24) Was the perpetrator wearing a baseball cap?

25) What was the perpetrators criminal act?

26) Approximately what was the perpetrators age?

27) Was the perpetrator wearing shorts?

28) Was the perpetrator wearing formal black shoes?

Video 2 Questions Question pairs involving inconsistencies: 29-33, 29-34, 30-33,

30-35

29) What was the criminal act?

30) Was the perpetrator a man?31) Was the perpetrator Asian?

32) What was the race of the clerk behind the counter?

33) How did the perpetrator try to conceal the criminal act?

34) Where did the criminal act take place?

35) What did the perpetrator and the clerk talk about?

36) Was the perpetrator wearing a hat?

37) At the time of the crime, how many were visible in the store?

Note. Boldfaced general questions have verifiable truths.



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Jeffrey J. Walczykis a professor of psychology at Louisiana Tech University. He is former associate editor of the Journal

of Educational Psychology. His research interests include cognitive and social aspects of deception as well as the psychology

of reading.

Diana A. Griffithis a research associate at Louisiana Tech. Formerly an editorial assistant of the Journal of Educational

Psychology, she writes grants and conducts research on deception.

Rachel Yatesreceived her masters degree in industrial-organizational psychology in 2009. Presently she is the administra-

tive assistant at the Center for Secure Cyberspace of Louisiana Tech.

Shelley R. Visconteis a doctoral candidate in counseling psychology at Louisiana Tech. Her research interests include the

study of autism.

Byron Simoneauxis a doctoral candidate in counseling psychology at Louisiana Tech. His dissertation concerns gender

differences in the attribution of deception in others.

Laura L. Harrisis a doctoral student in counseling psychology at Louisiana Tech.

criminal justice and behavior 2012 walczyk 887 909

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