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Does the Truth Come Out in the Writing? SCAN as a Lie Detection Tool

Galit NahariBar-Ilan University

Aldert VrijUniversity of Portsmouth

Ronald P. FisherFlorida International University

We tested the accuracy of Scientific Content Analysis (SCAN), a verbal lie detection tool that is used

world-wide by federal law enforcement and military agencies. Sixty-one participants were requested to

write down the truth, an outright lie or a concealment lie about activities they had just completed. The

statements were coded with SCAN and with another verbal lie detection tool, Reality Monitoring (RM).

RM discriminated significantly between truth tellers and outright liars and between truth tellers and

concealment liars, whereas SCAN did not discriminate between truth tellers and either kind of liar.

Implications of the findings for the suitability of SCAN as a lie detection tool are discussed.

Scientific Content Analysis (SCAN), developed by Avinoam

Sapir, a former polygraph examiner in the Israeli police, is a verbal

veracity assessment tool. It is used in countries such as Australia,

Belgium, Canada, Israel, Mexico, UK, US, the Netherlands, Qatar,

Singapore, and South Africa (Vrij, 2008). It is used by federal law

enforcement (including the FBI), military agencies (including the

US Army Military Intelligence), secret services (including the

CIA) and other types of investigators (including social workers,

lawyers, fire investigators and the American Society for Industrial

Security) (Bockstaele, 2008; www.lsiscan.co.il). http://www

.lsiscan.com/id29.htm provides a full list of past participants of

SCAN courses. According to (the American version of) the SCAN

website (www.lsiscan.com) SCAN courses are mostly given in the

US and Canada (on a weekly basis in those countries). In addition,

online courses are also available.

Our impression is that SCAN is used widely. The second author

gave a seminar on lie detection during the Second International

Investigative Interviewing Conference, held in July 2006 at the

University of Portsmouth (UK). That seminar was attended by

about 100 criminal investigators from many countries including

Canada, UK, US, and the Netherlands. When asked which lie

detection tool, if any, they mainly use, the most frequent answer,

from investigators on both sides of the Atlantic, was SCAN. It was

reported to be used even more frequently than the well known Reid

technique in lie detection.

In the SCAN procedure, the examinee is requested to write a

detailed description of all his/her activities during a critical period oftime in such a way that a reader without background information can

determine what actually happened. The handwritten statement is then

analyzed by a SCAN expert on the basis of a list of predetermined

criteria. It is thought that some SCAN criteria are more likely to occur

in truthful statements than in deceptive statements, whereas other

criteria are more likely to occur in deceptive statements than in

truthful statements (Sapir, 1987/2000).

We know of four published studies that examined the validity of

SCAN as a lie detection tool (Bachenko, Fitzpatrick, & Schonwet-

ter, 2008; Driscoll, 1994; Porter & Yuille, 1996; Smith, 2001).

Both Driscoll (1994) and Smith (2001) carried out field studies and

analyzed statements of actual suspects. They reported high accu-

racy rates, around 80%. However, Smith, who compared the

performances of experienced SCAN users with raters not trained in

SCAN, found no difference in accuracy between the two groups.

Smith also noticed that different experts used different SCAN

criteria to justify their decision of whether or not a statement was

deceptive. In other words, there was a lack of consistency in the

application of SCAN amongst SCAN users. Both studies, how-

ever, were limited in that the ground truth, the actual veracity of

the statements, could not be established. This makes interpreting

the findings problematic. Porter and Yuille (1996) carried out a

laboratory SCAN experiment in which participants did or did not

commit a mock theft and were interviewed about this alleged

crime. They examined three SCAN criteria: Structure of the state-

ment; missing information; and first person singular, past tense.

Truthful and deceptive statements did not differ from each other

regarding these three criteria. However, this experiment was also

limited. First, it tested only a small number (three) of SCAN

criteria. Second, as participants gave oral statements that weresubsequently transcribed, the procedure did not follow one of the

basic principles of SCAN, the request to write down a statement.

In a fourth study, some SCAN criteria including verb tense were

examined (Bachenko et al., 2008). However, the results for the

individual criteria were not discussed.

In sum, all four SCAN studies published to date were limited

and, therefore, not much is known about the accuracy of the SCAN

tool, despite the fact that it is used by many agencies. In the present

experiment, we examined whether SCAN could discriminate be-

tween true and false statements. We compared SCAN with Reality

Monitoring (RM), another verbal veracity assessment tool. Al-

This article was published Online First January 21, 2011.

Galit Nahari, Department of Criminology, Bar-Ilan University, Ramat

Gan, Israel; Aldert Vrij, University of Portsmouth, Portsmouth, UK; Ron-

ald P. Fisher, Florida International University, Miami, FL, USA.

Correspondence concerning this article should be addressed to Galit

Nahari, Department of Criminology, Bar-Ilan University, Ramat Gan

52900, Israel, E-mail: [email protected]

Law and Human Behavior 2011 American Psychological Association2012, Vol. 36, No. 1, 68 76 0147-7307/11/$12.00 DOI: 10.1037/h0093965

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though not used by professionals in the field, RMs validity has

been widely tested and it appears to discriminate truth tellers and

liars well above chance level (Masip, Sporer, Garrido, & Herrero,

2005; Vrij, 2008).

The underlying assumption of SCAN is that true statements,

derived from memory of an actual experienced event, differ in

content and quality from statements that are based on invention orfantasy (Smith, 2001). This is similar to the assumption underlying

RM. Unlike SCAN, RM provides a theoretical underpinning for

why specific differences between truth telling and lying will occur.

RM originally refers to the assessment of ones own memory and

describes the processes people use to decide for themselves

whether a given memory for an event was based on experience or

imagination. According to the reality monitoring theory (Johnson,

Foley, Suengas, & Raye, 1988; Johnson & Raye, 1981), memories

of experienced events are externally derived and originate in

perceptual experiences. They are characterized by spatial and

temporal contextual attributes (e.g., where and when the event took

place), sensory attributes (e.g., what the person felt, smelt, heard or

saw when the event took place), and affective attributes (e.g.,

expressions of emotions). In contrast, memories for imagined

events are internally derived and originate in self-generated

thought or imagination. They are characterized by cognitive oper-

ations, such as thoughts and reasons, which probably helped to

generate these memories. Empirical evidence shows that people

also use these attributes to judge whether other peoples memories

are externally or internally derived (Johnson, 2006; Johnson, Bush,

& Mitchell, 1998; Johnson & Suengas, 1989). Based on these

findings, it has been argued that RM can be applied to credibility

judgments (Sporer, 1997, 2004; Vrij, 2008). A statement is con-

sidered true when it is based on externally derived memories and

false when it is based on internally derived memories (Sporer,

1997, 2004).

Although SCAN and RM share the same underlying assump-tion, that truthful statements differ in quality from deceptive state-

ments, each tool takes entirely different sets of criteria into account

to assess the veracity of statements. This deviation may reflect a

difference in the theoretical underpinnings of the two tools. RM

focuses on the clarity, realism, and reconstructability of the state-

ments and examines perceptual, spatial, temporal and affective

information, and cognitive operations (Sporer, 1997, 2004). The

SCAN list of criteria is more extensive and includes a variety of

cues such as denial of allegations, out of sequence information and

change in language (see, Vrij, 2008). See Table 1 for definitions of

the 13 SCAN and eight RM criteria.

A careful examination of both lists of criteria gives the impression

that SCAN and RM are oriented to different types of lie: conceal-

ments (SCAN) and outright lies (RM), respectively. To demonstrate

the distinction between concealment and outright lies (DePaulo,

Kashy, Kirkendol, Wyer, & Epstein, 1996) consider the following

hypothetical example. Dan, a teenager, wandered around the city with

his friends on Friday night. During that night, among other activities,

he committed an act of vandalism against a school building. The

police have reasons to believe that Dan committed this act of vandal-

ism and invites him to the police station. During the interview, Dan

could use two alternative strategies. He could tell the truth about being

with his friends, and even could describe truthfully all their activities

during that night, but omitting the act of vandalism. Alternatively, he

could deny that he went out on that Friday night, and could make up

a story pretending that he did something else. If Dan chooses the first

strategy he provides a concealment lie, and if he chooses the second

strategy, he provides an outright lie.

RMs primary concern is assessing the richness in detail, and the

vividness of the statement. Outright lies are imaginations and

should therefore be less detailed and vivid than truthful accounts.

Concealed liars, in contrast, tell the truth about what happened butleave out details that may incriminate them. Therefore, conceal-

ment lies include descriptions of activities, conversations, and

events that the examinee actually has experienced. RM thus may

have difficulty in discriminating between truths and concealed lies.

We therefore predicted that RM should be able to discriminate

between truths and outright lies, (as was previously evidenced;

Masip et al., 2005; Vrij, 2008), but should not be able to discrim-

inate between truths and concealed lies (Hypothesis 1).

The SCAN literature does not mention an underlying theme for

the list of criteria. Examining the criteria listed in Table 1 gives the

impression to be a motivational approach in which liars attempt

strategically to select the exact words that reflect their knowledge

but hide their guilt. For example, at least four (out of 13) criteriaexplicitly deal with what the examinee did not say or concealed.

Within the missing information criterion, SCAN experts look for

words or phrases such as finally, later on, some time after,

which can imply that some information is left out. If someone says

I started to cook, and some time after I found my father lying on

the dining room floor, one could wonder what happened after the

examinee started to cook and before he found his father on the

floor. Another SCAN criterion is objective and subjective time.

Here, the proportions of the actual durations of the activities

(objective time) are compared with the number of words that the

examinee used to describe these activities (subjective time). When

the subjective time that was allocated to an activity is shorter than

the objective time, it may imply that the examinee is attempting toconceal information regarding that activity. Concealments can be

further reflected by the absence of social introductions in the

statement. This criterion relates to how the people who were

involved in the activity are introduced. If an examinee writes we

and it is not clear who we are, the examinee might be concealing

something regarding the identity of the other person. Finally,

extraneous information could indicate concealment. This crite-

rion relates to whether the examinee reports information that does

not seem relevant. If so, it could indicate that the examinee is

trying to hide important information. One could thus expect SCAN

to be able to distinguish truths from both outright and concealment

lies (Hypothesis 2).

In the experiment we also asked participants to reportwhether they had developed a strategy to appear convincing

and, if so, to describe their strategy. Research into the strategies

suspects use is emerging only recently, after DePaulo et al.s

(2003) plea to carry out such research (Colwell, Hiscock-

Anisman, Memon, Woods, & Michlik, 2006; Hartwig, Granhag,

& Strmwall, 2007; Hartwig, Granhag, Strmwall, & Doering,

2010; Strmwall, Hartwig, & Granhag, 2006; Vrij et al., 2009).

Yet, as Vrij, Granhag and Porter (in press) argued, for success-

ful lie detection it is important to take differences in strategies

between liars and truth tellers into account and to develop

interview protocols that exploit these differences.

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Method

Participants

A total of 61 Bar-Ilan undergraduate students (54 females and 7

males) participated in the experiment for course credits. Their

mean age was 23.20 (SD 2.17 years).

Procedure

Participants arrived individually at the laboratory at a predeter-

mined time. The experimenter told them that the experiment dealt

with examining the efficiency of certain tools to detect lies. All

participants signed a consent form indicating that participation wasvoluntary and that they could withdraw from the experiment at any

time without penalty. Participants were then assigned randomly to

one of three experimental conditions: (i) concealment liars (N

20): mock criminals who concealed their criminal activity but truly

reported their non-criminal activities, (ii) outright liars (N 20):

mock criminals who concealed both their criminal and non-

criminal activities and thus gave a completely false statement; and

(iii) innocents (N 21): truth tellers who gave a completely

truthful account of their activities.

The experimenter read aloud the instructions. The instructions

for guilty participants (concealment and outright liars) were as

Table 1

Definitions of the SCAN and RM Criteria

Criterion Definition

SCANSpontaneous corrections The presence of corrections in the statement, such as crossing out what has been written. Although explanations

and additions are allowed, examinees are explicitly instructed not to cross anything out. A failure to follow thisinstruction could indicate deceit.First person singular past tense The format in which a statement is written. It is thought that truthful statements are written in the first person

singular, past tense because the writer describes an event that has taken place (I saw the smoke coming out ofthe window). Deviations from this norm should raise suspicion.

Location of emotions The position of the emotions in the statement. Just before the climax of the story (liars), or throughout the story(truth tellers), and after the climax of the story (truth tellers).

Change in language Change of terminology or vocabulary in the statement. A change in language indicates that something has alteredin the mind of the writer. For example, if an examinee refers in his statement to all conversations he had asconversations except one conversation which he describes as a discussion, it is likely that he perceived thisconversation differently from the other conversations.

Lack of conviction and memory The examinee is vague about certain elements in the statement (I believe . . ., I think . . ., kind of . . .) orreports that s/he cannot remember something. Lack of memory indicates deceit.

Out of sequence Does the statement recount the events in chronological order. A deviation of the chronological order indicatesdeceit.

Missing information The inclusion of words that indicate that some information has been left out, such as sometime after, finally,later on, and shortly thereafter. Inclusion of those words indicates deceit.

Extraneous information Does the statement contain information that does not seem relevant. The presence may indicate deceit becauseexaminees could include extraneous information to hide more important information.

Objective and subjective time Objective time refers to the actual duration of events described in the statement, whereas subjective time refers tothe amount of words spent to describe these events. It is thought that in a truthful statement the objective andsubjective time will correspond with each other, unlike in a deceptive statement. For example, if someonedevotes five lines in a statement to describe a 30-minute period, and then three lines to describe a subsequenttwo- hour period, the objective and subjective time do not correspond and this may indicate deceit.

Social introductions How are the persons described in the statement introduced. They can be unambiguous (e.g., My wife Lisa . . .)or ambiguous (e.g., We went outside) without saying who we are. Ambiguous introductions indicate a lie.

Pronouns The use of pronouns (I, my, he, his, they, their etc.) in the statement. Pronouns signal commitment,responsibility and possession. Omitting pronouns (Left the house rather than I left the house) suggestsreluctance of the writer to commit him/herself to the described action and thus indicates deceit.

Structure of statement The balance of the statement. It is thought that in a truthful statement the first 20% is used to describe activitiesleading up to the event, the next 50% to describe the actual event, and the final 30% to discuss what happenedafter the event. Thus, a ten-line statement is thought to comprise two lines to introduce the event, five lines todescribe the event, and three lines about the aftermath. The more unbalanced a statement, the greater the

probability that the statement is deceptive.Denial of allegation Does the examinee directly deny the allegation in the statement by stating I did not . . . . Denials indicate truth.RM

Clarity The statement is clear and vivid.Realism The story is realistic and makes sense.Reconstructability of the story The event can be reconstructed with the information given.Emotions Are there emotions described in the statement.Perceptual information Information about what the examinee felt, smelt, heard or saw when the event took place.Spatial information Information about locations (It happened in a park) or the spatial arrangement of people and/or objects (The

man was sitting to the left of his wife).Temporal information Information about when the event happened (It was early in the morning) or explicitly describes a sequence of

events (When the visitor heard all that noise, he became nervous and left).Cognitive operations Thoughts and reasonings (e.g., I must have locked the door, because it was locked when I came home).

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follows: You are requested to commit a mock theft as part of an

experiment about deception. The mock theft is about stealing a

statistics exam from a mail box in the Criminology department.

First, please go to the Social Science library (First floor of this

building), look for the Prison Journal volume No. 77 (1997). Get

the article that appears on pp. 125134 and write down the article

authors names. You will be asked about it later. After the libraryassignment, you should come back to the department, and steal the

exam. The exam is in mail box No. 50 (Prof Aharonovitz mail

box). The mailbox is locked, and you can find the key under the

mail box of the secretariat. At the bottom of the secretariat mail-

box, you will find the key, which is attached with cellophane tape.

Take the key, open Prof. Aharonovitzs mailbox, find the exam

and hide it on you. Make sure that you leave the mailbox in the

same condition as you found it, so that Prof. Aharonovitz will not

notice that someone broke into his mailbox. Finally, re-attach the

key with the cellophane tape to the bottom of the secretariat

mailbox. When you take the key from the bottom of the secretariat

mailbox, please make sure that you keep the cellophane tape in

good condition so that you will be able to use it again. Please makesure that nobody witnesses you committing this crime. Also, do

not tell anybody that you took the exam.

You should be back here 30 min from now. In the remaining

time after you steal the exam, do your normal business. Make sure

that you carry out more than one activity and do not stay at one

place for more than 10 min. Please carry out as many activities as

you can, such as buying a coffee, having a conversation with a

friend, visiting the book shop, etc. Please do not do anything that

you may later be unable or uncomfortable to talk about. Please

return in exactly 30 min from now (the experimenter indicated the

exact time) to the lab for the second stage of the study.

The instructions for the innocent participants (truth tellers)

were the same, excluding the theft of the exam. The assistant

repeated the instructions to make sure that everything was clear,

and asked the participants whether they had any questions.

When the participants indicated that they had understood the

instructions, they were sent on their mission.

Upon returning to the lab after exactly 30 min, the experimenter

told the participant: While you were out a statistics exam had

been stolen from a mailbox in the Criminology department. You

are one of the suspects in this theft. In a short while, you will be

interviewed about it. The interviewer will ask you to write down a

statement about what you were doing during the last 30 min. She

does not know whether you are guilty. In case you stole the exam,

do not admit this under any circumstances.

At this point the experimenter suggested a different strategy

to the participants in the guilty conditions (concealment liarsand outright liars). To the concealment liars she said: The best

strategy will be to give a truthful statement about everything

you did during the last 30 min, except stealing the exam.

Therefore, report only your non-criminal activities and skip the

act of stealing. To the outright liars she said: The best

strategy will be to give a complete falsely statement about what

you did during the last 30 min. Therefore, avoid reporting any

of your activities, both criminal and non-criminal, and give a

complete falsely report by making-up acts that you did not do

in this period of time. No strategy was suggested to the

innocent participants.

The experimenter continued by saying to all participants:

While giving your statement, act as convincing as possible. The

interviewer will use your statement to determine whether you are

guilty or innocent. If the interviewer believes that you are inno-

cent, you will receive your course credit and be allowed to leave.

If the interviewer believes that you are guilty, you will be asked to

write a second statement about what actually occurred during thelast 30 min. You will be interviewed in 10 min, and the statement

you will be asked to write down is your only chance to convince

the interviewer that you are innocent. Please use these 10 min to

prepare the statement that you are going to write. Finally, the

experimenter reminded the participants that they should not con-

fess to the crime, and she repeated the suggested strategies to the

concealment and outright liars.

The participants were then left alone in the lab, giving them the

opportunity to prepare for the interview and plan a strategy. After

10 min they were asked to complete a pre-interview questionnaire.

The questionnaire included three main questions: (i) How would

you describe your level of preparation for writing the statement?

The participants rated their answer to this question on three 7-point

scales: (1) Shallow to (7) Thorough; (1) Insufficient to (7) Suffi-

cient; (1) Poor to (7) Good. The average score on these three scales

was used as the Quality of Preparation variable ( .85); (ii)

Have you developed a strategy to appear convincing? Partici-

pants who answered this question negatively were asked to explain

why not, and participants who answered it positively were asked to

describe their strategy; (iii) To what extent are you motivated to

appear convincing in your statement? Participants rated their

answer to this question on a 7-point scale (1not at all to

7completely).

After completing the questionnaire, participants were brought to

the interview room. The interviewer (blind to the participants

condition) sat opposite the participant and gave an instruction that

follows the standard instructions given by SCAN users in the field:An exam has been stolen from a mail box in the Criminology

department within the last hour. You are one of the suspects in this

theft. Please write down in as much detail as possible what you

were doing during the 30 min that you were out. Start your

statement from the time you left the lab and end it at the time you

re-entered the lab. Be sure that you mention all details, all activ-

ities, all people you have met, all conversations that took place,

etc. Give as much information as you can, including information

that seems irrelevant. I will only be asking this single question.

You will have this one opportunity to give me as much information

as you can. While writing your statement, you may explain or add

details as much as you want, but do not cross out anything that you

have already written.

After writing their statements, participants were asked to com-

plete a post-interview questionnaire. They were asked to rate on

7-point scales (1not at all to 7completely): (i) To what extent

they were motivated to appear convincing in their statement; (ii)

To what extent they found it difficult to appear convincing in their

statement; (iii) To what extent they thought they were convincing

in their statement; and (iv) To what extent they were concerned

about being asked to write an additional statement about what

actually had occurred. In addition, the participants reported

whether they (v) gave any truthful details in their statement; (vi)

any false details in their statement, and (vii) concealed any details

from their statement. Finally, they were asked to indicate what

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percentage of their statement they thought was true. Before

filling out the post-interview questionnaire, participants were

told that the experiment had ended, that their answers would not

influence the assessment of their statements as false or true, and

that they were requested to answer the questions truthfully.

Upon completing the questionnaire, all participants were de-

briefed and given their course credits. None of the participantswas requested to write a second statement.

Coding of the Statements with SCAN and RM

Six independent coders assessed the presence of SCAN and RM

criteria. The coders were not informed that these criteria were used

to determine true from false statements. Instead, they were told

that participants were requested to carry out some activities outside

the lab for 30 min and to provide a detailed statement about these

activities. The coders received a list of 13 SCAN and 8 RM criteria

which were mixed together. The SCAN criteria were taken from

Vrij (2008) and the RM criteria from Sporer (2004). In his list of

SCAN criteria, Vrij (2008) included the criteria that are most

emphasized in workshops on the technique (Driscoll, 1994) or areused in research (Porter & Yuille, 1996; Smith, 2001). The coders

were requested to rate the presence of seven criteria on 10-point

scales (1not at all to 10 very much) (e.g., to what extent is the

statement realistic?). They were asked to mark the frequency of

occurrence of 13 other criteria in the statement (e.g., the frequency

of occurrence of mentioning emotions in the statement). The

remaining criterion refers to where emotions appeared in the

statement (a SCAN criterion). The coders indicated whether or not

(0 no 1yes) emotions appeared (i) at the beginning of the

statement; (ii) throughout the statement; or (iii) at the end of the

statement. This SCAN criterion thus resulted in three dependent

variables.

The coders received a written list of the criteria with detailed

definitions and examples. The trainer (one of the authors) went

over each criterion, and explained the definitions and examples.

She answered all questions about the criterion and made sure that

all coders understood the criterion before she moved on to the next

one. This training took 90 min. The coders carried out their

assessments individually at their homes. They took with them thewritten explanations and were asked to read them again before and

during the coding. Each coder assessed 20 21 statements, and

each statement was assessed by two coders.

Inter-Rater Reliability

Variance was low for several criteria. For example, emotion was

rated as absent in 84% of the statements. Consequently, Pearson

correlations were not appropriate for assessing the inter-rater reli-

ability. We think this is not problematic as the important issue is

whether or not the coders agreed that the criterion occurred rather

than whether or not they agreed on its frequency of occurrence.

Thus, inter-rater reliability was calculated by determining for each

criterion the percentage of agreement about its presence in thestatement. We dichotomized the original data set: present (1) or not

present (0). Criteria that were originally measured on 10-point

scales were recorded as present when the original rating fell in the

6-to-10 range, and as not present when the original rating fell in the

1-to-5 range. Criteria that were originally measured by counting

the number of appearances in the statement were recorded as

present when they appeared at least once. Table 2 presents the

agreement percent between coders. High agreement was achieved

for the RM criteria (ranging between 71% and 98%), except

cognitive operations which achieved only 44% of agreement.

High agreement was achieved also for SCAN criteria (ranging

from 70% to 98%), although low agreement occurred for four

Table 2

Inter-Rater Agreement for the SCAN and RM Criteria

Criterion Method Cue for Coding method % of agreement

Clarity RM Truth Rating 87Realism RM Truth Rating 98Reconstructability of the story RM Truth Rating 93Emotions RM Truth Counting 84Perceptual information RM Truth Counting 74Spatial information RM Truth Counting 80Temporal information RM Truth Counting 71Cognitive operations RM Lie Counting 44Spontaneous corrections SCAN Lie Counting 66First person singular past tense SCAN Truth Rating 89Location of emotions SCAN

Beginning Lie 97Throughout Truth 87End Truth 90

Chang in language SCAN Lie Counting 72Lack of conviction and memory SCAN Lie Counting 74Out of sequence SCAN Lie Counting 98Missing information SCAN Lie Counting 61Extraneous information SCAN Lie Counting 84Objective and subjective time SCAN Truth Rating 70Social introductions SCAN Lie Counting 56Pronouns SCAN Lie Counting 64Structure of statement SCAN Truth Rating 70Denial of allegation SCAN Truth Counting 80

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criteria: Spontaneous corrections (66%), missing information

(61%), pronouns (64%), and social introduction (56%).

Since agreement between the coders was not perfect, all dis-

agreements between the two coders were relegated to a third coder

who made the final decision regarding the presence of the crite-

rion. The third coder was blind to the veracity status of the

statements.We calculated total scores for RM and SCAN, by using the dichot-

omized variables. A score of 0 was assigned when the criterion was

absent, and a score of 1 was assigned when the criterion was

present. Criteria that indicate lies (e.g., cognitive operations, sponta-

neous corrections, missing information) were re-coded; thus a score of

1 was assigned when the criterion was absent, and a score of 0

was assigned when the criterion was present. The total score for each

method (RM and SCAN) was the sum of all criteria that were

included in the method. Therefore, the total score for RM could range

from 0 to 8, and the total score for SCAN from 0 to 15 (As reported

earlier, location of emotions was divided into three sub-variables, thus

the SCAN total score could attain 15 points). According to the SCAN

and RM assumptions, the higher the score, the more likely it is that the

statement is truthful.1

Results

Manipulation Check

Significant differences emerged between experimental condi-

tions regarding the percentages of truthful details participants said

they reported in the statements, F(2, 58) 99.37, MSE 387.27,

2

.77, p .001. Scheffe tests revealed that innocents reported

more truthful details (M 99.52% of the statement, SD 1.50,

95% CI [98.84, 100.21]) than concealment liars (M 85.90% of

the statement, SD 18.56, 95% CI [77.21, 94.95]), who reported

more truthful details than outright liars (M 18.15% of the

statement, SD 28.90, 95% CI [4.62, 31.68]). This indicates that

the participants followed the experimenters instructions.

All innocent participants mentioned that they provided truthful

details and none of them mentioned that they provided false details

in their statements. Further, 90.5% (N 19) of the innocents said

that they did not conceal any information. All outright liars men-

tioned that they provided false details and concealed information.

Sixty percent (N 12) of the outright liars said that they did not

provide any true details, and most outright liars who said that they

provided true details did this only occasionally (mentioning that

between 1% and 10% of their statement was true). All concealment

liars said that they provided true details. Thirty five percent (N

7) of them also mentioned that they provided false details.

Participants Motivation

The motivation of the participants to be convincing was mea-

sured both before and after providing the statement. The reported

motivation was high both prior to interviewing (M 6.20, SD

.99) and after interviewing (M 6.26, SD 1.05). These two

motivation scores were highly correlated with each other (r .92,

p .001). Further, twenty eight percent (N 17) of the partici-

pants were concerned that they might be asked to write a second

statement (ratings of 6 or 7). There was no difference between the

three experimental conditions regarding motivation or concerns

about writing a second statement, all Fs (2, 58) 2.44.

Pre-Interviewing Preparation

The self-reported quality of preparation for the interview was

M 4.69 (SD 1.49). There were no differences among the three

conditions, F 1. Most of the participants planned a strategy(63.9%, N 39; 13 innocents, 12 concealment liars and 14

outright liars).

Innocents reported that they planned to provide details that are

easy to verify and to mention a potential witness for their alibi

(N 9), to be as detailed as they could (N 7), or to convince the

interviewer that they have no criminal record and that they are

honest people (N 2). Concealment liars planned to be very

detailed in reporting their non-criminal activities (N 8), and tried

to inflate their non-criminal activities to compensate for leaving

out their criminal activities (N 4). Outright liars thought that

they should mention only activities that are difficult to verify (N

5), thought of evidence they could provide for activities they did

not do (N 3), planned to report activities they carried out anotherday (N 2), thought about what they reasonably could have done

in 30 min (N 2), and tried to convince themselves about their

own lies, so that they would appear like innocents (N 2).

Participants who did not develop a strategy said they did not

need a strategy because they were innocent (N 8); because they

believe it would be easy to convince the interviewer since s/he can

(in case of innocents) or cannot (in case of liars) verify their

statement (N 4); or because planning may interrupt them from

being natural and from altering their statements if necessary (N

4).

Number of Words

The length of the statements differed between the three exper-imental conditions, F(2, 58) 9.87, MSE 4731.23, 2 .25,

p .001). Scheffe tests revealed that statements of innocents were

significantly longer (M 218.43 words, SD 91.35, 95% CI

[176.84, 260.01]) than statements of concealment liars (M

144.20 words, SD 52.77, 95% CI [119.50, 168.90]) and outright

liars (M 129.80 words, SD 53.60, 95% CI [104.71, 154.89]).

The length of statements of concealment and outright liars did not

differ significantly from each other.

Discriminating Between Groups by RM and SCAN

RM total score. In order to test the validity of RM criteria in

detecting outright and concealment lies, we first conducted an

1 After completing their coding, the coders were asked to rate on

10-point scales how difficult or easy they found it to assess each of the

criteria (1 very difficult to assess and 10 very easy to assess). The

coders found most of the criteria relatively easy to apply (about 57% (N

12) of the criteria were rated as 9 or 10). The criteria they found the

most difficult to assess were the SCAN criteria: social introductions,

pronouns, and structure of the statement (Ms are 6.83, 7.50 and 7.83,

respectively). The correlation between the difficulty in applying the crite-

rion (Table 3) and the inter-rater percentage agreement regarding that

criterion (Table 2) was (Spearman) r .50, p .05). That is, the more the

coders perceived the criteria as easy to apply, the greater was the agreement

between coders.

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ANOVA with RM total score as the dependent variable, and group

(innocents, outright or concealment liars) as a factor. This analysis

revealed a large and statistically significant Group effect, F(2,

58) 4.33, MSE .51, 2 .13, p .05. Scheffe tests revealed

that, as predicted in Hypothesis 1, innocents (M 6.71, SD .56,

95% CI [6.46, 6.97]) obtained higher RM total scores than outright

liars (M 6.15, SD .75, 95% CI [5.80, 6.50]), representing alarge effect size, d .92. However, contrary to our prediction,

innocents also obtained higher RM total scores than concealment

liars (M 6.15, SD .81, d .82, 95% CI [5.77, 6.53]).

We further tested the validity of RM criteria in discriminating

between groups. We ran three different discriminant analyses to

distinguish between (i) outright liars and innocents; (ii) conceal-

ment liars and innocents; and (iii) outright and concealment liars.

The objective group-belonging was the classifying variable and the

RM total score was the predictor. As Table 3 shows, a significant

discriminant function was found for distinguishing between out-

right liars and innocents, 2(1) 6.82, Wilks Lambda .84, p

.01. The function correctly identified 75.0% of the outright liars

and 66.7% of the innocents, resulting in the total accuracy of

70.7%. Discriminating concealment liars from innocents was also

significant, 2(1) 6.15, Wilks Lambda .85, p .05, but

achieved a lower total accuracy rate (63.4%). Rate of correctly

classifying innocents was identical as in the previous function

(66.7%), but the classification of the concealment liars was lower,

60.0%. Determining outright liars from concealment liars was not

possible, 2(1) 0.00, ns.

SCAN total score. Similar to RM, we conducted an ANOVA

with Group (innocents, outright or concealment liars) as a factor

and SCAN total score as a dependent variable to test the validity

of SCAN total score in detecting outright and concealment lies.

The effect was not significant, F 1, and the SCAN total scores

of all three groups were highly similar (innocents: M 9.57, SD

1.29, 95% CI [8.99, 10.16]; outright liars: M 9.55, SD 1.36,95% CI [8.92, 10.18]; concealment liars: M 9.10, SD 1.65,

95% CI [8.55, 9.65]; all ds for differences between means ranged

from .01 to .32). Hypothesis 2 is therefore rejected. We further ran

three discriminant analyses for SCAN, similar to what we had

done with RM. None of the three discriminant functions were

significant (2 ranged from .03 to 1.46).

Scan users do not use total SCAN scores. Instead, they examine

the individual criteria. We carried out two MANOVAs to accom-

modate this procedure. In the first MANOVA we compared truth

tellers with outright liars with the 15 SCAN criteria as dependent

variables. At a multivariate level the analysis was not significant

(F 1). At a univariate level only one of the fifteen variables

showed a significant effect (F[1, 39] 4.99, p .05). In the

second MANOVA we compared truth tellers with concealment

liars, and again, the 15 SCAN criteria were the dependent vari-

ables. The multivariate analysis was not significant (F 1),neither were any of the univariate effects (all Fs 1.72, all ps

.20).

RM SCAN. The correlation between RM total score and-

SCAN total score (r .08) was not significant, supporting our

observation that they measure different aspects in written state-

ments. Although SCAN by itself could not discriminate between

the three experimental groups, we tested whether it contributed to

the accuracy rate when added to RM. For this purpose, we ran

three more discriminant analyses, where the objective group-

belonging was the classifying variable and RM and SCAN total

scores were the two predictors. We used thestepwisemethod. In

discriminatinginnocents fromoutright liars or concealment liars

only RM total score emerged in the function.In other words, the

discriminant functions obtained in these analyses were identical to

the discriminant functions described in the RM section, and SCAN

did not contribute anything beyond the RM score.

Discussion

In the present experiment, we failed to find support for SCAN,

as the total SCAN score did not differ between truth tellers and

outright liars or between truth tellers and concealment liars. How-

ever, SCAN users do not examine total SCAN scores; they exam-

ine the individual SCAN criteria instead. Examining individual

criteria is problematic as it easily leads to a lack of standardization

with different SCAN users examining and relying upon different

criteria. This is exactly what Smith (2001) found in her field study.Even when we examined the individual criteria, however, SCAN

did not receive empirical support. Only one SCAN criterion dis-

tinguished between truth tellers and outright liars and none of the

criteria distinguished between truth tellers and concealment liars.

Only one out of thirty univariate tests (3.33%) yielded a significant

result, a percentage that could be expected by chance alone.

SCAN users may argue that our experimental design was inad-

equate for SCAN differences to occur between truth tellers and

liars. This would mean that SCAN cannot be used in all situations.

Table 3

Accuracy Rates From the SCAN and RM Tools in Different Types of Lies

Innocents versus outright Innocents versus concealment Outright versus concealment

Innocents (%) Outright (%) Total (%) Innocents (%) Concealment (%) Total (%) Outright (%) Concealment (%) Total (%)

RMHit rate 66.7 75.0 70.7 66.7 60.0 63.4

SCANHit rate 52.4 65.0 58.5 52.4 45.0 48.8 65.0 55.0 60.0

RM and SCANHit rate 66.7 75.0 70.7 66.7 60.0 63.4

Note. Discriminant analysis for RM and RM & SCAN among outright versus concealment could not be obtained (2(1) 0.00). Accuracy rates forsignificant discriminant functions appear in bold.

74


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SCAN users should then make clear under which circumstances

SCAN can be used and under which circumstances it cannot be

used. At present, SCAN users do not discuss this issue. Alterna-

tively, it could be that we did not conduct the SCAN procedure

properly. Such a criticism is unlikely, as the SCAN procedure is

very straightforward. It just invites the examinee to write down

his/her activities during a critical period of time in enough detail sothat a reader without background information about the examin-

ees activities could fully grasp the statement (Adams, 1996; Sapir,

1987/2000). Finally, someone could argue that the null findings

were the result of a lack of statistical power. However, one should

note that the largest effect size in the SCAN analyses (between

innocents and concealment liars) was still small, d .32. Admit-

tedly, drawing conclusions from null effect is problematic and

from a statistical standpoint we cannot conclude that SCAN is not

effective. However, we are still left with the conclusion that SCAN

has no empirical support to date.

The poor performance of SCAN is further highlighted by the

results for RM, the alternative veracity tool we examined. RM did

discriminate between truth tellers and outright liars as well as

between truth tellers and concealment liars. The findings compar-

ing truth tellers and outright liars support the growing body of

literature showing that RM can be used for lie detection purposes

(Masip et al., 2005; Vrij, 2008). RM being able to discriminate

between truth tellers and concealment liars is worth discussing, as

it was the first time that such a comparison was made in the RM

deception literature. We were skeptical that RM would effectively

discriminate between truth tellers and concealment liars. In their

statements, concealment liars do not include much information that

is deceptive, as their lie mainly consists of hiding vital informa-

tion. We argued that RM would have difficulty in spotting con-

cealments as the RM method examines what the examinee has

written (mostly truthful) rather than what the examinee has con-

cealed (a lie). The findings concerning the length of the statement(e.g., number of words) and the strategies the examinees said they

would use in their concealment lies enables us to explain this

finding. In order to be successful in concealing information, the

examinee needs to compensate the hidden information by elabo-

rating more thoroughly when describing the information they

present. The concealment liars did not do this. The statements of

concealment liars were significantly shorter than the statements of

truth tellers. In addition, only 4 out of 20 concealment liars

reported as a strategy that they would try to inflate their non-

criminal activities to compensate for leaving out their criminal

activities. As a result, the truthful information that concealment

liars reported was less detailed than the information truth tellers

reported, and this enabled RM to discriminate between the two

types of statement.

SCAN skeptics may argue that we were perhaps too optimistic

in expecting differences between truth tellers and liars, given the

lack of an underlying theoretical rationale for SCAN. Linguists, in

particular, have criticized SCAN for that reason. For example,

Shuy (1993) is concerned that SCAN does not take into account

socio-cultural variation in language use, and Heydon (2008) be-

lieves that SCAN strengthens the mythology of interviewing by

promoting certain views and beliefs as commonsensical. SCAN

skeptics may even go one step further: Why bother examining a

tool that has no theoretical foundation? We disagree with such

skeptics. First, although SCAN users do not give a theoretical

foundation for their tool, they may do so in the future. In that

respect, SCAN could be similar to Criteria-Based Content Analy-

sis (CBCA), an alternative verbal lie detection tool. CBCA was

presented (in English) in 1988 by Khnken and Steller, but the first

publication in English about its theoretical underpinning appeared

eight years later (Khnken, 1996). Second, we think that it is

important to examine SCAN since it seems to be used in practiceon a wide scale.

The self-reported strategies of truth tellers and liars revealed

more noteworthy findings. First, 8 out of 21 truth tellers did not

develop a strategy because, as they reported, they were innocent.

This supports the view that truth tellers are less likely than liars to

take their credibility for granted (DePaulo et al., 2003; Kassin,

Appleby, & Torkildson-Perillo, 2010; Vrij et al., in press). Truth

tellers typically assume that their innocence shines through (Gra-

nhag, Strmwall & Hartwig, 2007; Kassin et al., 2010; Vrij, Mann,

& Fisher, 2006), which could be explained with the illusion of

transparency (Gilovich, Savitsky, & Medvec, 1998), the belief that

ones inner feelings will manifest themselves on the outside, and

belief in a just world(Lerner, 1980), the belief that people will get

what they deserve, and deserve what they get. Second, the most

frequently cited strategy for truth tellers (9 out of 21) was to

provide details that can be checked, whereas the most frequently

cited strategy for outright liars (5 out of 20) was to provide details

that cannot be checked. Truth tellers strategy makes sense: The

best way for them to convince the interviewer that they are telling

the truth is to provide evidence that can be corroborated. Liars, of

course, cannot do this and need to avoid providing evidence that

can be corroborated. This differential strategy of truth tellers and

liars may result in a verbal cue of deceit that has not been

examined in the verbal lie detection literature so far: the use of

corroborated cues. That is, to what extent do examinees include

information in their statements that, in theory, can be checked?

The hypothesis is that truth tellers include more corroborated cuesin their statements than liars. This hypothesis is worth examining.

In sum, no support for the use of SCAN was found in the

experiment, whereas an alternative verbal lie detection tool, RM,

was successful in discriminating between truth tellers and liars.

Those findings do not justify the use of SCAN for lie detection

purposes in real life practice. The results further revealed a narra-

tive strategy that is worth examining: The use of corroborated

cues.

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