Aldert Vrij

DETECTING DECEIT VIA ANALYSIS OF VERBAL AND NONVERBAL BEHAVIOR

We examined the hypotheses that (1) a systematic analysis of nonverbal behavior could be useful in the detection of deceit and (2) that lie detection would be most accurate if both verbal and nonverbal indicators of deception are taken into account. Seventy-three nursing students participated in a study about “telling lies” and either told the truth or lied about a film they had just seen. The interviews were videotaped and audiotaped, and the nonverbal behavior (NVB) and speech content of the liars and truth tellers were analyzed, the latter with the Criteria-Based Content Analysis technique (CBCA) and the Reality Monitoring technique (RM). Results revealed several nonverbal and verbal indicators of deception. On the basis of nonverbal behavior alone, 78% of the lies and truths could be correctly classified. An even higher percentage could be correctly classified when all three detection techniques (i.e., NVB, CBCA, RM) were taken into account.

Criteria-based content analysis: a qualitative review of the first 37 studies

Statement Validity Assessment (SVA) is used to assess the veracity of child witnesses’ testimony in trials for sexual offences. The author reviewed the available SVA research. Issues addressed include the accuracy of Criteria-Based Content Analysis (CBCA; part of SVA), interrater agreement between CBCA coders, frequency of occurrence of CBCA criteria in statements, the correlations between CBCA scores and (i) interviewer’s style and (ii) interviewee’s age and social and verbal skills, and issues regarding the Validity Checklist (another part of SVA). Implications for the use of SVA assessments in criminal courts are discussed. It is argued that SVA evaluations are not accurate enough to be admitted as expert scientific evidence in criminal courts but might be useful in police investigations.

Pitfalls and Opportunities in Nonverbal and Verbal Lie Detection

The question of whether discernible differences exist between liars and truth tellers has interested professional lie detectors and laypersons for centuries. In this article we discuss whether people can detect lies when observing someone’s nonverbal behavior or analyzing someone’s speech. An article about detecting lies by observing nonverbal and verbal cues is overdue. Scientific journals regularly publish overviews of research articles regarding nonverbal and verbal cues to deception, but they offer no explicit guidance about what lie detectors should do and should avoid doing to catch liars. We will present such guidance in the present article.

Detecting true lies: Police officers' ability to detect suspects' lies

Ninety-nine police officers, not identified in previous research as belonging to groups that are superior in lie detection, attempted to detect truths and lies told by suspects during their videotaped police interviews. Accuracy rates were higher than those typically found in deception research and reached levels similar to those obtained by specialized lie detectors in previous research. Accuracy was positively correlated with perceived experience in interviewing suspects and with mentioning cues to detecting deceit that relate to a suspects story. Accuracy was negatively correlated with popular stereotypical cues such as gaze aversion and fidgeting. As in previous research, accuracy and confidence were not significantly correlated, but the level of confidence was dependent on whether officers judged actual truths or actual lies and on the method by which confidence was measured.

Outsmarting the liars The benefit of asking unanticipated questions

We hypothesised that the responses of pairs of liars would correspond less with each other than would responses of pairs of truth tellers, but only when the responses are given to unanticipated questions. Liars and truth tellers were interviewed individually about having had lunch together in a restaurant. The interviewer asked typical opening questions which we expected the liars to anticipate, followed by questions about spatial and/or temporal information which we expected suspects not to anticipate, and also a request to draw the layout of the restaurant. The results supported the hypothesis, and based on correspondence in responses to the unanticipated questions, up to 80% of liars and truth tellers could be correctly classified, particularly when assessing drawings.

LIE EXPERTS' BELIEFS ABOUT NONVERBAL INDICATORS OF DECEPTION

Beliefs about behavioral clues to deception were investigated in 212 people, consisting of prisoners, police detectives, patrol police officers, prison guards, customs officers, and college students. Previous studies, mainly conducted with college students as subjects, showed that people have some incorrect beliefs about behavioral clues to deception. It was hypothesized that prisoners would have the best notion about clues of deception, due to the fact that they receive the most adequate feedback about successful deception strategies. The results supported this hypothesis.

Detecting deception by manipulating cognitive load

Concern with crime and terrorism makes it increasingly important to be able to detect lying. Most lie detection tools used to date are arousal-based protocols. The majority of these protocols are based on the assumption that, because of their fear of being caught, liars will be more aroused when answering key relevant questions (‘Did you steal the money?’) than when answering comparison questions. According to the US National Research Councils well-documented report [1], however, this premise is theoretically weak. Liars do not necessarily reveal more signs of arousal when answering key questions. Conversely, truth tellers might be anxious and hence show signs of arousal when answering key questions.

Telling and detecting lies in a high-stake situation: the case of a convicted murderer

All deception studies published to date have been laboratory studies. In such studies people lied only for the sake of the experiment, consequently the stakes were usually low. Although research has shown that most spontaneous lies told in real life are trivial, such studies tell us little about lies where the stakes are high (such as police/suspect interviews). In Study 1, we discuss the behaviour of an actual suspect while he was interviewed by the police in a murder case. Although the man initially denied knowing and killing the victim, substantial evidence obtained by the police showed that he was lying. On the basis of this evidence, the man confessed to killing the victim and was later convicted for murder. To our knowledge there has been no other study published that has analysed the behaviour of a liar in such a high-stake realistic setting. The analysis revealed several cues to deception. In Study 2, we exposed 65 police officers to six fragments (three truthful and three deceptive) of the interview with the murderer and asked them to indicate after each fragment whether the man was lying or not. The findings revealed that the participants were better at detecting truths (70% accuracy) than lies (57% accuracy). We also found individual differences among observers, with those holding popular stereotypical views on deceptive behaviour, such as ‘liars look away’ and ‘liars fidget’ performing least effectively as lie catchers.

Why professionals fail to catch liars and how they can improve

In the first part of this article, I will briefly review research findings that show that professional lie catchers, such as police officers, are generally rather poor at distinguishing between truths and lies. I believe that there are many reasons contributing towards this poor ability, and will give an overview of these reasons in the second part of this article. I also believe that professionals could become better lie detectors and will explain how in the final part of this article

Suspects, Lies, and Videotape: An Analysis of Authentic High-Stake Liars

This study is one of the very few, and the most extensive to date, which has examined deceptive behavior in a real-life, high-stakes setting. The behavior of 16 suspects in their police interviews has been analyzed. Clips of video footage have been selected where other sources (reliable witness statements and forensic evidence) provide evidence that the suspect lied or told the truth. Truthful and deceptive behaviors were compared. The suspects blinked less frequently and made longer pauses during deceptive clips than during truthful clips. Eye contact was maintained equally for deceptive and truthful clips. These findings negate the popular belief amongst both laypersons and professional lie detectors (such as the police) that liars behave nervously by fidgeting and avoiding eye contact. However, large individual differences were present.