Individual Variation in Accuracy in Detecting Deception

It is usual in deception detection studies for accuracy rates to be reported for the group of observers as a whole; however, in a handful of studies, researchers have reported individual differences in accuracy between observers, and large differences have emerged among them.

For example, in a study in which both police and student participants viewed videos of people lying or telling the truth about whether or not they were in possession of a set of headphones, Vrij and Graham (1997) report that individual accuracy rates ranged from 20% to 90%. Similarly, in a study in which students and law enforcement personnel viewed videos of paroled felons making various honest and deceptive statements (for the sake of the experiment), Bond (2008) reports identifying two individuals, both correctional officers, who scored above 80%

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accuracy on both parts of a repeated deception detection task. Three studies investigating police accuracy when viewing high stakes lies produced similar results. In a study in which 52 police officers viewed deceptive people appealing for help with missing or murdered relatives, Vrij and Mann (2001b) report that three officers achieved a high accuracy score of 80%, whereas three officers achieved accuracy scores of 20% and one officer scored 0%. Similarly, in a study in which 65 police officers viewed truthful and deceptive fragments from a police interview with a murder suspect, Vrij and Mann (2001a) found that six officers achieved 100% accuracy, and five officers achieved a high accuracy score of 83%, whereas 11 officers achieved lower than 33% accuracy. Finally, in a study in which police officers viewed police suspect interviews, Mann et al. (2006) report identifying four officers who achieved 90% accuracy. It should be noted that the studies mentioned above were all limited by the use of a relatively low number of ‘senders’ (i.e. people producing the honest/deceptive communications); from one suspect producing six fragments (three honest, three deceptive), to 14 suspects (each producing honest and deceptive fragments).

It seems, therefore, that although there has been a lively debate regarding the existence of experts in deception detection (see, for example, Bond & Uysal, 2007; O’Sullivan, 2007), the evidence suggests that substantial individual variations in the ability to detect deception do exist. This, perhaps, should not be surprising. To detect deception, two processes must occur; first, there must be some differences in behaviours between honest and deceptive communications; and second, the observer must perceive these differences and understand them. As has been discussed, research indicates that there are some differences between honest and deceptive behaviours, even if these differences tend to be small and may not be consistent

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across all contexts; hence it might be expected that some people are better able than others to perceive these differences and to understand them.

Consequently, some attempts have been made to investigate factors, both innate and acquired, which may be related to individual differences in the ability to detect deception; for example, higher accuracy in deception detection has been variously related to left-handedness (Porter et al., 2002), a greater Need for Cognition (Reinhard, 2010), and the personality factors Openness to Experience, and Agreeableness (Enos et al., 2006). O’Sullivan and Ekman (2004) began a programme to investigate characteristics of accurate lie detectors that they had previously identified; in their initial report they comment that their ‘wizards’ of deception detection share a sensitivity to the nuances of language use, unusual childhoods, and high motivation. In another study, Mann et al. (2004) found that accuracy was significantly correlated with interviewing experience in a sample of police officers; however, other studies (Vrij & Graham, 1997; Vrij & Mann, 2001a; Vrij & Mann, 2001b) have found no relationship between accuracy and interviewing experience.

Although a detailed investigation of the variables that may affect accuracy in deception detection is beyond the scope of the present thesis, an important question that can and is addressed is, if some individuals are able to accurately detect deception, what are the cues on which they base their credibility judgements? It seems likely that the behaviours on which they base their judgements are reliable, and yet there has been very little research investigating this.

The method of investigating cues used by accurate lie detectors is nascent. For example, Mann et al. (2006) asked police officers with high deception detection accuracy rates to select fragments from clips of suspect interviews that they found most useful, and then compared accuracy ratings between subjects viewing whole

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clips, with subjects viewing just the fragments. Subjects were not more accurate in detecting deception when viewing only the fragments selected by accurate people, but they had not been told specifically which behaviours were considered important by the accurate participants. O’Sullivan and Ekman (2004) have also begun to investigate how their ‘wizards’ are able to accurately detect deception, and a few preliminary findings have been published: the ‘wizards’ report a frequent use of nonverbal behaviour, and use of inconsistencies and consistencies between verbal and nonverbal behaviour, as well as demonstrating high sensitivity to the nuances of language use. Bond (2008) found that accurate deception detectors reported using more nonverbal cues, and fewer verbal cues, than a control group. Also whilst one of the accurate deception detectors focused more on the face, the other focussed more on the arm/torso area.

Clearly then, there is substantial scope for further research in this area. As previously noted, DePaulo and Morris (2004) suggest that there may be cues to deception other than those which have been identified so far in laboratory research, which have yet to be investigated; an inductive, bottom-up approach, exploring the cues used by accurate deception detectors may be a useful method for generating previously unidentified cues, as well as expanding our understanding of the complexities of deceptive behaviour.