Challenging interviewees during interviews: The potential effects on lie detection

Abstract

The impact of interview styles on lie detection was examined. Thirty-six truth tellers and liars (undergraduates) were interviewed in three different ways: The interview started with an information-gathering interview style (Phase 1), which then developed into an interrogation (Phase 2), and finally transformed back into an information-gathering interview style (Phase 3). On the basis of DePaulo and Kirkendol's Motivational Impairment Effect, which suggests that when people are highly motivated to get away with their lies they actually look like they are controlling their behavior, it was hypothesized that the most prominent differences between liars and truth tellers would emerge in Phase 3. The findings supported this hypothesis, and thus suggest that specific interview styles could facilitate lie detection.     

Police officers’ judgements of veracity,tenseness, cognitive load and attempted behavioural control in real-life police interviews

Abstract

The present experiment examined the apparently incongruent findings that police officers (i) believe that suspects show nervous behaviour when they lie but (ii) seem able to detect deceit in suspects who do not show nervous behaviours. It was hypothesized that police officers’ judgements about whether a suspect is lying would not be correlated with their judgements regarding whether the suspect is tense, but, instead, would be correlated with their judgements regarding whether suspects are having to think hard or attempting to control their behaviour.

Each of 84 police officers saw seven truths and seven lies told by suspects during their police interviews. Participants in Condition 1 were asked to indicate after each clip whether the suspect was lying, whereas participants in Condition 2 were asked to note after each clip to what extent the suspect appeared to be tense, having to think hard or attempting to control their behaviour. Condition 3 was a combination of Conditions 1 and 2 and participants were asked all the above questions. The findings support the hypotheses and therefore negate the assumption that police officers primarily look for cues of nervousness when they attempt to detect deceit.     

Two heads are better than one? How to effectively use two interviewers to elicit cues to deception

Background. We examined the effect of a second interviewer's demeanour on cues to deception. We predicted that a supportive demeanour would be the most beneficial for eliciting verbal cues to deceit, as it would encourage truth tellers, but not liars, to say more. In addition, we examined the extent to which interviewees deliberately made eye contact with the interviewers. Liars take their credibility less for granted than truth tellers, and therefore have a greater drive to be convincing. Liars are thus more likely to monitor the interviewer to determine if the interviewer appears to believe them. Method. Participants appeared before two interviewers: the first asked all the questions and the second remained silent. The second interviewer exhibited either a supportive, neutral, or a suspicious demeanour. Results. Truth tellers provided significantly more detail than liars, but only in the supportive second interviewer condition. The effect of a second interviewer's demeanour on detail was perhaps remarkable given that the interviewees hardly looked at the second interviewer (less than 10% of the time). Liars displayed more deliberate eye contact (with the first interviewer) than truth tellers did. Conclusions. A supportive second interviewer has a positive effect on interviewing. We discuss this finding in the wider contexts of investigative interviewing and interviewing to detect deception.