Cues to Deception and Ability to Detect Lies as a Function of Police Interview Styles

This Project was sponsored by a grant from the Economic and Social Research Council (RES-000-23-0292). In Experiment 1, we examined whether three interview styles used by the police, accusatory, information-gathering and behaviour analysis, reveal verbal cues to deceit, measured with the Criteria-Based Content Analysis (CBCA) and Reality Monitoring (RM) methods. A total of 120 mock suspects told the truth or lied about a staged event and were interviewed by a police officer employing one of these three interview styles. The results showed that accusatory interviews, which typically result in suspects making short denials, contained the fewest verbal cues to deceit. Moreover, RM distinguished between truth tellers and liars better than CBCA. Finally, manual RM coding resulted in more verbal cues to deception than automatic coding of the RM criteria utilising the Linguistic Inquiry and Word Count (LIWC) software programme. In Experiment 2, we examined the effects of the three police interview styles on the ability to detect deception. Sixty-eight police officers watched some of the videotaped interviews of Experiment 1 and made veracity and confidence judgements. Accuracy scores did not differ between the three interview styles; however, watching accusatory interviews resulted in more false accusations (accusing truth tellers of lying) than watching information-gathering interviews. Furthermore, only in accusatory interviews, judgements of mendacity were associated with higher confidence. We discuss the possible danger of conducting accusatory interviews.