Strategic use of evidence during police interviews: when training to detect deception works

Research on deception detection in legal contexts has neglected the question of how the use of evidence can affect deception detection accuracy. In this study, police trainees (N=82) either were or were not trained in strategically using the evidence when interviewing lying or truth telling mock suspects (N=82). The trainees' strategies as well as liars' and truth tellers' counter-strategies were analyzed. Trained interviewers applied different strategies than did untrained. As a consequence of this, liars interviewed by trained interviewers were more inconsistent with the evidence compared to liars interviewed by untrained interviewers. Trained interviewers created and utilized the statement-evidence consistency cue, and obtained a considerably higher deception detection accuracy rate (85.4%) than untrained interviewers (56.1%).