The Effect of Co-Offender Planning on Verbal Deception

Abstract

Previous deception studies have mainly examined individual mock perpetrators and their deceptive behaviours during interviews, but not all crimes are committed by single perpetrators. In the present study, 48 mock perpetrators were individually interviewed after carrying out a mock theft in pairs. The time available for co-planning prior to the interview was manipulated so as to examine its effects on participants’: (1) verbal cues to deception; (2) cognitive load; and (3) attempted speech control during the interview. Having time available for planning was associated with greater statement immediacy, plausibility and within-pair consistency, but not with cognitive load or attempted control.

Key words:

• co-offender
• co-perpetrator
• cues
• deception
• interviewing
• investigative
• planning
• verbal