Reality Monitoring in the Forensic Context: Digging Deeper into the Speech of Liars

Reality monitoring (RM) indicates that truthful accounts contain more perceptual and contextual details than false accounts. Considering the tendency of liars to manipulate their accounts by adding false details, I compared truths and lies in terms of the amount and veracity of details provided by suspects across three conditions: a single statement provided immediately; a single statement following a two-week delay; or two statements, the first provided immediately and the second following a two-week delay. Distinguishing truths from lies was possible across conditions, but with varying intensity. Truth-tellers provided only truthful details, whereas liars provided both truthful and false details. While the opportunity to provide truthful details decreased over time for both truth-tellers and liars, only the latter compensated for this decrease by adding false details. The current study provides a new empirical approach and significant insight into the application of the RM framework in the forensic context. General Audience Summary The current study examined the verbal behavior of suspects, who tell the truth or lie when they are interviewed about their involvement in a crime, across three situations: when they provide a single statement immediately after the crime occurred; a single statement following a two-week delay; or two statements, the first provided immediately after the crime occurred and the second following a two-week delay. According to the reality-monitoring approach for lie detection, truth-tellers provide more perceptual (e.g., what they saw, heard, and smelled during the described event) and contextual details (e.g., times and locations) than liars. While truth-tellers usually provide truthful details in the interviews, liars, who are motivated to be convincing, manipulate their accounts by adding false details. Results showed that distinguishing truths from lies was possible in all situations, but with varying intensity. Truth-tellers provided only truthful details, whereas liars provided both truthful and false details. While the opportunity to provide truthful details decreased over time for both truth-tellers and liars, only the latter compensated for this decrease by adding false details. The current study provides new insights into the verbal behavior of liars and truth-tellers.