Social Indicators of Deception

Objective: This study addresses a practical homeland security issue of considerable current concern: In a situation in which the opportunity exists to question or interview concurrently two or more suspects, how does one determine truth or deception at a social level? Background: Recent world events have led to an increased emphasis on the capacity to detect deception, especially in military, security, and law enforcement settings. In many screening or checkpoint situations, the opportunity exists to question two or more suspects regarding their involvement in some activity, yet investigators know very little regarding characteristics of speech or behavior that are exhibited between two suspects that indicate truth or deception. Method: We conducted an empirical study in which pairs of police officers and firefighters who had served together as partners took part. In the “truth” conditions, each dyad described a recent event in which they had actually taken part, and in the “deceptive” conditions, each dyad fabricated a story that did not take place. We expected that the officers in the truth-telling dyads would be able to draw on shared or transactive memory of the actual event they had participated in and would describe this event in a more interactive manner than would those in deceptive dyads. Results: Results indicated greater evidence of synchrony of behavior as well as more interactive behaviors, such as mutual gaze and speech transitions, in truthful dyads than in deceptive dyads. Conclusion: This research provides a unique perspective on detecting deception in a social context, and the results have both theoretical and practical value. Application: These results can inform training programs and refine strategies used by screeners in field settings.