See no lies, hear no lies: differences in discrimination accuracy and response bias when watching or listening to police suspect interviews

In the present experiment, police officers attempted to detect truths and lies told by suspects in their police interviews in three different ways: They either saw the suspects (visual condition), only heard the suspects (audio condition) or both saw and heard the suspects (control condition). Research has demonstrated that vocal and speech‐related cues are better diagnostic cues to deceit than visual cues. Therefore, we predicted that participants in the visual condition would perform worst in the lie detection task. Having access only to visual cues may encourage observers to be more reliant on stereotypical beliefs when attempting to detect truths and lies. Since these stereotypes are related to the behaviour of liars, rather than to the behaviour of truth tellers, we further predicted that being exposed only to visual cues may result in a lie bias. The findings supported these hypotheses, and the implications are discussed.