People's insight into their own behaviour and speech content while lying

The present experiment examined participants' insight into their own behaviour and speech content while lying. It was hypothesized that participants would believe that while lying they show more behaviour stereotypical of lying than they in fact do (Hypothesis 1), whereas they would believe that their own speech content while lying contains fewer stereotypical features than in fact is true (Hypothesis 2). A stereotypical response was defined as a response people generally believe liars usually show. A total of 86 nursing students were interviewed twice about a film they had just seen. During one interview they were asked to tell the truth whereas they had to lie in the other interview. All interviews were videotaped, transcribed and then scored by independent coders. The coders' analyses reveal participants' actual behaviour and speech content. Participants themselves were asked to indicate in a questionnaire how they believed they behaved and what they believed they said in both interviews. To test the hypotheses, comparisons were made between participants' actual responses and their beliefs about their own responses. The results support both hypotheses and implications of these outcomes for the detection of deception are discussed.