Using an example statement increases information but does not increase accuracy of CBCA, RM, and SCAN

Verbal credibility assessment methods are frequently used in the criminal justice system to investigate the truthfulness of statements. Three of these methods are Criteria Based Content Analysis (CBCA), Reality Monitoring (RM), and Scientific Content Analysis (SCAN). The aim of this study is twofold. First, we investigated the diagnostic accuracy of CBCA, RM, and especially SCAN. Second, we tested whether giving the interviewee an example of a detailed statement can enhance the diagnostic accuracy of these verbal credibility methods. To test the latter, two groups of participants were requested to write down one true and one fabricated statement about a negative event. Prior to this request, one group received a detailed example statement, whereas the other group received no additional information. Results showed that CBCA and RM scores differed between true and fabricated statements, whereas SCAN scores did not. Giving a detailed example statement did not lead to better discrimination between truth tellers and liars for any of the methods but did lead to the participants producing significantly longer statements. The implications of these findings are discussed.