The effect of informing liars about Criteria-Based Content Analysis on their ability to deceive CBCA-raters

As soon as liars realize that evaluators use CBCA to assess the credibility of their statements, it is possible that liars will gain knowledge of CBCA and try to ‘improve’ their statements in order to make an honest impression on CBCA-judges. The present experiment investigated to what extent liars are capable of doing this. In all, 45 participants were randomly allocated to one of the following three conditions: a truth telling condition in which participants were asked to recall a videotaped event which they had just seen; an uninformed deception condition in which participants who had only been given guidelines about the content of the videotaped event were asked to recall the event as though they had seen the videotape; and an informed deception condition in whichparticipants received information about CBCA before they were asked to pretend that theyhad seen the videotape. CBCA-raters scored the accounts and a comparison was made between the total CBCA-scores of the three conditions. The study also examined the extent to which CBCA-assessments could correctly classify truthful and deceptive accounts, first bymeans ofa discriminant analysis (with the total CBCA-score as dependent variable) and secondly by asking a British CBCA-expert to judge the veracity of the statements. The results indicated that liars are capable of influencing CBCA-assessments. First, the CBCA-scores ofliars who were informed about CBCA were similar to the CBCA-scores of truth tellers and significantly higher than the CBCA-scores of liars who were not informed about CBCA. Secondly, the objective status of the participant (truth teller vs. informed liar) could notbe successfully predicted in a discriminant analysis on the basis of total CBCA-scores. Thirdly, statements of the majority of informed liars were assessed as truthful by a British CBCA-expert.