You don't act like you trust me: Dissociations between behavioural and explicit measures of source credibility judgement

This study compared explicit and behavioural measures of source credibility judgements based on two factors: a source's past record of accuracy and its production of predictions that participants would like to believe. The former is considered to be a rational factor for judging credibility, while the latter is considered nonrational (i.e., it does not predict actual credibility). In Experiments 1 and 2, participants saw an equal number of predictions from two sources, one of which was either highly or slightly more accurate/desirable than the other. In Experiment 3, either one source was high accuracy and the other high desirability, or one source was higher on both measures. For all experiments, participants then saw new accurate and inaccurate predictions and said which source they thought was most likely to produce each (behavioural task). Participants then gave a percentage rating for each source's perceived accuracy (explicit judgement task). Participants showed sensitivity to past accuracy differences using both tasks, but not to the size of the differences. Desirability influenced performance only on the behavioural task. However, when the two factors conflicted, participants responded solely using past accuracy information. Behaviours reflect source credibility judgements based on both rational and irrational factors, but participants appear to be both more strongly influenced by the rational factor and more aware of that influence.