Stereotypical behavioural cues — but not their order — influence credibility judgements

To what extent stereotypical deceptive behaviours such as gaze aversion and fidgeting actually influence people's credibility judgements remain largely unknown. In this study, we directly manipulated the presence/absence of such behaviours to investigate this. Participants were shown four truthful videos in which we manipulated the presence of stereotypical cues and asked them to judge how credible the person in each video is. Moreover, research consistently shows that decision making is influenced by various cognitive biases. One example is the primacy effect, which implies that people form an opinion early in the decision process. Information acquired early will have the largest influence on how subsequent information will be interpreted. To investigate a possible primacy effect, we also manipulated whether these cues were present towards the beginning or the end of the video (i.e. the timing of the manipulation). In line with our expectations, the presence of stereotypical cues significantly lowered the observed credibility, showing that the presence of these cues indeed influences credibility judgements. The timing of the cues had no effect.