Heuristic versus systematic processing of information in detecting deception: questioning the truth bias

Research on nonverbal detection of deception has normally been conducted by asking observers to judge the veracity of a number of videotaped communications. These video clips have typically been very short. Observers have a tendency to judge most of these statements as truthful. An experiment was conducted in which 52 participants (44 women, 8 men; M age = 22.2 yr., SD = 2.2) who were taking a psychology and law course were requested to make judgments of credibility at different points of the senders' statements. A strong truth bias was apparent when judgments were made at the beginning of the statements, suggesting that when exposed to brief communications, the observers make heuristic judgments. Over time, a decrease in the truth bias and an increase in overall accuracy were found, suggesting that later judgments were increasingly based on systematic information processing. These results suggest that the truth bias that has been found in previous deception research may be a result of having used very brief and uninformative behavioral samples as stimuli.