Detecting cues to deception from children's facial expressions: On the effectiveness of two visual manipulation techniques

Abstract

This paper looks into the extent to which facial expressions may reveal whether a person is telling the truth or not. More specifically, it studies selected clips from video recordings of children who had participated in an interactive story paradigm that naturally elicits minimal pairs of truthful and deceptive utterances in participants. In two perception experiments, these pairs of clips (with audio removed) were shown to adult observers who were given the task to guess which member of the pair contained the deceptive utterance. Experiment 1 tested whether the likelihood of correct detection could be enhanced when clips were slowed down compared to clips at normal speed. Results revealed that this manipulation indeed had a positive effect on lie detection, albeit that the effect interacted with the order of presentation (lies are easier to see when they are shown after rather than before the truthful utterance) and kind of lie (second attempts of children to lie reveal more cues than their first attempts). Experiment 2 explored whether lie detection is different for recordings in which the full face of a child is shown, or for recordings in which either the eye or mouth region is hidden after digital manipulation. This experiment revealed that the partial presentations of the face lead to more correct deception detection than the full face presentation. Implications of the outcomes of Experiment 1 and 2 for lie detection and for a general model of nonverbal communication are discussed.