Using sketch drawing to induce inconsistency in liars

Purpose. Consistency as a cue to detecting deception was tested in two experiments using sketch drawing and verbal reports in repeated interviews. Liars were expected to be less consistent than truth-tellers. Methods. In Expt 1, 80 undergraduate students reported truthfully or deceptively about an alleged lunch date – they sketched the layout of the restaurant and then answered spatial questions about objects in the restaurant. Ratings were given for the consistency between sketches and verbal reports. In Expt 2, 34 undergraduate students reported truthfully or deceptively about completing a series of unrelated tasks – they answered spatial questions about objects in a room and then sketched the layout of the room. Proportions were calculated for the consistency between verbal reports and sketches. Results. Expt 1. Liars were rated as less consistent than truth-tellers. Up to 80% of truth-tellers and 70% of liars could be correctly classified. Expt 2. Liars were less consistent than truth-tellers on consistency proportions. Up to 100% of truth-tellers and 77% of liars could be correctly classified. Conclusions. Using sketches to induce inconsistency may be a reliable, resource efficient way to help investigators detect deception.