Abstract

The ability to detect deception is one of the most intriguing features of our minds. Cognitive load can surprisingly increase the accuracy of detection when there is a substantial load compared to when the detection is performed without cognitive load. This effect was tested in two experiments. In the first experiment, the participants were asked to watch truth/lie videos while completing a concurrent task (N‐back in a 3‐back version; intuitive processing), providing verbal reasoning after watching each video (deliberative processing), or watching the videos alone (control group). The cognitive load caused by the concurrent task led to a higher accuracy in deception detection compared to the other conditions. In the second experiment, we examined how this effect worked under various amounts of cognitive load. Participants watching truth/lie videos were assigned to one of three experimental conditions (N‐back in three versions: 1, 3, and 5‐back) or to a control group. The participants in the 3‐back and 5‐back conditions exhibited a significantly higher accuracy in deception detection than those in the 1‐back and control groups. Thus, the effect of increased accuracy in deception detection is due to cognitive load and is related to the amount of cognitive load present.