A cognitive load approach to lie detection

We present two lie detection approaches based on cognitive theory. The first approach, ‘measuring cognitive load’, assumes that the mere act of lying generates observable signs of cognitive load. This is the traditional cognitive lie detection approach formulated by Zuckerman, DePaulo, & Rosenthal (1981). The second approach, ‘imposing cognitive load’, was developed by us (Vrij, Fisher, Mann, & Leal, 2006) and goes one step further. Here, the lie detector attempts to actively increase the differences between lying and truth telling by introducing mentally taxing interventions. We assume that people require more cognitive resources when they lie than when they tell the truth to produce their statements, and therefore will have fewer cognitive resources left over to address these mentally taxing interventions when they lie than when they tell the truth. This should result in more pronounced differences between lying and truth telling in terms of displaying stronger signs of cognitive load. We provide empirical support for this approach: Observers can discriminate better between lying and truth telling when interviewers actively impose mentally taxing interventions.