Another tactic for increasing liars’ cognitive burden is to insist that suspects maintain eye contact with their questioner. When people have to concentrate on telling their story accurately—which liars must, more than truth tellers—they typically look away to some motionless point, rather than directly at the conversation partner. Keeping eye contact is distracting, and it makes narration more difficult. Vrij also tested this strategy in the lab, and again observers spotted lies more easily when the liars were required to look the interrogator in the eye.
Drawing Out the Truth
A third strategy that could be surprisingly effective is to ask suspects to draw a picture. Putting pencil to paper forces people to give spatial information—something that most liars have not prepared for as part of planning their lies and that, therefore, overtaxes their mental resources. When Vrij and his colleagues asked volunteers what their offices looked like, after instructing half to tell the truth about their occupations and half to lie, both truth tellers and liars gave the same amount of detail in their verbal responses. But when Vrij asked them to draw their offices, the liars’ drawings were much less detailed than those of the truth tellers. In another of the experiments, volunteers were questioned about a lunch date that only some subjects had actually attended. The liars’ verbal descriptions of the restaurant did not match up as well with their drawings as did the truth tellers’—and the inconsistencies exposed the lies.
All these tricks may seem like overkill when we think about the fictional detectives we know, including NCIS agent Gibbs, who seem able to ferret out every fib they hear without using any strategies other than their intuition. But in real life, such people are exceedingly rare; psychological scientists call them “wizards” because of their seemingly supernatural lie-detection skills. Researchers have been trying—without a lot of success—to unravel these wizards’ strategies. Until they do, less sophisticated lie catchers may be able to exploit the mind’s cognitive deficits, using tricks such as Vrij’s, to catch the bad guys in their deceptions.
This article was originally published with the title The Burden of Lying.