How to Spot a Liar

When an international team of researchers asked some 2,300 people in 58 countries to respond to a single question — “How can you tell when people are lying?” — one sign stood out: In two-thirds of responses, people listed gaze aversion. A liar doesn’t look you in the eye. Twenty-eight percent reported that liars seemed nervous, a quarter reported incoherence, and another quarter that liars exhibited certain little giveaway motions.

It just so happens that the common wisdom is false.

Why do we think we know how liars behave? Liars should divert their eyes. They should feel ashamed and guilty and show the signs of discomfort that such feelings engender. And because they should, we think they do.

The desire for the world to be what it ought to be and not what it is permeates experimental psychology as much as writing, though. There’s experimental bias and the problem known in the field as “demand characteristics” — when researchers end up finding what they want to find by cuing participants to act a certain way. It’s also visible when psychologists choose to study one thing rather than another, dismiss evidence that doesn’t mesh with their worldview while embracing that which does.

Maria Konnikova writing in the New York Times