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Thursday, August 16, 2012

You can’t spot a liar

Think you can tell whether a person is lying by watching his eyes? You’re probably deceiving yourself. Richard Wiseman, a psychologist from the University of Hertfordshire with a love of the weird and quirky (see my ‘Just for fun’ post about him), and his colleagues from the Universities of Edinburgh and British Columbia have tested the notion that you can detect lies by watching eye movements. They found that you could not.

The belief in a connection between eye-movement and veracity is widespread. This view holds that a right-handed person will look up and to the left when drawing a thought out of his memory, but up and to the right when fabricating a thought. Thus, if a person glances up to the right as they answer a question, he’s probably lying. Except that’s not what Wise and his colleagues found.

The researchers conducted a number of experiments in which right-handed participants were filmed either lying or telling the truth. Independent observers watched the films with the sound off and counted how often each participant had looked up to the left or right. There was no connection between direction of gaze and truth-telling. In addition, people who had been primed to expect liars to look up and right were no better at detecting liars than those who had received no such instruction. Taken together, these data strongly suggest that the idea that you can tell if a person is lying by watching for eye movements is rubbish.

To be fair, the liars in this study were given a few minutes to compose their stories ahead of time. That is, they were not improvising lies on the spot and this foreknowledge may have affected their eye movements. However, Caroline Watt of the University of Edinburgh says that the experiments mirror real life, in which people also often have a moment or two to prepare a lie.