Few people can detect a liar

In daily life, without the particular pressures of politics, people find it hard to spot liars. Tim Levine of the University of Alabama, Birmingham, has spent decades running tests that allow participants (apparently unobserved) to cheat. He then asks them on camera if they have played fair. He asks others to look at the recordings and decide who is being forthright about cheating and who is covering it up. In 300 such tests people got it wrong about half of the time, no better than a random coin toss. Few people can detect a liar. Even those whose job is to conduct interviews to dig out hidden truths, such as police officers or intelligence agents, are no better than ordinary folk.

The Economist