Interactive Feature | Can You Spot the Liar? Subjects in a study on body language and lying were asked several general questions — and then told off camera to lie or tell the truth when answering. Can you tell truth from falsehood?

Like the rest of us, airport security screeners like to think they can read body language. The Transportation Security Administration has spent some $1 billion training thousands of “behavior detection officers” to look for facial expressions and other nonverbal clues that would identify terrorists.

But critics say there’s no evidence that these efforts have stopped a single terrorist or accomplished much beyond inconveniencing tens of thousands of passengers a year. The T.S.A. seems to have fallen for a classic form of self-deception: the belief that you can read liars’ minds by watching their bodies.

Most people think liars give themselves away by averting their eyes or making nervous gestures, and many law-enforcement officers have been trained to look for specific tics, like gazing upward in a certain manner. But in scientific experiments, people do a lousy job of spotting liars. Law-enforcement officers and other presumed experts are not consistently better at it than ordinary people even though they’re more confident in their abilities.

“There’s an illusion of insight that comes from looking at a person’s body,” says Nicholas Epley, a professor of behavioral science at the University of Chicago. “Body language speaks to us, but only in whispers.”

Read the full article in the New York Times, by John Tierney, March 23, 2014.

For more about the research cited in the article, see the Association for Psychological Science’s coverage of a study led by Leanne ten Brinke, which found that the conscious mind less accurately detects lies than the automatic associations of the unconscious mind.

For more recent coverage on deception, facial recognition, and body language, see What Faces Can’t Tell Us, about the research of CLBB Faculty Lisa Feldman Barrett.