Body language gibberish

Body language gibberish

by digby

This article is particularly concerned with the TSA training that has workers scanning travelers "body language" for hints as to whether they might be terrorists, but it applies to law enforcement in general. People generally rely way too much on their perceptions of when other people are hiding something, and those with government authority are not better than the rest of us at getting it right:
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.”

The T.S.A. program was reviewed last year by the federal government’s Government Accountability Office, which recommended cutting funds for it because there was no proof of its effectiveness. That recommendation was based on the meager results of the program as well as a survey of the scientific literature by the psychologists Charles F. Bond Jr. and Bella M. DePaulo, who analyzed more than 200 studies.

In those studies, people correctly identified liars only 47 percent of the time, less than chance. Their accuracy rate was higher, 61 percent, when it came to spotting truth tellers, but that still left their overall average, 54 percent, only slightly better than chance. Their accuracy was even lower in experiments when they couldn’t hear what was being said, and had to make a judgment based solely on watching the person’s body language.

“The common-sense notion that liars betray themselves through body language appears to be little more than a cultural fiction,” says Maria Hartwig, a psychologist at John Jay College of Criminal Justice in New York City. Researchers have found that the best clues to deceit are verbal — liars tend to be less forthcoming and tell less compelling stories — but even these differences are usually too subtle to be discerned reliably.


There are a lot of True Crime shows on cable now that show police interviewing suspects and it's obvious that a lot of cops put great store in the notion that people are supposed to act a certain way in certain situations. And when one doesn't act the way they think you should, you are automatically suspect. I'm sure that may of them have hones their instincts over years and have a lot of experience to back up their hunches. But the fact is that they also tend to make these judgement based on "training" that highly overrates this whole notion of body language. And it often leads the astray. (These jury consultants do the same thing.)

This stuff isn't exactly junk science but it's awfully close. We should be wary of of authorities using these techniques in the same way we'd be suspicious if they started bringing in psychics or fortune tellers (or oracles for that matter) to tell them who is about to commit a crime.

Minority Report is a work of fiction.
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