Detecting Lies- page 4 | Science | Smithsonian

Detecting Lies

From chewing rice to scanning brains, the perfect lie detector remains elusive

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(Continued from page 3)

But a lie detector based on functional imaging would suffer from a few potentially fatal flaws. Critics of the method often point out that functional imaging results are averaged from a group, not based on individual subjects. Such a limitation causes obvious problems in the world of criminal law.

In the fall of 2005, Langleben found encouraging evidence that functional imaging can detect deception on an individual basis. Using a modified version of his previous test, Langleben reported being able to correctly classify individual lies or truths 78 percent of the time. His results are the first evidence that functional imaging can detect deception for an individual person regarding an individual question. Still, 78 percent accuracy, while promising, is far from fool-proof.

Wizards

While driving on a dark night in northern California, Maureen O'Sullivan listened to J.J. Newberry, a former agent in the Bureau of Alcohol, Tobacco and Firearms, discuss how he had been betrayed by a friend. Newberry seemed very upset by the incident, and very involved in the telling of it, O'Sullivan recalls. Then, suddenly, Newberry asked O'Sullivan to pull over. In the middle of his engrossing story he had spotted a man slumped over behind the wheel of a parked car across the street.

Such preternatural awareness has helped make Newberry a lie detection "wizard," says O'Sullivan, who coined the term with her colleague Paul Ekman at the University of San Francisco. The distinction is a select one: in 30 years of testing, the researchers have found fewer than 50 wizards. These people score in the upper ranks on a battery of deception tests developed by Ekman and O'Sullivan.

"These people are super hunters," O'Sullivan says. "What they see is unbelievable."

Ekman and O'Sullivan began testing for people who could identify deception with great accuracy in the late 1980s. They eventually settled on series of three tests. The first involves spotting people lying about their feelings. For this test, potential wizards watch a videotape of ten women, half of whom are lying about their current emotions, half of whom are telling the truth.

The second test shows ten men describing an opinion they have, and the third shows ten men discussing whether they had stolen money. Again, in both cases, half the people are lying and half are telling the truth.

For a person to become a wizard, he or she must first correctly identify nine people in the emotional test, then go on to identify at least eight people in one of the two other tests. As of 2003, having studied more than 10,000 people, the researchers had found just 29 wizards. That number has grown to about 50, O'Sullivan said recently.

Many wizards spent time in the Secret Service, says O'Sullivan. The practice of scanning large crowds for odd behaviors has honed their acuity. Whereas regular people make a quick decision when watching the test videotapes, wizards hold their final analysis until the end, tracking intonation changes, word choice and eye gaze. Therapists also score high on the tests.

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