The Truth About Lie-Detection

http://blog.newsweek.com/blogs/nurtureshock/archive/2009/12/28/the-truth-about-lie-detection-what-works-and-what-doesn-t.aspx

Posted Monday, December 28, 2009 12:08 PM
The Truth About Lie-Detection – What Works And What Doesn't
Ashley Merryman and Po Bronson
During a trip to Dr. Victoria Talwar's lab at McGill University, Po and I took part in one of her experiments. Talwar investigates why and when kids lie, so she asked us to watch videos of children describing a bullying incident. Our job was to decide if each child was talking about a real event or just making up a story. Po was only able to correctly identify four of the eight, but I'd done even worse: just three right answers, making Po's 50 percent look stellar by comparison.

----- (skipping)

It's hard enough when you're trying to catch an adult in a lie. For kids, once they know enough to tell a reasonable version of what happened, it's darn near impossible to tell when they're lying. (For those parents and teachers out there saying, "I can tell with my kids," Talwar tested parents on their own kids, and they still can't reliably catch a lie.)

----- (skipping)

Outside the ideal setting of a laboratory, lie detection is even more difficult. Part of the problem is the myths out there on lie-telling.

Liars do not look down or look to the left. They do not shift from side to side. They don't fidget. Actually, liars often hold themselves still, restraining their movements so that they appear truthful. And liars don't get nervous, because they're sure you believe them. (In comparison, shy, truth-telling introverts often get anxious during a confrontation and thus mistakenly get accused of lying.)

----- (skipping)

In one study, Talwar had police officers come into the lab. During their years on the job, the officers developed a list of “sure-fire” behaviors to watch for. But it turned out that the officers had it exactly backwards. The behaviors they were looking for meant that they identified truth- tellers as liars, and they said liars were telling the truth.

Other studies have come up with similar results. In lab tests, FBI agents are better than average at identifying liars, but the longer they are in the field, the worse at it they become.

----- (skipping)

In study after study, trained coders can’t find any physical behaviors that reliably give kids’ untruthfulness away. In one round of experiments, Talwar’s team studied 47 physical behaviors: looking down, sitting on their hands, turning away, changing tone of voice, just to name a few. The kids were notably different on only two of the 47. More of the liars had a big smile at some point, while most truth-tellers had a relaxed mouth when they weren’t talking.

Most of the liars did look away, but almost 70 percent of the truthful kids looked away, too. Kids just seem to look away when they are thinking. (And these were behaviors the researchers observed while meticulously studying videotapes—it isn't as if the scholars identified them during live interactions.)

----- (skipping)