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Can you tell if someone <br/>is lying to you?

Can an average person develop the skill to reliably detect liars? Lanney, Sandia Park, New Mexico

"His eyes look shifty. He won't meet my eyes. He's shifting posture," the police officer thinks. "Odds on, he's lying." The interrogator may be right, but it's really even money. None of these signs are more common among liars than among truth tellers. In fact, they may be less common.

"Most liars can fool most people most of the time," says psychologist Paul Ekman of the University of California at San Francisco. Liars know we look for signs of nervousness, so liars quell the impulse to fidget.

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But the body also gives away clues that few can control, for instance, tiny micro-expressions. These subtle displays last only about 40 milliseconds - about 1/6th of an eye blink - but reveal much.

Take a look at this video of a man lying. Watch his lips; they show his disbelief in his own lie. He just took $50 from an envelope in an experiment that Ekman set up to detect liars. This young man took the money, and then tells Ekman he did not. His lip corners draw down in disbelief as he lies and shakes his head "no" he did not take the money.

We've learned much in recent years about what works and what doesn't in detecting lies. The best indicators are autonomous responses, which we are mostly unaware of doing. Micro-expressions are one such clue but, to be fairly sure, an interrogator needs more. Reliability goes up with the number of subtle clues the observer catches. A tiny drawing down of lip corners (disbelief), a lifting of the inner corners of the eyebrow (distress,worry or guilt), higher than normal voice (stress),dilated pupils (aroused emotions), eyebrows raised and pulled together (fear)... add up.

"The person is certainly experiencing fear and, in this situation, is probably lying," psychologist Maureen O'Sullivan of the University of San Francisco emails.

People can learn to improve their liar-detecting skills, says Ekman. For example, micro-expressions vanish so quickly, most people miss them. However, they can learn to detect the signs with "forty minutes" of training.

Trained interrogators score much higher than untrained ones. Psychologist Maria Hartwick and her team at the Göteborgs Universitet trained some of a group of 82 police recruits on interrogation techniques. The trained policemen detected liars 85 per cent of the time; the untrained policemen only 56 per cent.

Secret Service agents' reliability scores (73 per cent) are among the highest of all professions O'Sullivan tested in a recent study of 13,000 people. Perhaps it's because Secret Service agents spend much time studying crowds for nonverbal clues, she says.

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Detecting lies is tricky, and caution a worthy guide. "There are no absolute clues to lying itself, only to the emotions or [the]kind of performance that accompanies lies,"warns Ekman.

If someone suspects us of lying, when we are telling the truth, we can feel great stress. An incautious interrogator could conclude we're lying. That's one kind of error: a false positive. Then there's the other: a false negative. Nobody catches those who lie flawlessly. And some can do just that, says Ekman.

Sub head: Lies, damned lies and statistics

People admit to telling an average of two lies a day.

Untrained, ordinary people are about 54 per cent accurate in detecting lies.

University of California at San Francisco researchers found a group of 23 federal law enforcement officers accurately detected lies 80 per cent of the time, but truths only 66 per cent. The same pattern held for clinical forensic psychologists and a group of federal judges.

Of the 13,000 subjects O'Sullivan tested, only 50 were exceptionally good at detecting liars. No one was 100 per cent accurate. The best detectors were mostly professional lie catchers (e.g., attorneys). About 25 per cent reported childhood traumas, such as alcoholism in the family or a highly emotional parent. Perhaps their exceptional abilities developed as self-protection. Such children would be highly motivated and practiced.

A control group also had difficult childhoods, but they could not accurately detect lies. These poor lie detectors apparently denied their difficult childhoods, instead of developing skills to protect themselves.

Most of us don't want to detect white lies. (No those pants don't make your butt look big.) But we do want to know if the odometer has been turned back on that cherry '78 Pinto. Truth can hurt. However, Ekman asks: do you want to catch the person you hired who is embezzling from the company? And notes that those in law enforcement and antiterrorism do want to catch the liar.

Further Reading:

(Answered July 13, 2009)

Readers' Answers to the current question: Can an average person develop the skill to reliably detect liars?

Yes. I know this because my mom can. Me, Westerville, Ohio, USA

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Yes, it has to do with the person's body language. If they have eye contact, which direction they look when they break that eye contact. The eyes tell a lot. With pathological liars, they tend to keep eye contact, but they give off an overly serious feel by how they look at you. For instance, that guy "Coach" on the show Survivor 2009 had that look in his eyes and his personality didn't match up to his stories. If all that stuff really happened to someone, personally, I don't think that the person would have been so laid back.

Also the way a person moves his feet and/or hands and what he does with them. The thing is, it can't be just one part of his conduct. It has to be a combination of them. There are many more facets of a person's behavior that can tell you if they are lying or not; these are just a few. Adam, San Francisco, California, USA

Yes they can but some people will most likely take longer to learn than others. There's a certain way people talk when they lie but everyone is different so its a hard skill to pick up and could take up to a straight year of practice. There's also other ways to tell if someone is lying:

  • fidgeting
  • sweating
  • they answer really fast or really slow
  • they do something with their face before they speak such as biting their lip or swallowing saliva or eye twitch/excessive blinking etc..

Josh, Tulare, California, USA

Over time people can detect certain "traits" people do when they lie. for example - let's say you have a sister who, whenever she lies, blinks a lot (you might not notice this directly but somewhere in your brain you do). I'm only like 15. Micaela, Pflugerville, Texas, USA

Readers contributed answers to this question on liars. The next question is:

How many and what ratio of men and women will be required to create a healthy human population on another planet?

Click here to give April your answer : Answer the question. Deadline: Sep. 2. We will publish the best answers onSep. 14.

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