Tips from a professional lie spotter

Pamela Meyer knows all about liars: she is a certified fraud examiner. In her new book Liespotting: Proven Techniques to Detect Deception, she explains that learning to identify a lie has many benefits. You’ll be better able to build a loyal inner circle of colleagues. You’ll know when your teenager is telling the truth. You’ll pick a real estate agent you can trust.

“The first rule in deception detection is to watch the face,” writes the Harvard M.B.A. A fake smile should be your first clue something’s off. “When someone who is trying to hide the truth senses that his true emotions are threatening to become visible, he will actively work to cover it up with another expression”—most often, a smile. It’s easy to control the lip corners and cheeks to produce one, but “the eye-orbiting muscle, which narrows the eyelids and produces crow’s feet at the outer corner of the eye, is extremely difficult to move deliberately.” If you don’t see crow’s feet, chances are it’s a fake smile.

Don’t be thrown off by lack of eye contact. In fact, good liars are often skilled at staring into their questioner’s eyes. Blink rates are a better indicator of honesty: “People telling a lie will often involuntarily blink more than they do when they’re telling the truth.” Also, take note of pupil dilation. “Since virtually no one can control the size of his pupils, a person with unusually dilated pupils may be feeling fear or other emotions that he cannot conceal.”

Watch closely for asymmetrical expressions. “Genuine emotion, with the exception of contempt, usually presents itself symmetrically [on the face]. But when people make an expression deliberately, it’s often lopsided—a crooked smile or one raised nostril.” Similarly, writes Meyer, duration is relevant. “Genuine expressions of emotion rarely persist longer than five seconds, and almost never longer than 10. A fixed smile is likely to conceal anger, anxiety or some other negative emotion.”

How the person moves can be more important than what he says. “Liars tend to rehearse their words, not their gestures,” writes Meyer. An employee denying a leak to the press, for instance, may be “so busy making sure that he says the right words that he’s hardly paying attention to the fact that his leg is shaking nervously or that he’s twisting one curled toe into the floor.”

Or someone on the verge of lying may try to move as little as possible. “Stillness is unnatural,” writes Meyer. Most people move their hands and lean forward to make a point, but liars tend to “focus so much mental energy on their carefully scripted words that they don’t have much left over for the body.” Professional interrogators “often realize a suspect is lying when he freezes his upper body.”

When people are nervous, they may grab for a “barrier object” such as a purse or briefcase to place “between themselves and the perceived threat. That’s why professional interrogators see to it that there is nothing but empty space between them and the person they’re questioning. When a deceptive subject feels exposed, he has trouble concentrating.”

A little leg-bouncing in a tense situation is normal, writes Meyer, but watch for multiple signals that you’re in the presence of someone trying to hide her feelings. For instance, turning away to pick lint off clothing suggests she disapproves of what she’s seeing or hearing, and probably has an opinion she’s keeping to herself. Also, watch for hand-wringing and inward curled feet.

Listen, too, for formal grammar: “I did not take the money!” An honest person rejects an accusation “as quickly and forcefully as possible. ‘I didn’t do it!’ ” Dishonest people might also bolster their defence with phrases such as “honest to God.” Meyer explains, “The more vociferously a person invokes religion, the more likely it is that she is not telling the truth.”

Finally, when questioning someone, make it clear when the interview is over but keep chatting, suggests Meyer. “Most guilty subjects will exhibit enormous post-interview relief—a change in posture, a new breathing pattern, a nervous joke or laugh.” All are giveaways for a trained lie-spotter.