10 Ways to Catch a Liar

J.J. Newberry was a trained federal agent, skilled in the art of deception detection. So when a witness to a shooting sat in front of him and tried to tell him that when she heard gunshots she didn't look, she just ran -- he knew she was lying.

How did Newberry reach this conclusion? The answer is by recognizing telltale signs that a person isn't being honest, like inconsistencies in a story, behavior that's different from a person's norm, or too much detail in an explanation.

While using these signs to catch a liar takes extensive training and practice, it's no longer only for authorities like Newberry. Now, the average person can become adept at identifying dishonesty, and it's not as hard as you might think. Experts tell WebMD the top 10 ways to let the truth be known.

Tip No. 1: Inconsistencies

"When you want to know if someone is lying, look for inconsistencies in what they are saying," says Newberry, who was a federal agent for 30 years and a police officer for five.

When the woman he was questioning said she ran and hid after hearing gunshots -- without looking -- Newberry saw the inconsistency immediately.

"There was something that just didn't fit," says Newberry. "She heard gunshots but she didn't look? I knew that was inconsistent with how a person would respond to a situation like that."

So when she wasn't paying attention, he banged on the table. She looked right at him.

"When a person hears a noise, it's a natural reaction to look toward it," Newberry tells WebMD. "I knew she heard those gunshots, looked in the direction from which they came, saw the shooter, and then ran."

Sure enough, he was right.

"Her story was just illogical," says Newberry. "And that's what you should look for when you're talking to someone who isn't being truthful. Are there inconsistencies that just don't fit?"

Tip No. 2: Ask the Unexpected

"About 4% of people are accomplished liars and they can do it well," says Newberry. "But because there are no Pinocchio responses to a lie, you have to catch them in it."

Sir Walter Scott put it best: "Oh what a tangled web we weave, when first we practice to deceive!" But how can you a catch a person in his own web of lies?

"Watch them carefully," says Newberry. "And then when they don't expect it, ask them one question that they are not prepared to answer to trip them up."

Tip No. 3: Gauge Against a Baseline

"One of the most important indicators of dishonesty is changes in behavior," says Maureen O'Sullivan, PhD, a professor of psychology at the University of San Francisco. "You want to pay attention to someone who is generally anxious, but now looks calm. Or, someone who is generally calm but now looks anxious."

The trick, explains O'Sullivan, is to gauge their behavior against a baseline. Is a person's behavior falling away from how they would normally act? If it is, that could mean that something is up.

Tip No. 4: Look for Insincere Emotions

"Most people can't fake smile," says O'Sullivan. "The timing will be wrong, it will be held too long, or it will be blended with other things. Maybe it will be a combination of an angry face with a smile; you can tell because their lips are smaller and less full than in a sincere smile."

These fake emotions are a good indicator that something has gone afoul.

Tip No. 5: Pay Attention to Gut Reactions

"People say, 'Oh, it was a gut reaction or women's intuition,' but what I think they are picking up on are the deviations of true emotions," O'Sullivan tells WebMD.

While an average person might not know what it is he's seeing when he thinks someone isn't being honest and attribute his suspicion to instinct, a scientist would be able to pinpoint it exactly -- which leads us to tip no. 6.