How do you know if someone is lying to you?

You should pay careful attention to their facial expressions, body language, and speech patterns, says Lillian Glass, a behavioral analyst and body language expert who’s worked with the FBI on unmasking signals of deception.

When trying to figure out if someone is lying, you need to first understand how the person normally acts. For example, if this person usually blinks rapidly, they will likely do the opposite when lying, such as stare at you without blinking.

In her new book “The Body Language of Liars,” Glass reveals eight signs to look for to know if someone is lying:

 

1. They change their head position quickly.

If you see someone suddenly make a head movement when you ask them a direct question, they may be lying to you about something.

“The head will be retracted or jerked back, bowed down, or cocked or tilted to the side,” writes Glass. This will often happen right before the person is expected to respond to a question.

 

2. They stand very still.

It’s common knowledge that people fidget when they get nervous, but Glass says that you should also watch out for people who are not moving at all.

“This may be a sign of the primitive neurological ‘fight,’ rather than the ‘flight,’ response, as the body positions and readies itself for possible confrontation,” says Glass. “When you speak and engage in normal conversation, it is natural to move your body around in subtle, relaxed, and, for the most part, unconscious movements. So if you observe a rigid, catatonic stance devoid of movement, it is often a huge warning sign that something is off.”

 

3. They instinctively cover vulnerable body parts.

This may include areas such as the throat, chest, or abdomen.

“I have often seen this in the courtroom when I work as a consultant for attorneys. I can always tell when someone’s testimony has hit a nerve with the defendant, when I see his or her hand covering the front of his/her throat,” says Glass.

“I never appreciated the potential use of this very telling behavior until I joined the FBI as a Special Agent,” she says.

 

4. They touch or cover their mouth.

“A telltale sign of lying is that a person will automatically put their hands over their mouth when they don’t want to deal with an issue or answer a question,” says Glass.

“When adults put their hands over their lips, it means they aren’t revealing everything, and they just don’t want to tell the truth,” she says. “They are literally closing off communication.”

 

5. It becomes difficult for them to speak.

“If you ever watch the videotaped interrogation of a suspect who is guilty, you will often observe that it becomes more and more difficult for her to speak,” writes Glass. “This occurs because the automatic nervous system decreases salivary flow during times of stress, which of course dries out the mucous membranes of the mouth.”

Other signs to watch out for include sudden lip biting or pursed lips.

 

6. They stare at you without blinking much.

When people lie, it’s common that they break eye contact, but the liar could go the extra mile to maintain eye contact in attempt to control and manipulate you.

“[Bernie] Madoff, like most con men, overcompensated and stared at people longer than usual, often without blinking at regular intervals,” says Glass. “When people tell the truth, most will occasionally shift their eyes around and may even look away from time to time. Liars, on the other hand, will use a cold, steady gaze to intimidate and control.”

Also watch out for rapid blinking.

 

7. They provide too much information.

“When someone goes on and on and gives you too much information — information that is not requested and especially an excess of details — there is a very high probability that he or she is not telling you the truth,” writes Glass. “Liars often talk a lot because they are hoping that, with all their talking and seeming openness, others will believe them.”

 

8. They tend to point a lot.

“When a liar becomes hostile or defensive, he is attempting to turn the tables on you,” says Glass. The liar will get hostile because he is angry that you’ve discovered his lies, which may result in a lot of pointing.