Body Language 95 Liars

October 1, 2020

For the final few articles in this series on body language, I am highlighting some of the excellent content in a program entitled “Advanced Body Language” by Bill Acheson of the University of Pittsburgh.

In this article I will summarize his research on liars. First of all, Bill separates out two categories of liars: incompetent liars and competent liars. He makes some interesting distinctions.

We all wear a kind of “lie detector” every day. It exists of the way we configure our bodies. Once you know the secrets, you will be able to spot someone who is being untruthful rather easily.

His first observation is that we cannot convey trustworthiness verbally. To convince others that we are trustworthy it must come from what we do and our tone of voice. Professional interrogators listen for heightened vocal pitch as better than 90% accurate indicator of deception. Another sign is if a person touches the side of his nose when answering a question.

Incompetent Liars

Bill’s first point is that it takes a lot more mental energy to lie than to tell the truth. His research shows that when you tell the truth you actually use six centers of the brain. When you lie, you activate 14 centers of the brain, and there is so much mental activity going on that there is an automatic secretion of Adrenalin. This causes your body to move. Here are some things to give away an incompetent liar:

• Low level of eye contact – under 30%
• Looking down and shifting glance from side to side
• Dilation of the pupils
• Rapid eye flutter
•  Dry mouth – Decreased saliva leading to lip licking
• Lip biting
• Swallowing hard
• Wringing of hands
• Body moving side to side
• Face turning red or white
• May stutter or stammer

Competent liars

Rather than too little eye contact, with a competent liar you are likely to see too much. The person is actually staring at you with as much as 90% eye contact. Rather than stuttering, the competent liar sounds slick and contrived, like he has rehearsed the script to memory. Here are some of the things to look for with a competent liar:

• Significantly reduced hand gestures
• Violation of your personal space – like touching or putting an arm around you
• Acting more familiar with you than he has the right to be based on how well he knows you
• Holds one hand in the other to reduce his movements
• May put hands behind his back or in his pockets

Bill points out that we have a gut reaction to a stimulus before we deal with the stimulus logically in our brain. So, a first reaction to another person happens very quickly, perhaps in less than a second, but that gut reaction is taking in numerous signals that we process instinctively.

In the book “Blink,” Malcolm Gladwell calls these reactions “thin slices.” We make conclusions very quickly based on what we observe, and we protect ourselves instinctively.

Look for these behaviors when you are talking with another person. You may be able to pick out when the person is telling you the truth versus a lie by observing if there is a cluster of the above behaviors.


This is a part in a series of articles on “Body Language” by Bob Whipple “The Trust Ambassador.”