Most of the research on the nonverbal signs of lying is driven by the belief that deception is difficult to conceal because…
Lying takes more mental effort than telling the truth.
Emotions give people away when lying.
Lying causes more stress and anxiety.
When lying people are more likely to:
Offer shorter responses, Make more speech errors—more um’s, er’s, ah’s.
On a side note it should be pointed out that: People do NOT break eye contact when lying.
It’s our fight-or-flight stress response causes the need for throat clearing in liars as the moisture usually present in the throat reroutes to the skin in the form of sweat.
Similarly, the lack of moisture in the liar’s throat due to the fight-or-flight response causes hard swallows often referred to as the “Adam apple’s jump.”
Some liars open their mouths and slide their jaws back and forth. The back and forth movement of the jaw stimulates the salivary glands in the back of the throat. This movement is an attempt to moisten their dry throats due the fight-or-flight response.
Our eyes point to where the body wants to go. Liars often look toward the nearest exit, telegraphing their desire to physically and psychologically escape the anxiety caused by lying. (People who look at their watches telegraph the same message, signaling a desire to cut short a conversation.)
- Emotional in-congruence:
Sometimes you just have a gut feeling that something is off, like catching someone with a phony smile. A liar can look incredibly fearful that he or she will be caught, but be careful because truthful people can also look fearful that you won’t believe them.