When the body goes into stress mode — like when you know you're lying and suspect the person you're with is catching on — someone may blink five or six times in rapid succession. Turns out blushing doesn't just happen when you're embarrassed! Some people, often women, tend to blush when they're lying.
What's happening: When we tell lies — regardless of whether they're big or small — our bodies respond. Lying can trigger an increased heart rate, high blood pressure and elevated levels of stress hormones in the blood, psychologists have found. Over time, that can take a significant toll on mental and physical health.
Sweating or dryness: Autonomic nervous system changes can trigger liars to sweat in the T-area of the face (upper lip, forehead, chin and around the mouth) or have dryness in the mouth and eyes — the person might excessively blink or squint, lick or bite their lips or swallow hard, according to Glass.
They touch their face, mouth or throat.
This subconscious body language may indicate that someone is lying to you. If you notice someone touching their face who normally doesn't, it is a little red flag to keep in the back of your mind.
There is a popular belief that liars tend to avoid eye contact, as they feel guilty or nervous about their deception. However, this is not always true, as some liars may actually maintain more eye contact than usual, as they try to appear confident or convincing.
Hence, if someone is lying, they will feel the urge to satisfy the itch by continuously stroking their nose. Research also found that liars feel a heightened tendency to scratch their ears or neck when they lie. People who are lying also often fidget more than those who are giving straight answers.
If they feel that someone closes in on their lies and raises questions, liars tend to get angry and defensive. Even if no one is outright accusing them, they have an overblown reaction due to their fear of being caught. It also acts as a distraction and helps take the spotlight off their lies.
How To Tell When Someone's Lying. The direction of their eyes: A 2012 study published in Plos One debunked the myth people look to the left when lying. A study by the University of Michigan found when participants lied, they maintained eye contact 70% of the time.
Possible sign
Repeating a question before answering it. Speaking in fragments or using nonsensical language. Grooming behaviors such as a person playing with their hair, touching their head, or pressing their fingers to their lips. A lack of eye contact (or forced eye contact)
In an effort to reduce the anxiety caused by lying, liars increase hand-to-face contact to deplete excess energy. Liars often experience stress because they fear getting caught. Stress causes worry and anxiety.
Lying is a process that activates specific parts of the brain. Lying is also often accompanied by a feeling of guilt, which creates stress. Standard lie-detection techniques look for the body's reactions to this stress, such as elevated heart rate or blood pressure, faster breathing or sweating.
Lying can be cognitively depleting, it can increase the risk that people will be punished, it can threaten people's self-worth by preventing them from seeing themselves as “good” people, and it can generally erode trust in society.
Our Lying Brain
The amygdala—the brain hub for emotional and arousal processing, often associated with the fight-or-flight response—showed the highest level of activity when the very first self-serving lie was told. With every subsequent lie, however, the level of activity in the amygdala would drop.
Study the eyes
Researchers say no. Science shows that liars do not avoid eye contact any more frequently than those telling the truth. The key thing to look for in eye movement is deviation from their baseline.
Skipping contractions: "I did not do it."
Instead of saying "I didn't do it," they'll say "I did not do it." Or they'll say "I cannot remember" instead of "I can't remember." They're basically overselling their lie by trying to sound more powerful and less refutable.
Tightened jaw and forehead
Liars also tend to tense up when they're not being truthful, and this can include tightening the jaw and forehead. Both are connected to the "mental effort and stress" associated with telling a lie, according to Wenner.
When people lie and they are confronted with evidence that contradicts those lies, they may change their story or deny the truth altogether. They may also try to manipulate others to maintain their false story. Blaming others for their lies. They may try to deflect blame or shift responsibility onto others.
According to Andrew Pickett, trial attorney at Andrew Pickett Law, PLLC, "an increase in filler words such as 'uh' and 'um,' and a greater use of non-specific language" might mean you're being fed a falsehood. These words give the speaker more time to think and show low confidence in what they have to say.
“Many people believe that if someone is looking them straight in the eye that this is an indication of a truthful exchange, but actually practised and habitual liars tend to use eye contact to fool you – they engage greater eye contact than the average person to do this,” Barnett says.
When people lie, their brains have to work harder to come up with the falsehood. This increased mental effort can lead to physical manifestations, like the cluster of three different cues. For example, a person may touch their nose, then their neck, and then their face. Or, they may scratch their head, ear, and chin.