Truth or Lie? Signs of Deception

When interpreting non-verbal signals of deception, it’s critical to look for clusters before deciding that someone is lying to us.



As infants, reading body language signals was our “first language.” As we develop verbal skills, however, the reliance on verbal skills begins to dominate, relegating the reading of body language to our “second language.” Women tend to be significantly better at decoding this “second language” than men. When we talk about “women’s intuition,” we are really talking about women’s greater ability to decode non-verbal signals. In the research on gender differences and non-verbal decoding, 80% of the studies show a female advantage.


Despite what is portrayed in popular shows about deception such as “Lie to Me,” there is no one single sign that proves that someone is lying. Gestures and facial expressions can mean different things depending upon context and the combination in which the gestures or expressions occur. When interpreting non-verbal signals of deception, then, it’s critical to look for what are called clusters, which are at least three non-verbal markers of deception before deciding that someone is lying to us.


Physiological Signs of Lying


When a person is stressed as might occur when they are lying, more blood rushes into the face and neck area. So, we might notice that someone’s face suddenly flushes. That increased blood flow can also cause increased temperature changes in the body so we may observe sudden perspiration or itching, especially in the nose area. When people lie, their breathing also can become shallower.


Behavioral Indicators of Lying


One possible “tell “of lying is the covering of the mouth. It’s as if the lying person is literally trying to keep the truth from “spilling out.” As we go through developmental life stages, this gesture becomes more subtle. For example, children tend to cover the mouth with both hands when they are lying. By the time that child is a teenager, though, they may simply rub their fingers around the mouth area. And as adults, most people will still block the mouth but then pull away, and often do a nose touch instead.


Another possible indicator of deception is eye rubbing or eye-blocking, the latter of which manifests as the person appearing to blink just a little too long. When someone does an eye block, they are shutting out visual stimuli in order to allow greater concentration on fabricating the lie. Eye contact, on the other hand, is generally an unreliable indicator of deception. People have poor eye contact or overly intense eye contact for a myriad of reasons such as social anxiety or social deficits so deciding that someone is lying because they have “shifty eyes,” would be a mistake.


The shoulders can also provide clues when looking for signs of deception. For example, when both shoulders shrug together, this is typically a sign of truthfulness. When only one shoulder shrugs, it can be a sign of lying, particularly when the words follow the shrug instead of occurring simultaneously.

Verbal Indicators of Deception


When people are telling the truth, their words are typically fluid and in synch with their non-verbal signals. When lying, however, there is an incongruence present because it takes longer to think up a lie than it does to simply tell the truth. So, we'll often see the automatic non-verbal signal first followed by a word delay when people lie to us.


Repeating the question asked is one way that a liar attempts to gain more time to think. Other ways include using what are called filler words such as “Um,” or “Eh,” or eliminating the use of contractions, as in the example, “I did not have sex with that woman.”


Using language that over-emphasizes truthfulness, such as “honestly,” “actually,” or “To tell you the truth,” may also be a sign of lying, especially when combined with other markers or clusters of deception.