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How to Tell if Someone is Lying

The expert in deception deception reveals the clues to deceit

how to tell if someone is lying

How to tell if someone is lying

While there is no single, definitive sign that someone is lying, there are clues to deceit that can help you get closer to the answer. Here’s how to tell if someone is lying to you, based on decades of research and experience by Dr. Ekman:


1. Establish a baseline

An invaluable aspect of deception detection is first establishing a “baseline,” or a behavior considered to be “normal” for the individual in question. The basic process of behavioral deception detection then involves looking for clues that signal some kind of change or deviation from this baseline.


2. Look for clues to deceit

When looking for signs someone is lying, there are two clues to deceit you can reference: leakage, and deception clues. When a liar mistakenly reveals the truth, we call it leakage. When the liar’s behavior suggests he or she is lying without telling the truth, we call it a deception clue. 

For example, if a patient’s doctor notes hand-wringing as she tells him she feels fine, he would have a deception clue, a reason to suspect she may be lying about her emotional state. However, with this clue to deceit, he would not know how she really felt — she might be angry at the hospital, disgusted with herself, or fearful about her future — unless he obtained leakage. A facial expression, tone of voice, slip of the tongue, or certain types of gestures could leak her true feelings, as long as it’s measured against the baseline.

It’s important to note that while a deception clue can tell you if someone might be lying, it only answers the question of whether or not the person is lying; it does not reveal what is being concealed. Only leakage would do that. Often it does not matter. When the question is whether or not a person is lying, rather than what is being concealed, a deception clue is good enough. Leakage is not needed. What information is being held back can be figured out or is irrelevant.

But it is not always enough. It may be important to know exactly what has been concealed. Discovering that a trusted employee embezzled may be insufficient. A deception clue could suggest that the employee lied; it might have led to a confrontation and a confession. Yet even though the matter has been settled, the employee discharged, the prosecution completed, the employer might still seek leakage. He might still want to know how the employee did it, and what he did with the money he embezzled.

Sometimes leakage provides only part of the information the victim wants to know, betraying more than a deception clue but not all that is being concealed. In terms of how to tell if someone is lying, leakage can hint at what the deception may be about, but it does not give you the whole story. Deception clues or leakage may be shown in a change in the expression on the face, a movement of the body, an inflection to the voice, a swallowing in the throat, a very deep or shallow breath, long pauses between words, a slip of the tongue, a micro facial expression, a gestural slip. It is important to pay attention to many nonverbal behaviors that can indicate a person is being dishonest, and the most effective to monitor are micro expressions.


3. Observe micro expressions

When lying, the face often contains two messages: what the liar wants to show, and what the liar wants to conceal. Often, these hidden emotions leak in the form of a micro expression, a brief (half a second or less) involuntary facial expression revealing true emotion.

While Dr. Ekman cautions that a single micro expression or flash of leakage does not offer conclusive proof of lying, micro expressions are one of the most effective nonverbal behaviors to monitor to indicate a person is lying.


Learn how to read micro expressions and detect lies  

Based on this knowledge, Dr. Ekman developed these micro expression training tools to teach you how to tell if someone is lying. You’ll learn about reading facial expressions and the emotions behind them in order to get the leakage clues you’re looking for in your personal or professional life.  



Paul Ekman is a well-known psychologist and co-discoverer of micro expressions. He was named one of the 100 most influential people in the world by TIME magazine in 2009. He has worked with many government agencies, domestic and abroad. Dr. Ekman has compiled over 50 years of his research to create comprehensive training tools to read the hidden emotions of those around you.

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