Two clues to deceit
Have you ever wondered how to tell if someone is lying? For starters, there are two kinds of clues to deceit. A mistake may reveal the truth, or it may only suggest that what was said or shown is untrue without revealing the truth. When a liar mistakenly reveals the truth, I call it leakage. When the liar’s behavior suggests he or she is lying without revealing the truth, I 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 is 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 gestures could leak her true feelings.
The limitations of deception clues
A deception clue can tell you if someone is lying, but 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 trust 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….
Identifying emotional leakage
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.