Understanding clues of dishonesty
Channels of information for lie detection
What to pay attention to when suspecting deception
If you want to catch a liar there are a few channels of information you can focus on. These include: the words of the liar, the vocal cues and tone, body language, gestures, and facial expressions and movements.
Remember, there is no singular definitive indication of deceit, but rather, a variety of clues you can look out for in these various modes of verbal and nonverbal communication.
The Liar’s Words
Of all the channels mentioned, liars tend to be most careful about their choice of words. When preparing to lie, most liars think through what they will say. However, carelessness, forgetfulness, or a slip of the tongue can betray a liar through their words.
While we all know that words can lie, my research has found that people usually take others at their word and are often misled. I’m not suggesting that the words can be totally ignored. People do make verbal mistakes that provide both leakage and deception clues. Even if no obvious mistakes are made, the discrepancy between verbal cues and what is revealed by body language, facial expressions, and vocal cues of deception can often betray a lie.
The Liar’s Face
The face usually receives the next greatest amount of attention. This is because the face is the primary sight for the display of emotions, and together with the voice, it may tell the listener how the speaker feels about what is being said. Although this is not always accurate, since faces can lie about feelings through emotional masks.
While liars may be aware that the face is a valuable source of information, few are aware of the expressions emerging on their face until the expressions are quite obvious (macro expressions). Unlike words, the face is directly connected to areas of the brain involved in emotion, making it a rich source of information.
The face is a dual system, including expressions that are deliberately chosen and those that occur spontaneously, sometimes without the person even aware of what emerges on their own face. When people lie, their most evident, easy to see expressions, which people pay most attention to, are often the false ones. The subtle signs of these expressions are not felt, and the fleeting hint of the concealed emotions are usually missed.
Autonomic Nervous System (ANS) changes can also be registered in the face, such as blushing, blanching, and pupil dilation. These changes occur involuntarily when emotion is aroused, are very hard to inhibit, and for that reason can be very reliable clues.
One of the most helpful sources of facial leakage is through micro expressions. These expressions provide a full picture of the concealed emotion, but so quickly that it is usually missed. With practice, anyone can learn to read micro expressions with our online training tools. You can also test your ability to read micro expressions here.
The Liar’s Body and Voice
Compared to the amount of attention placed on the words and face, body language and vocal cues don’t regularly receive as much attention. This provides the lie detector with an additional, potentially valuable source of information, as it may not be as closely monitored by the liar.
The voice, like the face, is tied to the areas of the brain involved in emotion. It is very difficult to conceal some of the changes in vocal tone and quality that occur when emotion is aroused.
The body is also a good source of leakage and deception clues. Unlike the face or voice, most body movements are not directly tied to the areas of the brain involved in emotion. Concealment of body movement could be much easier than concealing facial expressions or voice changes in emotion, but most people don’t bother. Rarely are people held accountable for what they reveal in their bodily actions. The body leaks information because it is often ignored. Everyone is too busy watching the face and evaluating the words.
A slip in body movement, known as an emblematic slip can sometimes be a reliable clue to deceit.
The ANS also produces some noticeable changes in the body with emotional arousal: in the pattern of breathing, in the frequency of swallowing, and in the amount of sweating. These ANS-driven physical cues are challenging to control and can expose deceptive behavior.
