How to tell when another person is lying. Nonverbal cues and the detection of deception.

“Of course I lie to people. But I lie altruistically – for our mutual goal…”

-Quentin Crisp, 1984

If all lies were told for this reason, they might (underline might) be more ac­ceptable; at least, they would serve some social function. But it is a sad fact of social life that lies are not always told for altruistic purposes. On the contrary, lies are frequently presented for the benefit of the person who engages in de­ception; and if they are accepted as true, they prove costly to intended recipi­ents. Given this fact, it is often important for us to be able to tell when another person is lying. And here is where research on nonverbal communication comes in handy. Research on what social psychologists term detection of deception has continued for several decades, and the results of this work provide us with sev­eral important clues that can help us determine whether another person is lying. Before turning to these specific nonverbal cues, however, we should explain why it's possible to use such information to recognize deception even on the part of highly skilled liars.

The answer centers around the fact that, as we've seen, there are many dif­ferent channels of nonverbal communication. Because of this fact, research sug­gests, it's virtually impossible for individuals to monitor and control all of these separate channels at once (De Paulo, 1992; DePaulo, Stone, &: l.assiter, 1985). Thus, even persons who lie frequently and are highly practiced at lying (for ex­ample, negotiators, confidence artists, some salespersons) frequently reveal that they are lying through some channel of nonverbal cues. For ex­ample, if they focus on regulating their facial expressions and eye contact, then the fact that they are lying may be revealed through their body movements and posture, or through changes in the nonverbal aspects of speech—the tone of their voice, and related cues.

Now that we've clarified this issue, let's turn to the specific clues that can help you decide whether another person is being honest with you.

One nonverbal cue that can be very helpful in this respect is microexpressions. These are fleeting facial expressions lasting only a few tenths of a second. Such reactions appear on the face very quickly after an emotion-provoking event and are difficult to suppress (Ekman, 1985). As a result, they can be quite revealing about others' true feelings or emotions. So, when you have reason to suspect that another person may be lying, say something you think they'll find surprising or upsetting, and then watch their face very carefully as you say it. If you see one expression which is followed, very quickly by another, different one, watch out: they may be trying to deceive you. A second nonverbal cue we can use is known as interchannel discrepancies. These are inconsistencies between nonverbal cues from different basic channels. Such inconsistencies result from the fact that, as we noted earlier, persons who are lying find it difficult to control all these channels at once. For example, a defendant who is lying on the witness stand may succeed in managing her fa­cial expressions and in maintaining a high level of eye contact with the jury. At the same time, however, she may demonstrate postural shifts of body move­ments that reveal the high level of emotional arousal she is experiencing.

A third nonverbal cue involves nonverbal aspects of people's speech—what is sometimes known as paralanguage'. When people lie, the pitch of their voices often rises (Zuckerman, DePaulo, &: Rosenthal, 1981), and they tend to speak more slowly and with less fluency. In addition, they engage in more sentence re­pairs—instances in which they start a sentence, interrupt it, and then start again (Stiff et al., 1989). So listen carefully: if you observe these changes in another person's voice, the person may be lying.

Fourth, deception is frequently revealed by various aspects of eye contact. Persons who are lying often blink more frequently and show pupils that are more dilated than persons who are telling the truth. They may also show an un­usually low level of eye contract or—surprisingly—an unusually high one, as they attempt to feign honesty by looking others right in the eye (Kleinke, 1986).

Finally, persons who are lying sometimes show exaggerated facial expres­sions. For example, they may smile more—or more broadly—than usual, or may show greater sorrow or other emotion than is typical for them in this kind of situation. A prime example: Someone says no to a request you've made and then shows exaggerated regret. This is a good sign that the reasons the person has given you for the "no" may not be accurate.

Through careful attention to these nonverbal cues, we can often tell when others are lying—or merely trying to hide their own feelings from us. Our suc­cess in this respect is far from perfect—skillful liars do often manage to deceive us. But their task will be made more difficult if you pay careful attention to the clues described above. Perfecting your own skills in this respect requires con­siderable effort and practice; it goes without saying, though, that the benefits of being able to cut through attempts at deception can be substantial.