Several cues have been attributed to detecting lies. They generally fit into two broad classes. The first is nonverbal visual cues such as facial expressions, eye blinking, eye contact or gaze aversion, head movements, pupil dilation, nodding, smiling, hand movements or gestures, foot and leg movements and postural shifts. The second includes paraverbal cues including pitch, pauses, or speech errors.
Notwithstanding the myriad of hard fast research on lie detection, it is still a widespread belief in the population that nonverbal behaviours betray a liar. Worldwide, cross-cultural comparison has shown a universally held belief that liars are spotted through their bodies. Police training packages will often include nonverbal and paraverbal behaviours as part of the ways in which deception can be detected. A study by Lucy Akehurst of the University of Portsmouth found that when asked which behaviours they thought would be consistent with lying, both police officers and regular lay people agreed. There was no difference between what the experts thought betrayed a liar and what regular people thought. They also agreed that these behavioural changes would occur more frequently in others as they lied, than in themselves. This finding is replicated in other studies as well. For example, police officers and students agreed on which behaviours were consistent with lying and they also thought that they themselves would display these cues less during lying. The research therefore is inconsistent with the nature of lying. It can not happen both ways, and it seems that our attitudes about lying and lie detection are skewed.
Judgments of deception are heavily correlated with long held stereotypes. Person’s that display behaviours associated with lying are often judged as deceptive even though they may be telling the truth! Study after study shows that roughly only fifty percent of the time liars give themselves away, the remaining time, liars are passed off as truth tellers and truth tellers as liars. Pegging liars based on body language alone or some other mystical cue is a dangerous assumption. It can lead to marital break-ups such as if a spouse falsely labels her husband as a cheater, can put innocent people in jail, can lead to the firing of employees on suspicion of theft and so forth. Yet with this huge propensity for error and consequence, we still, by in large, believe that we can read people on this trait. What shouldn’t surprise us are the rewards achievable through lying and cheating.
Teachers, principles, lay persons and even intellectuals have been shown to all think similarly in terms of lie detection, and the body language associated (even if incorrect). Thus to avoid being detected, or mislabeled a liar (which is worse), we should still avoid displaying stereotypical lying body language that will serve to give us away.