Deception

Frequency of Lying and Types of Lies

Lying is a frequently occurring event. On average, people lie in one out of every four of their social interactions that lasts longer than 10 minutes. The lies people tell are outright (i.e., the information conveyed is completely different from what the liar believes to be the truth), exaggerations (i.e., over- or understated facts), and concealments (i.e., omitting relevant details). People lie to gain material advantage or to avoid materialistic loss or punishment. Such lies are often selfish, disruptive of social life, and hurtful to the targets. People also lie for psychological reasons, often to protect themselves from embarrassment (people don’t want to reveal all their inadequacies, errors, and indecent and immoral thoughts), to avoid tension and conflict in social interactions, and to minimize hurt feelings and ill will (people don’t want to tell the bold truth, thereby deliberately hurting the feelings of a good friend). Psychological lies act as a social lubricant and improve social relationships. The nature of lying is therefore two-pronged: it can be a selfish act or a social lubricant. Being able to detect selfish lies would benefit individuals or the society as a whole. To detect selfish lies, it is relevant to know how liars respond and how they possibly could be detected.

Lie Detection

Lie detection tools aim to distinguish truth tellers and liars based on their nonverbal behavior (e.g., gaze patterns, emotional expressions, posture), speech content (e.g., amount of detail, type of detail, plausibility, inconsistency), physiological activity (e.g., heart rate, blood pressure, galvanic skin response), and brain activity (e.g., P300 brain waves, cortex activity). All four approaches share a common element: A response uniquely associated to deception—a response always present during lying and never during truth telling akin to Pinocchio’s growing nose—does not exist. In [Page 469]addition, the cues that distinguish truth tellers from liars are faint and unreliable. The diagnostic value of the most revealing verbal or nonverbal cue to deceit is the equivalent of the difference in height between 15- and 16-year-old girls.

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