Excerpted from an article that originally appeared in The Guardian. Used with permission.
We learn to lie as children, between the ages of 2 and 5. By adulthood, we are prolific. We lie to our employers, to our partners, and most of all, one study has found, to our mothers. The average person hears up to 200 lies a day, according to research by Jerry Jellison, a psychologist at the University of Southern California. The majority of the lies we tell are “white,” the inconsequential niceties — “I love your dress!” — that grease the wheels of human interaction. But most people tell one or two “big” lies a day, says Richard Wiseman, a psychologist at the University of Hertfordshire. We lie to promote ourselves, to protect ourselves, and to hurt or avoid hurting others.
The mystery is how we keep getting away with it. Our bodies expose us in every way. Hearts race, sweat drips, and micro-expressions leak from small muscles in the face. We stutter, stall, and make Freudian slips. “No mortal can keep a secret,” wrote the psychoanalyst in 1905. “If his lips are silent, he chatters with his fingertips. Betrayal oozes out of him at every pore.”
Even so, we are hopeless at spotting deception. On average, across 206 scientific studies, people can separate truth from lies just 54 percent of the time — only marginally better than tossing a coin. Some people stiffen and freeze when put on the spot; others become more animated. Liars can spin yarns packed with color and detail, and truth-tellers can seem vague and evasive.
Humans have been trying to overcome this problem for millennia. The search for a perfect lie detector has involved torture, trials by ordeal, and, in ancient India, an encounter with a donkey in a dark room. In 1730, the English writer Daniel Defoe suggested taking the pulse of suspected pickpockets. “Guilt carries fear always about with it,” he wrote. “There is a tremor in the blood of a thief.” More recently, lie detection has largely been equated with the juddering styluses of the polygraph machine. But none of these methods has yielded a reliable way to separate fiction from fact.
That could change. In the past couple of decades, the rise of cheap computing power, brain-scanning technologies, and artificial intelligence has given birth to what many claim is a powerful new generation of lie-detection tools. Startups, racing …read more