TIME EUROPE
MARCH 13, 2000 VOL. 155 NO. 10
How To Spot A Liar
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In a series of tests, Ekman interviewed and videotaped a group of male American college students about their opinions regarding capital punishment. Some participants were instructed to tell the truth--whether they were for or against the death penalty--and some were instructed to lie. Liars who successfully fooled the interviewer received $50. Ekman then studied the tapes to map the microexpressions of mendacity.
One student, for example, appeared calm and reasonable as he listed the reasons why the death penalty was wrong. But every time he expressed these opinions, he swiftly, almost imperceptibly, shook his head. But the movement is so subtle and quick many people don't even see it until it's pointed out to them. While his words explained the arguments against capital punishment, the quick, involuntary shudder of his head was saying loud and clear, "No, I don't believe this!" He was, in fact, lying, having been for many years a firm supporter of the death penalty.
Another student also said that he was against the death penalty. But during the interview, he spoke very slowly, paused often, and rarely looked the interrogator in the eye, instead fixing his gaze on some vague point on the floor. Speech that is too slow (or too fast), frequent hesitations, lack of direct eye contact: these are all classic symptoms of lying. But this man was telling the truth. He paused and hesitated because he was shy. After all, even honest and normally composed individuals can become flustered if they believe others suspect them of lying. His lack of eye contact could be explained by the fact that he came from Asia, where an averted gaze is often a sign of deference and respect, not deception. This scenario highlights Ekman's admonition that before branding someone a liar, you must first know that person's normal behavior patterns and discount other explanations, such as cultural differences.
Ekman has used this tape to test hundreds of subjects. His conclusion: most people are lousy lie detectors, with few individuals able to spot duplicity more than 50% of the time. But Ekman's most recent study, published last year in Psychological Science, found that four groups of people did significantly better than chance: members of the U.S. Central Intelligence Agency, other U.S. federal law enforcement officers, a handful of Los Angeles County sheriffs and a group of clinical psychologists. Reassuringly, perhaps, the federal officials performed best, accurately detecting liars 73% of the time. What makes these groups so good at lie catching? According to Ekman, it's training, experience and motivation. The jobs--and in some cases, the lives--of everyone in these groups depend on their ability to pick up deceit.
Ekman has used his findings to assist law enforcement agents--including members of the U.S. Secret Service and Federal Bureau of Investigation, Britain's Scotland Yard and the Israeli police force--in criminal investigations and antiterrorist activities. He refuses to work with politicians. "It is unlikely that judging deception from demeanor alone will ever be admissible in court," Ekman says. "But the research shows that it's possible for some people to make highly accurate judgements about lying without any special aids, such as computers."
But for those who still prefer a bit of technological assistance, there's the Verdicator--a device that, according to its 27-year-old inventor Amir Liberman, enables anyone equipped with a personal computer and a phone or microphone to catch a liar. A person's tone of voice can be just as revealing as the expression on his face. A low tone, for example, can suggest a person is lying or is stressed, while a higher pitch can mean excitement. Liberman claims the Verdicator, a $2,500 piece of software produced by Integritek Technologies in Petah Tikvah near Tel Aviv, is between 85% and 95% accurate in determining whether the person on the other end of the line is lying, an accuracy rate better than that for traditional polygraphs. "Our software knows how to size you up," Liberman boasts.
The Verdicator delivers its results by analyzing voice fluctuations that are usually inaudible to the human ear. When a person is under stress, anxiety may cause muscle tension and reduce blood flow to the vocal cords, producing a distinctive pattern of sound waves. Liberman has catalogued these patterns and programmed the Verdicator to distinguish among tones that indicate excitement, cognitive stress--the difference between what you think and what you say--and outright deceit. Once linked to a communications device and computer, the Verdicator monitors the subtle vocal tremors of your conversational partner and displays an assessment of that person's veracity on the screen. "The system can tell how nervous you are," Liberman explains. "It builds a psychological profile of what you feel and compares it to patterns associated with deception." And the Verdicator has one great advantage over the polygraph: the suspect doesn't need to know he's being tested. To be accurate, though, the Verdicator must pick up changes--which might indicate deceit--in a person's normal voice.
During the Monica Lewinsky scandal, Liberman demonstrated the system on President Clinton's famous disclaimer, "I did not have sexual relations with that woman." After analyzing an audio tape of the statement 100 times, the Verdicator showed that Clinton "was telling the truth," Liberman says, "but he had very high levels of cognitive stress, or 'guilt knowledge.' He didn't have sexual relations, but he did have something else."
Integritek will not name the law enforcement agencies, banks or financial institutions that are using the Verdicator. But company president Naaman Boury says that last year more than 500 Verdicators were sold in North and South America, Australia, Asia and Europe. The Japanese firm Atlus is marketing a consumer version of the Verdicator in Asia. "We get the best results--close to 95% accuracy--in Japan," Liberman reports. "The Japanese feel very uncomfortable when lying. We get the poorest results--nearer 85% accuracy--in Russia, where people seldom seem to say what they really feel."
In moderation, lying is a normal--even necessary--part of life. "It would be an impossible world if no one lied," Ekman says. But by the same token, it would be an intolerable world if we could never tell when someone was lying. For those lies that are morally wrong and potentially harmful, would-be lie detectors can learn a lot from looking and listening very carefully. Cheating partners, snake oil salesmen and scheming politicians, beware! The truth is out there.
With reporting by Eric Silver/Jerusalem
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