Untruthful people are most likely to make eye contact and give confident, well-thought-out responses when they’re being deceitful, new research suggests.
Scientists at the University of Michigan have developed lie-detecting software based on real-world data that, unlike a polygraph, does not need to touch the subject in order to work. In experiments based on video footage of 120 U.S. court cases, the software could identify a liar 75 percent of the time, compared to human lie detectors that are only 50 percent accurate, Phys.org reported.
Previously, psychologists and law enforcers have believed that liars are typically shifty-eyed and tend to give hesitant answers, but the new study suggests the opposite to be true, likely because previous studies have been based only on lab experiments, the Telegraph reported.
“In laboratory experiments, it’s difficult to create a setting that motivates people to truly lie. The stakes are not high enough,” said Dr. Rada Mihalcea, professor of computer science and engineering who leads the project.
“People are poor lie detectors,” she said. “This isn’t the kind of task we’re naturally good at. There are clues that humans give naturally when they are being deceptive, but we’re not paying close enough attention to pick them up. We’re not counting how many times a person says ‘I’ or looks up. We’re focusing on a higher level of communication.”
The study, presented last month at the International Conference on Multimodal Interaction, found that people who lied were three times more likely to scowl or grimace, rather than keep a relaxed face. Liars were also more likely to make eye contact with the questioner, gesture with both hands and use language to distance themselves from their words by using “he” or “she” rather than ‘I’ and “we,” the Telegraph reported.
The researchers hope to soon add physiological signs to the tests, such as heart rate, respiration rate and fluctuations in body temperature, which can be picked up from a distance. This means a witness or defendant could be given a lie detector test without needing to be connected to a machine, the Telegraph reported.