Police in the UK no longer accept non-verbal cues as evidence of deceit or criminal contact. Nor do they use “accusatory” interrogation techniques. Sweating means nothing other than you’re warm. Looking away means you don’t like looking at a person. Shifty eyes? Maybe it’s a tic.
There’s a body of research reported in The Atlantic this month that basically says that flipping a coin is just as accurate — in some cases much more accurate — than trying to rely on non-verbal cues to determine dishonesty. People who are lying are perfectly capable of masking what they are doing. You won’t know by looking at them. It’s also why when tested by undercover agents, agents were able to smuggle weapons and explosives through TSA checkpoints 95% of the time. It’s also why in an experiment involving smuggling on airplanes, nonverbal clues worked 39% of the time. Flipping a coin would be more accurate.
The alternative is the use of verbal clues including sketch interrogations. People who are being honest can relate more, accurate details of an event than can liars — an average of 76% more.
The US police and the TSA don’t accept these research findings, and still used debunked methods to try to determine guilt. Which is why we have so many innocent people going to jail, and why the British police don’t use them.
“The mistakes of lie detection are costly to society and people victimized by misjudgments,” Hartwig says. “The stakes are really high.”psychologist Maria Hartwig, a deception researcher at John Jay College of Criminal Justice at the City University of New York