Here's Evidence That People Can Detect Lies Unconsciously

Despite common wisdom that there are easy tricks to help you spot a liar, there's not much evidence that suggests liars fidget or fail to make eye contact or look especially shifty.

These supposed tell-tale signs of liars are "old wives' tales" that aren't backed up by scientific literature, University of California at Berkeley psychologist Leanne ten Brinke told The New Yorker. Indeed, people are generally bad at spotting liars, Brinke says.

However, Brinke believes parts of your brain that are separate from your conscious thoughts can pick up on lies. She and two other Berkeley professors, Dana Carney and Dayna Stimson, have published a new study with an interesting experiment that backs up the theory of "unconscious lie detection."

"Although humans are poor lie detectors, evidence from primatology and neuroscience suggests that without conscious awareness, parts of the human brain can automatically detect deception, as can the brains of nonhuman primates," the study said.

Brinke sent us a copy of her study, which details exactly how she did the experiment. As part of a "high-stakes mock-crime paradigm," the study's participants were randomly assigned to steal an envelope with $100 or to refrain from stealing that $100 after the experimenter left the room. The experimenter returned and interrogated them, videotaping the whole thing while thieves and non-thieves both professed their innocence.

Then, 72 participants watched that video and were asked to distinguish the liars from non-liars. As expected, the participants weren't great at spotting a liar - their accuracy rate was just 46.83%, just below the chance rate of 50%.

Next, the participants were given an implicit association test (IAT) to determine whether they associated an image of a liar's face with "deception-related concepts" like liar, deceive, and dishonest. The study said the researchers were interested "in whether observing someone tell a lie would, outside of awareness, activate mental concepts associated with deception."

Indeed, the study found this method for deception detection produced a likelihood "significantly greater" than chance that somebody would associate a deceptive person with concepts related to lying.

"Thus, it appears that viewing a liar automatically activates concepts associated with deception," the study said.

So, what do we do with this information? Brinke told The New Yorker a story about how, in 2008, she saw a woman on television named Penny Boudreau pleading for the safe return of her missing daughter. Brinke thought, "Something is not right." Months later, news emerged that the woman had killed her daughter.

The moral of the story seems to be that sometimes you should trust your gut and not rely too much on your conscious.