Here's an Easy Way to Tell if You're Dating a Psychopath

Hint: Try it out the next time you're tired.

The term “psychopath” makes people a little nervous. So if you were regularly hanging out with a psychopath, you’d probably want to know, right?

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Scientists can help with that. They’ve now discovered an easy way to detect if someone has higher odds of being a psychopath: Watch how they yawn.

A new study published in the journal Personality and Individual Differences found that people with psychopathic traits are less likely to “catch” someone’s yawn.

For the study, researchers had 135 college students complete the Psychopathic Personality Inventory-Revised (a test to determine psychopathy) and then exposed them to a situation that was designed to cause them to yawn in response.

They found that people who tested higher on the psychopath scale were much less likely to yawn in response to other people yawning.

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You’ve heard about psychopathy but are probably fuzzy on what it actually is. Psychopathy is an antisocial disorder, but unlike other antisocial disorders, it lacks an emotional component. “While someone can be antisocial in the sense that they are violent or vengeful, they may still process the emotional aspect of a situation,” says lead study author Brian Rundle, a researcher at Baylor University.

Psychopaths, on the other hand, “may be conning, narcissistic, unable to form strong emotional bonds with others, fail to learn from punishment, callous, and have a lack of guilt,” says Rundle.

He isn’t sure exactly why the yawn-psychopath link exists but says psychopathic people or people who have high psychopathic traits tend to have a hard time gauging the emotions of other people, which most of us can do easily.

When someone yawns, it take a lot of social-cue processing to yawn in return, he says—and psychopaths might not be able to detect the emotional or mental state of another yawner: “They may just see someone yawn and take that at face value.”

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Of course, that doesn’t mean a person is a psychopath if they don’t catch your yawn.

“There are many reasons why any one of us would not respond to a contagious yawn, even if we know we are usually susceptible to them,” says Rundle, adding that a psychopathy diagnosis requires a few tests and clinical evaluation.

So if you notice that your S.O. doesn’t yawn when you do, don’t freak out. But if you find that someone you regularly hang out with is emotionally distant, self-absorbed, cunning, and they don’t yawn when you do, you might be on to something.