OK, we all know that a little bit of crazy in a person is good, but when you head into psychopathic territory, it’s not a great sign for everlasting happiness.

So, to help you weed out any potential psychos from your friendship group or dating pool, we’ve turned to science for the answers!

A new study has revealed that people with psychopathic tendencies are less likely to ‘catch’ a yawn because of their lack of empathy and emotional connections.

This research also found that those with a stronger emotional connection to you (ie. friends and family) are more likely to ‘catch’ your yawn, so to test whether or not someone is:

a) not a psychopath
and/or
b) likes you

Simply yawn in front of them and see if they catch it!

*This study, titled “Contagious yawning and psychopathy” involved 135 respondents and was published online in the journal Personality and Individual Differences.