Having a good laugh is, among other things, a great way to bond socially. In fact, we’re much more likely to crow when we’re with other people than we are when we’re alone.

And once you hear someone start, it’s hard not to crack up, too. However, a recent study in the journal Current Biology posits that this phenomenon might not be contagious for everyone, specifically for teen boys at risk of psychopathy.

Elizabeth O’Nions of the University College London and her team tested three gro