Why Are Emotions Contagious?

Have you ever been in a group of people who got the giggles? One person starts laughing about something no one else seems to have noticed, and soon everyone is cracking up. Or maybe you’ve had your mellow completely harshed by the Eeyore in your group. It’s as if our emotions harmonize, converging on a pitch, low or high. It’s the kind of thing most of us have noticed, at least occasionally. Scientists have noticed it, too. There’s quite a body of psychological research on this, and much of it connects the experience to feelings of empathy and sympathy. But it’s a surprisingly complex phenomenon that can involve physiological and psychological manifestations. It can occur even among strangers and over long distances.