Sophie Scott

However, humans are the only animals where contagious laughter has been shown.

So other animals laugh, but they don't laugh contagiously.

They don't just catch a laugh, which makes it very interesting, partly also because it's something we learn to do.

So contagious behaviors are not things we're born doing.

Babies don't blink unless they need to refresh their eyes.

They don't yawn when somebody else yawns.

They don't laugh when somebody else laughs.

So we teach babies to do these contagious behaviors.

And then that becomes a very, actually it's a very important aspect of social interactions.

The ability to mirror laughter back at each other very effectively is a great way for laughter to spread in a group of people.

And it's also a great way of, if you think about it, it's having this very important affiliative role

It's a great way of sort of getting that affiliative mirroring running in a very unconscious way.

People very rarely notice that they're doing it.

If you ask them why they're doing it, they will come up with a reason.

They'll say, well, that was funny.

But in fact, it wasn't.

It was just contagion.

Definitely.

If you think of that use of laughter to regulate emotions, so to deal with stressful situations, that's actually quite a common use of laughter.

We don't worry about it when it works.