Sophie Scott is fascinated by laughter—and she thinks that cognitive science and psychology are missing out by ignoring it. A cognitive neuroscientist at University College London, Scott studies how we distinguish between “social” or “voluntary” laughter (the way you politely laugh at a co-worker’s jokes) and “authentic” or “involuntary” laughter (the kind that causes you to gasp for breath). She’s found that children are unable to tell the difference between the two, and our ability to discriminate doesn’t hit its peak until we’re in our 30s. “That suggests that you’re learning about social laughter throughout your entire early adult life, probably because you can only learn about it in social interactions.”

Kurt Andersen: When you started doing this, did neuroscientists go, “Sophie what are you doing?”

Sophie Scott: Pretty much. I've had my work defaced by a colleague who wrote "Is this science?" all over it. There's something about laughter that just seems really trite and stupid. That has basically meant that we've entirely ignored positive emotional experiences. You could study psychology and neuroscience your whole life and never know that people fell in love with each other or found anything funny.

Laughter can be provoked in many situations and can serve many functions. In that sense, it seems not suited to science, which is about studying one thing at a time.

Nothing's ever simple with humans. One of the things that's interesting about laughter is, pretty much everything we think we know about it is wrong. So we think we do it less than we do. We think it's linked with jokes and humor. But most of the time when you're laughing in a conversation with somebody you're laughing to show that you know them, you like them, you agree with them. You're doing all this affiliative work with laughter.

You study the differences neurologically between involuntary and voluntary laughter. When you look at the brain, what are the different things going on?

In terms of perception, there are huge differences in how your brain deals with spontaneous, authentic laughter versus more posed, social laughter. In the brain, there's more response to social laughter than to spontaneous laughter. There’s lots of activation to spontaneous laughter, and it’s associated with audio processing. But when you listen to social laughter, you get all this activation in brain areas associated with thinking about what other people think. I think that's because you are trying to work out why that person is producing that behavior. There is an intention behind it. It's a sign that laughter’s never neutral, it's always meaningful, and we're trying to figure out what that meaning is.