Jane Warren

Transcription

My name's Sophie Scott, and I'm a professor of Cognitive Neuroscience here at the Institute for Cognitive Neuroscience at UCL, and I'm a Wellcome Trust Senior Fellow. My research is really focused on trying to understand how the human brain deals with human communication, so how our brains deal with hearing speech, how our brains deal with controlling speech output. And I'm also very interested in how it deals with the other kinds of things we do when we talk. We don't always speak if we get, for example, in very strong emotional states. We very often find that words aren't enough. And we'll start to other things. We'll start screaming or laughing or cheering. So I'm very interested in how our brains deal with this because these are sounds, which are very unlike speech. They're actually a lot more like animal calls than they are like speech. And so we've been doing quite a wide programme of research, looking at this. And something that's emerging out of it is that laughter is becoming more and more interesting to me. So it's a very interesting emotion. It seems to have quite a different role from some of the kinds of other classic emotions that we've studied, like fear and disgust and anger, which are very well recognised and very robust and you find in all human cultures. But you can imagine if I start screaming with fear, you would probably start to feel frightened because whatever's a threat to me is possibly threatening to you. If I start looking disgusted, you might start to think, ew, I'm not having what she's having. That's bad. Whereas if I start laughing, you're much more likely to start laughing along with me, even if you don't know anything about why I'm laughing. It has quite a social role, rather than something to do with there's an aspect of the environment that needs to be reacted to immediately. So its basis really is arising from how humans interact with other humans. And we're finding that it's quite universal, so as you might imagine, you don't only find laughter in Western Europe. My PhD student, Disa Sauter, has been travelling around the northern Namibian desert, testing really remote groups of people who live as part of the Himba tribe and finding that they recognise laughter from Europeans as well as from other Himba people. And people in Europe will recognise the laughter of the Himba. So it really is a widespread human emotional trait and expression. And you might expect it to be because humans aren't the only animals that laugh. You find laughter amongst animals. So chimpanzees laugh. Some people have even argued that rats laugh. If you tickle a rat, it will make this noise, and you have to record the noise and slow it right down to actually hear it, but it makes this very particular noise when it's tickled. It will even make the noise when it sees the rat-tickler arriving in their room in the morning, which sounds like a great job. So it's definitely something that's got quite an ancient evolutionary heritage. And interestingly, the thing that makes other animals laugh, which is being tickled, is also what you find is the first emergence of laughter for humans. So we first see laughter in human beings in infants when they're about 6-8 weeks old. And they start laughing when they're tickled. And that seems to have this very strong bonding relationship with the parent or care-giver and the baby because the baby loves being tickled and is laughing back and the parents are completely thrilled and starts laughing. And you sort of get this strong emotional interaction going and a very bonding one. And then as you grow up, it becomes elaborated to other widespread situations. So you don't have to be tickled to laugh. And interestingly, when we look at people's brains when they listen to emotional noises made by other people, what we find as you might imagine, is lots of auditory activation because if you hear somebody screaming or somebody going 'Ugh!' then you're hearing a complex sound. But we also find the activation in parts of the brain that have to do with actually producing movement-- say, of the face or if you were going to make a sound yourself. So even if people are lying silently in the scanner, listening to these sounds, part of their brain is getting ready to produce these sounds. And interestingly, the effects aren't the same for all the emotions. So while you get a little bit of effect for a sound like disgust, you get an enormous effect from sounds like laughter. So it really does seem to be the case that the behavioural contagion of laughter-- people starting to laugh even if they don't really know why they're laughing; they're laughing because other people are laughing-- is rooted in the fact that when the human brain hears laughter, it gets ready to laugh, even if people are lying in a scanner, which is probably one of the least amusing things that can happen to you, certainly as part of a psychology experiment. So I think for me it's interesting in a number of different ways. It's interesting right from its evolutionary heritage, right through to how it's being dealt with by the brain. And something that we're very interested in looking at next is how the brain can tell apart, for example, real laughs from posed laughs because people are very good at that and how exactly in this system are you starting to tease that information apart.