Jimmy Carr and the Science of Laughter Horizon

Tonight on Horizon, as part of BBC's sitcom season,

the science of laughter. THEY LAUGH

What is it? Why do we love it so much?

And what has it got to do with comedy?

But seeing as how the Horizon team aren't that funny

in and of themselves, they've decided to hire a studio...

..round up an audience...

..and asked me to take charge.

Horizon on laughter, like you've never seen it before.

HE LAUGHS

APPLAUSE

Hello, everyone, I'm Jimmy Carr.

In case you were wondering, this is still Horizon,

the proper grown-up BBC science documentary series.

Don't worry, I'll be on my best behaviour.

There'll be none of my usual innuendo, because if this works out,

I might get to meet Professor Brian Cox,

and I can't tell you how much I love Cox.

LAUGHTER

Come on!

So, I've got some great news -

science has taken time out from giving your job to a robot,

designing GM crops and cloning designer babies

to investigate laughter.

Rest assured, I'm not in charge.

When it comes to the science stuff, we've called in the experts.

We've got a group of eminent laughter scientists -

yes, that is a real thing -

and they're here, poised to enlighten.

It's like Laboratoires Garnier back there.

-Hello, the scientists. ALL:

-Hi.

We've also visited scientists who make people laugh

and others who make animals laugh.

We've caused pain, scanned brains

and visited some of the least funny places on the planet,

all in a bid to get to the bottom of laughter.

And we've got a room full of unsuspecting volunteers,

who think they're just an audience.

AUDIENCE LAUGHS

And that was nervous laughter.

AUDIENCE LAUGHS LOUDLY

EB White once said analysing comedy is like dissecting a frog -

few people are interested and the frog dies.

But what did he know?

This is going to be the most fun science show

since the one where they let Stephen Hawking use

the Large Hadron Collider as a water slide.

LAUGHTER Right, let's crack on.

Probably a good idea to start with some classic jokes.

Two monkeys in a bath.

One says to the other, "Ooh-ooh-ooh, ah-ah-ah."

The other says, "Well, put the cold tap on, then."

How do you make a cat go woof?

Pour petrol on it and light it.

These are the clean ones.

I was walking with my wife when I saw six men kicking and punching

my mother-in-law. My wife said, "Aren't you going to help?"

I said, "No, six should be enough."

A policeman came to my front door and said,

"I'm sorry, sir, but it looks like your wife's been in an accident."

I said, "I know, but she's got a cracking personality."

Now, here's a question you never hear a stand-up comedian ask.

Why did you laugh at those jokes?

Does anyone have any ideas on why they laughed?

I hate cats.

"I hate cats" is a very good answer.

I'm sure that's not the case, though,

that's just another joke on top of that one, so...

-Any ideas on why you laughed?

-Nostalgia.

-Because it's funny.

Nostalgia is a very good one, yeah,

cos they're old classic school jokes,

and the familiarity of that.

That is kind of a...that's a reason sometimes. Any other...

-thoughts?

-Breaking the ice?

Well, I suppose it is, yeah, that social activity.

I think we're going to talk about that later on - that idea that

laughter as a kind of group activity.

Don't panic, we're going to explain all this.

This is Horizon, so let's throw some science at the problem.

University College London...

..boasting impressive neoclassical architecture

and a solid academic heritage.

And, more recently, it's gained a reputation as somewhere

where laughter is taken very seriously indeed.

THEY LAUGH

Today, Professor Sophie Scott...

..is gathering raw material for her research.

What we're just going to do is go through some videos

-and just really find some stuff that makes you laugh, OK?

-OK.

Cos the point of this is, I don't really care what it is,

I'd just like to collect some really nice laughter from you.

And to ensure a perfect recording...

..she's using UCL's anechoic chamber.

It just means no echo.

What we're doing here is we're recording somebody

laughing spontaneously.

Get nice and comfortable.

So, I'm playing her something, which we're both fairly confident

is going to make her laugh.

VOLUNTEER LAUGHS

I just got really interested that everything done on emotions

is negative, and it turned out that the psychologist Paul Ekman

had suggested that there might well be positive emotions,

which might actually be basic emotions.

And in fact he'd said they may well be primarily conveyed

with the voice, so I thought, "Brilliant, that's what I do".

Sophie discovered that laughter is something all humans understand,

regardless of location, culture or language.

VOLUNTEER LAUGHS

I think it's really important to study laughter because first of all,

it's a basic expression of emotion.

It's a non-verbal expression of emotion,

but it's one we drop into all the time.

VOLUNTEER LAUGHS LOUDLY

We drop into this old mammal vocal behaviour,

to do a lot of the emotional work of an interaction.

VOLUNTEER LAUGHS

Right, I found a really nice bit of laughter and then I lost it again,

so that's what I'm trying to do.

VOLUNTEER LAUGHTER CONTINUES

There we go. Wasn't that lovely?

I realise that being delighted by a spectrogram

is sort of niche interest.

Well, fascinating stuff. And she's here to talk about her research.

Ladies and gentlemen, please welcome to the studio

Professor Sophie Scott.

-Hello. Proper science.

-Proper science.

-Hello, Professor Sophie Scott, how are you?

-I'm fine, thank you.

OK, so, you're saying everyone laughs?

As far as we can tell,

when we have done some cross-cultural work on this,

wherever you go in the world, people recognise laughter.

Even if you go to a culture where people might not laugh in public,

cos maybe it's rude, they still recognise laughter,

and they will still do it in some places.

-Even like Inverness on a bank holiday Monday?

-Potentially!

Technically, I should be able to get laughs out of those people,

even if, in reality, not the case.

They might know it when they saw it happening,

if you made someone else laugh, they might know what's going on.

You're saying it's a universal across humanity?

We don't have the same sense of humour,

-but we all recognise laughter?

-Exactly.

Humour can be very, very widely varying

across different times and places.

Laughter, as a behaviour, stayed pretty constant.

-OK, can we demonstrate this?

-Yes. We've got an example of somebody

producing some positive expressions of emotion from...

He's from the Himba tribe in Namibia.

Hi, hi-hi!

Hi-hi!

Hi, hi, hi...

Any guesses?

Obviously, if you're watching in Namibia... I mean...

Couldn't be more bloody obvious, could it?

Any idea what emotion that was?

It looked to me like he was clapping backwards.

Cos it was kind of... It was a weird kind of...

So, what he was doing is expressing triumph.

So, the sort of... Imagine that you all really like football

and the football team that you like has just scored a goal.

-Make the sound.

-AUDIENCE CHEER

So, that's what you tend to find in the UK,

people making a triumphant noise sensibly, so like a whoo sound.

And that's not the noise the Himba make,

and it's not cross-culturally recognised.

Let's have another look at this guy.

-Hi, hi-hi!

-HE LAUGHS

AUDIENCE LAUGHS

OK, so at the end there, did we all get what was he doing?

Yeah.

So, that's uni...

That's in every culture around the world, the laugh is...

You'd be able to tell someone was laughing?

Yes, you would know what was happening.

The idea with basic expressions of emotion is that they reflect

something about our evolutionary history, we share them

with other mammals. Things like fear, anger, disgust, sadness.

You find those in other mammals.

So, anger in a dog's face isn't that different from anger

in a human face.

It's possible that we need to add laughter

to this set of basic emotions.

Right. So, not everyone laughs at the same things, obviously,

we all have a different sense of humour. Take a look.

Americans don't tend to really know that much about the world,

so they don't get other people so much.

At the moment, the in-thing is about quail birds.

Just someone that's a grown man, maybe acting like a child.

Excuse me. Too much gas.

Armenians are famous for having a good sense of humour, and...

Yeah.

Got a new car. They say she's probably got a quail farm.

What makes me laugh is cheeky banter.

Squirrels, cats, ravens eating chips.

I think the British humour is so sharp and so cutting.

Do you want to hear a joke about helium? Hee-hee-hee.

Our satire is more like a gentle satire.

In the Philippines, we make fun of dumb people.

It's like trying to explain what makes a man's heart beat

when he sees a blue-eyed blonde with amazing jugs.

If you're looking good, you've probably...

Got a few quail birds...in your purse!

British people are famous for self-laughing.

Jimmy Carr's one-liners.

He's my favourite comedian I know of.

"We in America, we wash hands."

And the attendant guy turns to him and says,

"You know we in Lithuania, we don't pee on our hands."

What do you do with a dead chemist?

You barium.

And you end up wanting to look like a quail

because you're worth a lot of money.

So, it's a pain au chocolat meeting a croissant and he's asking,

"Why are you so weird? Why do you have a moon shape?"

And the other one says, "What are you talking about?

"Because you have, like, shit all over your ass."

SHE SPEAKS FRENCH

So, laughter is universal but what we laugh at

is cultural and personal.

Sophie, everyone does it, everyone understands what it means,

but what actually is laughter?

Laughter's more like a different way of breathing

than it as anything else. So, what we are all doing right now,

hopefully, is using the intercostal muscles,

the muscles between our ribs, to get air in and out of our bodies.

It's called metabolic breathing. Exactly.

You breathe in, you breathe out.

Air's being drawn in and then squeezed back out again.

-I'm good at this.

-So, were I to look at your chest wall moving...

Well, that feels weird.

I've over-thought it.

-Go on. My chest wall is moving in and out...

-You keep going with that.

You'd see this almost sinusoidal movement, this very smooth movement.

You start doing it the minute you're born,

that's it the whole rest of your life.

When we start laughing, those same muscles start to contract.

They're really large deflections, just squeezing air out of you,

and that's basically all laughter is.

It's an extremely primitive way of making a sound.

Ultimately, if you couldn't stop laughing, it'd kill you.

-Yeah.

-Basically, I'm a deadly weapon, is what you're saying.

You definitely are. It's just squeezing air out of you,

it stops you breathing, it stops you talking, it's trying to kill you.

-And we've rigged some people up, so we can show this.

-Exactly.

And what we'll notice is, hopefully, if you can make them laugh,

that both the very fine movement you get during talking

and the smooth movement that you get during breathing, should go away.

And instead, what we get is just these big zigzags

as air's just being squeezed out of you.

OK, so, are we looking at them breathing first?

Well, hopefully they're already breathing.

-OK, so are they breathing?

-Hopefully!

-I can see them breathing.

-They're breathing now and you're happy?

Sinead, your PhD assistant... Hi, Sinead. How are you?

So, you're saying those two ladies are alive?

-Fantastic.

-This is incredible science.

-So, I've got to try and make them laugh now?

-Please.

Right, I'll do some jokes from over here.

We've got a performance area with... Yay, everyone.

-AUDIENCE:

-Yay!

-OK.

I look like this, obviously, because my dad is Irish and my mum is...

Roger Federer.

LAUGHTER

I feel like you're laughing at me, not with me, there.

A nurse finds a rectal thermometer in her pocket and thinks,

"Some arsehole's got my pen."

I got talking to a North African girl recently

in her native language, for hours.

We just...clicked.

That's enough of that.

We should be able to see some sort of difference then, so...

-Did you see anything there? Oh.

-Oh, look at that.

Can you see at the bottom there, she's breathing,

and then you're really making her laugh. Can you see the big zigzags?

-Then breath, breath, breath and then zigzags again.

-Hang on,

I'm going over to have a look. I'm going to use

one of these technical fingers. So, that was the laugh?

-Yes, that's the laugh there.

-That's a pretty big laugh.

That's pretty big, and there's a big...

If you look at the top as well, the person at the top is also laughing.

Yeah, but she wasn't really into it. LAUGHTER

-You were funny earlier.

-It feels like, if I was...

If I'm going to work as an assassin,

and that is ultimately the goal of this show,

I would not be able to kill the lady in the yellow,

but the lady in the orange, I think...

-Yeah.

-You better watch yourself, love.

OK, so, supplemental to that,

if you were to make someone laugh uncontrollably,

-could it be a dangerous thing?

-Well, it can be.

I mean, it literally is stopping you from breathing.

It's just squeezing air out of you

and it's stopping you doing anything else.

And there's even a postural reflex

that means that we're all sitting in our chairs,

we don't just slump to the ground.

So even when your muscles aren't working,

they're holding you in place, and that is suppressed

when you start laughing. That's why you become weak and floppy

when you're laughing, and that, inevitably, at some point

you can become helpless with laughter, at which point,

if a tiger came in or something, there would be a brief window

when you wouldn't be able to do much about it.

Well, my mother, weirdly, had a very odd laugh.

She had a laugh where she made no noise at all

-and lost muscular control.

-Right.

So she would just literally, kind of...

And then, with her last bit of energy she would go,

"Stop, just stop," and obviously you would never stop.

I think it's part of the reason I got into doing this for a living,

because it was the most fun thing in the world to...

Oh, my mum has melted. Genius.

So, laughter's different, physiologically, to normal speech.

If you couldn't stop laughing, it could genuinely harm you.

I believe we have some MRI scans.

-We do. We're going to start...

-Excellent.

-Science in...

-I'm sorry, I didn't have time to get to the doctor's,

so we're going to quickly go through these now,

see if I'm going to make it. So, what are we looking at?

What we're looking at first is...

We're running the MRI machine like a video camera,

so you're literally taking a movie of somebody speaking here.

What she's doing is she is talking her way through some nursery rhymes

and you can see everything that's happening during speech -

very complex movements of the tongue,

you've got the jaw moving up and down, the lips, the soft palate,

the bit at the back of your nose, the larynx,

the voice box is moving up and down.

So, that's speech -

very complex, nothing like that out there in nature.

And then if we move on to the next one,

which should be somebody laughing. It's the same person laughing.

We made her laugh in the scanner,

and if you look, none of that is happening, basically.

She's moving up and down a lot cos her ribcage is moving.

The tongue is staying in the bottom of the mouth,

and if you've ever laughed until the back of your throat hurts,

you can see why that's happening there, cos actually

you can see she's squeezing the tongue right back up

against the pharynx,

so you're squeezing all that air out through an even narrower pipe.

I'm sorry, what did you nail her to, to get this to happen?

Who doesn't move their head even slightly when they laugh?

She's in something that looks disturbingly like

a kind of sarcophagus.

She's in something that's holding her head and shoulders in position

-so we can image all this bit here.

-Where is she now?

She's alive, she's well, she escaped, she made it through.

She escaped? LAUGHTER

OK, so laughter is more like an animal call than speaking -

primal and contagious. OK, I get that.

So, that's what laughter is, but what exactly is it for?

Well, thankfully, one scientist has taken time off

from developing jet boots, to find out.

Oxford University boasts some of the prettiest academic buildings

in the world.

These grand palaces of learning are largely the preserve

of the humanities.

But because Professor Robin Dunbar is a scientist,

he's forced to work here...

..in this architectural abomination.

Out of the sight of tourists and university website photographers.

Here, geographically and aesthetically isolated,

Dunbar causes people pain.

Because he claims it throws light on why we laugh.

So, what we're doing here is we're looking to see whether

pain threshold increases after you've laughed.

First, the baseline measurement.

OK. Now!

Stop.

Stop.

We have a winner.

Stop.

Good work.

And now the fun part.

Professor Dunbar is an experimental psychologist

and an evolutionary biologist...

..which is quite a mouthful.

But what it means is he's able to both formulate ideas

about our species development and also test them in a lab.

And one of his main ideas is about grooming.

Monkeys and apes create their friendships,

their relationships with each other and thereby bond their social groups

by grooming, social grooming - grooming each other.

It turns out that that light stroking

triggers an endorphin response in the brain.

The problem with grooming is it's a one-on-one activity -

you can only groom one individual at a time.

So, the problem is how to sort of groom

with several people simultaneously.

Robin's theory holds that laughter is effectively remote tickling,

producing the same chemical high.

And if he's right, the laughing volunteers in the lab

will now be flushed with pain-beating endorphins...

..and they'll beat their previous times

in the wall-sit test.

OK?

Go.

Stop.

Stop.

Stop.

Stop.

It's direct evidence that laughter does produce endorphins.

Yes, you'd normally expect something between, on average, I don't know,

about five seconds and anything up to 20 seconds increase in time,

and that's pretty much what we have here.

All statistically significant.

So, laughter can help you get through a painful experience,

which is why you hear so much of it at my shows.

Ladies and gentlemen, please welcome my next guest,

evil genius, Professor Robin Dunbar.

Thanks so much for coming. Take a seat.

-Hi.

-Now, you know Sophie, right?

-Yep.

Of course, all scientists know each other.

We do, it's a small community.

So, how did grooming begat laughter?

Well, essentially, the real problem is that we needed to

be able to groom, if you like, with more individuals simultaneously

in order to be able to have much bigger groups

than is typical of monkeys and apes.

So, how many in a typical group of monkeys and apes?

The most social species, baboons, chimpanzees, something like that,

about 50 is the typical group size.

And what do they call that, Professor Dunbar?

-Is it called the Dunbar Number?

-Ah.

What's the Dunbar Number?

Cos you went ahead and named something after yourself...

LAUGHTER

..which is, I mean, ego-wise, pretty terrific.

-Do they pay you money to say these things?

-They do, yeah.

No, Dunbar's Number is technically

the number of the size of human groups,

or the number of friends and family that you have, and that's 150,

that's three times bigger than the kind of typical biggest groups

you get in monkeys and apes.

So, that's because they can individually groom

other monkeys and apes up to about 50,

and then they break off and start another group.

Essentially, that's what ends up happening,

because if you don't bond with the individuals

you are part of the group with, the group will gradually split up and...

..into two separate groups, and that happens with us.

I mean, if we don't engage constantly with our friends

and relations and so on,

gradually those relationships just die quietly away.

So we have to keep this, kind of what's effectively

a form of grooming, going.

And we do it by grooming in the way that monkeys and apes do -

with the patting and the touch on the shoulder and the cuddling

and all that kind of stuff.

We do all that but it's a one-on-one thing

and you can't do it with more than one person at once.

Oh, you can. HE LAUGHS

Welcome to showbusiness, Professor Dunbar.

But no, I take your point there.

So the idea of remote tickling, I find very pleasing. The idea that...

I've kind of, I like to think of myself as a drug dealer,

but the drug that I'm dealing is endorphins,

and you've already got the drugs on you

and I'm just bringing the kind of release mechanism

-that saves on the transport costs.

-It does.

But, I mean, remember endorphins are related to morphine

and the opiates in general,

and that's why you get this kind of light-headed kind of relaxed feeling

from them, they give you an opiate high.

-So, you're saying we should try drugs?

-Yeah, um...

You spend all day...

But the difference with endorphins is you don't get addicted to them

in the way that you do the normal kind of morphine opiate-type drugs.

Chemically, they're just slightly different,

so you don't suffer that kind of physiological addiction.

But the point is that laughter triggers that system,

and then allows you in effect to groom with several other people

at the same time,

so it then becomes a much more efficient use of time.

So, we can use the same amount of social time during the day,

but groom with many more people.

-Fantastic, so that allows us to have bigger groups...

-Yeah.

-..and therefore to specialise...

-Well, then you can have

all the things that emerged out of our history, as it were,

you know, sort of...

You can have culture because you've got many more minds

to create novel ideas - write books, tell jokes...

Excellent. So, laughter is remote grooming, it's a social activity,

and you're actually 30 times more likely to laugh

when you're with other people.

It's an intensely social activity, yes.

I mean, it's this extraordinary contagion effect of it.

So you could tell a joke in some language that I don't understand

and everybody else laughs, I cannot help but laugh with you.

I simply don't know why I'm laughing, but I have to do it.

I weirdly have a thing in my relationship where we watch

certain shows together that I'd never dream of watching

without the other half.

And there's a thing about if I do watch something on my own

on the iPlayer on the computer, you find yourself going,

-"Oh, that was really funny," but I don't laugh.

-Yeah.

-Mmm-hmm.

But if I'm with the other half at home,

we just really fall about laughing, and it's a lovely...

I don't know, it's a very comforting sound, hearing your partner laugh.

OK, so we've put the theory to the test.

We've isolated one of our audience members.

Hello, Sherry.

-Hi, Jimmy.

-Hello.

So, we've stuck you in isolation to watch the programme.

-Are you enjoying it?

-Yes.

Good. LAUGHTER

Well, it's been lovely chatting.

So, you're on your own, watching the show.

So we're going to have a look at your reaction

to me telling jokes earlier, to see whether you laughed on your own.

Let's have a look.

..designing GM crops and cloning designer babies

to investigate laughter.

AUDIENCE LAUGHS

..thermometer in her pocket and thinks...

"some arsehole's got my pen."

AUDIENCE LAUGHS

So, Sherry, my question to you, why are you being a dick about it?

I mean, it's a really good example, though,

of you're watching the show and you seem pretty engaged, but...

-You're not laughing.

-I am laughing...inside.

You're laughing on the inside?

No, I mean that's... That's fair enough.

And then we locked you in a room so you're...

-You're not well pre-disposed to...

-I just feel very much at home now,

cos this is something that I do just at home by myself,

watching you.

LAUGHTER

Well, you made this weird, Sherry.

What I do on Snapchat is very much my own business.

That's a... We'll get you to come into the studio

for the rest of the show, because we've done this bit.

But I think that really demonstrates that idea of the social activity,

and I feel like, as my job being a stand-up,

people come out to shows partly because they think the person

onstage is funny, but partly because they want to laugh

with their partner, with their friends.

They sort of organically know that they enjoy that experience

of being together with a room full of people

that all have the same sense of humour as well.

But what's kind of interesting, actually,

if you looked round the room when you could hear laughter,

it's not everybody that's laughing here.

And in fact one of the weird things is,

if you look at people in pubs laughing,

you almost never get more than three people laughing together.

But actually, if you think about it, that already makes laughter

three times more efficient than grooming,

for triggering the endorphin system,

because when you groom, it's only the other person that gets the hit.

When you laugh, you as the joke-teller, laugh as well.

What you're saying there is when you tell a joke in a pub,

-three people laugh.

-No, two.

-And you laugh, yeah.

-I'm a pro, my friend.

I can get the whole room.

But most of the time, if you look,

you've got...it's like a kind of Mexican wave effect.

You've got little pockets laughing.

It sounds like a lot of people laughing, but if you actually look,

it's sort of going round in little waves.

I often find that with certain types of jokes as well,

-you sort of have a ripple effect of...

-Yeah.

..people are laughing and then they're laughing

-at someone else laughing...

-And also a good laugher to trigger it.

If you've got a good laugher, who laughs at everything,

it will trigger the waves of laughter round the room.

Oh, I work with several professionals.

So, laughter is a group activity but it's also linked to grooming

in that it strengthens relationships.

Couples that laugh together, stay together - certainly makes sense.

There must be something that's stopping the Chuckle Brothers

from killing each other. Take a look.

At the University of North Carolina, it's graduation time.

Students may be leaving, but for staff like Sara Algoe,

the work goes on.

I was really interested in laughter

because it seems like the kind of behaviour that happens

really frequently and is so relevant to the way

that people think about

their best relationships, and yet there is very little research on it.

In another disproportionately ugly psychology department...

..on an otherwise very pretty campus...

..Sarah's PhD student Laura Kurtz is running an experiment

to try to put some numbers on the idea that people who laugh together

stay together.

For this first interaction,

we're interested in hearing about the first time you met.

What was the first thing you said to me?

"I'm going to marry you one day," and you said, "No".

What I really love about this research is that it's so intuitive,

so everyone can think of a time when they laughed with somebody.

So you can think of probably a time in the past day or two,

when you laughed with your friend or your romantic partner,

but we can also think of a time when we laughed at something

but the person next to us did not laugh,

and suddenly in that moment...

..what could have potentially been a really powerful thing,

a powerful behaviour, all of a sudden takes a nosedive.

After filling out a questionnaire that will tell the researchers

how happy each of them is in their relationship,

couples are recorded talking about the first time they met.

-Yeah.

-I thought that was really cute.

It was cute. I was most probably lying about it, but...

After the couples left the lab,

we had a coder go back through all of those

video-recorded interactions,

coding for every start and stop time stamp of a laugh.

-You were expecting me to be boring?

-Well, you were a librarian.

-You read my e-mails.

-Yeah, but...

Yeah, but it was still a librarian. I'm sorry!

HE LAUGHS

This is the way that we're able to quantify how much time

they're spending actually laughing at exactly the same time,

versus each person laughing separately.

Oh, my gosh.

So, what we found was that moments of shared laughter

actually are predictive of greater closeness

and feeling more supported by one's partner.

So, those couples who laughed more tended to report more support

and also generally feeling closer to their partner.

-I had my eye on somebody else at that time.

-Oh, really?

-Yes, I did.

Oh, I didn't know that.

HE LAUGHS

So, the message is pretty clear.

Folklore has it that laughter may well ignite romantic attachment...

..but science says, if you want to make it past infatuation...

SHE GIGGLES ..and enjoy a long and happy

relationship, you better carry on laughing.

That was an interesting film.

Finally, what every couple watching at home wants to see -

a scientific way of determining exactly how doomed

their relationship is.

Well done, science.

So, do couples that laugh together really stay together?

One of the important things that kind of comes out of that, actually,

I think, is that laughing together actually ramps up

the endorphin production in the brain,

it actually doubles it, in effect.

We don't understand why, we have no idea why,

but it's almost as though the system is designed to give you this

-sort of real boost.

-To encourage you to laugh with other people?

-Yeah, yeah.

-Yeah, buy two tickets.

So, its sort of functionality is it releases endorphins

and that feels good, but also it's a form of communication

-in and of itself?

-Yeah, and it lets you, together,

regulate your emotions, cos it only works if both of you do it.

If one person's going, "Ha-ha, it was funny,"

and the other person's going, "No, it was quite a serious problem,"

they're not... It's not going to work.

So, there's two different types of laughter -

there's laughter you do when you hear a joke

and there's social laughter,

laughter that peppers our communications.

There's real laughter, at stuff we find funny,

and there's posed laughter, which serves a vital social function.

Sophie, you've done work on this, right?

Yes, we've been looking at it in quite a lot of detail,

because it does seem to be, essentially,

two entirely different kinds of laughter that we use.

Posed laughter - that sounds like... Is that someone going, "Ha-ha...ha"?

-Well, it could be. It's...

-LAUGHTER

It sounds really bad, sort of...

It was like you bounced it straight back.

-SHE LAUGHS That was real.

-Yeah.

It sounds awful to say, "Who would want fake laughter?

"I don't want you putting that on," but actually most of the laughter

you encounter in conversations is so well-coordinated

with the conversation that you're having,

that it has to be part of your voluntary communication system.

If you look at people laughing when they're having conversational...

and they're talking to each other, they don't laugh randomly,

they laugh at the ends of sentences, and then you start again

and maybe somebody else picks up or you carry on.

OK, well, shall we play in some real and some posed laughter

and see if people can differentiate?

OK, so... Well, take it away, Sophie.

OK, we've got somebody laughing here. They may look familiar.

OK, what do you think, audience?

-AUDIENCE:

-Real.

-Real.

Does everyone think it's real? Does anyone think it's posed?

Posed.

Who thinks it's posed?

And you're saying that only a psychopath would do that, yeah?

And they need to be institutionalised now.

We'd need more than N=1 for data, but it's a worrying start.

I'm fairly certain that one's real cos I start crying when I laugh.

TYPEWRITER PINGS

OK, let's have an old-style typewriter write it in green.

If that doesn't say Horizon, I don't know what...

That's science, my friend.

That's a real laugh. See if we can try another one.

OK, so real or posed?

-AUDIENCE:

-Posed.

-Posed.

-And does anyone think it's real?

Genuinely, if anyone thought... It's fine.

I can see maybe someone does and then they're going,

"I'd better not say."

Posed laughs, they've got their own thing going on.

They're not just weak versions of real laughs.

So, you quite often get nasality, a kind of heh-heh-heh quality

to posed laughter that you never, ever find in spontaneous laughter,

in fact, you couldn't do that when you were laughing helplessly.

It's like we're marking it, we're showing it for what it is.

I'm giving you my laughter. I'm voluntarily giving you

this laughter.

So we're going out of our way, possibly,

to actually show people that this is a voluntary behaviour.

OK, so we humans are not the only mammals that laugh.

Now, can any other animal fake laugh?

In chimpanzees, you do seem to find something that looks like

a difference between a spontaneous laugh and a posed laugh.

So, chimps laugh differently if they are being tickled

than if they're trying to make play last longer, so that's...

What if they're filming something for PG Tips?

Cos often they've heard those jokes before.

They're being polite.

Yeah, so can we demonstrate that humans are the only ones

that really know how to pose laughter?

We're going to try this.

I think we have a volunteer over there.

Yes, you're our volunteer, come up.

-What's your name, sir?

-Phil.

-Hello, Phil, how are you?

-I'm good, thank you.

I believe we need you to regress maybe ten million years, is it?

How far are we going back?

We're sending him back to walk on all fours.

I'll cede knowledge here to Robin, but we need a quadruped.

Just here is fine. I don't know if you...

Yeah, go ahead, dude.

-There we go.

-Ah, you left your dignity at the table.

LAUGHTER

"Yeah, Mum, it's great news, I'm going to be on Horizon, but..."

As soon as you start having to do this,

you're having to use your four limbs, like all other mammals,

to support your weight, and that means you can't use them

for all that fine stuff we're doing when we're using our voice

voluntarily - we're talking, we're doing social laughter.

So, this is a slightly strange way of demonstrating

how weirdly dependent we are on actually the fact that we're walking

upright for a lot of the stuff we can do with our voices.

So, could you fake a laugh now in that position, is that...?

HE LAUGHS AND SPLUTTERS

AUDIENCE LAUGH

No, not really.

I mean, definitively not.

And we need him there for the rest of the show.

It's a shame, really. He was probably quite enjoying it.

See, now... So you're saying the reason we can fake laughter

-is cos we're bipeds...

-Bipeds, yeah.

-..and if we had to walk on

all fours, as this man has to... LAUGHTER

Contractually obliged to walk like this for the rest of the show.

I mean...

Probably a kinder sort of host would've got you to stand up

by now, but...

Go on, you'd better stand up. Our volunteer, everyone.

Thank you very much. Great demonstration. It worked.

So that kind of tightness in speech

and the idea that you couldn't really sort of relax and pose

and enjoy it as much if you're kind of, yeah.

Absolutely. I mean, if you stress it even more, if you've got...

you know, you try and take all your weight onto your arms,

like doing pull-ups, then you just can't talk, you can't laugh,

you can't do anything.

So, I believe we have some brain scans of real and posed laughter.

-We do.

-Let's have a look at some brain scans, everyone.

So, what we did here is we played people some sounds

and buried in there we had real laughs and posed laughs.

We didn't tell people anything about what they were going to hear,

and we didn't tell them anything about laughter,

and what we found is that the brain still cares.

You get different patterns of activation when you hear real laughs

versus posed laughs. So, for example, these regions here in blue,

they're showing you areas of activation in the auditory cortices,

just here above your ears,

and that is greater for the real laughs

than the posed laughs, significantly greater.

And what that seems to be because is when you hear real laughter,

you hear all these sounds you do not hear in any other context.

It's completely sort of unambiguous.

In contrast, we all see all these regions in pink,

which are significantly more active to the posed laughter,

and this is a bit surprising to us, cos we were expecting the brain

to care very much about posed laughter as it's a bit, you know,

it's not spontaneous, it's not real,

but in fact it gives you more activation.

And the activation it's giving you is not in auditory parts

of the brain, it's in the parts of the brain you would expect to find

if you were to sit down and deliberately think about

what somebody else is thinking. So, I think what this speaks to

is the fact that when you hear somebody producing

a clearly posed laugh - a-ha-ha-ha -

there is some reason why that human being has produced that behaviour

and you are trying to work it out.

Are they laughing cos they're in pain? Cos they're embarrassed?

Cos they like you? Cos they want you to like them?

There's a reason why they're doing it

and that's why you're dwelling on it,

even if you're having your brain scanned and it sounds like

it's got nothing to do with you.

It's such an important social signal.

So, what happens if someone doesn't have the ability

to tell the difference?

Well, this is a very interesting question

that we're trying to go into at the moment.

So we've been doing some work, looking at how laughter is perceived

by people with different kinds of problems.

We've done some work in collaboration with colleagues at UCL

looking at teenagers who have conduct disorders,

and what you find is that, although the can behaviourally

tell the difference between real and posed laughter,

what they can't do, what they don't seem to do,

is to show this contagion.

They don't show this behavioural reaction,

so they don't want to join in when they hear the laughter

and their brains respond differently to the laughter.

So there does seem to be something genuinely different happening

when people process laughter

who are at risk of having more serious problems,

in terms of their social interactions.

Wow, interesting.

OK, so we've found out what laughter is

and we know why we enjoy doing it.

Final question - why do we laugh when we find things funny?

Well, if only someone had a grand, unifying theory of comedy.

Bit of luck - they do.

Nestling beneath America's mighty Rocky Mountains

is the University of Colorado at Boulder.

One of its many architecturally unambitious buildings contains a man

who claims to have discovered why we find things funny.

His name is Professor Peter McGraw.

We're at the University of Colorado, Boulder, at the lead school

and we're headed to the human research lab

which we affectionately refer to as HuRL.

Unfortunately, even the science of humour

has a kind of boring backdrop.

I wish I could tell you that in a room over here

we had a whole bunch of rubber chickens and whoopee cushions

that we need to just pull out for our studies.

Yet, despite, or maybe because of, this anodyne beige interior,

it's here that Professor McGraw has devised

his grand, unified theory of comedy.

Humour deconstructed, laid bare and explained.

So, most things in the world are OK.

They're benign.

They're not funny.

And then, of course, there's a certain set of things in the world,

you know, whether it be...

..bad traffic or an annoying co-worker...

..a tragedy...

..that's a violation.

This creates a boring reaction, this creates a negative reaction.

But when you bring these two appraisals together

and you create a benign violation,

this sort of sweet spot that sits between being bored

and being offended,

and you have this moment of levity, this uplifting feeling of amusement,

you say, "Hey, that's funny,"

and then you laugh to communicate to others

that this violation is actually benign.

Word of the theory's power has spread.

Local comedian Nathan Lund is keen to see

if benign violation theory can rescue one of his jokes

that even he thinks might be too offensive.

-What's the joke?

-Saying that I've been working on

a type of clear mayonnaise

called I Can't believe It's Not Cum, but...

But that's...

-That's kind of a violation...

-That goes too far.

-Yeah, that one goes too far, right?

-It might.

-I don't know yet.

-People...

-When it gets that "Uuggh."

I also wonder if it's just too much, like, to go from,

you know, clear mustard, that's pretty harmless,

and then all of a sudden I'm bringing up...

You know.

After much debate, Professor McGraw and Nathan Lund come up with

a solution they hope moves the joke away from violation

just far enough to be funny.

Happy to have him here.

Please give a nice Boulder Comedy Show welcome

to Nathan Lund, everybody.

Now it's crunch time for clear mayonnaise,

for Nathan and for benign violation theory.

I don't have a lot of money, I'm hoping to make some money this year

with a new product I have coming out.

Clear mustard is what I've invented.

I'm calling it Ham Sanitizer.

LAUGHTER

So, if you see Ham Sanitizer in stores, that's me, give it a shot.

But I'm also working on a follow-up condiment - clear mayonnaise,

which I'm calling I Can't believe It's Not Semen.

-LAUGHTER

-So, if you see...

If you see that, that means people have been buying Ham Sanitizer,

if I can follow it up with more clear condiments.

So, do I have to explain all forms of comedy

for this theory to be right?

No.

I just have to be able to explain comedy better

than the other humour theories.

And so, in many ways, it's kind of a horse race

and I think I have a pretty fast horse.

APPLAUSE

Well, freshly arrived from Colorado in a matter transporter

that we'll be looking at in next week's Horizon,

ladies and gentlemen, please welcome Professor Peter McGraw.

APPLAUSE

Thank you for coming.

Come in, take a seat.

So, you think you have a pretty fast horse,

you think your theory is pretty good on comedy.

I mean, there's not a lot of good competition, so...

Well, there's three main theories on comedy,

-so let's go through those first.

-Sure, sure.

So, these are, these theories go back 2,500 years

to Plato and Aristotle.

So, Robin will remember some of them.

LAUGHTER

Go on. So, the first theory...

..is superiority theory.

And this is the notion that comedy is a game -

there's a winner, there's a loser -

and we laugh at other people's follies.

-OK, excellent, so that's the first theory.

-First theory.

-Superiority.

And then there's release theory or relief theory.

Er, Freud gets a lot of the credit for this.

And the notion is that we laugh at things that kind of release

these sort of sexual and aggressive tendencies

that we sort of hide away,

that are part of our personality that are not supposed to come out,

and so comedy is a safe way for these things to come out.

OK, and the third theory?

Is incongruity theory.

-Which is the big...

-It's the big one, it's the 800 pound gorilla.

It's the one that people sort of spontaneously come up with

when you ask them what makes things funny,

and it takes various forms but the most common

is sort of a mismatch of expectations and reality.

So you expect one thing and you get something else,

and that is supposed to be delighting.

OK, so those are the three main theories in comedy,

and had been for a very long time.

-Yes.

-No-one's really given it much thought beyond that.

So your theory is, again, benign violation.

That's right, yeah.

So, the theory takes into account that many of the things

that we laugh at kind of have a dark side,

so that's acknowledged in superiority theory,

it's acknowledged in relief theory.

That is that there's something wrong, there's something amiss,

there's something threatening about that situation.

But of course the things that are wrong or amiss and threatening,

they don't make us laugh, they make us cry,

they disgust us, they offend us.

And so you have this negative arousal

that comes from that dark side,

and then it flips and then you delight

and you have this positively arousing feeling, and then...

I like to believe that laughter is that signal that this situation

that seems wrong is actually OK.

I mean, the thing I love about your theory

is the idea that everyone has a different Venn diagram.

-Yes.

-Everyone's drawn it very differently.

So something that I might find...

I might say, "Well, that isn't a violation to me,

"I'm happy to laugh about that,"

someone else might go, "Not on the BBC, thank you."

And someone else might go, "You gotta give me more."

The things that are wrong, and the things that are OK in the world

change over time.

So you listen back to old comedy

and sometimes it's horribly offensive and bigoted now,

from our perspective,

and sometimes it's totally boring and confusing,

and it's because the world has changed.

And so, in many ways,

good comedy really reflects the values of a society

and the moral norms and the beliefs in a society,

and those are constantly in flux.

So, it's not just the individuals that move

those kind of Venn diagrams of, you know, where that line is,

it's a society as a whole that moves them

and different nations have them in different places as well, yeah.

Yes. Every so often you find something that lasts.

I mean, it still won't last forever,

but my son is very keen on listening to

very old Tony Hancock radio programmes,

and it's surprising how much of that has lasted,

probably because it was hugely influential.

It was basically you could draw a line straight from that to Seinfeld,

and it's quite interesting how every so often you run across something

that's almost jarringly out of place.

It's very interesting, from my perspective,

the kind of comedy that I do,

the idea that no-one's ever laughed at an offensive joke,

because, by dint of laughing, they're saying that,

"No, this isn't a violation to me, this is all fine."

-Mm-hmm.

-We can laugh about anything.

It's not that it's completely fine, right?

That's the thing that's so difficult about it all.

The things that are completely fine

is like you listening to me, not very funny.

Right? And so, there has to be something edgy that plays that role.

-This guy.

-This guy right here.

-I think... I really like the theory.

I mean, I really feel like it makes sense to me

in a way that the others don't.

But I'd be very interested to know what Sophie and Robin make of this.

No pressure.

Well, I was going to say, actually, this is kind of interesting because,

if you look at the origins of laughter as we have it in humans,

it actually comes from the play vocalisation in monkeys and apes,

and what that basically is is a comment on what I'm doing now.

When I bite you, don't take it seriously.

So, it's doing exactly this,

it's just saying, "Look, it may look aggressive, but actually it's not."

And I think it's... The thing I find interesting,

and you mentioned it in the film,

is that people are kind of appraising the situation,

they're coming to a decision about it.

And there is some very interesting data

showing that people will rate jokes as being funnier

if they think they've been told by a comedian

than if they think they've been told by somebody who's famous but not...

does not have that role.

So, if somebody thinks a joke's been told by Jimmy Carr,

they'll rate it as more amusing

than if they think it's been told by Jamie Oliver,

and that does suggest that people aren't just...

Their appraisal is including the person who is producing it.

And I think that kind of might speak in, socially,

to the kind of the people who you will and won't let make you laugh.

You know, you are going to laugh more with people you know and like,

and you may read their intentions as being more benign.

I think that's very true of political correctness as well,

cos I often get called out for saying, "Oh, you're not very politically correct,"

but I always think I am within context.

Onstage, in front of 1,000 people, telling jokes,

political correctness doesn't really belong in that space for me.

So, as soon as whenever you get called out by the press

as a comedian and they say, "Ban this filth,"

it tends to be that they've taken it from a comedy show,

put it on the front of the Daily Mail

and gone, "This is disgraceful!"

Well, you shouldn't have printed it, then.

OK, how about some good news?

Take a look.

When this man started his career,

his ideas were considered

even more avant-garde than the buildings he now inhabits.

Today, however, he's established a global reputation

as one of the world's leading neurobiologists.

And all because he discovered he could hear rats squeak.

RATS SQUEAK

You're hearing the squeaking through the ultrasound detector.

If we didn't have these detectors on,

you would not be hearing anything.

Once he'd heard the squeaks,

Panksepp was determined to discover what they might mean.

One morning I woke up and said,

"What if that is laughter?

And I said, "Well, then you should be able to tickle animals."

And we tickled the first rat, and it chirped like crazy.

The second rat...

As a matter of fact,

every rat except some really neurotic ones have chirped.

To the casual observer,

it might look like the rats aren't laughing at all,

that their tiny chirps are in fact cries for help.

But not only are the vocalisations identical

to the noises made in play,

the rats' behaviour tells its own story.

They are following my hand

because it's a hand that has brought them great joy.

HE CHUCKLES

Oh, he just bit me.

-HE LAUGHS

-But he didn't hurt me.

So that's their way of indicating, "Come on, let's play." Ooh!

-I love rats.

-HE LAUGHS

They're such fun animals, so smart and so emotional.

As far as we can tell, we've got the same basic emotions as rats.

But Panksepp's idea, that rats have emotions,

did little to endear him to his colleagues.

People say you've been giving human qualities to animals -

anthropomorphism -

and I tell them I have not been doing anything of the sort.

I am doing zoomorphism.

I am trying to understand the animal mind

as a way to illuminate the human mind.

The critics argue that our complex brains are so different

to rats' brains that any comparison is meaningless.

But the reality is emotions occur in the evolutionary ancient brain,

the part we share with all mammals, including rats.

And we know that animals that have been bred for high laughter

are resistant to depression.

That means they have chemistries that protect them

against the vicissitudes of life.

Animals that have been bred for lower laughter

are susceptible to depression.

If we understand animal emotional processes

at the fundamental instinctual level,

I think we will have a science of human basic emotions,

and that's very valuable for understanding ourselves

and having a more sophisticated biological psychiatry.

Panksepp's idea was to use the rats' laughter to identify

the precise area in the ancient brain involved in happiness,

and in so doing to identify the neurochemistry responsible.

Using that approach, a group from Northwestern University in Chicago

identified a happiness neurotransmitter.

They call it GLX-13.

Catchy.

And they've also developed a drug to stimulate its production.

In 2013, they started human clinical trials.

The results were so impressive,

that two years later it was bought by a drugs company for 560 million.

Surprising as it is,

£560 million is not bad for buying the rights

to the most powerful item on the horizon.

It's a new way of treating depression -

an antidepressant that, instead of reducing sadness,

promotes happiness.

It's an approach that shows great promise,

and all this from tickling rats.

Rat laughter forces you to think about the molecules of social joy,

so, you know, I am pleased and surprised in retrospect

that we got that far.

And, you know, it's one of the wonderful things of science -

there's always surprises.

So, that's me out of a job.

Comedy in pill form - I suppose it had to happen sometime.

We had a good run. LAUGHTER

So, back to our questions - what is laughter?

Why do we laugh? And what has it got to do with comedy?

-I think we've answered it, haven't we?

-Yeah.

Laughter's a social emotion.

Social activity,

pre-language vocalisation.

OK. Why do we laugh?

Originally it really is designed to allow us to bond with each other,

but actually the endorphins that trigger out

in effect tune the immune system.

So they actually do make you healthier.

But it's very ancient, it is,

I mean, it predates language

probably by about a million and a half years, I would say.

Wow. OK. And what's it got to do with comedy?

Well, comedy fundamentally is about pointing out

what's wrong with the world

and doing it in a way that is acceptable to the audience,

so creating benign violations and delighting others.

Here's a question for all three of you.

Could it be said that laughter makes us human?

No.

-I would say so.

-I don't think so.

-It's just too...

-OK, so Robin's my favourite.

-LAUGHTER

-I get the free tickets to his shows.

I'd like to thank Robin and the other two guests... Meh.

So, you think it...?

Well, in the sense that it does mark a key boundary point

from which everything else spins.

And of course the big thing about laughter is this breath control

and all this sort of control of the musculature,

the intercostal muscles in the chest wall,

and without that, language couldn't have evolved.

I mean, we've literally nailed this episode of Horizon.

LAUGHTER I'd like to thank our guests -

Sophie Scott, Robin Dunbar and Peter McGraw,

and thank you all for laughing.

APPLAUSE