Are You Thinking What I'm Thinking? Royal Institution Christmas Lectures

I've got to pay the director and I've only got £5. Can you help me?

Yeah. You just got to do this.

Fold it once like so, twice like that.

-Three times, just squeeze it.

-Yup.

-Give it a magic blow.

And your fiver should look more like a tenner.

-That works.

-That'll cover his expenses. Thanks very much.

Watch this lecture and I'll explain how Billy does her magic.

APPLAUSE

Welcome to the 2011 Royal Institution Christmas Lectures.

I'm Bruce Hood and I'm about to amaze you with some mind-reading.

I don't need a brain scanner to do this - I'm going to use

my own mind to read yours!

I've got some playing cards here.

I'm going to put them out on the table. Let's see...yes, OK.

Now, I want you to select one of the cards.

But I'm going to read your mind, I'm going to influence your mind.

So, choose a card, and concentrate on it. I'm trying to read your mind.

Now I'm controlling your mind. Focus on the card.

Have you got it? Have you got it in your mind? Hold it there.

Yes...let's see.

I think it's going to be... It's going to be that one.

OK, prepare to be amazed.

Your card is no longer there!

AUDIENCE GASPS

Did I read your minds and control your thoughts?

Of course not.

That would require psychic powers, which simply don't exist.

Despite what you have seen or heard, humans do not have

supernatural powers and if they claim they do,

they are either fooling themselves or using a trick, just like I did.

What I really did was I got you to focus your attention

on one card, so that you ignored all the other cards

All I had to do was change all the cards so every card is different.

Even though that mind-reading was a stunt,

we can mind-read others and actually we do this all the time.

Not with any supernatural spooky powers,

but with just the way we understand others

and try to predict what they're going to do next.

If you think about it,

how often do you try to figure out what someone else is thinking?

You try to work out what's on their mind

by watching their behaviour, looking at their expressions

and imagining what you would do in their situation.

In a sense, you are putting yourself in their shoes.

In fact, you are the best mind-reader in the animal kingdom.

How do we get so good at mind-reading?

Well, the answer is childhood. It's not a time of immaturity -

it's the research and development phase of our lives.

We are absorbing ideas from those around us

and trying to work out

what they think, and new ways of seeing the world.

The more time a species spends in childhood,

the more creative their minds are, the more social they are

and the more sophisticated their brains.

Our childhood is all about becoming human.

CHIRPING

AUDIENCE: Ah!

Other species have hardly any childhood at all.

For example, these are baby chicks, only a few days old.

Aren't they cute? Yeah?

Hi, guys! You're on television.

LAUGHTER

I'd like to introduce you to another baby,

not a chick this time, but a young human called Finn.

Now, quietly. Here we go.

Hello! This is baby Finn.

-How old is he? Can I hold him?

-Of course you can.

He's 11 weeks old today.

Happy birthday, weekly birthday, Finn. Can you see him?

-So, how far is he walking at the moment?

-Not very far!

-Oh. Is he reading?

-No, not much!

-Not reading.

What school is he at?

-No school.

-Not at school yet.

LAUGHTER

-Well, what does he do?

-Sleeps, eats, poos.

I was only joking, of course. He can't do very much on his own.

If we left him by himself he probably would be in trouble.

Whereas these chicks are much younger,

and they probably would survive a lot better.

So Finn always needs his mother. Let me give him back.

It might look like Finn's not doing very much,

but his brain is busy wiring up, taking in all this information,

listening to me as we speak,

taking in the social interaction, storing it in his brain.

By the time he reaches maturity, Finn will have a social brain.

With this social brain, Finn will learn from others

and actually all about others.

When he can do that, he can predict what they will do next.

Finn, are you thinking what I'm thinking? Are you?

LAUGHTER

Big smile.

How do we know that babies are so social and when does it all begin?

Let me take you all back to just before you were born.

Let's imagine we're inside the womb. Let's bring the lights down.

RHYTHMIC BEATING SOUND

You can't see very much inside the womb, can you?

Just listen. What's that sound? Hands up.

What do you think that is?

Is it the heart?

It's the heartbeat, that's right.

And sometimes you can hear your mother's voice.

'Well, we've decided not to find out if it's a boy or a girl...'

The human voice has a melodic quality

infants pick up on, and even before

they're born, babies can recognise their own mother's voice.

In one study the mothers read Cat In A Hat by Dr Seuss.

You can just hear it.

'The sun didn't shine. It was too wet to play

'so we sat in the house all that cold, cold, wet day.'

When the babies were born, they preferred

their mother's version of the story in comparison to anyone else's.

The only way they could have learned their mother's voice

was by listening to it whilst still in the womb.

So your brain starts learning before you are even born.

And after you are born, even though the senses are still very limited,

babies will pay special attention to humans.

For example, humans can recognise faces

and prefer them in comparison to other patterns.

Can I have some patterns here?

These are patterns used in these studies.

Here's one which looks like a face

and one which is all the same but a kind of random pattern.

Let's see if Finn still prefers faces to random patterns. Yeah?

OK, so can you...

Hello. Are you going to hold them? OK.

LAUGHTER

OK.

LAUGHTER

(Shh! Quiet, quiet.) Let's see, how about this face?

Oh, is that interesting?

(Not as interesting as his hands.)

Do you see how Finn,

when he sees the pattern, follows it with his eyes?

OK. Now, when scientists did this...

Finn is 11 weeks old but the scientists did it with newborns

and newborns seemed to come out ready, looking for faces.

So faces are like magnets to baby, capturing their attention

so that they can hardly look away.

We'll not give a loud round of applause, he seems settled.

We'll wave goodbye to Finn.

(Bye, Finn, you can go now. Bye.

(There you go.

(Thanks very much.)

See you in 15 years!

LAUGHTER

Faces are important to Finn, but what happens when you get older?

I'd like to introduce you to Esme. Come on through, Esme.

-Hi, there.

-Hi.

Esme is wearing these eye glasses, which are special.

What these glasses are, is they have a mirror and a small camera.

So the reflection of Esme's eyes are being fed into the computer,

and the computer is processing this information,

and you'll be able to see exactly where Esme is looking

when she looks around the world.

So, if you look on screen... Let's bring you over here, Esme.

I have my assistant here. ..tell me what you can see.

I can see a brain, some drinks, some apples and some tea.

-Um, some mugs.

-OK.

-A cash register.

-OK.

Let's try you with another pattern.

So, if you look at the... That's that one.

So here's the same scene again. What are you looking at?

I'm looking at the people who are talking on the phone

and being very busy.

In the same scene, when you have faces present,

faces are much more interesting and important

to humans, so the human face is something we're interested in.

Let's see what it is about the human face that you enjoy.

OK?

OK. There we go. She's actually tracing out a triangle.

Her eye movements are on the eyes, and looking at the mouth,

and then between the eyes.

In fact, the eye region is the most important part of the human face.

If you measure brain activation, it's driven a lot by the eye region.

Let's have a look around at the audience, shall we?

Why don't you look at this section over here?

What can we see?

So Esme is looking around, and picking out all the faces.

There you are, don't you all look good? Give a little wave.

Hello, Esme! There you go.

Thank you very much, Esme, we can let you go.

Round of applause for Esme.

We've become so good at recognising faces

that there are areas of our brain devoted just to this.

These are found in a small processing area

just behind your ears.

In some unfortunate cases, when people

get damage to these regions can lose the ability

to tell faces apart

or fail to recognise famous faces, friends and family.

Anything resembling the structure of a face

with two eyes and a mouth can trigger these brain areas,

which is why we tend to see faces all the time.

Take a look at some of these examples up here.

Does that look like a face?

Yeah? Anyone see it?

Yeah. How about this one?

Yeah.

That's an easy one.

You see, that's a face there, isn't it?

I like that one! Very good.

That looks like a shark.

And there we have...

In the Royal Institution toilets, look at the taps

you'll see faces on the taps.

We are programmed to find faces anywhere.

Here's another face, take a good look. Anyone recognise who it is?

AUDIENCE MURMURS: Albert Einstein.

-Shout it out.

-AUDIENCE: Albert Einstein!

Yes, it is Albert Einstein. But have another look at the face again.

There's something a little bit peculiar about it.

As it's moving, it looks like his eyes are following you.

Tell you what, let's bring in Albert Einstein,

because I want to show you this effect a little more closely.

Round of applause for Albert Einstein.

OK. This is called the hollow face illusion, discovered by

another Christmas lecturer, Richard Gregory.

Faces usually point out the way.

We don't often see faces,

as in the case of a mask, pointing in the way.

When you see the inside of the mask,

your brain just assumes it's the face pointing out the way.

And that's why you get this strange effect -

the eyes appear to rotate in the opposite direction.

You don't have a model for an inverted face in your brain.

But you do have them for faces that point out the way.

And that's why you experience this very bizarre, peculiar illusion.

So I think it's a big round of applause for Albert Einstein.

The more faces we see, the stronger the mental model of a face becomes.

Faces are one of the most important ways we tell each other apart.

Here's a familiar looking face. Does anyone know who it is? Shout it out.

AUDIENCE: Brian Cox.

Professor Brian Cox. Are you sure?

Or is it...his evil twin?

What's wrong with his face?

Anyone know? Yes.

-His eyes are upside down.

-Yes, his eyes and his mouth are upside down.

But so long as the eyes and mouths are in roughly the correct location,

we take it to be a normal face.

As you get older, and more experienced with faces,

you process them differently using lots of short cuts

so you tend not to notice details so much.

What's really interesting is that younger children would be faster

to notice that something is wrong with Brian's face

because they look at the features, rather than the face as a whole.

So why are we so interested in faces? They communicate

huge amounts of information, particularly about emotions.

These emotions are states of the body that prepare you for action.

They affect behaviour, breathing, pulse rate,

even how we digest our food.

All the really important things we need to do to survive.

If I show fear and panic on my face, then I'm signalling to you

and you know there's a problem

and we should get out of here pronto.

There are six basic types of emotion. Look up here on the screen.

See if you can tell which emotions these are.

All right. What do you think emotion A is? Anyone like to suggest?

Shout it out.

ALL: Angry.

Angry? Hands up for angry. OK, that's right.

What about B?

ALL: Fear.

Do we have fear? Hands up for fear. I think that is fear. What about C?

ALL: Surprise.

That's an easy one. That's surprise. Now, what's going on in D?

ALL: Happy.

That's well and clear. What about E?

-ALL: Sad.

-Sad. And F?

-ALL: Disgust.

-Disgust, great.

Charles Darwin first suggested we use emotional expressions

as a form of communication. Let's see how good you are with that.

I'll get you over here, Andy.

Joe, why don't you come? See if you can do some emotions.

OK, would anyone like to pull an emotional face?

OK, chap at the end here. Let's pull one.

What's that supposed to be? Anyone?

LAUGHTER

I think that's fear, isn't it? Anyone else?

That's happy.

LAUGHTER

OK, what about up here?

Here, go for it.

LAUGHTER

Ah, it's definitely fear. Round of applause for fear. Well done.

APPLAUSE

We're so good at reading emotional expressions,

we can even tell when someone is faking a smile.

Have a look at these two pictures of the same person.

Which one do you think is the genuine smile and which one is fake?

Is A the genuine smile? Put up hands if you think so.

Oh, a couple for A. What about B?

Yes, clear winner. B is the correct smile.

Now what is it about the faces which makes the difference?

Well, let's just narrow it down and see.

It's all to do with eyes.

She's smizing, smiling with her eyes. She's using a different

set of muscles which control the eye region. Wrinkles around the eyes

show the smile is genuine.

Some emotions are programmed by evolution,

while others are shaped over childhood by those around us.

Babies do express some emotions early on.

Even blind babies smile,

though they've never seen a smile to copy or imitate.

But emotions can also be shaped by experience.

Take disgust. This emotion isn't present in the newborn.

Babies can be quite disgusting if you think about it.

However, somewhere around the age of two,

children start to learn what is disgusting by watching others.

Ah, I could do with a drink actually. I'm feeling a bit parched.

That's good juice. Anyone want to try some apple juice?

How about you?

-Now what's your name?

-Emily.

-Come here, Emily.

-Would you like to try some of my apple juice?

-Yes, please.

-We should use a new glass.

-Yes.

Good. I've got a new container. How about, er...?

LAUGHTER

This is what I use when I run out of glasses.

Look in there.

ALL: Eurgh!

-Would you like to have some apple juice?

-No, thanks!

LAUGHTER

-You sure?

-Yes.

-Seems all right to me.

No? Ah, maybe you need a straw.

LAUGHTER

I know what you'd like. Would you like to have a straw?

-No thanks!

-You sure?

Why? It's all right. Look.

ALL: Urgh!

LAUGHTER

It's delicious! No?

Big round of applause for Emily.

APPLAUSE

TOILET FLUSHES

It's a brand-new toilet. Perfectly clean, safe to drink from.

What's that? That was the wrong toilet?

LAUGHTER

I'm joking, of course. We've come to learn that toilets are for waste,

so we can't easily overcome our disgust

triggered by the thought of drinking out of a contaminated toilet.

Even when we know it's brand-new, you can't help feeling revolted.

After that drink, I'm feeling a little bit peckish.

-Snacks! Get your snacks here!

-Ah, something to eat.

Joe, come over here.

What have we got here?

That's right - bugs.

GROANING

Mm!

I'm feeling quite good about this now. Anyone for a bug?

How about... Would you like to have a little nibble of a bug?

No? No? Really? They're really quite Delicious.

What about this one? It's got nice legs.

LAUGHTER

No? can't tempt you? They're really OK, honestly.

LAUGHTER AND GROANS

Mm, delicious. Actually I need something to wash that down.

No, no, no. Not the toilet.

LAUGHTER

These are grasshoppers.

Grasshoppers are considered a delicacy in some countries.

They're very nutritious and highly prized.

They taste a little bit like roasted peanuts.

However, Westerners generally won't eat insects.

Our culture has an influence on what we find disgusting.

One reason disgust evolved

is it's a useful way of showing others what's safe to eat.

Humans are omnivores, so we can eat many different things.

In other words, children are using adults as their food tasters

by watching their expressions. Emotions aren't all in the mind,

they can physically affect us too.

Just look at your reactions to someone doing something disgusting,

like when I drank out of the toilet.

Have a look up here.

LAUGHTER

It affected your behaviour. Now, let's try a different emotion now.

Try this out.

Remember the straws I gave you? OK.

Now first of all,

I want you to put the straw in your mouth like this.

So you're pouting, OK?

Right, everyone got it? Put your straw in your mouth, sir.

In the gallery, put your straws like this.

OK? Now I'm going to play this.

Listen carefully.

RECORDED LAUGHTER

OK, not much.

Take the straw out and put it like this. Ready?

RECORDED LAUGHTER

AUDIENCE LAUGHING

Funnier, isn't it? Why is it funnier when you've got the straw like that?

Why did you laugh?

When you have the straw in your mouth like that,

you're forcing your mouth into a certain posture.

You're forcing a smile and your brain associates physical actions.

It's difficult to laugh when you're pouting.

But when you had it like this, this is the same structure

that you have when you're smiling.

Of course, the other thing was I played a laughter track.

Laughter is just one of those contagious emotions.

When you hear someone laugh, you feel the urge to laugh yourself.

Emotions communicate information about our environment

and they bind us together socially. Let's see if we can actually measure

the physical symptoms of this by measuring our blood flow.

Now, I'm going to actually have to give my own blood sample here.

I've got a specialist. Charlotte's coming in.

-You're going to take a blood sample, are you?

-Mm-hm.

-OK, what shall I do?

-Just take your jacket off, please,

-and sit down for me.

-OK.

If you could just take a seat.

-Ah, I'm not very good with needles.

-It'll be absolutely fine.

I'm going to put a tourniquet on first, so we can find your veins.

-What's that smell?

-It's just so it's hygienic.

OK.

I'm just going to swab you down now.

I have to say, I'm actually not very good with needles.

LAUGHTER

I'm just going to prepare the needle now.

LAUGHTER

Right, ready?

LAUGHTER AND GROANS

It's just going to be a sharp scratch. Ready?

No, stop!

Stop, stop, stop!

I can't go through with it. Thank you, Charlotte.

-Round of applause.

-APPLAUSE

Of course, the real purpose of this demo was not to take a blood sample,

The real purpose was to show how we can literally experience

someone's suffering by watching and putting ourselves in their shoes.

A lot of you didn't look happy when you saw that needle.

We have one person in the audience

wearing a heart monitor throughout the lecture.

We can put their heart rate up on the screen above here.

You can see that up to that point when I mentioned an injection,

his heart rate has been fine. But as soon as you hear

the word injection, It's been rising.

So their anxiety has been increasing watching that,

even though there was absolutely no risk to them.

So why did their heart rate go up?

Well, when you're watching someone else enduring a painful experience,

you empathise with them both mentally and physically.

So, who was wearing the heart monitor?

-Hello, Alex.

-Hello.

-You don't particularly like needles.

No, that was quite clear there.

You can see, if we can put up this thing here.

Oh, actually your heart rate is going sky high again!

Is that because we're all looking at you?

LAUGHTER

Is it really? As I'm talking to you, your heart rate's climbing.

Up to 120... Um, wow!

LAUGHTER

I'm worried about you!

I'm worried about you. Well, of course.

We're social animals, as soon as we become the attention of everyone,

everyone in the Royal Institution here,

we get self-conscious. That's very anxiety inducing.

Thank you for being such a good sport, Alex. Big round of applause.

APPLAUSE

Scientists are fascinated by our ability

to copy emotions and behaviours.

How does the brain do this? One theory is there is a mechanism,

the mirror neuron system, that responds to watching

other people's movements as if we're moving ourselves.

Humans have an amazing capacity to copy and learn by observing.

It's even present from birth.

At first this imitation is restricted to emotional expressions

such as smiling, something most of us do in a social situation.

If you smile at a baby, there is a very strong likelihood

they will smile back at you. We got this earlier

when Finn was in. I'll just show you.

Here's me interacting with Finn again.

LAUGHTER

ALL: Aw!

Whenever we watch other people we're doing things,

our neurons resonate with their activity.

In effect, our brains become synchronized.

One way we express this is through movement.

Look at this pattern on the screen now.

It's a series of dots.

Can you see anything among those dots?

Can you see the invisible person?

Well, watch this. Can we have them move?

Isn't that remarkable?

With just a few dots, you can read and see someone there immediately.

For example, what sex do you think this person might be?

ALL: Male.

Hands up for male.

Well, that's pretty clear. Very good. OK, so this is a man.

Let's see if he's going to be a happy man.

Can we have a happy man please?

LAUGHTER

He's in a good mood, isn't he?

What's going to happen now, I wonder?

Shall we get someone else to come along maybe?

They're shaking hands.

-AUDIENCE MEMBER: Lady.

-It's a lady?

Who thinks it's a lady?

That's right. Let's have some fun, get them to do different actions.

Shall we get them to clap? Let's see clapping.

There we go, clapping.

How about... Can you pat your head and rub your tummy?

OK. Let's have a bit of dance moves.

Can you do a John Travolta?

You see, with just a few dots you can read incredibly things.

The brain can extract surprisingly complex social information

from just movement alone. From a few dots, our brains

can work out the gender and even state of mind of someone.

Let's get these guys in, just to prove that they're not dots,

but real humans. Can we bring in the team

from London Southbank University? Come on in, guys.

Big round of applause please.

APPLAUSE

-Here we go. This is...

-Will

-Lex.

-Lex.

-Darren.

-And Darren. Let's look at what they're wearing.

They're wearing these light spots. This is what you saw on the screen.

They're reflective and their images in the cameras were being captured

and this movement produced all this rich information.

So, Darren, tell us a little bit about why you use this?

What's going on with this?

This is the kind of technology major computer game developers

use for animation. I'm sure you know the football games.

This is the exact technology used.

Great. Research and development as well?

Yeah, we've got three themes of research, so we have sports,

we've got clinical and commercial. So if you take our sports angle,

we've got two focus sports - tae kwon do and basketball.

By analysing our athletes' movements,

we can pick the important parts out and improve their performance.

Great. Well, thank you, Lex. Thank you, Will.

Good luck with the research, everyone.

Big round of applause for London Southbank.

APPLAUSE

What might surprise you is that babies as young as four months old

can also see moving spots of light as people.

Not only do they see movement as people,

but they also start to use movement to work out what someone is like.

Have a look at this clip of this video here.

This is an animation, but see if you can think about it another way.

There we go.

Which do you think is the more friendly object?

Hands up for green?

Hands up for the yellow square?

It's amazing, really. It's just an animation,

yet we think of these things as having personalities.

In fact, babies, when they watched this,

were given a choice of a square and a triangle.

And when they saw the square being helpful,

they preferred to play with a square object.

So these babies are giving them personalities.

From the very beginning, we see the world as populated with others

who act with goals and intentions.

We even apply that reasoning to inanimate objects.

Do you speak to your toys?

Or if you have a computer, do you get frustrated

and shout at it when it crashes and say,

"Don't crash, I haven't saved my homework"?

This is what we do. We give inanimate objects these qualities

to make it easier to interact with them.

It's a way our brain is making assumptions about the world

and adding extra information. Movement provides

not only a rich source of what someone is like,

but a channel of communication

where no words are exchanged. Synchrony is essential

to many human activities,

such as dancing to music. Whilst some pets can be trained

to dance, others can do this spontaneously.

Take a look at this cockatoo called Snowball.

ROCK MUSIC PLAYS

Cockatoos are social birds that bond for life,

which is maybe one reason they'll copy another person's movements.

Obviously, Snowball is copying his owner.

Sociable birds spend longer as fledglings,

so they have long childhoods in the bird kingdom,

and they're more intelligent generally

and actually have bigger brains.

So I want to try out some copying with you.

But for that, I'm going to need a volunteer to be a pirate.

Let's see, who's going to be a pirate?

I think we could have...

Let's have the lady there. Would you mind coming down?

-Yeah?

-APPLAUSE

-What's your name?

-Olivia.

-OK, Olivia.

I'm Captain Bruce Hook.

We're on this ship, and I'm the worst captain on the seven seas.

And I reckon you're going to mutiny,

so I've got to teach you some discipline.

I'm going to make you walk the plank.

This is my cockatoo. So get on the plank,

and see if you can walk in a straight line.

Just balance with your two legs. OK, hold it there.

Get yourself stable, girl. There you go.

Put your hands out if you wish. Are you stable? Good.

Now look what happens.

Avoid the sharks.

Oh, it's really hard to keep the balance!

You're doing very well. Can we make her tip over?

Yes, I think so.

Over into the ocean to Davy Jones' locker!

Are you finding that harder?

Thank you. Was that much harder? Round of applause.

That was pretty good balance. Well done.

When we watch other people, we copy their behaviours and movements.

It's difficult to maintain balance, when watching someone else wobble.

As a social animal, we prefer to be in synchrony with others.

Synchronisation is useful for picking up information from others.

One very powerful form of synchrony is called joint attention.

Whenever humans interact,

they have to coordinate their focus of attention. Imagine a conversation

without looking at someone in the eyes.

Not only is it difficult to do, but the experience would be very odd.

Now, I didn't tell you to look up, did I?

But you instinctively followed my direction of gaze.

That's called joint attention.

This is because you interpreted my behaviour

to indicate that there was something of interest worth looking at.

Joint attention first appears in babies before they have language.

Pointing to objects of interest is also uniquely human.

Chimps and monkeys will point to food if they want it,

but they don't point to things just to share the sheer joy of interest.

Now, this human bias to share our attention

with others can be manipulated and controlled by magicians

who don't want us to see everything all of the time.

Would anyone like to see some magic?

Do you want to see some magic?

ALL: Yes!

OK. Ladies and gentlemen,

I would like you to give a warm welcome to the amazing Billy Kidd.

-Billy, you're always full of surprises.

-I know.

What are you going to show us?

Today, I'm going to show you guys

one of the oldest magic tricks in the world, simply known

as the cups and the balls.

We use three cups in this trick,

and three balls as well -

ball number one, ball number two

and, if I can find it, ball number three.

-Bruce, your job is to watch very close.

-OK.

-Really close.

What we do is, we take ball number one. And we vanish it, like this.

Bruce, I'll do it again. You're all paying close attention now.

Ball number two, see if you can catch me. We do it like this. And...

You caught that, didn't you?

Yeah, I saw that.

All right, I'll do the real magic. Ball number two goes like this.

It's easy, you just need a magic wand.

-Ball number three goes my favourite way, actually. Watching close?

-Yeah.

MUMBLES: And that ball...is gone.

LAUGHTER Some of you are shocked, I know.

I'll tell you what. Just like that,

the balls...come back.

Now, Bruce, I can tell this is

-somewhat melting your brain a little bit.

-It is indeed.

Being a scientist and all, so I'll make it simpler for you.

I'll take ball number one, and eliminate it,

which would leave how many balls?

-There's two there.

-Very good. He's a scientist.

Bruce, if I take a second ball and eliminate it from the game,

how many balls would we have under the middle cup?

-There's one, definitely.

-But why does that one come back?

-Not so sure.

-Magic.

-Ah.

This one goes away, and if I tap this one...

OK, I'll put this one away as well.

This one comes...

You know what? Let's make it simple. How many in the middle cup?

I think there's one.

-Oh, there's two.

-Try again.

-How many in the middle cup?

-Two.

-No, it's three.

-Oh!

-Listen to the kids.

Even simpler, for Mr Science Man. Three balls, going in as a group.

-How many here now?

-There's nothing there.

No, you see, that's...a big one.

But...

I'll make it even more difficult for you,

because I know you like a challenge.

-Watch close.

-I am.

-Watch the hat. Nothing in the hat, OK?

Watch this ball, because in a moment,

I'm going to make this ball vanish from the hat.

With the power of the magic stick, we do this.

And like that, the ball's vanished.

-You don't believe me, do you?

-No.

-All right, sceptic.

I'll bring it back.

That's not fair. Come on.

All right, we'll do it for real. Ready?

-How many under the hat?

-One.

-Very good. How many now? Shh!

-I can see three.

-How many? Just Bruce.

-I saw three.

You caught me that time, they were rolling around.

The thing is, you shouldn't be watching the balls.

You should be watching the cups.

Wait for it.

Oh, round of applause!

I have no idea.

Billy, I have no idea.

I think I'll need a volunteer to watch you a bit closer.

Can we have a volunteer?

Let's choose someone from...

Let's choose...

Sir, why don't you come down?

-This way. What's your name?

-Eric.

OK, Billy's going to show you a routine.

-Hello, Eric. You all right?

-Yeah.

Stand right here.

I'm going to show you something, but do you know what this is?

-A red spongy thing.

-Very observant.

We'll call it a sponge ball for now. It's not just any sponge ball,

it's two, OK? Now, if you hold your hands out like this,

straight in front of you, I'll put one in your hand here

and one in your hand here, so you can feel them. Regular balls, yes?

I'll take one and put it in my hand.

You hang on to this one and squeeze nice and tight, OK?

Put your other hand on top as well. Watch close.

When I squeeze mine, it vanishes. And when you squeeze yours,

open them up slowly... you have two again.

OK.

OK. Round of applause.

So what magicians like Billy are doing is using

-the power of the gaze to misdirect attention, right?

-Yeah.

This is why you don't notice them performing manoeuvres.

Now that you know how it's done, watch it one more time.

-Billy will explain.

-So what I actually did,

when I take this ball, I put it in my hand, and I look over here.

My body and eyes are looking at this hand,

which makes you guys look at this hand,

but in reality I have it over here.

So I took this ball, right,

and I made you close your hands nice and tight together.

-I felt that.

-You felt it this time.

You see, mine vanished, right, like before,

-so how many did you have in your hand?

-Two.

Three.

Round of applause, well done.

Thank you very much.

OK, Billy. I suppose you're going to disappear again, aren't you?

-Of course.

-Let's see it.

-Ready?

See you.

Billy Kidd.

APPLAUSE

Billy showed us how she can manipulate others

by using misdirection, and the eyes are very powerful.

Direct gaze is a powerful social cue that explains

why strangers don't look at each other when standing close,

because it could be seen as a threat.

You can try that the next time you're in an elevator.

If you see someone close, look them in the eyes

and they might be a bit surprised. Of course, it's all right to do this

in some Mediterranean cultures. Staring at each other's acceptable.

Now, when someone starts staring at you,

this triggers brain activation

as you're processing the faces.

Let's see if this works. I want you to see two pictures of me.

OK, have a look at these. Hands up if you prefer picture A.

And hands up if you prefer picture B.

Well, that seems to work. That's pretty good.

I think picture B is the winner. Who preferred picture B?

Put your hand up.

Young lady, why did you prefer picture B, do you think?

Do you know? Not sure?

Anyone else? Did you prefer picture B?

-Yeah, because you're smiling.

-You think I'm smiling.

Anyone here?

-Why did you prefer picture B?

-Your eyes are less kind of...

They're less kind of...?

That's right. Actually, look at the pupils and you'll see

that in fact, the eyes are very dilated. The pupils are much larger

in picture B than they are in picture A.

And when you show people pictures

which are identical except for the eyes,

the tendency is to prefer the one where the pupils are larger.

When someone looks at us,

this creates activity and arousal and our eyes dilate,

which is why we usually prefer images with larger pupils.

This signals that they're interested in us,

and of course, we like people who like us.

All of the these cues are just some of the ways

humans read each other's behaviour.

When you interact with another person,

one of the most important things is to work out what they're thinking.

Before you can know what someone's thinking,

you have to have a sense of your own self.

How do we develop this? Well, meet Simon,

the Siamese fighting fish.

Siamese fighting fish are very territorial.

The males will attack any male which encroaches on their territory.

So let's see if Simon has a sense of self.

He seems quite placid at the moment,

but let's put a mirror against his tank.

I'll put this behind him

and see if he notices that there's another fish.

So when he turns round, let's see if he spots himself.

You should see that he will swim directly towards it,

and the gills will flare out

as a territorial display. Let's see if he spots himself.

There he goes. Ah! See how fast that was?

He's fluttering his gills and trying to attack the other fish.

He'll keep bouncing on the glass, swimming backwards and forwards,

until this predator, this interloper disappears.

See how remarkable that is?

LAUGHTER

He's not giving up. He's quite a toughie, our Simon. There we go.

Because he doesn't have a sense of self,

he doesn't recognise that it's his own reflection.

And this is a technique that scientists use to determine

whether children and animals have a sense of self.

If a baby looks in the mirror when they're very young,

they just treat the reflected baby as another baby.

But when they get to about 18 months,

if you put a little dab of red marker

on the front of their forehead and they look in the mirror,

they realise that their reflection must be their own self.

This is a technique we use

to study the sense of self in other animals. For example,

here's an elephant called Happy. She's in the Bronx Zoo in New York.

We haven't put rouge on her forehead,

but we put a little mark.

And she's spotted herself in the reflection

and is trying to remove the tapes on the side.

So she knows that that image is her, and that mark must be on her head.

Elephants, dolphins and other social animals

have this idea of self-recognition.

But back to us humans again. As you grow up, you develop

a sense of who you are.

By the end of infancy, you start to consider others.

You're becoming more social,

helping others and feeling their feelings.

Very young children think that everyone around them

shares the same thoughts as them.

But between three and four, they begin to understand

that others have different points of view. Now we'll try something

to see if you can predict what someone else is thinking.

I'll need two volunteers for this.

So I am going to choose one from...someone at the back...

Oh, green-handed man there, come on down.

Sorry, green top there.

And I'll choose someone from this section.

Could you get down there, lady? Yes, that's you. Come on down.

There we go. Can you go that way?

Round of applause for both of our volunteers.

-OK. So, what's your name?

-Mark.

This is Mark. And what's your name?

-Olivia.

-Olivia, is that right?

I need one of you to go outside for the moment.

Olivia, would you go outside for the moment?

He'll take you outside.

Mark, you're going to help me with my next demonstration.

Let me just move this cabinet forward.

This is the cabinet where I keep my brain.

Could you just check that they're empty?

Are you happy with that?

OK, so this is my brain that we're going to use.

Would you put the brain in the brown box for me?

Put it in there, and put the lid on it.

OK, good.

I was just telling... Just wait a minute.

I was telling the audience about how we use our social brain,

it helps us to predict what people

will do based on what they think is true.

Yeah? And... Actually, can I have the brain, Mark?

You see, when we're thinking about the brain, it's...

It's just... Mark, can I have my...?

-LAUGHTER

-How did that happen?

I don't know. Maybe there's a secret trap door in the bottom of the box.

You reckon? Must be something like that. But why did you search here?

-Because I put it in there originally.

-Come round here.

I'm going to show you something, Mark. Come here.

The reason you couldn't see or didn't know the box was over there

was because what you didn't know... You kind of guessed it somewhat,

but the audience didn't know, is...

HE KNOCKS ON THE BOX

It's Billy Kid again. Thank you very much. Come here.

OK. So you looked in the brown box because that's where you put it,

-so you believed it was in the brown box.

-Yes.

-OK.

-But you didn't know how it got there, to the blue box.

-No.

So your belief was false, wasn't it?

So can you can work out what someone else'll do if we do the same thing?

-OK.

-So it was Olivia. Wasn't our guest...?

-Yes.

What do you think Olivia will do if I put the box...

If I put the brain in the brown box, where will she look?

She'll look in the...brown box.

Yes, because she believes it's in the brown box.

-But we know that Billy always moves it, doesn't she?

-Mmm.

-So where will it really be?

-In the blue box.

-That's right.

You realise you've just done something very clever, haven't you?

You've worked out what Olivia will do.

You've been able to put yourself in her shoes.

That's quite a unique ability. We'll have a bit of fun with that.

-We'll get her back in, see if we can pull the same trick.

-OK.

No-one give away the secret, OK?

You stand back and watch what's going to happen.

So quiet, everyone.

I'm going to go and get Olivia now, OK?

-Hello, Olivia. It's Olivia, is it?

-Yeah.

-Come on. Just come here.

I was just explaining to Mark about this experiment we're doing.

This is where I keep my brains and these are the...

You can have a look in there. It's empty.

Look in there. It's empty, too. We keep the brains here. This is mine.

So, Olivia, would you put the brain in that box,

because I'm going to talk to the audience about the social brain.

The thing about the social brain

is that it's one of the most remarkable things

cos we can predict what people will do based on their beliefs.

Erm, Olivia, can I have my...brain, please?

-It's not in there.

-LAUGHTER

-Where is it, do you think? There are two...

-In this box.

You want to look for it?

SHE GASPS LAUGHTER

APPLAUSE

Well done. Come on, I'll show you.

It's Billy again!

Big round of applause. Both of you back to your seats. Thank you.

APPLAUSE

That was a bit of fun but this is a recreation of a famous experiment

for a core component of human nature called Theory of Mind.

You see, once you knew that Billy was hiding underneath,

you knew Olivia was in for a surprise, that's why it was funny.

You understood she could not know what was coming up

and she had a false belief. When you think about it,

comedy, drama and many aspects of human storytelling

requires us understanding a Theory of Mind.

People who have difficulty

understanding others' points of view,

such as very young children or children with autism,

would typically fail this type of task.

They cannot see things from someone else's perspective.

They do not understand that others can have false beliefs.

When we develop a Theory of Mind,

we start to care about what others think of us.

As children develop a sense of their self-identity,

independently of their family,

they seek out the approval of all their friends.

However, one problem is they feel they're constantly being judged,

which shows up as activation in parts of the brain

that monitor social interactions. So it's tough

being a teenager. We all know how horrible it feels to be left out.

Of course, brain imaging studies have shown that when this happens,

this sort of rejection lights up

those parts of the brain which respond to physical pain.

So this social rejection pain is real.

Maybe this need to belong

explains why social networking has become so popular.

Hands up if you're on Facebook or Twitter.

That seems just about everybody. That's really good.

Can I ask you, you're on Facebook. Why do you like being on Facebook?

I keep in touch with friends from primary school.

Keep in touch with friends. Anybody else? Hands up.

Why do you like being on Facebook?

-Yes, sir, what do you like?

-It's just easy to contact people.

It's easy to contact people. Any others?

You can show people what you're doing.

You can show people what you're doing. Anybody else?

One at the back there.

It's just nice to talk to people you haven't talked to for a while.

So you can increase the communication

and the physical boundaries which make difficult social interactions

are that much easier when done electronically, isn't it?

In fact, do any of you have friends in different countries on Facebook?

See how easy it is

when you can start talking to people across the globe.

I think this is a really interesting part

of our development as a society.

We now have the technologies to speak to anyone

around the world at any time,

so the boundaries of physical space are no longer a problem.

I sent out a tweet on Twitter.

I'm not sure if anyone's on Twitter but a lot of people ask,

"What's the point of Twitter? It seems to be for gossiping."

But let's look at some of the responses we got.

Here we go. We've got Nicola said, "Depending on how often you tweet,

"Twitter can help us feel closer to each other."

And I like this one. This is Tim. He says,

"I would not have met my lovely, fantastic, smart girlfriend

"if it were not for Twitter."

The bottom one I really like as this is someone who's clever,

who's thought about how we can communicate.

He thinks Twitter's a little bit like a virtual brain.

"Users are like neurons and the followers are like dendrites.

"These are the connections,

"and the whole network's greater than the sum of the parts."

So this technology and the future is unknown but it is exciting

and you guys are right at the prime, about to find out.

Throughout these lectures,

we've been considering the workings of the human brain

very much from an engineering perspective.

A biological computer, if you like.

This has been a dream of science - to build an artificial brain

that can perform the same skills and think like a human brain.

When we started building machines to copy what human brains can do,

the skills we thought would be really difficult,

such as playing chess, turned out to be easy for computers.

In fact, our best grandmaster chess players can be beaten

by machines today.

But the things that are trivially easy and effortless for humans,

such as picking up a chess piece,

turn out to be actually really difficult for computers.

Robotics is developing at a rapid pace

but could we really ever build a robot

that thinks and feels like a human? Could a robot ever feel empathy?

Things like computers, they can do things like voice recognition

but getting a computer to understand a joke or a story

is still a long way off.

ROBOT: 'Is that so?'

Well, yes, robots can seem very human and life-like,

but that's because we programme you to behave like that.

But you can't really understand what I'm saying.

'If I cannot understand what you're saying

'then how can I answer you back?'

You've been programmed to. Look over there.

'Doctor Dahl is operating me from his laptop.

'Hello, Doctor Dahl.

'But I can recognise your face,

'so if you move yours, I will move mine.'

Really? OK, let's try that out.

Ah.

Not unlike baby Finn.

'And I can also be programmed to recognise special voice commands.

'I also have movement and touch sensors,

'so I can learn. How do humans learn to talk?'

We're also programmed to learn language from others

when we're very young.

'If I am programmed and you are programmed, what is the difference?

'Are not humans complex machines as well?'

I guess we are in a way,

but at the moment computers cannot understand human language

because it's really just too complex.

-'We could learn, couldn't we?'

-I guess so.

But for the moment, you can only do what we tell you.

So let's leave it at that, shall we?

Who's presenting this lecture anyway?

I'll finish by saying how clever the human brain is.

So turn yourself off and go to sleep mode, would you?

'Just you wait.'

All right. Applause for Nao.

Nao's right. There are robots learning from their experience

and reprogramming themselves.

Achieving the flexibility and creativity of the human brain,

however, is a long way off

but in principle it's not impossible.

In the first lecture, we looked at what the human brain is.

In the second lecture, we thought of the things it can do.

And in tonight's lecture,

we've discovered how it's evolved skills

to learn from and pay attention to others.

But why is it so important?

Take a look at that clock.

That's the estimated population of the world.

There are currently nearly seven billion human brains

living on this planet.

In the past hour or so, the world's population has already risen

by almost another 10,000 brains.

Are you thinking what I'm thinking?

Somehow we're all going to have to get along

if we're going to survive as a species.

It's a challenge but luckily

we have brains especially evolved for interacting with others

and really this is one of the main joys of life.

So good night and look after your brain.

APPLAUSE

Subtitles by Red Bee Media Ltd

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