Why Do I Need You? The Brain with David Eagleman

What does a brain need to be healthy?

Well, it needs nutrients from the food you eat,

it needs oxygen from your blood, plenty of water.

But there's something else, something equally as important.

It needs other people.

CHEERING

Human beings are extremely social creatures.

We come together, we team up,

we share moments of intense joy and disappointment.

We don't just seek out other people to have a good time.

Your brain function depends on the social web that you're in.

Your neurons require other people's neurons to thrive and survive.

I want to show you how our brains are fundamentally wired

to work together...

..how this social network that envelops us

from birth is vital for our survival.

Yeah? OK!

Understanding how brains deal with each other allows us

to understand what bonds our species, driving us to help

one another and what makes us hate...

..what allows acts of human violence.

It helps us to make sense of our past

and holds the key to our future.

There are seven billion people living today - seven billion brains

moving, choosing, acting,

believing and connecting with other brains.

Brains are traditionally studied in isolation but, in fact,

much of the circuitry of the brain has to do with other brains.

We're fundamentally social creatures

and our society is a complex web of interaction.

On any normal day, we intersect with an enormous number of people.

'Our lives are built on these intersections,

'not just between us and our family and friends and work colleagues,

'but also between them and the people they meet.'

'Even the most basic encounter...'

like getting a cup of coffee...

'..relies on trust with a stranger.'

-Could I get a latte, please?

-Definitely.

-Thanks.

Everywhere we look, we see complex social interactions, relationships

forming and breaking, bonds of love and support, social networking.

'We clump into large groups to share our knowledge.'

You've got all these random spots in your brain that get

wired up into an associative neural network.

'We work to impress each other and we swap ideas.'

I'll stick around for any questions that anyone has. Thank you.

CLAPPING

'Most research looks at one brain at a time,

'but that misses the fact that a great deal of our brain activity

'is dedicated to communicating with each other,

'interpreting each other.'

'Our social drive is deeply rooted in our neural circuitry.'

Take a look at this film from the 1940s.

What do you see happening here?

Is this just a simple animation of some shapes or something more?

Do you see a chase, a fight, a love story?

The big one seems to be pushing the little one around.

It seems like the two triangles are in a little bit of a squabble.

There are relationships here

in terms of one is more dominant than the other.

Back in the 1940s, psychologists Fritz Heider

and Marianne Simmel created this film as part of an experiment.

-The ball doesn't seem to want to be in there.

-It's freaking out.

It's scared. It looks like a trap to me.

It looks like the smaller triangle is being shut out and, like,

trying to peer in.

-They are paired in a way that seems friendly.

-Yeah.

-This is really fun.

-It's fun, right?

'What Heider and Simmel found, as I did,

'is how easy it is to look at moving shapes and to see meaning

'and motives and emotion, all in the form of a social narrative.'

I kind of get the sense that they're cats and dogs.

It seemed like the big one might have been,

like, his dad or something.

Just call it more of, like, a mating ritual -

two competitors going for one possible mate.

These are just shapes on a screen but we can't help

but tell stories about them. Why?

It's because our brains are so primed for social interaction

that we look for intention in relationships all around us.

One way we navigate the social world

is by judging other people's intentions.

Is she is trying to be helpful?

Are we a trustworthy team?

Our brains are good at making these sorts of judgements

and we do it constantly

but do we learn this skill from life experience or are we born with it?

To figure out which one it is, I've invited over some people who

don't have much experience with the world.

SHE CRIES

I've invited them to a puppet show.

These babies are all under 12 months old.

They're just beginning to explore the world around them.

You could say they're all a little short on life experience.

We decided to run a simple experiment

developed at Yale University.

Here's a duck struggling to open a box.

One bear helps the duck.

The other is mean to the duck.

OK, Booey. Here you go. There are two puppets.

'When the show's over, I let the babies choose a bear to play with.'

Yeah, OK. Is that the one you like? All right.

'Almost every one of them chooses the bear that's been kind.'

'These babies can't walk or talk

'and yet they already have the tools to make judgements about others.'

Yeah? OK!

It's often assumed that trust is something that we

learn from our experience in the world, but these experiments

demonstrate that, even as babies, we come equipped with

social antennae for feeling our way through the world.

The brain comes with inborn instincts for figuring out

who's trustworthy and who's not.

BABY GURGLES

As we grow, our social challenges become even more subtle

and complex.

Understanding others is one of the most demanding operations

that our brains perform.

They have to interpret words and, more than that, inflection,

facial expressions, body language.

Does she like me?

Is he interested in what I'm saying?

Do they want my help?

Society runs on our ability to read each other's social signals.

Take that ability away and the world becomes a very strange place.

Car enthusiast John Robeson has always struggled to read

other people.

When I was a little boy, I was bullied and rejected by

other kids, and that didn't happen with machines, you know.

I could stand by a tractor in my grandparents' farm

and I could learn how to adjust it and it wouldn't tease me

or do anything bad, it wouldn't run away, it would

always be there and I could count on it.

And I guess I learned to make friends with

the machines before I learned how to make friends with other people.

In time, John's affinity for technology took him

to places his bullies could only dream of.

By 21, he was a roadie for the band Kiss.

This was me, back with Kiss in the '70s.

I'm older and fatter and stuff. I don't look the same any more.

Surrounded by legendary rock and roll excess,

his outlook remained different from other people's.

People would come up to me all the time and they would say,

"What's this guy like?" or, "What's that guy like?"

I would say, "Yeah, their stage set-up,

"they had Sunn 2000S bass amps," or, "Gene played Sunn Coliseums,

"and we had seven bass amps chained together,

"we had 2,200 watts in the bass system for that."

But I maybe couldn't tell you

the first thing about the musicians who sang through them.

Now I realise that shows that I did kind of live in

a different world all those years - a world of machines and equipment.

When he was 40, John was diagnosed with Asperger's - a form of autism.

Many regions of the brain are engaged during

social interaction, but in autism, that brain activity isn't seen

as strongly, and that's paralleled by diminished social skills.

I didn't really understand that there were complex messages

in faces until I was well into adulthood and learned about autism.

I knew that people could display signs of crazed anger..

..but if you asked about more subtle expressions, you know,

I think you're sweet and I wonder what you're hiding,

or, I'd really like to do that, or, I wish you'd do this or that, I...

I had no idea about things like that.

But then came a transforming moment in John's life.

In 2008, he was invited to Harvard Medical School to take part

in an experiment on his brain - overseen by Dr Alvaro Pascual-Leone.

It was an attempt to try to understand

how activity in one area

affects activity in another area and how that affects behaviour.

The experiment was only meant to help the scientists gain

greater knowledge about the autistic brain.

But then, something unexpected happened.

John was given transcranial magnetic stimulation, or TMS.

Magnetic coils were placed next to his head to generate

minute electrical currents in the brain and alter its activity.

The researchers targeted different regions of John's brain to see

whether interfering with his brain activity had

-any effect on his behaviour.

-They would test me after the session.

I would go home, kind of not knowing what to expect.

At first, there was no result,

but then they targeted the dorsolateral prefrontal cortex,

a region involved in flexible thinking and abstraction,

and something dramatic happened.

Somehow, I became different.

He contacted us, very excited, to say, you know,

"The effects of the stimulation seemed to have unlocked

"something and the effects are still lasting

"and I now can do things that I could never do!"

After TMS, I was able to sort of read signals from other people

and understand what was going on.

So I listened to that, fascinated by it, and thought, OK, well, whatever.

It'll go away. But it didn't.

It actually remained something that had really

fundamentally changed in him.

Somehow, and entirely accidentally,

the TMS had unlocked a whole new world for John.

A vegetable sandwich to bring home...

'I'd be tempted to say I couldn't read people and now I can,

'but that's not really true.'

-OK, how about a full-sized... One of them?

-Sure.

It's more accurate to say I had no idea there were these

messages emanating from other people.

'TMS showed me those messages, and now that

'I'm aware that they're out there, everything I do is different.'

All of a sudden, you can walk around and engage the world...

'..and it's a big, big thing.'

OK, thanks.

We don't know exactly what happened neurobiologically

but I think it now offers the opportunity for us

to understand what behavioural modifications, what interventions

might be possible to learn from him that we can then teach others.

John's transformation is a reminder that all

the activities of the human brain,

including the subtle interplay of emotions and relationships,

are rooted in the detailed patterns

of trillions of electrochemical signals.

Somehow, humans can look at each other

and study the arrangement of facial muscles

and then process that information into an understanding of

other people's thoughts and emotions.

It's an astonishing skill because the cues are so subtle

and the processing is so rapid

that the whole operation runs under your radar.

It only takes 33 milliseconds for your brain to process basic

information about someone's facial expression and start reacting to it.

So we're going to put one electrode right above your eyebrow...

'So how does it do that?'

..and the other right on your cheek. There we go. Great.

'I've invited a group of people to run an experiment.

'I've wired up to a machine that measures movements in their

'facial muscles and I've asked them to look at photographs of faces.'

When participants are looking at a photograph with a smile

or a frown, we see this activity on the graph,

which indicates that their own facial muscles are moving.

Why?

Well, it turns out that they are automatically mirroring,

with their own faces, the expressions that they're seeing.

-That was fun, right, the last one?

-Yeah.

-Yeah, that was a fun test!

But what purpose does this mirroring serve?

I've invited a second group of people.

They're similar to the first group except for one thing.

This is the most lethal neurotoxin on the planet.

If you were to ingest even a fraction of this,

your brain could no longer tell your muscles how to contract,

and you would die of total paralysis.

So it seems unlikely that anyone would pay to have this

injected into themselves, but they do.

This is known as botulinum toxin or Botox.

If you put in your forehead muscles, it paralyses them

to reduce wrinkling.

But there's a less well-known side-effect.

When our participants with Botox went through the same tests,

their facial muscles responded less. No surprise there.

But replicating an experiment out of Duke University,

we had both groups look at facial expressions

and now they were asked to choose the word that best described

the emotion they were seeing.

Panic.

Panicked.

Upset.

On average, the Botox group was worse at identifying

the emotions correctly.

Sceptical?

It seems that the lack of feedback from their facial muscles

impairs their ability to read other people.

The paralysed faces of Botox users not only makes it hard for us

to tell what THEY'RE feeling,

those same frozen muscles make it hard for THEM to read US.

And that tells us something.

When I'm happy or sad, part of that feeling

relies on the unconscious feedback from muscles in my face.

And our social brains take advantage of that,

so when we're trying to understand what someone else is feeling,

we try on their facial expression.

This automatic mirroring of expressions is just one way

in which we understand others.

The brain also has a deeper way,

one that's best explained at the movies.

One ticket, please.

Thank you.

When we go to the movie theatre,

we know full well that it's make-believe.

The people on the screen are just acting.

And yet, we still react. We gasp and flinch and cry.

Why do we fall for it?

To understand why we care about other people getting hurt,

we need to understand what happens in your brain when you get hurt.

So imagine that somebody

were to stab your hand with a syringe needle.

That activates a network of areas in your brain that we call

the pain matrix.

There's no single spot in the brain where pain is processed.

Instead, the perception of pain arises from several different

areas networking together.

Strangely enough,

this pain matrix is at the heart of how we connect with others.

Now, when you watch someone else get stabbed,

your pain matrix becomes activated.

Not the parts that tell you you've actually been touched,

but the parts involved in the emotional experience of pain.

In other words, watching someone else in pain and being in pain

use the same neural machinery and that's the basis of empathy.

To empathise with another person is to literally feel their pain.

You run a compelling simulation of what it would be like

if you were in that situation.

And our capacity to do this is why stories and movies and novels

are so absorbing and why they're so pervasive across human culture

because whether it's about total strangers or made-up characters,

you experience their agony and their ecstasy, you fluidly become them

and live their lives and stand in their vantage points.

You can tell yourself that the stories aren't real,

but some neurons deep in your brain can't tell the difference.

Our capacity to feel another person's pain is part of what

makes us so good at taking other people's perspective,

to step out of our shoes and into their shoes, neurally speaking.

We can't help but connect with others.

We're hotwired to be extremely social creatures.

And that raises a question - what would happen

if the brain were starved of human contact?

In 2009, peace activist Sarah Shourd

and her two companions were hiking in the mountains of northern Iraq,

an area that was at the time peaceful,

but they accidentally strayed into Iran and they were arrested.

They pulled us apart and threw us in separate cells and slammed the door.

And um...

That was the beginning of the next 410 days of my life in that cell.

In the early weeks and really months of solitary confinement,

you're reduced to an animal-like state.

I mean, you are an animal, in a cage.

And the majority of your hours are pacing,

and the animal-like state sort of eventually

transformed into a more plant-like state.

When your mind starts to slow down and your thoughts become repetitive.

Your brain turns on itself

and it becomes the source of your worst pain and your worst torture.

I would relive every detail of my life.

And eventually, you run out of memories and you've told them

all to yourself so many times and it doesn't take that long.

Extreme social deprivation causes deep psychological pain.

Without interaction, the brain suffers.

Solitary confinement is designed to eat away at

and really attack what essentially makes us human.

Sarah's brain used the scant sensory information it had

to construct a reality.

The sun would come in at a certain time of day at an angle

through my window and all of the little dust particles in my cell

were illuminated by the sun.

I saw all of those particles of dust as being

other human beings occupying the planet.

And they were in the stream of life, they were interacting, they

were bouncing off one another, they were doing something collective.

And I saw myself as off in a corner, you know,

walled off by myself, out of the stream of life.

In September 2010, after 410 days in solitary confinement,

Sarah was finally released and allowed to rejoin the world.

But for a long time, she suffered from extreme post-traumatic stress.

The philosopher Martin Heidegger said we can't talk about being,

we can only talk about being in the world.

In other words, the world around you is a part of who you are.

In a vacuum, you lose your sense of self.

It's not easy for science to study people

while they're experiencing solitary confinement,

but a simple experiment designed by neuroscientist

Naomi Eisenberger can give us

an insight into what's happening in the brain when we feel excluded.

It's based on a game of catch.

While volunteers played a computer game of catch, Eisenberger

and her team scanned their brains.

The volunteers thought the other characters were controlled by other

participants, but in fact, they were just part of a computer program.

At first, the other characters played nicely,

but after a while, they'd cut the volunteer out of the game.

And simply play between themselves.

She found that being left out of the game activated the pain matrix.

Not getting the ball might seem insignificant,

but to the brain, social rejection is so meaningful that it hurts.

But that pain, in turn, is useful.

It pushes us in the direction of bonding with others.

We all seek out alliances.

We join with friends, with family,

with colleagues.

It could be which team we support.

What style we go for.

What our hobbies are.

It gives comfort to belong to a group.

And that gives us a critical clue into our success as a species.

Survival of the fittest isn't just about individuals.

It's also about groups.

We're safer, we're more productive, we overcome challenges.

The drive to work in groups has helped human populations

thrive across the planet and build entire civilisations.

And yet, there's a flipside to this drive to come together.

Because for every ingroup, there are outsiders.

And the consequences of that can be very dark.

History is plagued with examples of one group turning on another

that was defenceless and posed no threat.

If you were to look at my family tree,

you would see that most of the branches end in the early 1940s.

This is because my family is ethnically Jewish.

That small social marker was enough to prompt Nazi genocide.

Under normal circumstances,

you wouldn't find it conscionable to go and murder your neighbour.

So what is it that allows hundreds or thousands of people to

suddenly do exactly that?

What is it about certain situations that short-circuits the normal

social functioning of the brain?

While the Nazi holocaust was on an unprecedented scale,

it wasn't unique.

Genocide continued to occur all over the world

and within a generation, it returned to Eastern Europe.

This time, it was in Yugoslavia.

The Bosnian war from 1992 to '95 saw atrocities on both sides.

In one of the worst, more than 100,000 Bosnians Muslims,

known as Bosniaks,

were slaughtered by Serbians in actions known as ethnic cleansing.

One of the most horrible incidents happened here at Srebrenica.

Over the course of just ten days,

8,000 people were systematically killed.

How does something like this happen?

Here in 1995, thousands of Bosniaks took refuge inside this

United Nations compound

because this village was surrounded by siege forces.

But then, on July 11th,

the UN commanders made the decision to expel all the refugees

and they delivered them right into the hands of their enemies,

who were waiting just outside this gate.

Women were raped and men were executed

and even children were killed and this was just the beginning of what

would be the largest genocide on European soil since the Holocaust.

The Dutch were there.

I mean, the world was there, the UN,

the Serbs were there as perpetrators.

Everything was mixed.

The refugees were there, the babies were crying.

I was there, being protected with that UN ID card that said

UN Language Assistant, whatever...

Hasan Nuhanovic's status as a UN translator made him

part of a protected group.

But his family members were marked out by their identity as Muslims.

At that very moment when my family was being sent out of the compound

to actually die, I lost my mother, my brother and my father.

You know, like, you are in a situation where your family

is being killed.

And I was thinking, "My God...

"Why?"

One of the most striking things

is that the perpetrators weren't strangers.

They were people with whom his family had previously shared

a great deal.

The continuation, you know, of the killings, of torture,

was perpetrated by our neighbours.

You know, the very people we had been living with for decades.

They were capable of killing their own school friends.

I remember they said they arrested a dentist who was a Bosniak,

the best dentist in the town.

They tied him up for a light pole, like this.

In front of the post office. He was hanging there like this.

And they beat him with a metal bar, they broke his spine.

And he was there, dying for days, while Serb children went to school.

Walking by his body, you know.

I mean, there are universal values

and these universal values are kind of very basic.

Don't kill.

April '92, this... Don't kill...

suddenly disappeared.

It was like - go and kill.

It was allowed to kill.

This is where Hasan's family is buried and each year,

there are new bodies that are found and identified

and they're brought here.

Many of these graves are fresh.

And across the human species, this is just one genocide of many.

Genocides keep happening. Rwanda, Darfur, Nanking,

Armenia... And my interest is in understanding why.

Traditionally, we ask this question through the lens of history

or economics or politics, and those are all important vantage points,

but I think for a complete picture, one more lens is needed.

We need to understand genocide as a neural phenomenon.

I've been researching this back in my laboratory

and here is my main question - when we interact with someone,

does our brain function differ according to which group they're in?

For every ingroup we belong to,

there's at least one group that we don't.

And that division can be based on anything.

Race, or gender, or wealth, or religion.

We put 130 participants in the scanner.

And here's what they saw - six hands on the screen

and the computer randomly picks one of these

and then that hand gets stabbed by a syringe needle.

Now, that activates the pain matrix, which is what comes online

when you're in pain or you seem someone else in pain.

Now, here's the trick.

We now added a label to each hand -

Jewish, Christian, Muslim, Hindu, Atheist, Scientologist.

And the question is - would they care as much

when they see a member of their outgroup getting stabbed?

So, here's what we found.

Here's a subject and when he watched a member of his ingroup getting

stabbed, there was a large neural response in this area of his brain.

But when he watched a member of one of his outgroups get stabbed,

there was essentially a flat line.

We scanned a range of volunteers

and there are individual differences, but the trend is clear.

A single-word label is enough

to change your brain's basic preconscious response

to another person in pain.

In other words, how much you care about them.

Now, you might have opinions about religion

and its historical divisiveness,

but even atheists here care more about other atheists'

hands getting stabbed than they do about other people.

So it's not really about religion. It's about which team you're on.

This is just the first step in understanding how we get to this.

To understand how groups of people can commit atrocities,

it can help to look at the behaviour of individuals, like psychopaths.

Some of the most callous,

inhumane crimes ever recorded have been committed by psychopaths.

But what's different about their brains that allows them

to act that way?

There are networks in the medial prefrontal cortex that

underlie social interaction.

When we interact with other people, this area becomes active.

But in the brain of someone with extreme psychopathy, this area

has a lot less activity.

A psychopath doesn't care about you.

He might be able to run a simulation

of what you're going to do or how you might react,

but when it comes to an emotional understanding

of what it's like to be you, he doesn't get that.

To him, you're just an obstacle to be worked around or manipulated,

rather than a fellow human being.

So what accounts for genocide? Is it driven by armies of psychopaths?

Well, that can't be it

because psychopaths only make up a small fraction of the population,

but genocide typically engages a wider community.

So here's the question - how do you get ordinary citizens on board?

At the University of Leiden in Holland, Dr Lasana Harris

has been conducting an experiment to understand a piece of this puzzle.

So now we're going to start the experiment.

What you're going to see is a bunch of pictures of different people.

Your job is just to react naturally to those pictures.

Lasana is looking at activity

in the brain areas involved in human social interaction,

in particular the medial prefrontal cortex.

This comes online when we think about other people.

It's less active when dealing with something inanimate, like a cup.

What Lasana found is that this region has a similarly low

response when we deal with certain types of other people.

What he sees now are stereotypical

images of people from different social groups.

What we see here is that this network of brain regions,

including medial prefrontal cortex, is less active

when our participant looks at the homeless people.

So what this pattern of activity

suggests is a type of mental avoidance.

They are not thinking about the mind of the homeless person

in the same way they thought about the mind

of the college student that they saw or the businesspeople.

So if, for instance,

you imagine that interacting with a homeless person will be unpleasant,

it will make you feel bad.

You may feel some demand to donate some of your money

and all of these unpleasant pressures that come along with it.

By shutting off the system, you never experience those feelings.

To a brain that responds this way, homeless people are dehumanised.

They are viewed more like objects and that can enable us to not care.

Of course, if you don't properly diagnose this person

as a human being - which is happening here -

then the different moral rules we have

that are reserved for human people may not apply.

So, under the right circumstances,

our brain activity can look more like a psychopath's.

But to understand how we can get to genocide,

we need to understand one more thing about group behaviour.

Genocide is only possible

when dehumanisation happens on a massive scale -

not just a few individuals,

but whole sections of the population.

We are talking about a group of people committing atrocities.

And if all the members of that perpetrating group are complicit,

it's as if they have all somehow experienced

the same reduction in brain activity

when they think about their outgroup.

This can be understood and studied like a disease outbreak -

a kind of group contagion, one that is most often spread deliberately.

The perfect tool for this job is propaganda.

It plugs right into neural networks

and it dials down the degree to which we care about other people.

Just like all sites of genocide,

that's what happened in the former Yugoslavia.

The people who went on to torture and kill their neighbours

were bombarded with propaganda.

State-controlled broadcasters demonised the Bosnian Muslims

with distorted news stories.

We knew from the beginning

that somebody is helping the Muslims and arming them.

They went so far as to claim that the Muslims

were feeding Serbian children to the lions at the zoo.

Across place and time, the language of propaganda changes very little.

It always plays the familiar tune of dehumanisation.

"Make your enemy less than human.

"Make him like an animal."

Propaganda is a weapon.

And, over the course of human history,

it's become an art and a science

and it's become ever more dangerous.

In our connected age,

any extremist group can reach millions of people with a keystroke.

The internet is the perfect carrier for propaganda messages

to reach the people most likely to act upon them -

young men.

The political agendas around us

actually manipulate the brain activity inside of us.

So is there any way to stop what has happened in the past

from continuing into the future?

One possible solution lies in an 1960s experiment

that was conducted not in a science lab,

but a school.

It was 1968,

the day after the assassination of Martin Luther King.

Is there anyone in the United States

that we do not treat as our brothers?

-Yeah.

-Who?

-Black people.

The black people. Who else?

Jane Elliott was a teacher in a small town in Iowa

and she wanted to show her class what prejudice really felt like.

How are black people treated?

They don't get anything in this world.

-Why is that?

-Because they are a different colour.

These two men were in that class.

This was Rex, back then...

..and this was Ray.

How many of you in here have blue eyes?

OK. How many in here have brown eyes?

Jane says, "We are going to have this exercise,"

and she right away launches into the propaganda

of "blue eyes are better than brown eyes".

Blue-eyed people are better than brown-eyed people.

Ray and Rex both had blue eyes.

You brown-eyed people are not to play

with the blue-eyed people on the playground

because you are not as good as blue-eyed people.

The brown-eyeds were denied privileges given to the blue eyes,

and they had to wear special collars.

You begin to notice today

that we spend a great deal of time waiting for brown-eyed people.

Do you remember what your own behaviour was like

when you were on top?

-I was...tremendously evil to my friends.

-How so?

I was going out of my way to pick on my brown-eyed friends

for the sake of my own promotion.

What did you do?

I recall...telling Mrs Elliott - Jane - that she should keep

the yardstick at hand in case those brown-eyeds got out of control.

I don't see the yardstick, do you?

It's over there.

Mrs Elliott, you'd better keep that on your desk,

so as the brown-eyed people don't get out of hand.

At that time, my hair was quite blonde and my eyes were quite blue,

and I was the perfect little Nazi.

I looked for ways to be mean to my friends

who, minutes or hours earlier, had been very close to me.

But next day, there was a reversal of fortune.

Yesterday, I told you

that brown-eyed people aren't as good as blue-eyed people.

That wasn't true. I lied to you, yesterday.

Oh, boy, here we go again.

The truth is...

..that brown-eyed people are better than blue-eyed people.

The person you trust stands before you

and says, "I was wrong. Now, here's the truth."

Takes your world and shatters it,

like you have never had your world shattered before.

You blue-eyed people are not to play with the brown-eyed people.

Blue-eyed people, go to the back,

the brown-eyed people, come to the front.

It's not fair!

Tell me a little more about what it was like

when you were in the down group.

You have such a sense of loss of personality and self,

that makes it almost impossible to function

with what is going on in the room.

Should the colour of some other person's eyes

have anything to do you with how you treat them?

-CLASS: No.

-All right, then -

should the colour of their skin?

CLASS: No.

Should you judge people by the colour of their skin?

CLASS: No.

If I were just going to riff, guess at it,

it's that one of the most important things we learn as humans

is perspective-taking

and kids don't often get really meaningful exercise in that,

and when you're forced into understanding

what it is like to stand in someone else's shoes,

that opens up a lot of cognitive pathways for you.

I remember saying something to my dad about a comment he made,

saying "No, that's not appropriate."

And it did change within the family.

But you talk about a little kid making that statement, it's huge.

But it reaffirmed that you can do that -

you could begin to change.

The brilliance of the blue eyes/brown eyes experiment

is that the teacher, Jane Elliott, switched which group was on top

and that allowed the students to extract the larger lesson,

which is that systems of rules can be arbitrary.

They learned that the truths of the world are not fixed

and they are not even necessarily truths.

And this is what empowered the children as they grew

to see through the smoke and mirrors of other people's political agendas

and to form their own opinions -

surely a skill we should be teaching to all of our children.

Should the colour of some other person's eyes

have anything to do with how you treat them?

CLASS: No.

GUNFIRE

When people are armed with an understanding

of how propaganda works,

the power of propaganda is reduced.

As we come to understand the deep importance of cooperation,

we stand a chance of not only reducing dehumanisation,

but achieving our potential as a species.

Genocide doesn't have to be the norm.

Instead, our fundamentally social nature

can hold the key to our success as a species.

Our future, our survival,

is intimately, permanently bound up with that of the people around us.

Our social drive is at the root

of extraordinary acts of bravery and generosity.

Who you are has everything to do with who we are.

Our brains are so fundamentally wired to interact

that it is not always clear where each of us begins and ends.

Our species is more than just seven billion individuals,

spread out across the planet.

We are something more like a single, vast super-organism.

Because what your friends know and love as you

is really a neural network,

embedded in a far larger web of other neural networks.

In this age of digital connection,

we desperately need to understand the links between humans.

If we want our civilisations to have a bright future,

we'll need to understand how human brains interact,

the dangers and the opportunities,

because there is no avoiding the truth

that is etched into our neural circuitry.

We need each other.

Next time on The Brain, I am going to look into the future.

What if the brain could do more? Handle more?

What if there were other ways for it to operate?

We will look at how we can use our brains

to control new kinds of bodies.

How our sensory experience can be expanded to new horizons.

We will look at how we might one day separate our minds

from our physical selves.

What if the study of the brain could address our mortality?

What if, in the future, we didn't have to die?

So, what is next for our brains?

What do the next thousand years have in store for us?

And, in the far future, what is the human race going to look like?

What will we be capable of?

We are heading for a fundamental change in the relationship

between the body, the brain and the outside world.

We are marrying our biology with our technology

and that is poised to transform who we will be.