Original subtitles

We all spend our lives

on a search for something so close,

yet always just out of reach.

Some call it the ego.

Others, the soul.

Now modern science is prying into our thoughts,

our memories, and our dreams,

and asking the profoundly puzzling question,

"What makes us who we are?"

Space, time, life itself.

The secrets of the cosmos lie through the wormhole.

Through the Wormhole 03x04 What makes us who we are? Original Air Date on June 20, 2012

== sync, corrected by elderman ==

What is it that makes me me?

Or makes you you?

Is it the things we know?

The people and places we've experienced?

What makes me the same person now as when I was 40?

Or when I was 10?

What is it that gives each one of us

our unique identity?

Scientists are beginning to tackle this profound puzzle.

To do so, they must probe

one of the last great frontiers of our understanding --

the brain.

Every summer, I used to go camping with the Boy Scouts.

Each item of clothing I took with me

had to have my name sewn onto it.

"Morgan."

It was a name I never really liked when I was a boy.

I wondered how my life might be different

if I had been called something normal like Robert or John.

Well, like it or not,

the name I was given framed my identity.

It helped make me who I am.

Happy Birthday!

Look, he's walking!

Show your mom.

Bye!

It's beautiful!

Wish you were here.

Alison Gopnik is on a search

to discover how and when we first understand who we are.

She's a child psychologist

at the University of California at Berkeley.

So, the process of forging an identity,

of figuring out who it is that we are,

that's a process that really takes us our whole lifetime.

But some of the most crucial parts of that

seem to be things that we're learning

in this very, very early period of our lives.

As adults,

it's easy to take our identities for granted.

We accept that who we are now

is the same as who we were a minute ago.

But Alison has discovered

that identity is not so solid for young children.

They spend much of their time

trying to figure out just who they are.

So, when kids are just doing the everyday things that kids do,

when they're playing and exploring and pretending,

what they're actually doing is being involved

in this great, existential, philosophical research program.

What it means to be a person.

One of the first milestones in this program

is called "The mirror stage."

It begins when a child is first able to recognize

his or her own reflection.

The thing about a mirror isn't just

that you see a body and a face, which is fascinating,

but you connect it

to your own kinesthetic feeling of yourself --

the way your own body feels.

Alison uses a clever experiment on her toddlers

to detect which of them have developed an awareness

of their reflections.

She places a smudge of blue ink on their noses

and tells them to look in the mirror.

There we go. There he is.

There he is. Right there. Yeah.

15-month-old John is hardly fazed

by the blue-nosed child staring back at him

because he's not able to recognize

that the child in the mirror is him.

They're interested in the fact

that that baby in the mirror has a spot,

but they don't seem to connect that to the fact

that there's actually a spot on their own noses.

When Alison tries the same test on Karen,

who is just a few months older than John,

she does something quite different.

Look at that!

There we go. Yeah!

What is that?

And now the baby seemed to realize, "oh, yeah.

"That person in the mirror,

that's the same person that I am."

It is a big first step

on a long journey of self-discovery.

But Alison's work has shown that her subjects have

a lot more philosophical research ahead of them.

This is 3-year-old Geneva.

Alison tempts her

with what looks like a box filled with cookies,

but Geneva will soon find out

that she can't judge a box by its cover.

What do you think is inside this box?

Hmm.

What do you think this is?

Good cookies.

Good cookies. Should we find out?

Let's open the box and find out what's inside.

Markers.

Markers! There's markers inside.

Hmm.

When I first showed you this box all closed up like this,

what did you think was inside it?

Markers.

Markers!

Geneva cannot reconcile

that she now knows the box is filled with markers

when she once thought it was filled with cookies.

The concept that there is a you who is the same person

even if your thoughts have changed

is not an understanding you're born with.

It is something you come to learn.

Alison tries the cookie box test with 4-year-old Jim.

I have a question for you.

What?

When you first saw this box all closed up like this,

what did you think was inside it?

Cookies with chocolate chips.

Uh-huh. And what's really inside it?

Markers!

Yeah! That's great!

So, a very important part of my identity

is being able to say,

"Well, when I was 16, I believed different things than I do now,

but I was me who believed those different things."

When children realize

their identities can survive any change in their beliefs,

they stop forgetting the things they don't believe anymore,

and for the first time,

they unlock the astonishing power of human memory.

In this very hall, I used to perform in the choir.

It takes me back.

In this very hall, I used to perform in the choir.

My own memories are so richly detailed,

and I spent many hours in this hall,

rehearsing, practicing.

It just takes me back.

Neuroscientist Donna Addis

is head of the memory lab at the University of Auckland,

where she investigates how memories shape us.

She does this by peering in

to a horseshoe-shaped area in the brain

called the hippocampus.

For the last 50 years, scientists have known

that the hippocampus is critical to the storage of memory.

We learned this thanks to one man,

known as "Patient H.M."

He had severe epilepsy and, in 1953,

received a radical, new treatment.

His hippocampus and part of his inner temporal lobes

were cut out.

After the surgery,

H.M. never suffered a bout of epilepsy again,

but he had completely lost

the ability to form new memories.

He said, "Each day is like waking from a dream."

He had lost his identity.

His sense of who he was was frozen at age 27.

As days turned into decades,

he could no longer recognize

the man staring back at him in the mirror.

How much of who we are

is built upon the memories we make each and every day?

Traditionally, memory research has really focused on the past,

and in the last few years, researchers such as myself

have been looking at the ability to imagine the future

and how memory might actually play a role in that.

Donna and her team set up an experiment

to determine just how the hippocampus and our memories

help us perceive our future selves.

So, what we do is

we have subjects come into the lab

and we have them retrieve around 100 memories.

I remember going to visit my cousin in Germany.

We walked along the beach,

and at the end, there was a cave.

And I gave my grandmother a seashell for Christmas.

And for each memory,

they identify a person, a place, and an object

that might be important.

-The Autobahn. -My mother.

-Two penguins. -Boston.

-My book bag. -Auckland waterfront.

-My girlfriend, Sarah. -The hospital.

-My partner, Wayne. -Eastern Beach.

-Amsterdam airport. -A cave.

A week later, Donna brings her subjects back,

places them in an fMRI machine,

and shows them details from their recalled memories.

But she deliberately jumbles the details.

An object from one memory

has been grouped with a place from another memory

and a person from yet another.

Donna then asks them to make a story

out of these mixed up memories,

to imagine something that has not happened yet

but potentially could.

We ask them,

for each person, place, object that they're seeing now,

to imagine a future event that might happen to them

within the next five years or so.

While the participants are imagining their futures,

Donna measures their brain responses.

To her surprise,

the part of the brain that is vital

to storing memories of the past, the hippocampus,

is blazing with activity.

The hippocampus is playing a really important role,

not only in remembering,

but also allowing us to build these future simulations.

Memory is important not only for the past,

but also for the future,

for building up that sense of who we are.

Our memories are crucial to forming our identities,

but one group of scientists have discovered

that our memories can be manipulated

without our even knowing it.

Are we really who we think we are?

Our ability to remember is truly remarkable.

In the course of our lives,

the average person will grasp the meaning of 100,000 words,

get to know around 1,700 people,

and read over 1,000 books.

From these vast mental stores of experience

we each build our own identity,

a pattern of memories that is uniquely ours.

But what if those memories could be rewritten?

Could we change who we are?

Neuroscientist Tali Sharot

from the University College London

and Micah Edelson

from the Weizmann Institute of Science in Israel

love going to dinner parties.

But they're not just having fun.

They're doing it for the sake of science.

They study how social pressures alter who we are.

Well, imagine a situation

that you're sitting in a dinner party.

You have a pretty good memory of some situation that happened,

and you actually remember it happening in a certain way,

but all of your friends are telling you

that you're actually wrong.

They're saying that something else happened.

And Tali got the umbrella, and she slid the umbrella

- through the letterbox. - Are you sure it was Tali?

No, no, no. I'm quite sure it wasn't me.

No, it was definitely you. You were definitely holding the umbrella.

It was definitely Steve.

I really thought it was Tali, though.

No, because we were really impressed

that Steve managed to hook it around.

Remember? We had that big fanfare

because we were out in the rain.

When someone changes their memory

so that it fits other people's opinion,

do we actually change a signal in the brain

that is representative of the memory,

or is it just that we try to please other people?

Social pressures

can make us change the way we tell stories.

But can they also make us change the stories we tell ourselves?

Our actual memories?

Tali and Micah set up an experiment to find out,

not in a restaurant, but in a lab.

They bring in a group of volunteers

to watch a film together.

Afterwards,

the volunteers answer basic questions about the film

to test what they remember.

A few days later,

the participants take the same questionnaire

inside a brain scanner,

only this time, Micah and Tali apply a social pressure.

This time, they were exposed to fake answers

that were supposedly given by their fellow group members.

The group is led to believe

that the others who took the test

remembered the character in the film was not wearing a hat.

And most people changed their answers

to go along with the crowd.

Almost 70% of the cases,

the participants conformed and they gave a wrong answer,

even though they were initially pretty confident

about the correct answer.

But were they just outwardly complying with a social norm,

or did their memories actually change?

So, we test them again a week after,

once we've removed the social pressure.

And we assume that if they're still making an error,

that means that their memory was actually changed.

Tali and Micah found

that most test subjects stuck with the wrong answer

even without peer pressure.

The falsehood has taken root in their brains.

It actually causes a long-lasting memory error,

and using our brain data,

we are able to actually identify

when such a long-lasting memory error will occur.

The brains of those people who changed their memories

showed high activity not just in the hippocampus,

where memories are stored,

but also in a part of the brain

that is connected with emotional and social responses,

the amygdala.

A lot of what we know

about the amygdala and its function

comes from the animal world.

So our reaction to anything that's emotional --

if we suddenly hear a noise which is frightening

or of processing emotional expressions on one's face --

the amygdala is crucial for all of these functions.

And it probably helps us increase memory

because, in a fearful or emotional situation,

the amygdala activation is heightened

and it also increases activation

in related structures like the hippocampus.

The amygdala is like a bouncer at a nightclub.

It decides which memories

get to play a part in shaping our life histories.

The ones that carry emotional weight are allowed in.

The ones that don't are not.

The participants who changed their memories

were emotionally affected by the pressure to conform,

setting their amygdalas ablaze,

and the false memory snuck in.

So, by looking at amygdala activation,

we can actually predict

which memories are gonna be changed for a very long time

and which are not.

You have to realize

that memories are not like a videotape.

'Cause people can be extremely confident

that things happened like they think they happened

when they didn't.

Our memories are not just a record

of the events that took place in our lives.

They are malleable and fallible.

Our identities are created with constant input from our society.

No man is an island.

But could we go a step further

and deliberately re-engineer someone's identity?

To do that,

you have to be able to peer into a person's innermost thoughts,

and believe it or not,

that technology is already here.

We are all actors, to some extent.

Who we appear to be can change

depending on our mood or the company we keep.

But there is one time

when who we really are comes to the fore --

when we dream.

What if we could see our dreams and study them?

Could we know each other

in a more profound way than ever before?

During an average life span,

a human being spends about six years dreaming.

That's more than 52,000 hours of imagery

buzzing through our unconscious brains.

Computational neuroscientist Yuki Kamitani

believes one day it will be possible

to watch and record what people are dreaming.

When that happens,

we will all get to know ourselves

on a much deeper level.

I believe that if we can reconstruct

or decode the contents of a dream,

the identity is revealed.

If we remember our dreams,

it is often as a series of emotionally charged images.

In fact, scientists have found

that the visual cortex of a dreaming brain

is highly active.

Patterns of electrical activity wash over it,

which makes Yuki wonder,

can we learn to read those patterns

and convert them into images on a computer?

Brain activity can be seen as a code or an encrypted message

about what's going on in the visual world.

The patterns of images we make in our brains

are highly distorted,

in the same way a pair of shattered glasses

distorts our view of the world.

But if we collected data

on hundreds of images seen through those shattered lenses,

we could find a correspondence

between the distorted images and the real ones.

It might take a while,

but if we gave that job to a powerful computer,

it could decode the scrambled images into recognizable ones.

And this is how Yuki tries to crack the code

that turns images

into patterns of activity in the visual cortex.

We measure the brain activity of human subjects,

and we let the subject go into the scanner

and scan their brain.

And during that,

we present some images to the subject.

Typically several hundreds or thousands of images

in single experiment.

The images Yuki shows people

are simple black-and-white shapes --

a square, a cross, a line.

Using a powerful computer array,

he records the precise pattern of activity

in the visual cortex.

After multiple trials with the same person,

the computer learns to distinguish

the patterns triggered by each image.

In other words,

the computer can judge purely from the brain activity

which of the shapes the subject is looking at.

And then Yuki does something remarkable.

He shows the subjects brand-new images,

images the computer has never seen,

and lets the computer try to draw a picture

of what the subjects are seeing.

These are the images

the computer reads inside people's brains.

And these are the images they are actually looking at.

This is the first time

anyone has been able to know what people are seeing

purely by looking at their brains.

Looking at the visual cortex,

we have just succeeded in reconstructing seen images.

We are now trying to reconstruct imagined images

or images in your dreams.

Yuki's method, as yet,

only works on pixilated black-and-white images,

but with a few more years of refinement,

Yuki believes we will be able to record our dreams

as full-color, high-definition movies.

And that would truly be a window into our souls.

Those, you know, unconscious aspects of our mind

defines what we are and what the identity is.

So, I think if we can reveal some dream contents

which someone is not aware of,

then that might reveal some deep property of that person.

Our true identities

could soon be laid bare for all to see,

including the parts we don't want seen,

like our deepest-held secrets and fantasies.

But you may not have to worry.

Because the power to edit the contents of our minds

is close at hand.

Our brains are filled with memories.

Some of them bring us joy.

Others make us wish we could forget.

Whether we like it or not,

our memories shape how we think and how we act.

But now one group of researchers thinks it has found a way

to change memory and perhaps change who we are.

Can we deliberately change our sense of identity?

Neuroscientist Andr? Fenton from the State University of New York

doesn't see why not.

To him, the brain

and its pathways of connections between neurons

are like the labyrinth of streets in New York City --

a maze he navigates on his daily runs.

And just like Manhattan traffic,

conditions for the flow of electricity around the brain

are not the same on every route.

If you experience something,

there's been an electrical activation

somewhere in the brain

that spreads through the brain,

and that is your experience.

As in a city,

there are roads that connect one district to another district,

and those roads can be very big boulevards

that send a lot of traffic,

or they can be small alleys that send very specific information,

but nonetheless, not very rapidly or very easily.

For years,

scientists thought the pathways in our brains

were set in stone after we matured from babies to adults.

Alleys could not become wider.

Highways could not become narrower.

But now it has become clear

that the roads in our adult brains

are under constant construction.

Every time we store a new memory,

electrical activity propagates through millions of neurons.

Just as Andr? is forced to find a new route

if his pathway is blocked,

our neural pathways adjust themselves

to process and record new experiences.

And so, what neuroscientists understand is

that there's a sufficient amount of this plasticity

throughout life,

and that it is affected

and modulated and controlled by experience.

Recently, scientists have identified

a molecule in the brain

that jumps into action when we are forming new memories.

It is called PKMzeta.

PKMzeta stands for "protein kinase mzeta."

It's my favorite molecule.

When PKMzeta gets told to deploy in a neuron,

it gets told to do that

on the basis of a recent experience,

and what it does is it mediates efficient

or increased efficiency of neural transmission.

When a memory needs to navigate its way

through the traffic of our brains,

PKMzeta clears the way,

making sure the memory safely reaches long-term storage.

Those long-term memories,

the ones that you form now and you will keep forever,

that kind of information storage seems to be mediated by PKMzeta.

But Andr? knew of a chemical

that could neutralize PKMzeta,

called zeta inhibitory peptide, or ZIP,

and he wondered if he injected it into a living brain,

could he prevent it from forming long-term memories.

So, the logic of the experiment we did

is very straightforward.

What you want to do is produce a memory.

A rat is in a rotating carousel,

and the key here is that

whenever it enters that part of the floor,

it becomes electrified.

And so, they very quickly and rapidly learn

to stay away from that part of the room.

In this computer-generated read-out of Andr?'s experiment,

the rat runs around the carousel

but consistently avoids the triangular-shaped shock zone.

30 days later, Andr? puts the rat back in the chamber

and observes that it still remembers to stay away.

It has stored a new long-term memory in its brain.

But when Andr? injects the rat's hippocampus with ZIP,

he sees something extraordinary.

When the rat is put back in the carousel one more time,

it runs right over the shock zone

as though it had never been shocked before.

You could see that the animal behaved

more or less like a naive animal,

so it was very exciting.

Andr? has erased a piece of the rat's memory.

The ability to forget people we have met,

places we have been, things we have done

is now a pharmaceutical possibility.

But Andr? can't see inside his rat's brain,

and so he cannot be sure

how many memories the ZIP molecule erased.

As we begin to work out

the synaptic organization of memories,

we'll then be in a position to understand

whether it's possible

to actually make selective manipulations

of particular memories.

We are always going to be confronted

with the possibility of erasing all memories,

which could never be a good idea.

Using ZIP to erase a specific memory

is still a ways off.

But in Montreal, one doctor has found another way.

He is washing away painful memories

that make his patients prisoners inside their own identities.

Who we are depends on where we have been,

who we have loved, who we have lost.

For some of us, painful memories can linger like an open wound.

They can hold us back from becoming who we want to become.

Doctor Alain Brunet is a psychologist

at McGill University in Montreal.

He specializes in treating people

with post-traumatic stress disorder.

Alain himself has a deep understanding for the condition.

In 1989, at the University of Montreal,

a deranged man carried out the worst mass shooting

in Canadian history.

Alain was on campus,

studying for his master's degree in psychology.

He shot -- he went through the corridors.

He shot 12 women,

and eventually there were 13 deaths.

The crisis intervention

that had been conducted after this event was very poorly done,

and many of us were left with a bad taste in our mouth,

and so, it did have a profound effect on me

and on what I decided to study.

This horrific event started Alain on a path

that he is still following today.

He helps people who suffer from PTSD

get back a part of themselves that seems to be lost.

PTSD can be conceived as a disorder of memory.

Because in a sense,

it's really about things that you wish you'd forget.

That memory has been burned into your brain

and is way too powerful,

and it's making you fearful

in situations where you shouldn't.

Memory is a little bit like writing with ink.

So, you can see that the ink is still wet.

If I use my fingers and go over my writing,

it will smear what I just wrote.

And this is exactly like the workings of memory.

But when a memory is emotionally powerful,

proteins in the brain

build connections between neurons

and the memory is transferred

to a separate long-term storage area.

There, it leaves a lasting impression.

Once the ink is dry, the memory is there for good.

Of course, it might fade with time,

but that memory will still be accessible.

Many scientists believe

that once the ink of a memory is dry,

it is fixed and indelible.

But Alain believes that every time we recall a memory,

it is like we are creating a brand-new memory all over again.

When you recall a memory,

it becomes active again,

and it becomes buzzing with electrical activity.

It's really a little bit like

if you were rewriting the word "Rouge" again with fresh ink.

The moment someone recalls a painful memory,

Alain believes he has an opportunity to modify it.

I've had a lot of traumatic events happen in my life,

which I was able to, you know, work through and live through,

but then the death of my daughter --

it was too much.

I couldn't function. I couldn't work any longer.

I had absolutely lost who I was.

There's no doubt about that.

Lois Bouchet, who has come to Alain for help,

is in for an intense treatment.

As a first step,

he asks her to methodically recall her painful memory

by reading aloud a personal account of the traumatic event.

Okay.

"I heard the doorbell at 5:00 a.m.

"I went to the door in my nightgown,

"thinking it was my daughter.

"When I saw that it was the police,

"I excused myself to go get my housecoat on.

"As I'm walking down the hallway to the bedroom,

they ask if anybody is at home with me."

While Lois reads,

she's under the influence

of a drug Alain administers called Propranolol,

a simple beta blocker that reduces high blood pressure

and has a well-known side effect of slight memory loss.

"I know that something is terribly wrong.

"I get a knot in my stomach.

"My heart starts beating faster,

"and I can feel myself shaking inside.

"When I come back to the living room,

"he tells me Nikki has been hit by a truck on the 401

"and my Nikki is dead.

"All of a sudden, I crouch down

"and start to sob uncontrollably.

"The pain is incredible. My chest hurts.

I think, 'How can I make it through this?'"

they did that once a week for six weeks,

and then we tested them with a battery of tests, interviews,

and psychophysiological measurement of their responding

while they're listening to an account of their trauma.

After six weeks of treatment,

70% of Alain's patients

show hardly any signs of PTSD symptoms.

They could talk about the pain

without being forced to relive it.

And that really blew our mind,

because they had only received one small dose of a medication,

and those people had been suffering from PTSD for decades.

Alain's patients

have written over their traumatic memories.

They have a second chance to reclaim their lives

and to reclaim a sense of self.

As you carried on, it got easier.

You never forgot the feelings.

Like, I'm always gonna be upset about it.

My daughter died. That's never gonna go away.

But now I can think about what happened

without feeling like I'm going to lose my mind.

With trauma,

there will always be a time before and a time after,

but in my opinion, people gain back their old self.

Alain seems to have found the fine-tuned tool

that can target specific memories.

But even if we can envision a time

when our identities can be transformed or restored,

we still haven't grasped the most fundamental aspect

about what makes us who we are.

What is it that makes our brains

able to question who we are in the first place?

One man thinks he has the answer.

He's trying to re-create

the essence of what makes us us

in pieces of silicone hardware.

The core of who we are

is something we carry with us everywhere we go.

It lives somewhere in the web

of billions neurons in our brains.

Now some scientists are trying to discover

if this biological network can be replicated

in silicone hardware,

whether we can build a robot that will ask itself,

"Who am I?"

Computer engineer Steve Furber

from the University of Manchester

is on a quest to find out

if a human identity can be built.

He is attempting to make the first replica of the brain

that works in real time.

If he succeeds,

he could unlock the secret of what makes us who we are.

I think the whole issue of understanding the brain

is fascinating.

It's so central to our existence.

We're pretty sure that our understanding of the brain

is missing some fundamental ideas,

and one of these is

how information is represented in the brain.

Steve believes

there is a neural code that runs our brains,

that one code is responsible for controlling multiple jobs --

seeing, hearing, learning language.

It's just a matter of finding out what the code is.

He suspects the best place to look

is in the part of the brain that is far more evolved in humans

than in other species --

the thin, wrinkly, outer layer called the neocortex.

So, the neocortex is a very interesting area of the brain

because it's pretty much the same at the back,

where it's doing low-level image processing,

and at the front,

where it's doing high-level functions.

So, if you're born without sight,

a lot of your visual cortex

will be taken over processing sound.

And it's quite common that people who don't have sight

have much more acute hearing.

So there must be something in common

about the algorithms that are used there,

if only we could see what that was.

Computer engineers

have been trying replicate biological brains for decades,

using standard computer technology.

But Steve believes they've been going about it all wrong.

In a conventional computer,

data gets moved around in large chunks.

That would be like a chef

dumping an entire dinner and dessert into one pot

and serving a pile to one unfortunate customer.

But the brain is more like a cocktail party.

Small bits of data are passed around and shared.

Before you know it, connections are being made

and a complex situation is underway.

This highly interconnected way to arrange small packets of data

is what Steve wants to replicate

in a custom-designed silicone circuit.

He has created a brand-new type of computer chip

specifically engineered to mimic

the way neurons work in the brain.

It is called the SpiNNaker chip.

SpiNNaker is a compression

of spiking neural network architecture.

If you say it quickly enough, it comes out like "SpiNNaker."

The SpiNNaker chip is a massively parallel computer

designed to run models of the brain in real time,

which means that our model runs at the same speed

as the biology inside your head.

Each one of Steve's SpiNNaker chips

can be programmed to replicate the behavior of 16,000 neurons.

That's only a tiny fraction

of the 100 billion neurons we have in our brain,

but it is a significant step beyond

anything that has been done before.

Steve and a team from the Technical University of Munich

are now wiring these brain-like chips to robots.

This might look like a remote-controlled toy,

but it is not.

It is controlling itself by sensing the world around it.

So, the robot is basically following the line

entirely under neural control.

It has a vision sensor on the front.

The vision information is being sent into the SpiNNaker card.

The SpiNNaker card is executing the real-time neural network,

and then the outputs from the SpiNNaker card

are being sent back via the laptop to the robot

and controlling its movement.

The brain is over there, and the body is over here.

The robot's SpiNNaker chip brain

mimics the way a real biological brain works.

Just like a child,

it interacts with its environment

and uses its physical body to understand the world around it.

The more it experiences, the smarter it gets.

Our current systems have four chips on.

They can model about 50,000, 60,000 neurons.

In a few months' time,

we'll have boards about 10 times bigger than that,

and they'll be getting up to the level of complexity

of a honey bee, which has 850,000 neurons.

And then beyond that, we'll build systems

and get up to mammalian brain sizes.

The human brain is a formidably complex system,

and it would take millions more SpiNNaker chips to build one,

but Steve is confident it is possible.

If you had a model of the mind running in a machine,

I don't see why it shouldn't behave in exactly the same way.

The question of whether machines modeling the brain

may ultimately be capable of supporting the imagination,

dreams, and so on

is a very hard question,

but I don't see any fundamental reason

why we shouldn't expect that.

Steve believes

that human brains run on simple algorithms,

and what works for humans will also work for his machines.

The journey to forming an identity begins

when a body, guided by networks of neurons,

struggles to navigate its way through the world.

It learns, adapts, remembers,

and eventually becomes self-aware.

What makes us who we are?

Our identities are built bit by bit

from our memories, our dreams, and our imaginations.

No one's sense of self is fixed.

Life is a journey that makes us all unique,

and discovering who we are

is our greatest and longest adventure.

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