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MICHAEL MOSLEY: This man is blind.
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Yet he can climb
the world's most terrifying peaks.
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These fishermen can see under water
better than almost anyone else on Earth.
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And this delightful young girl
is alive and well
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despite having just half a brain.
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Their stories are part
of YOUR story...
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...the story of what makes YOU human.
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Hidden deep under your skin
is a wonderful inner universe...
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...a place of raging torrents,
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electrical storms...
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...and triumph against the odds.
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This is a fantastic voyage through
the most extraordinary organism on Earth.
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the human BODY
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how our brain is made
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Strange as it might seem,
this bizarre-looking creature is you.
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Or rather, what you look like
just three weeks after your conception.
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This was when your brain was born.
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It was the start of an
astonishing transformation...
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...as you went from
a small handful of brain cells...
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...to the exquisite network
of a hundred billion brain cells
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that you carry around
inside your head.
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We call this transformation...
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childhood.
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It's a remarkable time that we'll
share with three young girls,
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each on the brink
of momentous change.
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Baby Phoebe is rapidly
growing brain connections
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as she discovers her senses.
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Eleven-year-old Wendy
is learning to speak.
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Not one,
but eleven different languages.
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And Stephanie teenage brain is
pushing her to explore a wild side.
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Together, they reveal the extraordinary
story of how you built your brain.
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It all started before you were born.
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In the womb, you grew 8,000
new brain cells every second.
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By the time you were
ready to be born,
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you had all the brain
cells you'd ever need.
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But this baby is about to experience
the shock of her life.
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Come on, big, big push. Big push.
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Push down.
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Don't scream, just push. Get angry
and push down into your bottom.
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Come on. Push.
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It's got hair!
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What time is it?
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It's, er, about...
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This is Phoebe.
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As she emerges,
her eyes are dazzled by light.
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She's come from a gloomy, watery
world into a bright, noisy room.
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It's time for her
to meet Mum and Dad.
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Oh, that was...
that was pretty difficult.
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Yeah.
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And hot.
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MIDWIFE: I think we gathered that.
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And painful.
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And...there is a reason
why it's "labour"!
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Phoebe's brain is being flooded
with new sensations.
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The chill of the room.
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The smell of her dad.
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Hello.
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And, most puzzling of all,
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the strange images that
are pouring in through her eyes.
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The lens that lies in the centre of the
eye can't focus on anything for long.
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Even so, newborns recognise their
mum's face after just a few hours.
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At the back of the eye
is the red plane of your retina.
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Here, light from outside shines down,
casting images across the surface.
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Underneath, these rays
enter a dense forest
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of 125 million light-sensitive cells.
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These rod cells each detect
just a tiny part of any image.
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They send these fragments to your brain,
which has to piece it all together.
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Phoebe's rod cells give her the ability
to see things that move quickly.
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They also allow her
to see in the dark.
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(?) And incredibly ??? working when
she was still in her mother's womb.
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Your rods are so sensitive
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they could detect the dim light that
passed through your mother's belly.
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So, they were training your
brain to see in black and white
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months before you were born.
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But in daylight, the amount of light
around can increase a millionfold.
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And just like the
moment of your birth,
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this totally bleaches
out your night vision.
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So, a whole new set of sight
cells spring into life:
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your cones.
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You have a richer experience of the
world than most other mammals
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because your cones detect not two
but three different colours.
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In one location,
they begin to group together,
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causing the retina's
surface to bulge.
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Year after year,
they continue to rise,
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creating a volcano-like structure.
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It's not until you are four years old
that the mound is finished.
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This is your fovea.
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It's the only part of your eye
where your vision is crystal clear
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and, thanks to your cones, capable of
sensing millions of different colours.
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But the complexity
and the beauty of the human eye
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is nothing without your brain.
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You blink up to 20 times
every minute.
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Each blink lingers
for less than half a second.
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But add all those blinks of an eye up
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and you're living in the dark
for over an hour every day.
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Your brain is so good
at filling in the gaps
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that you're not even aware of it.
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Your eyes are an
extension of your brain.
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They are so adaptable
that you can learn to see
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in places where human
eyes normally struggle.
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This is the remote
Thai island of Koh Surin,
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home to a group of sea gypsies
known as the Moken.
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To survive, they've become
expert underwater foragers.
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Finding food underwater
is difficult,
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particularly without goggles.
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That's because our eyes
have adapted to see clearly in air.
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In water, the world becomes blurry.
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As you descend,
light levels drop quickly.
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Your eye reacts by
opening the iris,
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making the pupil larger
and allowing more light in.
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The image becomes brighter,
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but underwater, a larger pupil
also makes the image more blurred.
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But Goon has learnt how to overrule
this automatic reflex
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with an astonishing adaptation
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seen clearly with the help
of an infrared camera.
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Instead of opening his pupils, he
closes them as far as they will go.
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This means Goon can see twice
as well underwater as you or I.
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Recent studies suggest that any child
can quickly learn this trick.
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The Moken show how well the human brain
can adapt the body to suit its needs.
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This adaptability
has enabled our species
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to thrive on all seven
of Earth's continents.
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But at three months old,
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Phoebe's brain is still hopeless
at pretty much everything.
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Hey! Hey, Phoebe!
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It can tell her mouth to suck
but can't feed itself,
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can't maintain body temperature,
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can't even control
when she goes to the loo.
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I now am utterly and totally
responsible for another human being
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who has to take priority
over my life in everything.
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She has to come first,
otherwise she can't survive.
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Phoebe is so very helpless because
her brain is still getting organised.
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Bit by bit,
her brain is creating her mind.
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This remarkable time lapse
shows living brain cells
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sending out tendril-like arms,
which connect with each other.
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Each of Phoebe's
hundred billion brain cells
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will, on average,
make 10,000 different connections...
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and we can follow this
on the outside.
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Oh, I've gone away!
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At six months, Phoebe thinks
that when she can't see someone
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they vanish from the world entirely.
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I'm here.
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Watch Phoebe's face
as Charlotte hides.
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- Now you don't see me.
- She immediately loses interest.
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Where's Mummy gone? Where's
Mummy gone? Shall I come back?
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But when her mother reappears...
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- I've come back!
- her delight is obvious.
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I'm here! Yes, I am!
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Going to come back, I'm here.
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- Where's Mummy gone?
- Three months later,
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and Phoebe's brain has now learnt
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that just because something is hidden
doesn't mean it's disappeared.
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Here I am! Yes!
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A childhood game of peekaboo
has helped her build connections
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that will stay with her
for the rest of her life.
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And the longest connection
Phoebe's brain will ever make
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is the one between
her head and her toes.
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Remarkably, the connection
between your head and your toes
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won't be fully mature
until you are three years old.
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Long before that,
your brain just can't resist
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the urge to take its first big step,
as you try to walk.
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Learning to balance and
coordinate your body is so complex
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that the area of your brain
devoted to this one task
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involves as many cells
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as the whole of the rest
of your brain put together.
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Some people learn how to walk
sooner than others.
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But there is a place where
people pull off this feat
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sooner than anywhere else.
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This is Kaumba.
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She is mother to a
baby girl called Kosini.
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They live in Rhumsiki,
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a tiny village in the remote
northern highlands of Cameroon.
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Here, mothers are keen
to get their babies off their backs
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and walking as soon as possible.
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Ever since Kosini was a month old,
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her mother has repeated
the process of "kitete",
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which means "to make jump".
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Every day, she takes hold
under the arms and bounces her.
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Kosini responds with
a kind of stepping reflex.
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You had this reflex, but it
disappeared after a couple of months.
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But here in Rhumsiki,
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this daily encouragement
means that the reflex remains
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and gradually develops
into mature walking.
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Now she's seven months old,
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it's time for Kosini to try
and stand up by herself.
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So her mother sets about
another ritual practice.
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She washes her
with a warm herbal liquid.
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This seems to stimulate her legs,
preparing them for walking.
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The leftover warm leaves
are laid on the ground
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and Kosini is placed on them.
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It's uncomfortable and
she soon wants to get off
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giving her the gentle encouragement
she needs to use her legs.
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These rituals seem
to be accelerating
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the connections that Kosini is making
between her brain and her feet.
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But before you can stand
up for any length of time,
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there is a strange part of your body
that your brain must learn to understand.
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This cavern is buried
deep inside your head.
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It's part of a labyrinth of twisting
tunnels completely submerged in fluid.
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00:19:45,560 --> 00:19:50,830
The tunnels are the three great
loops of your semicircular canals.
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(?) Inside each loop, there is a saddle
top flashing mountain, your crista.
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00:20:11,700 --> 00:20:17,400
(?) The mountain slips are covered
in a thick forest of tiny hair cells.
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For the moment, they lie still.
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But this inner sea never
remains calm for long.
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As you move your head,
it generates a shockwave
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which races through the tunnel
and pummels the mountain.
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00:21:00,420 --> 00:21:05,540
On its flanks, the hair cells are
thrown about in the turbulent waters.
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(?) The pressure builds until electricity ???
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grating a powerful electrical current.
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00:21:25,930 --> 00:21:30,100
All this activity going on
inside your semicircular canals
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creates your sixth sense:
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your sense of balance.
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00:21:44,340 --> 00:21:51,390
To walk, your brain has to sense when
you are overbalancing to one side
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00:21:53,740 --> 00:21:59,610
and then instruct your body to shift
your weight back to the centre.
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00:22:00,140 --> 00:22:04,220
All of this has to happen
within a fraction of a second.
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00:22:08,100 --> 00:22:11,750
To begin with,
it's a real struggle.
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00:22:15,900 --> 00:22:22,210
But Kosini's half-brother, Tisema,
is already a master of bipedalism.
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00:22:22,520 --> 00:22:25,090
He is just ten months old.
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00:22:25,100 --> 00:22:29,750
At his age, most children are
shuffling around on their bottoms.
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00:22:32,300 --> 00:22:35,370
From now on,
and for the rest of Tisema's life,
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00:22:35,380 --> 00:22:37,990
walking will be automatic.
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By the age of one, your brain has
made over 500 trillion connections.
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So many, that your brain can
cope with almost anything
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that life throws its way.
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00:23:08,940 --> 00:23:12,340
Angelina is a rather
remarkable one-year-old
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because she was born
with just half a healthy brain.
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She has a rare disease
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which affects the blood vessels
on the right side of her head.
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She's a happy, active little girl,
but every now and then...
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Angelina? Angelina?
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00:23:35,590 --> 00:23:36,680
Angelina?
230
00:23:36,690 --> 00:23:39,100
Angelina?
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00:23:39,560 --> 00:23:42,840
You all right? OK?
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00:23:44,840 --> 00:23:47,810
Angelina's having what we
call a complex vocal seizure.
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As you can see, she was very, very
active and now she's gone very distant.
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00:23:52,410 --> 00:23:55,310
One indication
is that her head lags.
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She's slightly heavy
in her breathing.
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00:23:59,550 --> 00:24:05,170
Angelina has a rare condition,
Sturge-Weber syndrome.
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This one is going on quite a bit,
isn't it?
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00:24:07,960 --> 00:24:10,990
Angelina? Angelina?
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00:24:11,000 --> 00:24:12,870
Her parents, Lisa and Stephen,
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00:24:12,880 --> 00:24:17,310
have had to deal with her seizures
ever since she was born.
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00:24:19,180 --> 00:24:23,830
Angelina's brain scans show
the cause, abnormal blood vessels,
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00:24:23,840 --> 00:24:27,950
seen here in white,
on the right side of her brain.
243
00:24:29,520 --> 00:24:35,350
But they also show that the left half
of her brain is perfectly healthy.
244
00:24:40,400 --> 00:24:42,830
There is a treatment
for her condition,
245
00:24:42,840 --> 00:24:45,990
but it involves radical surgery:
246
00:24:46,220 --> 00:24:51,310
cutting off the damaged half
of Angelina's brain.
247
00:24:52,600 --> 00:24:56,190
We're in a position we don't know what
we've got to face after this operation.
248
00:24:56,200 --> 00:24:57,990
I pray to God
she comes back to us at all,
249
00:24:58,000 --> 00:25:01,560
but what she does come back as,
we accept.
250
00:25:08,900 --> 00:25:13,430
The surgeon who must navigate
his way through Angelina's tiny brain
251
00:25:13,440 --> 00:25:15,890
is Mr. William Harkness.
252
00:25:17,140 --> 00:25:21,930
We've lifted the bone flaps, so
we've made our trap door in the skull.
253
00:25:23,220 --> 00:25:26,120
And now we're beginning
to see the brain.
254
00:25:28,340 --> 00:25:31,350
It seems impossible
that you can disconnect
255
00:25:31,360 --> 00:25:35,310
half of someone's brain
and expect them to recover,
256
00:25:35,320 --> 00:25:39,690
yet that is exactly what
the surgeons are hoping will happen.
257
00:25:39,700 --> 00:25:42,780
Because the brain does adapt
at this age of life,
258
00:25:42,790 --> 00:25:45,970
we would expect most of the functions
to transfer to the other...
259
00:25:45,980 --> 00:25:48,110
other side of the brain.
260
00:25:49,640 --> 00:25:52,250
It takes four hours
of micro-surgery
261
00:25:52,260 --> 00:25:57,730
to find the bridge between
the two sides of Angelina's brain.
262
00:25:58,940 --> 00:26:02,060
And this is what's called
the corpus callosum...
263
00:26:02,460 --> 00:26:07,110
which connects one side
of the brain to the other.
264
00:26:07,820 --> 00:26:10,940
Now, he cuts through it.
265
00:26:10,950 --> 00:26:14,010
Angelina's healthy brain
is finally free
266
00:26:14,020 --> 00:26:18,410
from the disruption caused
by the damaged right half.
267
00:26:27,060 --> 00:26:29,590
Hopefully, if this child
becomes seizure-free,
268
00:26:29,600 --> 00:26:33,010
I think that we will have given her
the best opportunity for the future
269
00:26:33,020 --> 00:26:37,920
because the type of epilepsy that
she had clearly is life-threatening.
270
00:26:48,030 --> 00:26:50,340
She's so sleepy.
271
00:26:52,780 --> 00:26:54,550
I haven't even given
her a kiss yet.
272
00:26:54,560 --> 00:26:57,340
- Haven't you?
- No. Come here, lovely.
273
00:27:00,530 --> 00:27:02,940
Come on, my darling.
274
00:27:03,380 --> 00:27:04,430
Hello, sweetheart.
275
00:27:04,440 --> 00:27:06,760
Who's a strong little girl, eh?
276
00:27:06,860 --> 00:27:10,070
Who's Daddy's strong little girl?
277
00:27:10,740 --> 00:27:12,900
You have a nice dream.
278
00:27:12,910 --> 00:27:17,330
All her parents can do
is wait and hope.
279
00:27:17,680 --> 00:27:22,230
It was essential for Angelina
to have the operation at this age
280
00:27:22,830 --> 00:27:24,620
because after your first birthday
281
00:27:24,630 --> 00:27:28,720
your brain loses
some of its flexibility.
282
00:27:29,430 --> 00:27:31,950
While there's still room
for plenty of development,
283
00:27:31,960 --> 00:27:36,290
there's less scope
for fundamental change.
284
00:27:43,310 --> 00:27:48,330
But as your young brain starts to explore
the world from its new, lofty position,
285
00:27:48,340 --> 00:27:51,660
there is an immediate and
rather wonderful consequence.
286
00:28:01,690 --> 00:28:06,570
That's because walking releases
two powerful natural tools:
287
00:28:07,420 --> 00:28:09,080
your hands.
288
00:28:09,090 --> 00:28:13,270
I've kind of developed a skill with
my hands that when I touch things,
289
00:28:13,280 --> 00:28:15,690
I get information from it.
290
00:28:17,320 --> 00:28:20,390
A bit more than an average human.
291
00:28:28,400 --> 00:28:31,510
From a young age,
street magician Dynamo
292
00:28:31,520 --> 00:28:35,760
has been fine-tuning the
control of his hands.
293
00:28:39,540 --> 00:28:41,770
If I put a pack of cards
into your hand,
294
00:28:41,780 --> 00:28:44,810
you'd just feel the edges
of the cardboard, right?
295
00:28:44,820 --> 00:28:48,910
Whereas I can actually feel how many
cards there is in the, you know, in the...
296
00:28:48,920 --> 00:28:50,760
in my hand.
297
00:28:52,020 --> 00:28:56,560
I've built up, you know,
a sense that allows me to do it.
298
00:29:00,030 --> 00:29:04,670
His hands are so nimble
your brain cannot keep up with them.
299
00:29:39,790 --> 00:29:46,030
Your hands' versatility springs from
a mixture of strength and sensitivity.
300
00:29:46,040 --> 00:29:49,160
At the tip of each finger is the
densest collection of nerve receptors
301
00:29:49,950 --> 00:29:53,530
found anywhere on your body...
302
00:29:54,790 --> 00:29:58,900
feeding your brain with information
about the temperature, pressure
303
00:29:58,910 --> 00:30:02,720
and vibrations of anything you touch.
304
00:30:06,310 --> 00:30:09,880
They're so sensitive
they can detect lumps and bumps
305
00:30:09,890 --> 00:30:13,760
less than a 100th
of a millimetre across.
306
00:30:15,000 --> 00:30:17,830
(?) Just reach and then pull out any card.
307
00:30:19,430 --> 00:30:21,390
(?) Show it to ???
308
00:30:25,280 --> 00:30:29,940
(?) I'm gonna put it about halfway down ???
309
00:30:29,950 --> 00:30:32,050
Just put your hands like this, please.
310
00:30:33,790 --> 00:30:37,220
(? ) Really focus on the card,
all right, and watch.
311
00:30:40,540 --> 00:30:47,360
- That was incredible, Dynamo, you are the man.
- You are amazing, Dynamo, I'm telling all my friends.
312
00:30:47,370 --> 00:30:51,760
(?) Brilliant. Group hug,
thank you so much. That was amazing.
313
00:30:52,810 --> 00:30:58,790
Your hands allow your brain
to reach out and change the world.
314
00:30:58,920 --> 00:31:04,580
As a result, our species is the only
one to have built a civilisation.
315
00:31:08,430 --> 00:31:10,620
Standing upright and walking
316
00:31:10,630 --> 00:31:14,630
releases the potential
of your wonderful hands,
317
00:31:15,460 --> 00:31:18,110
and it's followed by
another milestone,
318
00:31:18,120 --> 00:31:21,620
an ability that is uniquely human:
319
00:31:22,050 --> 00:31:24,290
the ability to talk.
320
00:31:24,650 --> 00:31:30,830
When I was one, I spoke Vietnamese only,
like, it was just like baby words.
321
00:31:32,630 --> 00:31:34,510
When I was two,
322
00:31:34,520 --> 00:31:37,050
I spoke English, Vietnamese,
Spanish and Chinese,
323
00:31:37,060 --> 00:31:38,960
so four languages
when I was two years old.
324
00:31:38,970 --> 00:31:42,030
Well, I started learning them.
325
00:31:42,920 --> 00:31:48,280
(?) From an early age, Wendy ???
brain has been bursting with languages.
326
00:31:49,570 --> 00:31:52,930
She hasn't stopped
at just four languages.
327
00:31:53,980 --> 00:31:55,800
Wendy spends an hour every week
328
00:31:55,810 --> 00:32:00,010
talking to a range of different
people in their native tongues.
329
00:32:00,210 --> 00:32:04,570
I am Winita from India,
and I teach Wendy Hindi.
330
00:32:10,500 --> 00:32:14,600
My name is Rashida and I
teach Wendy Arabic from Yemen.
331
00:32:18,530 --> 00:32:20,310
And I teach Wendy Spanish.
332
00:32:20,320 --> 00:32:24,530
She speaks Spanish a lot better
than some Hispanic kids do.
333
00:32:27,870 --> 00:32:31,310
At the Russian languages,
she is very good.
334
00:32:33,580 --> 00:32:35,520
Portuguese...
335
00:32:37,460 --> 00:32:40,780
She is at the top because
she can switch very...
336
00:32:40,790 --> 00:32:44,060
in a few seconds,
from one language to the other one.
337
00:32:45,900 --> 00:32:50,070
And she can think,
speak, write. It's unbelievable.
338
00:32:50,840 --> 00:32:54,060
Vietnamese, English,
Spanish, Chinese,
339
00:32:54,070 --> 00:32:59,960
French, Japanese, Hindi, Arabic,
Russian, Cantonese and Portuguese.
340
00:33:00,730 --> 00:33:07,410
Add them all up and Wendy has 11
different voices packed inside her head.
341
00:33:16,460 --> 00:33:19,660
But speaking is only half the story.
342
00:33:21,140 --> 00:33:24,400
For meaning to fly
from one person to another,
343
00:33:24,410 --> 00:33:28,780
the words have to travel
deep into your body.
344
00:33:30,430 --> 00:33:35,930
Inside your ear, sounds set off
a complex chain of events.
345
00:33:36,670 --> 00:33:38,620
They enter as pressure waves,
346
00:33:38,630 --> 00:33:43,160
which push and pull your eardrum,
making it vibrate.
347
00:33:49,790 --> 00:33:51,910
On the other side of the eardrum,
348
00:33:51,920 --> 00:33:56,160
these vibrations
set a series of bones jiggling.
349
00:34:00,390 --> 00:34:06,140
They end with the smallest bone in
your entire body, called the stirrup.
350
00:34:06,150 --> 00:34:10,090
It is smaller than a grain of rice.
351
00:34:10,230 --> 00:34:13,950
These bones allow you to hear.
352
00:34:14,160 --> 00:34:16,470
If a sound is too loud...
353
00:34:19,000 --> 00:34:24,170
..a muscle pulls the stirrup away
from the most sensitive parts.
354
00:34:24,510 --> 00:34:27,340
Temporarily, at least,
you go a bit deaf,
355
00:34:27,350 --> 00:34:30,580
but the rest of your ear
is protected.
356
00:34:34,950 --> 00:34:40,690
Beyond the stirrup is a fluid-filled
cavern, your cochlea.
357
00:34:43,470 --> 00:34:50,340
The incoming sound waves tickle clumps
of tiny, hair-like sensors on the floor.
358
00:34:51,150 --> 00:34:55,710
These begin to dance to
the sounds of the world outside.
359
00:34:58,030 --> 00:35:00,640
You have 30,000 sensors.
360
00:35:00,650 --> 00:35:03,520
Each picks out
a different part of the sound
361
00:35:03,530 --> 00:35:06,520
and sends it straight to your brain.
362
00:35:08,670 --> 00:35:15,790
The cochlea is most sensitive to the
sounds of another person's voice.
363
00:35:23,150 --> 00:35:25,660
SPEAKS RUSSIAN
364
00:35:25,670 --> 00:35:28,500
RUSSIAN DIALOGUE
365
00:35:31,830 --> 00:35:36,020
Finely-tuned ears
and a wonderfully versatile voice...
366
00:35:37,230 --> 00:35:42,630
have allowed humans to invent
over 7,000 different languages.
367
00:35:45,070 --> 00:35:47,030
SPEAKS IN FOREIGN LANGUAGE
368
00:35:47,710 --> 00:35:48,660
THEY GIGGLE
Hello!
369
00:35:48,670 --> 00:35:52,400
Bonjour...
VARIOUS FOREIGN LANGUAGES
370
00:35:52,410 --> 00:35:57,300
And each of us, as we grow, pick up
over a thousand new words every year.
371
00:35:57,310 --> 00:36:00,270
SPEAKS IN FOREIGN LANGUAGE
372
00:36:01,250 --> 00:36:02,640
By your early teens,
373
00:36:02,650 --> 00:36:06,300
you have a working vocabulary
of over 10,000 words,
374
00:36:06,310 --> 00:36:09,540
as you head towards the
brain's next challenge:
375
00:36:09,550 --> 00:36:11,450
puberty.
376
00:36:28,560 --> 00:36:31,620
Stephanie Bean is 14 years old
377
00:36:31,630 --> 00:36:36,380
and like all teenagers she's maturing...
phisically.
378
00:36:46,060 --> 00:36:49,690
(?) We really don't talk
about the puberty thing ???.
379
00:36:49,700 --> 00:36:53,930
I know some girls
think it's embarrassing.
380
00:36:57,400 --> 00:37:00,910
???
381
00:37:03,620 --> 00:37:08,650
Like the rest of her teenage friends,
Stephanie's brain is maturing too.
382
00:37:08,660 --> 00:37:12,050
The way it does this is bizarre.
383
00:37:12,430 --> 00:37:17,010
During her teenage years,
she will loose 40% of the connections
384
00:37:17,020 --> 00:37:20,820
she spent more than
a decade building.
385
00:37:21,060 --> 00:37:26,310
This extraordinary image was made
from hundreds of teenage brain scans.
386
00:37:27,010 --> 00:37:29,780
It shows how, as the brain matures,
387
00:37:29,790 --> 00:37:33,720
the areas which are packed with
connections, colored red and yellow,
388
00:37:33,730 --> 00:37:38,950
make way for areas that contain
far fewer, colored blue.
389
00:37:39,730 --> 00:37:45,010
The brain is prunning away the
connections that it doesn't need.
390
00:37:47,070 --> 00:37:52,600
Scientists believe that this leads to
more efficient and faster thinking.
391
00:37:57,540 --> 00:38:00,940
But perhaps the most puzzling
change during puberty
392
00:38:00,950 --> 00:38:05,160
is that your brain seems
determined to travel a dark road
393
00:38:05,170 --> 00:38:08,710
to risk taking and recklessness.
394
00:38:13,030 --> 00:38:17,830
As well as being a cheerleader,
Stephanie Bean has another hobby.
395
00:38:17,840 --> 00:38:22,650
She's also the world's
youngest stock car racer.
396
00:38:29,140 --> 00:38:31,810
I started racing stock cars
when I was ten years old,
397
00:38:31,820 --> 00:38:34,790
so I've been racing them
for four years.
398
00:38:39,000 --> 00:38:42,610
She's competing
on the Winchester Speedway,
399
00:38:42,620 --> 00:38:46,780
also known as the world's
fastest half mile.
400
00:38:48,420 --> 00:38:54,070
At 37 degrees, these are the steepest
curves in American motor sport.
401
00:38:57,380 --> 00:39:01,750
It's pretty awesome 'cos
whenever you go round it's like
402
00:39:01,760 --> 00:39:07,800
you get all that speed in you and it
builds up, and it's like, I wanna go.
403
00:39:21,780 --> 00:39:27,380
Stephanie is prepared to take risks that
many of her adult competitors will not.
404
00:39:27,390 --> 00:39:30,610
One reason is that part
of her teenage brain
405
00:39:30,620 --> 00:39:34,690
is releasing neuro-chemicals
that encourage risky behaviour.
406
00:39:34,700 --> 00:39:37,540
There will probably be
about 20 cars out there going like
407
00:39:37,550 --> 00:39:44,990
around 90 to 100 miles an hour, very
close, like inches away from the wall.
408
00:39:47,170 --> 00:39:50,250
Whenever she takes a risk,
her teen brain rewards her
409
00:39:50,260 --> 00:39:55,020
with a much stronger natural high
than her grown-up competitors.
410
00:39:55,030 --> 00:40:00,400
Whenever a car's next to me, it just
makes me want to go even more faster.
411
00:40:01,450 --> 00:40:05,120
If there's a gap, then,
you know, take chances.
412
00:40:07,500 --> 00:40:12,530
It's her brain's accelerator pedal
pushing her to take risks.
413
00:40:14,460 --> 00:40:17,070
Go, Stephanie, go!
414
00:40:20,810 --> 00:40:25,200
But the scan of her developing
brain reveals something else.
415
00:40:29,020 --> 00:40:34,050
The last part of the brain to turn blue
and mature is the bit at the front,
416
00:40:34,060 --> 00:40:38,260
which thinks through the
consequences of taking a risk.
417
00:40:41,460 --> 00:40:44,030
Stephanie's isn't fully mature,
418
00:40:44,040 --> 00:40:47,010
so even when she recognises
that something is dangerous,
419
00:40:47,020 --> 00:40:50,140
she will probably do it anyway.
420
00:40:53,020 --> 00:40:57,090
But why are teenagers wired
to take risks?
421
00:40:57,980 --> 00:41:02,220
One theory is it's to encourage
you to try lots of new things
422
00:41:02,230 --> 00:41:05,960
before you settle
down into adulthood.
423
00:41:14,840 --> 00:41:20,830
Ever since that time, long ago,
when you were just a tiny embryo,
424
00:41:20,840 --> 00:41:24,660
you've been busy
nurturing your brain cells.
425
00:41:26,140 --> 00:41:29,730
You've assembled so many
that their numbers now rival
426
00:41:29,740 --> 00:41:34,860
the hundred billion stars
that populate our galaxy.
427
00:41:38,780 --> 00:41:41,930
And this vast, beautiful network
428
00:41:41,940 --> 00:41:46,910
has been shaped by the kaleidoscope
of sights, sounds and feelings
429
00:41:46,920 --> 00:41:49,650
that you've lived through.
430
00:41:54,610 --> 00:41:59,760
Now, finally,
after 20 years, it's done.
431
00:42:01,100 --> 00:42:06,020
You are the proud possessor
of an adult brain.
432
00:42:08,650 --> 00:42:10,720
Until recently, scientists believed
433
00:42:10,730 --> 00:42:14,750
this would pretty much be
the end of the brain story.
434
00:42:14,760 --> 00:42:21,000
That from then on, it was just a
slow gentle decline into old age.
435
00:42:22,530 --> 00:42:24,800
But we now know that
your brain would retains
436
00:42:24,810 --> 00:42:30,560
that wonderful child-like melody
to learn throughout your life.
437
00:42:41,980 --> 00:42:46,250
Adventurer Erik Weihenmayer
is a striking example
438
00:42:46,260 --> 00:42:50,920
of how well a middle-aged brain
can respond to new challenges.
439
00:42:51,340 --> 00:42:53,330
There's that step again, Erik.
440
00:42:53,340 --> 00:42:57,290
Erik went blind
when he was 13 years old.
441
00:42:57,300 --> 00:43:01,980
Every week, you know, I would wake
up with different levels of vision
442
00:43:01,990 --> 00:43:06,240
because my retinas were
splitting away from my eyes.
443
00:43:20,320 --> 00:43:23,910
Today, Erik, with his friend,
Greg Childs,
444
00:43:23,920 --> 00:43:29,360
is going to attempt to scale
Utah's formidable Castleton Rock.
445
00:43:49,160 --> 00:43:52,120
It's Erik's first climb here.
446
00:43:52,790 --> 00:43:58,170
To help him, he has brought along
an impressive bit of new technology.
447
00:44:02,370 --> 00:44:06,450
I don't know if you've seen this.
This is a brain port device.
448
00:44:06,460 --> 00:44:12,290
This is the camera
on these sunglasses here.
449
00:44:13,120 --> 00:44:15,130
The camera picks up images
450
00:44:15,140 --> 00:44:19,320
and sends a feed to a computer
on Erik's hip...
451
00:44:20,180 --> 00:44:25,740
..which translates the images into a
low-resolution picture of the world.
452
00:44:32,240 --> 00:44:35,060
These blocky images are then sent
453
00:44:35,070 --> 00:44:39,100
to one of the most sensitive parts
of Erik's body.
454
00:44:40,410 --> 00:44:42,850
This is the tongue display.
455
00:44:44,370 --> 00:44:49,170
On the surface are hundreds
of tiny electrical stimulators.
456
00:44:50,690 --> 00:44:53,310
If the camera sees
a distinct outline,
457
00:44:53,320 --> 00:44:59,380
a corresponding line of stimulators
buzz away, tickling Erik's tongue.
458
00:45:00,050 --> 00:45:05,300
I can feel each dot and together
they create lines and shapes
459
00:45:05,310 --> 00:45:11,610
and, ultimately, images
that my brain then reinterprets
460
00:45:11,620 --> 00:45:14,600
as the space around me.
461
00:45:23,550 --> 00:45:26,470
Three decades
after he lost his sight,
462
00:45:26,480 --> 00:45:32,240
the visual part of Erik's brain,
his mind's eye, is back in action.
463
00:45:33,550 --> 00:45:37,380
Except now,
he's not seeing with his eyes.
464
00:45:37,390 --> 00:45:40,890
He's seeing with his tongue.
465
00:45:45,080 --> 00:45:48,560
Is that sight?
Well, kind of, you know,
466
00:45:48,570 --> 00:45:54,360
because I think seeing is more
in your brain than in your eyes.
467
00:45:59,310 --> 00:46:04,830
In rock climbing, most of the risk
is taken by the lead climber.
468
00:46:05,390 --> 00:46:07,340
Greg led most of the tower.
469
00:46:07,350 --> 00:46:12,400
He's making sure, you know, that if I
fall, I'm not going to fall too far.
470
00:46:24,120 --> 00:46:25,530
OK!
471
00:46:36,090 --> 00:46:39,650
Well, sometimes I like
to lead the rock face too.
472
00:46:39,660 --> 00:46:42,400
And that's really fun for me,
because I'm now the first person
473
00:46:42,410 --> 00:46:45,750
going up the rock face,
and I'm taking the risk.
474
00:46:45,760 --> 00:46:49,250
- Last pitch to the top.
- Excellent.
475
00:46:49,670 --> 00:46:51,650
OK, are you ready?
476
00:46:51,660 --> 00:46:55,700
Erik is feeling so confident
with the brain port device
477
00:46:55,710 --> 00:46:59,350
that he decides
to lead the final push.
478
00:47:02,720 --> 00:47:07,870
And now I'm Greg's safety, for me,
you know, that's a real honour,
479
00:47:07,880 --> 00:47:12,220
being blind and still being able
to be a real part of the team.
480
00:47:45,930 --> 00:47:49,060
You pop over this lip
and it's completely flat
481
00:47:49,070 --> 00:47:51,400
and the wind just gusts in your face.
482
00:47:51,410 --> 00:47:57,080
And you're up there on this flat tower,
1,000 feet above the desert floor.
483
00:48:14,330 --> 00:48:16,660
- It's a privilege.
- I know.
484
00:48:16,670 --> 00:48:18,760
This is totally beautiful.
485
00:48:20,930 --> 00:48:28,430
Erik is a great example of the brain's
astonishing ability to remodel itself.
486
00:48:29,650 --> 00:48:34,970
It's this that makes us
so wonderfully adaptable.
487
00:48:54,930 --> 00:48:59,120
And six months on from the
operation to split her brain,
488
00:48:59,130 --> 00:49:05,320
it's this adaptability that is giving
Angelina the chance to flourish.
489
00:49:07,330 --> 00:49:09,170
It's just wonderful to see now
490
00:49:09,180 --> 00:49:12,700
that the development is just
coming on in leaps and bounds.
491
00:49:12,710 --> 00:49:14,060
Are you going to come to Mummy?
492
00:49:14,070 --> 00:49:16,240
Come to Mummy. Good girl.
493
00:49:16,250 --> 00:49:22,180
To hear her start to talk, start to
walk, it's just absolutely amazing.
494
00:49:22,190 --> 00:49:26,140
For you?! Say "hello".
495
00:49:28,610 --> 00:49:32,610
Rock, paper, scissors, shoot.
496
00:49:32,620 --> 00:49:36,700
Whatever your age, if you continue
to stretch your brain,
497
00:49:36,710 --> 00:49:41,040
you can be sure
it will rise to the challenge.
498
00:49:41,050 --> 00:49:44,770
Stone, paper, scissors, shoot.
499
00:49:47,250 --> 00:49:51,790
This is adventure,
you know, this is total adventure.
500
00:50:05,210 --> 00:50:08,250
Original subtitle by:
E-mail subtitling@bbc.co.uk
501
00:50:09,250 --> 00:50:13,550
review for this release by:
Tio Beto from Brazil
502
00:50:14,560 --> 00:50:19,560
... =Peace Through Anarchy=...