Brain Games - Peripheral Vision (9 min)

>> When it comes to your attentional spotlight,

you probably assume you only
see what your eye is taking in,

but the light entering your eyes is
just the first piece of the puzzle.

The real magic is what your
brain does with that information.

Without your brain's visual cortex making sense
of everything, the world would appear to you

like a random collection of colors and shapes.

This is the raw data your eyes actually
take in, and this is what you see

when your brain stitches it all together.

Sounds like a pretty flawless system, right?

Think again.

Even with your eyes and brain working together
perfectly, there are still limitations.

For example, you probably think
that if your eyes see something,

your brain can't unsee it, right?

Not exactly.

We're about to blow your mind with
nothing more than a few footballs.

See the four footballs on the screen?

All you have to do is pick
one and stare directly at it.

That's it.

Don't let your eyes flicker
to any of the other footballs.

Are you focused on one?

Good. Keep looking at it, because right about
now something strange should be happening.

Are the other footballs fading?

Have any of them disappeared completely?

We promise you, we aren't
altering the image in any way.

The footballs aren't disappearing
from the screen.

They're disappearing from your brain.

And the reason why will amaze you.

So, why did the footballs disappear?

>> It's because your brain decided that
it wasn't in the world to begin with.

Because the light sensitive part of your eye
is actually in the very back of the eyeball,

it's up to your brain to figure out what
stimulation is coming from the world

and what's coming from inside your own eye.

In this case, because the football stay fixed
in the same position and didn't play along

with the rest of the motion, your brain
decides that the football isn't in the world

in the first place and it's gone.

>> It's not just your brain that can miss
things when it's trying to be helpful.

The structure of your eye can also
lead you to see less than you think.

>> The fovea takes up less than
5% of the surface of your eye,

but 50% of your brain's visual cortex is
devoted to processing what the fovea delivers.

This is why your fovea produces
such a sharp, high definition image.

The other 95% of your eye, your
peripheral vision, is very low resolution,

like a cell phone camera from 1998.

>> You have to ask yourself, if
everything outside the center

of your gaze is blurry, can
you trust what you see?

Let's find out.

[ Music ]

Professor Brian Scholl has come to this college
campus to put peripheral vision to the test.

He's going to ask our volunteers
to stare at this X,

forcing them to use only
their peripheral vision.

You can play along with the volunteers on this.

>> Come on over.

Nathaniel, This is Sadie.

Sadie is holding a big white X.

>> Dig that.

>> In just a minute, I'm going to ask
you to ask you to close your eyes.

[Laughing] While your eyes are closed, we're
going to bring out two more cheerleaders.

When I say go, you're going to open your
eyes for one second, then close them again.

>> Okay.

>> While your eyes are open, you
are going to stare at that white X.

That white X is your entire world now.

Okay? And then after your eyes are
closed, you are going to choose one

of the two other cheerleaders
to be on Sadie's team.

You got it?

>> Sounds good.

>> Eyes closed.

>> Sounds pretty simple, right?

All our volunteers need to do
is use their peripheral vision

to pick the prettier cheerleader.

>> You ready?

Go.

[ Music ]

>> Right.

>> Fantastic.

Let's have group two.

You ready?

>> Yep.

>> And go.

[ Music ]

>> Right.

>> Group three, please.

>> So, have you noticed anything weird?

Let's see the test from a different angle.

Nathaniel is only 10 feet away, but his
peripheral vision isn't good enough to catch

that half of the cheerleaders are guys.

In case you didn't notice,
one of each pair is a dude.

And if you did, your peripheral
vision is truly exceptional.

We're going to run this test
on a few more volunteers.

Do you think they'll catch what's going on?

[ Music ]

>> Go.

[ Music ]

>> Um, left.

[Buzzer] Um, right.

[Bell ding]

>> And go.

[ Music ]

It's your choice.

>> Left. [Buzzer]

[ Music ]

Right. [Buzzer]

>> How are you feeling about your choices?

>> Pretty fantastic.

>> Pretty good.

>> All right.

>> No idea.

>> So, let's have you close
your eyes one more time, please.

>> Oh boy.

>> Okay.

>> Let's bring out Nathaniel's
cheerleading team.

[ Cheering ]

>> Oh no.

>> Yeah.

>> Oh no. [Laughter]

>> What do you think?

>> Ah, they're just the perfect squad.

[Laughter] Lots of strength.

>> Nathaniel and Russell each
picked two girls and two guys.

>> It turns out that the vast majority

of our visual field is extremely
blurry, fuzzy, very low resolution.

Only the smallest part of our visual
field is actually in high definition.

>> I never thought that my
peripheral vision was that bad.

>> Which goes to show, your peripheral
vision is so weak at resolving detail,

you have no better than a 50/50 chance.

>> All right.

[ Laughter and Music ]

>> Except for Craig.

His peripheral vision is a perfect 100%.

>> Why don't you guys open your
eyes and see how Craig did?

>> One hundred percent wrong.

Yep, he picked a full lineup of dudes.

[Inaudible]

>> Eyes of a tiger.

>> Green team, right there.

>> None of our volunteers caught on that half
the people they were looking at were guys.

Now, you may be thinking, There's no way
you'd fall for this if you were there.

You would never miss something so obvious
as bulging muscles, hairy legs, and beards.

>> When I first opened my eyes, I initially
saw hair color, skin width, height,

and that was really all because
it was just a blur.

But while you might be laughing at these
guys, let's see if you can do any better.

In just a minute, you'll get a chance to
pick which cheerleader is actually a girl.

Let's just hope your peripheral vision
doesn't let you down like you did them.

[ Music ]

Our last experiment revealed just how weak
peripheral vision is at seeing detail.

And if you think yours is better,
here's your chance to prove it.

You need to stare straight ahead at this X.
In a second, we'll show you two cheerleaders.

All you need to do is pick which one is a woman.

Don't cheat and look away from
the X. Ready and make your pick.

So? Which one did you choose?

If you picked the one on the right,
you chose pretty wisely, [bell ding]

but if you picked the one on the left,
[buzzer] you might not be so happy.

Yep, that's a dude.

We gave you the easy one first.

So, if you're feeling good about
yourself, get ready for the next one.

Okay, stare straight at the
X and make your pick.

Which one did you pick this time.

If you chose the one on the
right, [bell ding] good job.

If you picked the one on the left again,

[buzzer] you've just learned something
profound about your sense of vision.

This test reveals just how much of
your field of vision is an illusion.

Your brain creates a seamless,
high-resolution field of view

because your eyes are simply incapable
of delivering it on their own.

But it's not all bad.

Your peripheral vision is
the way it is for a reason.

>> The good news is that our peripheral vision
has other strengths, like detecting motion

and seeing dim, uncolored patterns,
especially when they happen quickly.

This is what allows a quarterback to make
good sense of the entire field during a game,

or for a person driving a car to
notice someone in the next lane.

For them, it doesn't matter if it's a
man or a woman, they just need to keep

from getting rear ended or tackled.

So, the next time you're driving or
watching the game, you have to ask yourself,

where should I direct my visual focus
and place my attentional spotlight?

Am I in control or is my brain?