How to pronounce "circumference"

Vision is the most important

and prioritized sense that we have.

We are constantly looking

at the world around us,

and quickly we identify and make sense

of what it is that we see.

Let's just start with an example

of that very fact.

I'm going to show you a photograph of a person,

just for a second or two,

and I'd like for you to identify

what emotion is on his face.

Ready?

Here you go. Go with your gut reaction.

Okay. What did you see?

Well, we actually surveyed

over 120 individuals,

and the results were mixed.

People did not agree

on what emotion they saw on his face.

Maybe you saw discomfort.

That was the most frequent response

that we received.

But if you asked the person on your left,

they might have said regret or skepticism,

and if you asked somebody on your right,

they might have said something entirely different,

like hope or empathy.

So we are all looking

at the very same face again.

We might see something

entirely different,

because perception is subjective.

What we think we see

is actually filtered

through our own mind's eye.

Of course, there are many other examples

of how we see the world through own mind's eye.

I'm going to give you just a few.

So dieters, for instance,

see apples as larger

than people who are not counting calories.

Softball players see the ball as smaller

if they've just come out of a slump,

compared to people who had a hot night at the plate.

And actually, our political beliefs also

can affect the way we see other people,

including politicians.

So my research team and I decided to test this question.

In 2008, Barack Obama was running for president

for the very first time,

and we surveyed hundreds of Americans

one month before the election.

What we found in this survey

was that some people, some Americans,

think photographs like these

best reflect how Obama really looks.

Of these people, 75 percent

voted for Obama in the actual election.

Other people, though, thought photographs like these

best reflect how Obama really looks.

89 percent of these people

voted for McCain.

We presented many photographs of Obama

one at a time,

so people did not realize that what we were changing

from one photograph to the next

was whether we had artificially lightened

or darkened his skin tone.

So how is that possible?

How could it be that when I look at a person,

an object, or an event,

I see something very different

than somebody else does?

Well, the reasons are many,

but one reason requires that we understand

a little bit more about how our eyes work.

So vision scientists know

that the amount of information

that we can see

at any given point in time,

what we can focus on, is actually relatively small.

What we can see with great sharpness

and clarity and accuracy

is the equivalent

of the surface area of our thumb

on our outstretched arm.

Everything else around that is blurry,

rendering much of what is presented

to our eyes as ambiguous.

But we have to clarify

and make sense of what it is that we see,

and it's our mind that helps us fill in that gap.

As a result, perception is a subjective experience,

and that's how we end up seeing

through our own mind's eye.

So, I'm a social psychologist,

and it's questions like these

that really intrigue me.

I am fascinated by those times

when people do not see eye to eye.

Why is it that somebody might

literally see the glass as half full,

and somebody literally sees it

as half empty?

What is it about what one person is thinking and feeling

that leads them to see the world

in an entirely different way?

And does that even matter?

So to begin to tackle these questions,

my research team and I decided to delve deeply

into an issue that has received

international attention:

our health and fitness.

Across the world,

people are struggling to manage their weight,

and there is a variety of strategies

that we have to help us keep the pounds off.

For instance, we set the best of intentions

to exercise after the holidays,

but actually, the majority of Americans

find that their New Year's resolutions

are broken by Valentine's Day.

We talk to ourselves

in very encouraging ways,

telling ourselves this is our year

to get back into shape,

but that is not enough to bring us back

to our ideal weight.

So why?

Of course, there is no simple answer,

but one reason, I argue,

is that our mind's eye

might work against us.

Some people may literally see exercise

as more difficult,

and some people might literally

see exercise as easier.

So, as a first step to testing these questions,

we gathered objective measurements

of individuals' physical fitness.

We measured the circumference of their waist,

compared to the circumference of their hips.

A higher waist-to-hip ratio

is an indicator of being less physically fit

than a lower waist-to-hip ratio.

After gathering these measurements,

we told our participants that

they would walk to a finish line

while carrying extra weight

in a sort of race.

But before they did that,

we asked them to estimate the distance

to the finish line.

We thought that the physical states of their body

might change how they perceived the distance.

So what did we find?

Well, waist-to-hip ratio

predicted perceptions of distance.

People who were out of shape and unfit

actually saw the distance to the finish line

as significantly greater

than people who were in better shape.

People's states of their own body

changed how they perceived the environment.

But so too can our mind.

In fact, our bodies and our minds

work in tandem

to change how we see the world around us.

That led us to think that maybe people

with strong motivations

and strong goals to exercise

might actually see the finish line as closer

than people who have weaker motivations.

So to test whether motivations

affect our perceptual experiences in this way,

we conducted a second study.

Again, we gathered objective measurements

of people's physical fitness,

measuring the circumference of their waist

and the circumference of their hips,

and we had them do a few other tests of fitness.

Based on feedback that we gave them,

some of our participants told us

they're not motivated to exercise any more.

They felt like they already met their fitness goals

and they weren't going to do anything else.

These people were not motivated.

Other people, though, based on our feedback,

told us they were highly motivated to exercise.

They had a strong goal to make it to the finish line.

But again, before we had them walk to the finish line,

we had them estimate the distance.

How far away was the finish line?

And again, like the previous study,

we found that waist-to-hip ratio

predicted perceptions of distance.

Unfit individuals saw the distance as farther,

saw the finish line as farther away,

than people who were in better shape.

Importantly, though, this only happened

for people who were not motivated

to exercise.

On the other hand,

people who were highly motivated to exercise

saw the distance as short.

Even the most out of shape individuals

saw the finish line

as just as close,

if not slightly closer,

than people who were in better shape.

So our bodies can change

how far away that finish line looks,

but people who had committed to a manageable goal

that they could accomplish in the near future

and who believed that they were capable

of meeting that goal

actually saw the exercise as easier.

That led us to wonder,

is there a strategy that we could use

and teach people that would help

change their perceptions of the distance,

help them make exercise look easier?

So we turned to the vision science literature

to figure out what should we do,

and based on what we read, we came up with a strategy

that we called, "Keep your eyes on the prize."

So this is not the slogan

from an inspirational poster.

It's an actual directive

for how to look around your environment.

People that we trained in this strategy,

we told them to focus their attention on the finish line,

to avoid looking around,

to imagine a spotlight

was shining on that goal,

and that everything around it was blurry

and perhaps difficult to see.

We thought that this strategy

would help make the exercise look easier.

We compared this group

to a baseline group.

To this group we said,

just look around the environment

as you naturally would.

You will notice the finish line,

but you might also notice

the garbage can off to the right,

or the people and the lamp post off to the left.

We thought that people who used this strategy

would see the distance as farther.

So what did we find?

When we had them estimate the distance,

was this strategy successful

for changing their perceptual experience?

Yes.

People who kept their eyes on the prize

saw the finish line as 30 percent closer

than people who looked around

as they naturally would.

We thought this was great.

We were really excited because it meant

that this strategy helped make

the exercise look easier,

but the big question was,

could this help make exercise

actually better?

Could it improve the quality

of exercise as well?

So next, we told our participants,

you are going to walk to the finish line

while wearing extra weight.

We added weights to their ankles

that amounted to 15 percent of their body weight.

We told them to lift their knees up high

and walk to the finish line quickly.

We designed this exercise in particular

to be moderately challenging

but not impossible,

like most exercises

that actually improve our fitness.

So the big question, then:

Did keeping your eyes on the prize

and narrowly focusing on the finish line

change their experience of the exercise?

It did.

People who kept their eyes on the prize

told us afterward that it required

17 percent less exertion

for them to do this exercise

than people who looked around naturally.

It changed their subjective experience

of the exercise.

It also changed the objective nature

of their exercise.

People who kept their eyes on the prize

actually moved 23 percent faster

than people who looked around naturally.

To put that in perspective,

a 23 percent increase

is like trading in your 1980 Chevy Citation

for a 1980 Chevrolet Corvette.

We were so excited by this,

because this meant that a strategy

that costs nothing,

that is easy for people to use,

regardless of whether they're in shape

or struggling to get there,

had a big effect.

Keeping your eyes on the prize

made the exercise look and feel easier

even when people were working harder

because they were moving faster.

Now, I know there's more to good health

than walking a little bit faster,

but keeping your eyes on the prize

might be one additional strategy

that you can use to help promote

a healthy lifestyle.

If you're not convinced yet

that we all see the world through our own mind's eye,

let me leave you with one final example.

Here's a photograph of a beautiful street in Stockholm, with two cars.

The car in the back looks much larger

than the car in the front.

However, in reality,

these cars are the same size,

but that's not how we see it.

So does this mean that

our eyes have gone haywire

and that our brains are a mess?

No, it doesn't mean that at all.

It's just how our eyes work.

We might see the world in a different way,

and sometimes that might not

line up with reality,

but it doesn't mean that one of us is right

and one of us is wrong.

We all see the world through our mind's eye,

but we can teach ourselves to see it differently.

So I can think of days

that have gone horribly wrong for me.

I'm fed up, I'm grumpy, I'm tired,

and I'm so behind,

and there's a big black cloud

hanging over my head,

and on days like these,

it looks like everyone around me

is down in the dumps too.

My colleague at work looks annoyed

when I ask for an extension on a deadline,

and my friend looks frustrated

when I show up late for lunch because a meeting ran long,

and at the end of the day,

my husband looks disappointed

because I'd rather go to bed than go to the movies.

And on days like these, when everybody looks

upset and angry to me,

I try to remind myself that there are other ways of seeing them.

Perhaps my colleague was confused,

perhaps my friend was concerned,

and perhaps my husband was feeling empathy instead.

So we all see the world

through our own mind's eye,

and on some days, it might look

like the world is a dangerous

and challenging and insurmountable place,

but it doesn't have to look that way all the time.

We can teach ourselves to see it differently,

and when we find a way to make the world

look nicer and easier,

it might actually become so.

Thank you.

(Applause)