While apes can master words and numbers,

other research shows that something else is limiting their cooperation:

apes have emotional issues -rivalry, violence-

and most of all, they're impulsive.

In a celebrated study that investigated impulse control,

Sally Boysen of Ohio State University asked chimps to choose between two dishes of sweets.

Now, you watch real carefully.

We're going to put one, two, three, four down here.

Are you watching, Miss Priss?

Sheeby?

And we're going to put two in here.

Give those to Sarah. Okay.

Well, I have to give these to Sarah, and Sheeba gets two.

So Sarah gets four and Sheeba only gets two.

Aw, too bad.

The twist was that the chimp got the sweets that she didn't point to.

Could she learn to resist her impulse to reach for the bigger pile?

You want Sarah to have these?

It's okay, it's okay. You get to have that one.

Yeah, Sarah gets five, and Sheba gets one.

Oh, that is such a shame.

Amazingly, in the study chimps never overcame their greedy urges.

They always reached for more and, so, ended up with less.

Impulse studies have also been run on humans.

In a classic experiment of the 1970s,

a researcher gives a four-year-old a simple choice.

So, if you wait for me to get back,

I'll give you this bowl with all of these gummy bears, okay?

But if you can't wait, you can push that button, like this,

and then I'll come back and you can have this bowl with just this one gummy bear, ok?

Okay, I'll be right back.

According to an inconclusive but intriguing study,

the longer children resisted temptation,

the higher their school test results would be years later.

In any case, the differences between people are small

compared to the gap separating humans and apes.

Maybe one of the first things that happened during our species evolution

is we became much less emotionally reactive.

And maybe that's one of the big differences

that may explain why we solve problems so differently.

We sort of got control of our emotions.

Can apes be given skills to help them master their emotions?

Now you watch real carefully.

Sally Boysen trained a chimp to understand numerals.

She then repeated the experiment with the sweets,

but offered different pairs of numerals rather than treats.

You want to give two to Sarah? Ok.

Two goes to Sarah, and you get six.

Remarkably, chimps were now able to learn what they couldn't before:

point in to the smaller number to get the bigger prize.

Symbols can make you free.

They can help distance an ape from its impulses.

But outside of the lab, apes don't seem to use symbols.

Still, ape minds seem to share many of the amazing features of the human mind.

They have sophisticated social emotions.

They can cooperate.

They have culture.

Their mental rocket is on the launch pad.

Why isn't it taking off?

On an average day, human beings file thousands of patents,

post tens of thousands messages over the Internet,

and think millions of thoughts that have never been thought before.

Our closest relatives are different.

On a good day, an ape is lucky to use a tool to crack a nut.

What prevents ape culture from igniting like the human version?

Recent studies that compare the human and ape mind are revealing something surprising.

Bonobos like Kanzi show their own kind of genius.

Kanzi, could you take off Sue's shoe?

Could you take my shoe off, please?

You might need to untie it.

Even skeptics agree that Kanzi

understands more words than any other non-human animal.

He also uses an array of visual symbols to communicate.

But on closer inspection, Kanzi, like all great apes, lacks the full mental package.

Take Kanzi's use of language:

Most of the time, he will use these symbols to request things,

to say "Take me there," or "Give me that."

Now, Kanzi will not use those symbols to talk about the weather

or to just make small talk, which is a very human thing.

When human infants communicate with others,

they engage in a real conversation where each conversational turn is responsive to the turn that came before.

And they even ask for clarification if they need.

So you say "Huh?" or you say "Yeah,"

and you let the other one know how the communication is going.

To engage in a real conversation,

each speaker needs a sense of what the other is thinking.

Call this skill mind-reading.

Young children have not fully developed it.

Hey, so Zoe, guess what we're going to do today?

We're going to play a game with my Princess Sally here.

See, this is Princess Sally. And she's got a ball that she really likes.

This is her ball.

But she needs to go away for a little bit,

so Princess Sally is going to hide her ball right over here in the bag.

See Princess Sally hiding her ball right over there in the purple bag? Yeah?

So here she goes. She's going to go away for just a little bit.

Now while Princess Sally is away, we're going to play a little trick on her, okay?

We're going to move her ball from the purple bag over here to the green bag.

See how we moved the ball over there?

Okay, so guess what? Princess Sally is coming back.

Here she is. She came back.

Can you tell me, where is Princess Sally going to first look for her ball?

Over here in the green bag?

Can you tell me, why is Princess Sally...

Three-year-olds make consistent mistakes about what others know.

The thing that's amazing about three-year-olds

is how convinced they are about their wrong answer.

They're so sure that she's going to look for her ball where it really is

because she wants it and that's where it is.

But by the age of four, most children are accomplished mind-readers.

Where is Sally first going to look for her ball?

She's going to look in the purple bag so she can find her ball.

As recently as 2001, studies seemed to show that apes don't know what others are thinking.

But then new experiments began to reveal unexpected skills.

In one study, as a chimp approaches a treat, Brian Hare moved it out of reach,

establishing himself as a competitor.

Next Hare blocks his own view of one treats but leaves another within his sight.

It looks like they're generating a plan and saying to themselves,

"Ok, I want that food, and the one I'm most likely to get is the one he's not looking at,

or the one that, if I sneak around, he won't see me,

and therefore I can have my yummy banana treat."

This chimp seems to know what's on Hare's mind,

what he can see and what he can't.

So chimps seem to share some of our skills of mind-reading.

Do we have any mental skills which are uniquely our own?

A key clue comes from a new experiment.

Back at the University of Texas,

Victoria Horner shows a chimp how to operate a puzzle box to get a treat.

First, she taps.

Then she slots.

Next she pokes.

The chimp copies fairly well and gets the sweet.

This game we're going to play is about this special box I brought, alright?

There's a gummy bear. It's your turn.

Children copy the actions, much as the chimps did.

Look, you got him. Alright!

There's the gummy bear. Good job.

The second box that I show the chimpanzees is this one,

and it's identical to the opaque box

except that it's made out of material which is see-through.

Only now is it obvious that the tapping and poking don't achieve a thing:

the box has a false ceiling.

The chimps cut to the chase.

They skip the needless steps.

For the apes it's all about the treat.

What this study shows is that apes don't just mindlessly ape.

They also understand something more about cause and effect.

We found something quite surprising.

The children were pre-disposed to copy,

even when it meant that they were doing something that was really rather silly.

So this seems a little like the chimps are outsmarting the kids in this particular study.

There he is. You got him out.

Why do children imitate slavishly?

At the root of the children's behavior is the fact that they viewed me as a grownup,

possibly as a teacher.

That children expect to be taught is a vital difference.

While apes can copy, most researchers believe they don't teach each other.

Learning from someone else is the fastest way to get a new idea:

faster than learning by imitation,

faster than inventing a new technology in the first place.

In children, a penchant for teaching appears -even before language kicks in-

in the form of a deceptively simple gesture: pointing.

A toddler knows that the cup being pointed to is the one that hides a treat.

Parents love it when their kids start pointing

because it's evidence that the kid's trying to communicate with them.

Parents definitely notice the difference between

babies who just point to ask for things and babies who point to show them things.

Apes don't seem to get that kind of pointing.

It doesn't matter whether Brian Hare points

or stares or orients his body,

this young bonobo is unaware that he is trying to communicate.

They were clueless at using the information.

Even after lots and lots of trials, they didn't use the information I provided them.

And it was a big surprise to everybody.

Pointing relies on a particular mental skill,

a little difference that makes a big difference.

Whenever I point, I'm actually directing your attention towards a third object.

And you have to understand that my attention is on that object,

and that I'm asking you, now, to attend to the same object.

So there's sort of a triangle between us and the object.

This mental skill, this "triangle," turbocharges teamwork.

What you'll see with the human mother and baby

is that the mother is constantly trying to show the baby what to do,

and the baby is trying to tune into what the mother wants.

And so you have a full triangle of mother and baby

and the thing in the environment that they are trying to work on.

It's a special cognitive achievement.

For some reason kids do this naturally, almost immediately.

And curiously, apes can't get into that.

At the moment we have no evidence

that apes have shared goals based on shared commitments.

They do things together, they coordinate their actions together,

but they don't have a shared commitment to a shared goal.

The triangle is the core skill that makes teaching possible.

Humans have it; apes seem to lack it.

But apes are also missing one more thing.

It's a key emotional driver:

the passion to cheer each other on.

"Good," "good job," "well done."

This kind of facilitation, giving a hand, encouragement, is the base of teaching.

It seems like it's not just a cognitive capacity that's necessary for teaching.

There's this other thing, which is wanting to teach,

that seems to be really pervasive in humans and maybe mysteriously missing in apes.

The pieces are now coming together.

Apes have a culture, a rare achievement in the animal world.

They can learn from each other through imitation.

But this process is passive, often slow and can easily backslide.

Probably there's a lot of slippage.

There's a lot of loss of cultural innovations

between generations when you're talking about a chimpanzee.

If an ape invents something new and important and interesting,

maybe some others will learn it, maybe they won't.

Unique among animals,

humans have both the passion and mental skill to teach each other.

When you're a student rather than a spectator, learning happens rapidly.

That's because teaching locks in progress.

Human culture traditions have a cumulative quality

that each generation builds on the things of the previous generation.

So if you looked at the history of any interesting technology,

it started out simple, and the children of that generation learned the simple version.

But then some genius made an improvement to it,

and everyone follows right away, and we get this ratcheting up in complexity.

An ape may stand on another's shoulders,

but only humans can stand on the intellectual shoulders of giants.

 

It's such a great privilege to be able to work with these animals and try to understand

what's going on in their head when they look at you so gingerly and softly.

Is it they're thinking, "Oh, he's such a nice guy,

and boy, I wish I knew what was going on in his head?"

Or is she thinking, "Gosh, what's that spot?

Is it dirt? Could I eat that?"

In spite of their limitations,

when we look into the eyes of a fellow ape, we don't feel a gap but a deep connection.

We can't resist a chimp reaching out for help,

or a group of unrelated bonobos rallying to the defense of another,

or a mother refusing to let go of her dead baby.

But as the most social of apes,

we can't help reading thoughts and feelings into the mind behind any familiar face.

And perhaps that says more about us than them.