What Makes Us Clever? A Horizon Guide to Intelligence

What is intelligence?

8175 backwards?

-57118.

-What does an entomologist study?

Wow! That was tough. Did a lot of people get this one in two minutes?

And why do some people apparently have so much more of it than others?

Where does intelligence come from?

Is it a matter of luck, biology

or just a good education that makes this guy cleverer than me?

Is there anything that I or my parents could have done to make me more intelligent?

Well, scientists have been battling thorny questions like these for

decades, making intelligence one of the most studied traits in science.

But it's only really now that we are beginning to get some answers.

For nearly 50 years,

Horizon has been following that search to understand our mysterious mental power,

looking at everything from our evolutionary history to whether a computer could outsmart us.

And asking the questions, how do you test for intelligence?

Is it inherited or innate?

Nature or nurture?

In so doing, science has begun to redefine our understanding of what makes every one of us unique.

The benchmark for measuring one person's intelligence against

another is the iconic IQ or Intelligence Quotient test.

Most of us will have sat through one of these at one time or another.

It is the dreaded IQ test, with sections on spatial awareness, general knowledge and reasoning.

And it tots up different areas of skill to create one score.

A single mark that can brand you with either a low, high or maybe an average IQ.

Now, we've been judged on the merits of this test for years now.

What's remarkable about it is that it was introduced in 1912.

So, essentially, this has remained the same for almost 100 years.

In 2006, Horizon tested the IQs of seven experts in their field to see who would come out on top.

Seven people from seven very different backgrounds.

All highly successful.

And all seven prepared to do battle over the elusive nature of intelligence.

The test lasts 30 minutes.

What it revealed would show how our understanding of intelligence

has changed since the IQ test was first devised.

We have spent 100 years on IQ tests that are basically the same.

Imagine if physics or chemistry or medicine or biology were the same today as they were 100 years ago.

That's essentially the state of the testing industry.

It's unusual to find a methodology that has changed so little.

And perhaps this reflects the century-long struggle to work out how intelligence develops.

In their bid to understand human intelligence, scientists have looked for evidence of it in other animals.

During the 1980s, Dr James Gould searched for

signs of intelligent behaviour in the complex lives of bees.

Even now, when I look at bees, it's hard to imagine that these tiny,

nervous little insects could be intelligent.

Yet, in all this apparent chaos, there is a tremendous amount of order.

Bees are not behaving randomly, they are going about the task of solving a series of specific problems.

They spend the first few days feeding the queen and taking care of her.

And then they spend a few days building honeycomb in the hive.

And then a few days guarding the hive's entrance and

then, finally, several weeks gathering food from flowers.

These are all clever things and yet this behaviour is driven by biological cues.

All through the life of a bee,

an innate sensitivity to certain cues helps guide its behaviour.

And this is by no means an exception, this is the rule in the animal world.

And it makes sense, too.

If the behaviour is sufficiently predictable and the cues are sufficiently predictable,

it makes sense for an animal not to reason out what it ought to do, but to simply respond automatically.

A good example of this is tits open milk bottles

because instinctively they peel back bark to look for grubs.

Gould concluded that, unlike humans, the short lifespans of many insects and animals means they simply don't

have enough time to work out solutions to problems.

Their apparently intelligent behaviour is just a response to a series of biological cues.

However, there are animals that do appear to display a capacity for intelligent problem-solving.

Research into one species - chimpanzees - has begun to

reveal greater capabilities that go beyond pure instinct.

Writer, Danny Wallace, went to Uganda to find out more.

He was keen to investigate an experiment to test a chimp's ability to solve a complex problem.

This box of bananas placed away from the cage poses a tricky problem.

Ah.

I see what you've done.

'To get the bananas to come towards me, I would have to pull both ends of the rope.

'But they were too far apart.'

Right, OK. I can't.

Diana? Will you be another chimp, please?

Chimp-cam.

'I could see that if I didn't get Diana involved, I'd get no bananas at all.

'And that didn't bear thinking about.'

One, two, three.

We did it, we got the bananas.

Now for the chimps. Chimp one has a rational choice.

Share the bananas with chimp two or get no banana at all.

Three, two, one. Release the chimp.

OK. So, he's going a bit mad.

Chimp one can't get the bananas.

Chimp two is going mad, chimp one is wondering what's going on.

Oh, he has let him out. That's amazing.

That's incredible.

Chimp one, he's very happy, and off they go.

That was brilliant.

That was quicker than me.

The chimp appeared to be making a thoughtful decision,

suggesting that chimps are intelligent enough to co-operate.

A key human trait.

Yet human intelligence still sets us apart from our closest evolutionary cousins.

Thank you for taking part in this experiment. This is for you.

Scientists have delved deep into our prehistoric

past to try to find out when we developed superior intelligence.

When did our ancestors cease being brute animals

and first become truly human?

When did we learn to think?

Thinking is the defining trait of humankind.

It has given us machines.

Technology. Power.

No other animal has the ability to look at the world outside and transform it.

Where all other animals live from day to day, we alone plan ahead.

Dream. And create.

Find the day we learned to think and you would have identified perhaps

the single most important moment in human history.

But it was not going to be simple. Thinking leaves no traces.

There are no fossilised thoughts waiting to be dug out of the ground and dated.

It was like investigating a murder scene without a body.

So, scientists had to look for indirect clues.

Not fossils, but other evidence for when thought began.

And then they realised that thought must have come hand-in-hand with something else.

What are we going to look for,

first of all, that's going to give us evidence that humans were behaving in a modern way?

So we look, in a way, for proxies.

But there was one kind of evidence archaeologists could look for.

The obvious line of evidence is art.

When you get unquestionable art that's widespread and common,

I think you can say you're dealing with people just like us.

Only humans create and can make sense of art.

I'm sure that dozens of dogs have walked down this street in the past years

and perhaps not a one has glanced up in awe or wonder

and thought to himself, what does this mean?

For a dog, this is colour on a wall.

Perhaps even less than that.

But to a human being, a painting is far more than just a collection of colours.

An expression of thought.

Suddenly, what they had to look for was clear.

Discover the earliest forms of human art

and you would have found the day we learned to think.

At Blombos, on the east coast of South Africa,

anthropologist Chris Henshilwood had been quietly excavating his prehistoric cave for over a decade.

This is Blombos cave here.

A very special find.

We're really looking at what has been left here

almost as if it was put down here yesterday.

As they dug down through the floor of the cave, his team were going back to

an ancient time of human habitation tens of thousands of years ago.

We came down onto this layer you can see over here, which really was quite remarkable.

On the surface were lying the most beautifully made artefacts.

Bone points, spear points as well.

And immediately I realised we had gone back a very long way in time.

The beautifully crafted objects were dated to over 70,000 years ago.

But there was still not proof the people in the cave were thinking people,

like us.

One type of item started appearing over and over again.

We noticed large numbers of pieces of ochre.

8,000 pieces of ochre in the old levels alone.

Then, one day, Henshilwood found a piece of ochre that was different from the rest.

We found this piece of ochre, brushed up the side and there was

this absolutely remarkable pattern revealed.

There was huge excitement, you can imagine.

The ochre piece appeared to have been marked with a clear image.

What seemed like an abstract geometric pattern.

This was a deliberate construction of a series of crosshatches in each direction.

A line across the top, a line through the middle and a line down the bottom.

So it actually circumscribed that engraving.

As if they had made the crosses and deliberately surrounded it with these other lines as well.

Here is the first example of the ability of humans to store something outside of the human brain.

You're storing a message that somebody else who is part of

that same group can pick up and they will understand what that meant.

This is the beginning of things like art, writing and everything else that follows.

It was the earliest evidence of the thinking brain.

There is still much that we don't know about the evolution of human intelligence.

But it was during the second half of the 19th century that the ideas of

Charles Darwin began to profoundly influence our thinking.

Francis Galton was the first scientist

to propose that intelligence was a biologically-based mental faculty.

He was Darwin's cousin and was much inspired by reading his book, On The Origin Of Species.

Galton thought that human mental abilities were inherited in just

the same way as the plant and animal traits outlined by Darwin.

And he set out to prove it.

Galton was obsessed with measuring things.

He was convinced that everything was inherited, from arm length to reaction time.

According to his theory, people with bigger heads, such as himself,

would have a greater capacity for intelligence than others.

So he started to measure the heads of a group of Cambridge students

and compared those measurements to the test results.

But, disappointingly for him, the correlation between those two sets of data was low.

The evidence simply didn't stack up.

But Galton stuck doggedly to his conviction that intelligence was inherited.

He coined the phrase, "nature versus nurture",

which has proved to be one of the most enduring questions at the heart of the intelligence debate.

But it was Galton's disciple, a psychologist named Cyril Burt,

whose research was to have a huge impact on both our thinking about and our testing of intelligence.

Horizon dramatised Burt's youthful idealisation of Galton,

which would have an enduring influence on his work.

Galton was one of Burt's heroes, maybe the only one.

Of all the psychologists whose names were mentioned

in my discussions with Burt, I think the only one that he seemed to talk about admiringly was Galton.

This is young Loddy, Sir Francis.

-Loddy?

-Loderick, sir. It's a shortening.

My first name is Cyril, then Loderick.

Are you good at your schoolwork, Loddy?

Oh, yes, sir. Very good.

He's a very diligent boy.

He has a diligent father.

He will have inherited his father's intelligence.

Burt seemed to worship Francis Galton.

He kept on mentioning the one occasion on which he met him.

And he certainly tried to follow in his footsteps.

Oh, no. Do you read classics?

I want to be a scientist.

Burt was particularly drawn to one of Galton's ideas.

In 1883, Galton had coined the term eugenics, meaning good birth.

He believed that people of high rank had greater intelligence and should be encouraged to marry and have

children to preserve these traits, while the poor be strongly discouraged from breeding.

Burt adopted this idea with enthusiasm.

For example, Burt has written out on his hand: "The problem of the very poor.

"They must be segregated, prevented from reproducing their own kind".

This is the kind of atmosphere, obviously, to which he was exposed.

Working in the 1930s, Burt was determined to prove intelligence was inherited.

He brought together more evidence for the inheritance of intelligence

than any other person had done at that time.

His papers were more impressive in terms of the number of different

kinds of kinships on which heritables had been estimated.

The fine grain detail in which the analyses were carried out. And so on.

Burt introduced the IQ test as a way of measuring schoolchildren's intelligence.

He was also to influence the introduction of the 11 Plus test,

which was to become a key decider of a child's academic future.

By 1945, every child's intelligence was tested.

In order to study the inherited element of intelligence, Burt looked for subjects that were

the same in every way, except the environment they were brought up in.

Identical twins who had been separated at birth.

So now, if you can find, when they are old enough to be IQ tested, a fair number of pairs of such twins,

you can give them all IQ tests, and if their measured IQs resemble one another, that must be due to the only

thing they have in common, namely their identical genetic make-up.

It cannot be due to their environment, in theory, because they don't have that in common.

Burt announced his findings with a great flourish, stating that he had

found genetics were responsible for 80% of his subjects' IQ.

In the crucial matter of separated monozygotic twins,

and the measurement of the genetic heritability of intelligence,

over the years we have been fortunate enough to steadily increase our

sample size to the point where our data, based on 52 pairs of twins,

is some 30% greater than that of its closest rival.

Burt's research was highly respected and in 1946 he became the first British psychologist to be knighted

for his contributions to psychological testing.

But his ideas on eugenics had rather lost their appeal.

Adolf Hitler adopted this philosophy to murder thousands of people he labelled mentally defective.

The scientific community began to distance itself

from the idea of engineering society according to intelligence.

Burt continued to defend his ideas, but it was only after his death in 1971

that scientists, including Professor Leon Kamin, scrutinised his results and came to some uneasy conclusions.

As the sample size increased progressively, in successive papers,

one noted an absolutely incredible thing.

The correlations, the statistical results that he reported, remained identical to the third decimal.

Well, theoretically, that sort of thing could happen.

Also theoretically, the sun might not rise tomorrow morning, and that's probably a more probable event than

what one would have had to have believed if one took Burt's number seriously.

All of them remain identical to the third decimal place.

Clearly something was drastically wrong.

There's universal agreement among psychologists that Burt

couldn't possibly have tested 53 pairs of twins.

That at least the last 32 pairs must be figments of his imagination.

I take perhaps an even more sceptical view of Burt.

I think it's reasonable to suppose that he may never have laid eyes on

a separated twin in his entire lifetime.

But Kamin was convinced that Burt was motivated only by his genuine belief in inherited intelligence.

I don't think Burt thought of himself as a manipulator and misleader of the public.

I think Burt had the intellectual audacity to think that he knew the truth prior to any

actual investigation of the facts, and therefore on account of noblesse oblige, he was letting the rest of

us get a handle on the truth by presenting us numbers that would help us to accept it.

And he did us the courtesy of inventing the numbers for us.

Comprehensive proof of the part genetics play in intelligence still remained elusive,

but as the '70s got underway, that didn't deter one man from adopting a radical new approach.

In a rather sinister echo of Burt and Galton's theories, Californian doctor Robert Graham

reasoned that if there were intelligence genes to be had, he could find a way of passing them on.

In 2006, after Graham's death, Horizon looked back at his extraordinary quest.

My name is Robert Klark Graham and I had a dream.

To single-handedly saved the human race, one child at a time.

Robert Graham believed that the gene pool was going downhill and that we needed to do something about that.

He had this grandiose plan to remake all of humanity.

It had the air of James Bond movie meets Disney, or something.

Using the sperm of clever men, I hope to create intelligent kids.

He was this strange scientist

that was trying to breed the super race.

What we're doing is exploring the possibilities of genetics.

I was accused of being a racist and a Nazi.

I can't say that I know much about Hitler or his vision.

Yet my sperm bank was operational for nearly 20 years.

Despite tremendous controversy, I was responsible for the creation of over 200 children.

I would not be here without Robert Graham, without his existence, and in a way, I owe him my life.

Well, I'm Tom Grunwal, and live here in Temecula in southern California.

I'm Andrea Grunwal and I live with Tom.

I had had two children with my first wife,

then with my second wife, I took the steps to have a vasectomy.

The next thing you know, I'm divorced.

I never really thought I would ever have another child in the rest of my life.

Until I met Andrea.

I finally just spilled my gut and said, Tom, I don't know

how to say this, but I would really like to have a baby and I don't know how you feel about that.

And I said, OK, if you can figure out how,

let's go for it.

I wanted to offer these women the seed of clever men,

and for me, scientists were the pinnacle of intelligence.

With proven, measurable, practical ability.

I figured, let's start at the top.

We were trying to have

outstanding genes and Nobel Prize winners possessed them.

Due to your outstanding achievements, you

would be an excellent donor for our Repository for Germinal Choice.

We hope to create some very bright children, possibly a genius or two.

I managed to convince three Nobel laureate scientists to each provide an anonymous sample for my bank.

I actually was a little surprised that some of these older fellows were able to produce specimens so quickly.

Bob was very pleased when we took that first look at the specimen under the microscope and saw

thousands of sperm swimming vigorously.

He beamed with joy.

Good job!

It's peculiar, but I didn't think it was weird.

My name is Dr Afton Blake

and I live in Los Angeles, California, in a little place called Mount Washington.

Om....

When I first called the repository, they were very friendly.

They came up the next day to meet me and interview me.

And I think the very next month I tried my first insemination.

Choose me as your mother.

Then, 10 months after I had tried the first time, I conceived.

In August 1982, having been impregnated with donor

codenamed Red 28, Dr Afton Blake gave birth to a boy she named Doran.

It was ecstasy from the moment he came out, looked in my eyes, and stopped crying,

immediately that we made contact and the bond was like so incredible.

Everybody liked the name Doran, which means in Greek, a gift from the gods.

I could never imagine life without him. It was like suddenly,

what did I have before I had Doran?

I didn't know, because this was everything.

Do you want to hand me the dog?

I am immensely pleased with the outcome of the mating between Dr Blake and Number 28.

We've had a splendid result.

I think no question about it.

Doran is about as ideal, as nearly as we can judge at his early age,

about as ideal as we could hope.

Everyone wanted to know about my genius sperm bank child.

Doran represented what Dr Graham was trying to achieve.

Smart, beautiful.

Everybody wanted a Doran.

They just wanted to come to our bank and get a Doran.

The phone rang off the hook.

We had arrived.

After 20 years in operation, my genius sperm bank was

ultimately responsible for the production of 217 children.

We've got lots of baby pictures.

Jessie ended up being the 15th baby born to the repository.

People used to just be amazed at his abilities.

I look at myself as being an intelligent person and I think that

I'm achieving in the world all that I can achieve.

And that's something that

I don't think can be said for a lot of people around me.

I really need to make a contribution to realise myself or my potentials.

And what about the repository's poster boy, our second born child, Doran Blake?

He had showed such great promise as a youngster.

I'm exceptional statistically.

You know what I mean? I've always understood it that way.

I'm like, OK, so most people have an IQ here and my IQ is here.

As a child, Doran was good at everything.

-"I".

-He was in a highly gifted programme from first grade on.

By the time he got to Exeter, Doran was taking existentialism and

Buddhism, and he took six separate music lessons.

Throughout my life, I've felt like I have not had to work as hard for the

level of achievement that I've reached as most of my peers did.

I turned out very well. You know, my IQ was off the charts

and is basically everything that Robert Graham wanted.

While at least some of the children did appear to have inherited their

donor's intelligence, the sperm bank's success at producing geniuses could never be fully tested.

Most of the children remained anonymous.

Scientists continued to search for the inherited component of intelligence throughout the

1980s and '90s, as genetic research became increasingly sophisticated.

But even though the genome was fully sequenced in 2003,

no specific genes for intelligence have yet been identified.

Behavioural geneticist Professor Robert Plomin

has analysed the little we do know about intelligence genes.

We don't know how many genes we're talking about and if there are very, very many, they're going to

have very, very small effects and be very, very difficult to find.

But I think these genetic differences, when they're expressed,

are going to show up throughout the brain.

It's not going to be this gene does that bit of the brain, this gene affects another bit of the brain.

Now, that's a hypothesis for now but it's a very testable one when we find

these damn genes, if we ever do find them.

Scientists have now gathered data from combined studies of

over 11,000 pairs of twins to give a more up-to-date measure of nature versus nurture.

And it shows that Galton, Burt and Graham were at least partly on the right track.

A large part of intelligence is inherited.

You know, this is one of the most highly heritable characteristics around, intelligence.

In adults, we're talking about at least 50 or 60%

of the variance in the population is due to genetic differences among us.

So, if according to current estimates, about 50% of our intelligence is genetic,

then that of course leaves the other half up for grabs, and that's where environment or nurture comes in.

Scientists began to look at the impact of everything, from diet and supplements,

to good old pushy parenting when fostering intelligence in children.

David Baddiel investigated just how far

a fertile educational environment could affect a child's abilities.

-Hello.

-Hello, David. Please do come in.

Hello, nice to meet you.

-Hello.

-Hi.

Now, let's deal with...

Zaheib, the younger brother, answers the first question.

-So if this is theta...

-OK, so theta is that angle?

-This angle.

-Right.

-The vertical must be T...

-cos theta.

-That's very good. OK.

When do you first remember, either of you, doing a maths problem?

-When I was a toddler.

-Really tiny?

-Addition.

-Really?

-Addition, yeah.

-And what about you?

-Yeah, same.

You remember when you were counting 99s?

Oh, yeah. In nursery, I knew my 99 times table.

-How old were you then?

-In nursery you did your 99 times table?

-Yeah.

You were about three-and-a-half or something.

I can't do my 99 times table! Apart from 99 times one is 99, that's it!

Beyond that, I'm slightly struggling.

And I'm 44.

Which I think is a multiple. No, it's not!

-OK, so you are starting on A level maths now?

-Yeah.

-It is that right?

-Yes. And when are you planning to take your A level maths?

-In January.

And what's very special about that?

If I get A, I'll break the world record.

-You'll be the youngest...

-Ever. Ever, ever.

Child ever to get A level maths.

Why has it become important to you to push your children?

Why is that important to you?

To give them something to think about so that their mind is engaged in something useful all the time.

-Right.

-It's very important for them to be independent thinker.

So do you feel that mathematics specifically is almost a spiritual

training, then, for kids, in that it will actually train their brains and

their minds to become better thinkers, better opinion formers? Is that what you're saying?

That's exactly right because I did mention maths is the key thinking tool.

-Most of the time, they are not actually studying.

-So how much time do they spend?

-When they don't go to school, they spend on average about five hours.

-Right.

During school days, about three hours.

So they'll have their school day and then another three hours of study?

-Yes, yeah, on average.

-It seems quite a lot to me.

But that means most of the time they are not studying.

Because there are 24 hours in the interval.

-Yeah, but then they're sleeping for quite a lot of that.

-Yes, sleeping, yes.

But it isn't just a highly educational environment that can enhance intelligence.

Baddiel also looked at a revealing experiment which showed that other behaviours instilled in very

early childhood can predict a great deal about future academic success.

Now, if you had to choose the one marshmallow or the

three marshmallows, which one do you prefer?

The three marshmallows? OK.

40 years ago, a rather extraordinary experiment was carried out in this nursery at Stanford University.

The nursery is re-running the experiment for David.

All it consists of is a bell, a group of four-year-old children and a plate of marshmallows.

The question is, can a child resist eating the

one marshmallow in front of them for the promise of getting three later?

If they don't want to wait the time, they can ring the bell.

It's like watching a primeval battle between man or woman and their own desire.

The waiting time is ten minutes, just five minutes shorter than in the original.

First to go is Bridie.

See, she's now thinking, when's he coming back?

See, I'm not absolutely convinced that she is now thinking about the marshmallows.

I think she might be thinking about whatever, kid's thoughts, now.

Now she's thinking about the marshmallows.

If Bridie is going to succeed, she will have to devise strategies like the children in the

original study, to look away or stop thinking about the taste and smell of the marshmallow.

Just 30 seconds to go and Bridie is still resisting.

I'm feeling a bit sorry for her now.

Ooh. Oh-oh.

She's gone for the bell, she's gone for the bell.

Is she ringing or is she just looking at the bell?

Now she's rung the bell, she rang the bell. I'm so disappointed for her.

Next up is Olivia.

God, has she eaten one?

Oh, my God, she's eaten a marshmallow before the experiment's started.

But that's ruined it.

That's a shame because she's clearly one with impulse control issues.

So it's over to Jayden.

I think I know which way she's going to go, I tell you.

Finally, it's Keira.

Welcome back to Stanford for round two of the marshmallow experiment.

At first, she seems to be losing heart.

I think she can't bear it.

I can hear the devil on her shoulder saying, "eat the marshmallow!"

This must seem so long if you're a child.

If you think that children have a relative idea of time that is about ten times that of an adult.

Some of the children who'd succeeded before had managed to stop thinking

about the marshmallow as a real marshmallow.

They'd imagined it away.

I wonder if she's actually consciously thought, if I don't look at them,

I won't desire them so much.

So therefore I'll be able to get through it.

She did it! She did it!

She did it. I'm so pleased for her.

The scientists tracked the lives of the original children for 40 years.

What they found was that those who could resist the marshmallow did better at school.

And not only that, they were less likely to fall ill, or get divorced.

It seems being able to resist a sweet at four could predict academic success and a happier adult life.

This experiment serves as just one example of the traits which can be affected by nurture.

Now, after decades of scrutinising human intelligence, we are beginning

to understand that it can be affected by many variables,

not only by who your parents are, but also the environmental influences on your upbringing.

And it's not just the causes of intelligence that are wide-ranging.

We're also beginning to broaden our definition of intelligence itself.

100 years ago, it was simple.

Intelligence was a measure of problem solving ability,

general knowledge and memory that could be assessed by one all-encompassing test.

But now we have to look again at whether that stood the test of time.

The IQ test has lasted so long because it's got an almost magical property.

It seems to show that we have one general all-round ability, a kind of

all-purpose thinking skill that can be represented by a single number, the IQ score.

Very convenient, if you want to compare people.

Horizon brought together seven experts from seven very different disciplines to sit the test.

The IQ test consists of many sections that seem unconnected.

What does an entomologist study?

There are sections on vocabulary and general knowledge.

What's the capital of Jordan?

-Amman.

-What's the distance between London and Hong Kong in miles?

I would suspect it's around a third of the way around the globe, so about 8,000 miles.

A section on memory.

Eight, one, seven, five, backwards.

Five, seven, one, eight.

And a section to test spatial ability.

-You're doing just fine.

-Wow, that was tough.

Do a lot of people get this one in two minutes?

I can't see how that works.

Common sense might tell us that we're good at some of these sections

and bad at others. But that's not the case.

On average, if we're good at one of these sections, we tend to be good at all of them.

And from this comes the idea that intelligence is some kind of general, all-round ability.

Based on a range of difficult IQ problems, the results were predictable. Well, almost.

In third place, fighter pilot, Gary.

In second place, IQ specialist, Nathan.

But he was beaten to the top spot by quantum physicist, Seth Lloyd.

But when the winner was announced, there was an immediate objection.

So I'd actually like to say this is unfair because actually these

tests were things that fit extremely closely with what I do on a day-to-day basis.

Seth's modesty at coming top in the IQ-type problems shows why some people think the IQ test is flawed.

That means the electron, in some funky quantum sense, reads zero and one at the same time.

Was Seth good at the tests merely because of what he does every day?

My job consists of trying to solve hard mathematical

problems related to the physical world, like, you know, how does a black hole evaporate, for instance.

I'm constantly pushed to the very edge of what I can actually do.

So, it's actually fun for me to do something like these puzzles which are relatively easy.

Or did the tests capture something essential about Seth?

We could say he has a high general intelligence as revealed by the

tests, and that this means he's the most intelligent.

But that's not the whole story.

Not even test manufacturers would say the result of this test will tell you how intelligent somebody is.

They would say it's a small component of making those

judgments and that you should be looking at a much broader spectrum of skills, abilities and aptitudes.

The IQ test looks at a lot of old knowledge, like, you know what the capital of Italy is, or, can you add

two-plus-four, can you compare slavery and freedom, those are IQ-kinds of tests.

But they don't tell you anything about whether the person will

actually ever do anything that's productive in the world.

Professor Howard Gardner has come up with a newer, broader way of testing intelligence.

The major move I've made in the study of intelligence is to pluralise it.

I've come up with an alternative view which is called multiple intelligence theory.

To perform some kind of an action in the area of music, or in the area of navigation

is very different than to perform in a scholastic kind of assignment.

And my whole analysis over many years suggests it's a mistake.

It's a category error to lump all these together and to call them intelligence.

Professor Gardner is convinced we have at least eight relatively separate intelligences.

This is completely opposite to IQ, which assumes that we all have just one general intelligence.

So, you might be wonderful at understanding other people

but a disaster at doing crossword puzzles, or flying an airplane.

So we do know that an individual's high-performance in one area

simply doesn't predict high performance in other areas.

Horizon put its line-up of high-flyers through Professor

Gardner's new intelligence tests to see if the outcome would be any different to the standard IQ tests.

But there's no agreed system for measuring them.

This could be a drawback for Professor Gardner's approach,

but he still defends the value of non-academic intelligences.

Wow, this collapsed.

Football players may well not be scholastically intelligent and so they

don't do well in a school with reading and writing and so on.

If we lived in a non-literate society,

the people who do well in school would not emerge at all, and perhaps people who are good at football

would be better hunters, and better strategists about survival, and then we'd be calling them smart.

And the people who had the potential to read and write

would be irrelevant because there'd been no reading and writing there.

Based on the combined outcomes of the IQ tests and the newer intelligence tests,

the results should reveal who has the most mental flexibility and all-round intelligence.

Tied equal in third place, fighter pilot, Gary, and musical prodigy, Alex.

In second place, IQ specialist, Nathan.

And in first place, an interesting tie.

One of the winners did fantastically well on the standard IQ test,

but the other one wasn't even in the IQ test top three.

Taken across all the tests, quantum physicist, Seth Lloyd, shared higher scores with dramatist, Bonnie Greer.

Horizon's assessment of the experts show that the IQ test

only identifies a very particular type of intelligence.

It couldn't predict how good someone would be at a wider ranging set of skills.

But the IQ test hasn't been consigned to the history books just yet.

It might not pinpoint everyone's unique intelligence type, but it

has turned out to be useful in a way no-one could have predicted.

You have 45 minutes to do the test, OK?

OK.

Write the three letters between A and E.

And cross out of the middle one.

Bill and Davina are 79 years old.

This is the second time they've done this test.

If H comes before K, write X, unless S comes before Q...

The first time was in 1932 when every 11-year-old in Scotland was put through an intelligence test.

The results were rediscovered recently in an Edinburgh basement.

If you want to know how our intelligence changes as we

get older, these results are a potential goldmine.

We've brought hundreds of people back and we got them to sit the exact

same test they had sat when they were aged 11.

Now, these people were now 79 or 80 years old.

We gave the same instructions, we gave the same test, and we gave the same time limit.

It was a little stickier than I thought it would be.

I walked through it quite happily, quite honestly.

I felt I must have been very bright at 11 if I sat that exam and passed.

There were some intriguing results.

Almost everyone had a better score at 80 than they did at 11.

But some had gone from being just averagely intelligent to a much higher level.

Now that's what really drives our research.

Why are those people who've gone from IQ 100 at age 11, up to 110 or 120?

What have they done right? What can be the recipe for successful ageing?

We're finding that the person with more education,

even though they had the same IQ in childhood, is doing slightly better in old age, on average.

The person who had a more professional job in old age is doing slightly

better, on average, than the person who had a manual job despite the fact that they started at the same level.

The people who smoked have got slightly less good mental ability than you would expect.

What's even more remarkable is that the kids who had higher IQ scores at

11 are the very ones still alive today.

So it seems high IQ in childhood is good for survival.

Maybe an IQ score is a record of how well wired together your brain is, and that might, highly speculative,

that might be associated with how well wired up the rest of your body is.

But if our intelligence can increase as we grow older, can we go one step further and boost it artificially?

Marcus du Sautoy investigated one technique.

At the University of Goettingen in Germany, they're pioneering

technology that could greatly extend our control over our own brains.

They're developing a means to turbo-charge our grey matter.

The aim is to improve the volunteer's ability to subconsciously learn.

The test itself is simple.

When Leila sees a dot appear on the screen, she has to tap a corresponding key on the keyboard.

There is a pattern to when the dots appear.

But it's impossible to detect.

At least before the artificial stimulation of her brain begins.

What we want to do is to facilitate the

excitability of her motor cortex.

-And in order to be able to do that, we have to fix an electrode.

-I presume this is perfectly safe.

I mean, I'd be a bit nervous about having electricity shot through my brain.

Well, they're very weak currents.

They're so weak, she doesn't notice anything.

They're so weak that they just manipulate the membrane potential of nerve cells a little bit.

So, now we will stimulate the motor cortex here.

By anodal electricity, positive electricity, for 10 minutes.

So, now stimulation starts.

So there's now electricity passing through Leila's brain.

-Can you feel anything?

-No, nothing.

There's no smoke. I can't see any.

And during this stimulation, Leila will move her fingers and do the implicit learning paradigm.

Then we will measure simultaneously how quick she can respond to the visual target during this time.

What we expect to see is with motor cortex depolarisation

that's more excitable and then her reaction time

will improve.

And then we'll see an increase in speed that she's not constantly picking up a pattern, but

subconsciously, she's getting better at learning.

The longer the stimulation lasts, the greater its effects will be.

In previous experiments lasting 24 hours, permanent improvements to the brain were forged.

We know from other research, basic animal research, that

new connections between individual nerve cells will be built after about 30 minutes.

And after about a day, they start to become functional.

-So it's really changing the structure of the brain by doing this?

-Yes.

It's not just a temporary effect?

Yes, so we have structural alterations which allow you to move your fingers quicker in this case.

With measuring the reaction times, we will see that you'll probably speed up in the range of 10% or so.

10%, and that's significant, is it?

10%, you wouldn't expect that?

-Not without stimulation.

-Right.

The idea of being able to enhance our intelligence, if you don't mind

having your brain stimulated, hints at the dawn of a brave new world.

But if you're going to involve computers, then why stop there?

Some scientists think the creation of artificial intelligence

could transport us to new levels of interaction and understanding.

It's something that has occupied the minds of technology researchers for decades,

and Horizon has featured some of their wilder predictions.

Our descendant will not be the child of the loin,

but the child of the brains, the thing we call the computer,

which does not have to pass through the birth canal.

And does not grow by a tablespoonful of grey matter every 100,000 years,

which is the case in the rapid growth of our brain,

but grows a factor of 10 in power every seven years.

The computer generation.

There's no question that it'll match us in narrow reasoning power by 1990,

and go beyond us to become the great new intelligent race of the future.

The artificial intelligences of the future will be worried about

weighty problems that we simply can't understand.

And they may condescend to talk to us. They may...

amuse us on occasion, or play games that we like to play.

And in some sense, they might keep us as pets.

Although those predictions haven't been borne out, work on artificial intelligence has continued to race

towards the goal of a man-made super-intelligence, leading one

man to predict that a computer will equal a human brain's power by 2029.

His name is Ray Kurzweil, inventor and visionary.

He believes that our understanding of the human brain will soon be complete.

25 years from now, we will have actually mastered human intelligence.

We'll have both the hardware and the software to recreate human intelligence in a machine.

Kurzweil was one of the first to make a computer that could read.

MACHINE: 'For score and seven years ago, our fathers brought forth upon this...'

If his latest prediction is right, then we will understand the human brain

at almost exactly the same time as computers equal its power.

It's this culmination of events that would lead to the singularity.

There's really a point in human history where human society will be

profoundly transformed by creating non-biological intelligence.

Machines that are ultimately billions of times more capable than human beings today.

And we will integrate with this technology, and it will enhance human potential.

We'll have to wait until 2029 to find out whether Kurzweil's prediction is correct.

Until then, science can only continue in its quest to fully fathom our unique mental abilities.

Understanding what makes my intelligence different from

that of someone like Einstein's could be a question of my genes, or the way I was brought up.

Maybe I'm just intelligent in a different kind of way?

He was pretty good at physics. I'm pretty good at...

Well, anyway, 2029 is not so far away

so maybe we'll just have to wait and see who's so clever then.

Subtitles by Red Bee Media Ltd

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