All language subtitles for BBC.The.Joy.of.Winning.720p.HDTV.x264.AAC.MVGroup.org

They say life is a competition.

The fight to be first.

The survival of the fittest.

Winning.

Nobody wants to be a loser.

Now, winning basically means getting
more of what you want in life,

and, as a mathematician, I can help
with that.

Because there is a real science
to success,

based on ideas from some of the last
century's most beautiful minds.

# Everyone's a winner, baby
That's the truth. #

From how you can analyse and take
advantage of your opponents...

You need to find a way to be as
unpredictable as possible.

..to deciding whether to cheat or
play fair...

You can put a good apple in a barrel
of bad apples,

it's always going to turn bad.

..being more strategic will help you
get ahead.

But if all of this sounds a bit
selfish,

I'll also be showing you how
cooperation can trump conflict,

and how everyone can be a winner.

Hello, Sheriff.
Hi, Hannah. How are you?

You are walking away with no money
because you are an idiot.
No. You're an idiot.

Whether it is happier relationships
you are after, a bargain,

or a better world,

a look at the science of winning can
help

and reveal some surprising truths.

So join me.
You'll lose out if you don't.

To get the best result in any
situation, maths can help.

Let's take just one example.

Something as simple as ordering
dinner.

Should you choose burger or steak?

Now, you absolutely cannot
afford it,

but that steak does look incredibly
tempting.

And it's almost your birthday,

surely you deserve a £25 splurge
every now and then?

First of all, ask yourself, what do
you really want -

steak or savings?

Well, you need to decide
what winning means for you.

And that might change
when your mates arrive.

Let's imagine that everybody has
exactly the same choice.

Burger or steak.

But you know that your friends are
notoriously frugal, so

if they all go for the burger and
you split the bill evenly,

you could end up getting
that tasty steak for a lot less.

The £25 hit from your steak

combined with the £5 for their
burgers means

everyone pays £10 each,

which frankly, for you,
is an amazing bargain.

But hold on. The waiter is coming
over and is heading towards

your friend, who you know loves
a rib eye.

Is she thinking
what you're thinking?

And what about the others?

And so begins a frankly very British
game of silent guessing and

calculating. If she goes for the
steak as well as you,

then you're shelling out £15 each,

but if he goes for the steak too,
then that's £20 a head,

which is far more than you can
possibly afford.

But is it really fair that your best
friend,

who always does the generous thing,

ends up spending £20
for a measly burger?

So what is the real win here?

Well, it's complicated.

Do you prefer saving money,

a delicious dinner,
or being fair to your friend?

Having been fleeced, will she ever
want to meet up again?

The key thing is that what you want
can be scored,

and mathematicians like me give it a
fancy name - your expected utility.

We express your preferences

as values that capture just how much

you instinctively want something,

against the price, and then factor
in other stuff, like risk.

In this case, that your dear friend

might ditch you for busting
her budget.

Looks like steak pipped friendship
this time.

So there you go.

If you can figure out everyone's
preferences

and you know what YOU want,

then the key question becomes,
at the lowest cost to yourself,

without having any control over
other people's actions,

how do you get what YOU want?

Well, thankfully, mathematics can

help you find a winning strategy,
too.

Whatever decisions we make,

having a good strategy means the
difference

between knowing what you want
and getting it.

It was the mid-20th-century maths
genius John von Neumann

who, more than anyone else,

turned our winning instincts into
a science.

Von Neumann established a completely
new field of study,

called Game Theory, which was
concerned with the mathematics

of both cooperation and of conflict.

How to avoid losing
and, more importantly, how to win.

His efforts culminated in this here.

A Theory Of Games And Economic
Behaviour, 641 pages,

packed to the brim with formulas,

which was once described as one of
the most-influential

and least-read books
of the last century.

Written with the economist Oskar
Morgenstern and published in 1944,

it proved how we can all get ahead

when one party's loss
is the other's gain.

It's not for the mathematically
faint-hearted,

but at the core of the book is a
strategic principle

that is surprisingly intuitive.

And easily explained with some
cold, hard cash.

So, you and me are here.

I'm going to have a go on those slot
machines

and I have got a nice bag of
2p coins

that you and I are going to share.

Now, the polite way to do this is
just to let you help yourself.

After all, I trust you to play fair.

But actually, I really shouldn't.

Von Neumann assumes, rightly so,

that we both want
as many coins as we can get.

So, what SHOULD I do?

Well, I should split this into
two piles, as evenly as possible,

and then let you decide
which half you want.

Given that you're watching me like a
hawk, the only way I can guarantee

I don't lose out to you is
by me splitting and you choosing.

I don't get as many 2ps as I might
like, but I win by minimising the

maximum amount of fun at the fair
that I can lose to you.

This is known

as the min-max theory,
and as strategies go,

you can apply it to pretty much
anything.

So, if you have got two kids that
are fighting over toys,

just get one of them to make two
piles

and the other one to pick which
pile they prefer,

or if you've got boring household
chores, you write two lists,

and your partner chooses which list.

It sounds pretty simple,

but you have to remember that your
split will take into account

your preferences, so you get to
decide if you think

the utility of a huge pile of
ironing and doing

all of the hoovering is the
equivalent of

the utility of unblocking the loo,
and sorting out all of the bins.

Now, strangely, Von Neumann didn't
get into that particular conundrum

in his book, but his proof that you
can always minimise the losses

and maximise the gains, while taking
into account

the preferences of two warring
parties was hugely influential.

Such an analytical approach
to winning

gripped people's imagination.

And crucially, Von Neumann took
inspiration

from one rather unpredictable game.

Von Neumann was an exceptional
mathematician.

And perhaps because of its strategic
complexity,

he was particularly interested
in poker.

He said that real life is about
bluffing,

about little tactics of deception,

about asking yourself, what does
the other man think I mean to do?

"And that is what games are about
in my theory."

When it comes to winning big at
poker,

there's one woman you need to know.

Wow! This is bold.
Four bet of 4,100.

Sick move. Liv Boeree is the
European top-ranking

female poker player.

Really strong play by Liv Boeree,

she's clearly been eating
her vitamins.

Vitamin B - for bluff.

I'm meeting Liv to find out how
poker strategy might help us

get more of what we want in life.

These days, the very best players
are very analytically minded folks

who are comfortable working with
maths,

to sort of really get a solid
understanding

of the theory behind the game.
And then the psychology is,

I like to think of it
as the cherry on top.

OK, let's talk about the basics,
then.

What calculations are you making?

Um, if I'm going to bet chips, if
it's 30% of the time

I'm going to be the best hand,
and 70% of the time I'm going to be

the worst, then I can multiply those

numbers against the chips that are
involved, and that'll be my expected

value from a situation.

And that applies in many real-life
situations, too.

Say I am running late for a flight.

I have two options. I can either...

..go to the airport and try to make
my flight but run the risk

of then missing it and losing the
value of the flight,

and having to buy a new one,

or I can stay home and do the sort
of safer bet,

and call and pay the change fee.

Thinking rationally and quantifying
things is the very first step to

thinking strategically.
Exactly. Yes.

It's very hard to build strategies

if you don't have a numerical idea
of the value of the outcomes

of different strategies.

By evaluating both the chances of
something happening

and the outcome when it does,

you have a better view of your best
options.

But at this level, everyone is just
as calculating.

To beat the optimal strategy,
you have to find an edge.

There something that's called
game theory optimal, where,

if you're playing this style, then
it means that you are unexploitable,

basically. The best case that an
opponent can do to counter it

is to also play
game theory optimal,

therefore you just sort of reach the
same very high standard of play,

and you're trying to not deviate
from it at all.

And that's where sort of the more,
like, creativity

and, I guess, the artistic side of
the game comes in,

where you can do these deviations
from the optimal play

to exploit your opponent's
weaknesses.

But they could be doing that to you
as well.

Exactly. So you need to find a way
to be as unpredictable as possible.

Von Neumann's maths proves that
poker players must bluff,

unpredictably,

to avoid exploitation
by a savvy opponent.

It is an essential strategy and it
can be applied elsewhere.

You know, if you're in a business
negotiation,

what is the minimum amount
you will take?

There's a great opportunity to bluff
and give a high number because

you're giving yourself the option

for them to pay you
that high number.

It might seem obvious, but bluffing
like this

is exactly what gives you the edge
over others.

Particularly if their loss
is your gain.

Anything that is a competition,
to make yourself unexploitable

will just put you at a huge
advantage.

So quantify everything, folks.

And don't make yourself
too easy to read.

In win-lose games your carefully
calculated strategies

can only get you what you want
if your opponents are in the dark.

But what if you're involved in a
conflict where everyone could lose?

During the second half
of the 20th century,

the biggest problem that game
theorists has had to contend with

was the Cold War.
The US and the Soviet Union

were facing off against each other,
and just as in poker,

every strategy, every move and
countermove had to be analysed.

Except, this time, the stakes could
not have been higher.

As an ally to the US, Britain had
to prepare for the worst.

In 1961, a top-secret facility was
set up here in rural Worcestershire,

Regional Seat of Government 9.

It is one of a network of bunkers

from which the British Government
would

have operated in the event
of a nuclear war.

The moment that the Second World War

ended with such a devastating
show of nuclear force,

the talk in the West began to focus
on trying to prevent

a military face-off that would mean
that nuclear bunkers like this one

would become a necessity.

Now, the strategy that was on the
table at the time was referred to,

somewhat euphemistically,
as preventative war.

The idea being that the Americans
would launch an unprovoked attack

on the Soviet Union before they had
the chance to acquire the bomb.

But it would at least avoid a slow,

expensive and far more dangerous
cold one.

Preventative war is an argument
still used today over North Korea

and at the time, its supporters
included Winston Churchill

and von Neumann himself.

In 1950, von Neumann remarked,
"With the Russians,

"it's not a question of whether,
but of when.

"If you say, 'Why not bomb them
tomorrow?' I say, 'Why not today?'

"And if you say,
'Today at five o'clock,'

"I say, 'Why not one o'clock?'"

You can see where this kind of
reasoning ends,

and it is perfectly rational.

If someone has to win, better
that it be us.

Despite the impeccable logic,
America didn't attack Russia.

And then it was too late
because Russia got the bomb, too.

By 1953, there was no outcome in
which only one side could win.

This demanded a new strategy.

Something which became known as

mutually assured destruction,
or MAD for short. Basically,

the threat of you using massively
destructive weapons on your enemy

prevents your enemy from using
those same weapons on you.

Once everybody is armed,

nobody has an incentive to either
initiate a conflict or to disarm.

And so, nuclear war was avoided,
but places like this

and a hugely expensive, vast global
nuclear arsenal, was the result.

Compared to von Neumann's games,

in which one person's loss is the
other's gain,

mutually assured destruction,
strangely,

is something we come across far more
in real life.

Because most conflicts, whether
at work, with friends or family

have the potential to end up
in a stalemate.

So often we choose strategies
that mean no-one wins.

To explain why,

I'd like to begin with a rather
unusual detective story.

I'm looking at the Instagram page
of the rapper Ludacris.

In 2015, he shared this picture with
his millions of followers.

It had originally been posted on the
Facebook page of the police

department in Franklin County,
Kentucky.

And it reads...
"Attention, drug dealers.

"We offer a free service to help you
eliminate your drug competition."

And then under a quite large
marijuana leaf,

there are a series of sections
where dealers

can identify their competitors.

You can fill out who your
competition is, where they live,

their phone numbers,
even their hours of operation.

It might seem like a gimmick, but
the fact is,

Franklin County PD
were onto something.

I think I need to find out a bit
more about this,

so I'm going to call the sheriff.

RINGING TONE

Hello, Sheriff.

Hi, Hannah. How are you?
I'm good, thank you.

Why would a dealer call in and
tip off one of their competitors?

Obviously, if they eliminate it,

the more they get,
the more business they do,

the more money, the potential
earning that they have,

that they will make. And it helps
you get rid of your competition,

you're the only game in town.

Especially by having law enforcement
do it.

Does this really work for you,
then, as a tactic,

getting the criminals to do
the dirty on each other?

Yes. It's something that was very
simple to do

and, at the end of the day, if we
have got drug dealers

turning in drug dealers,
that is a win.

Police 1, drug dealers 0.

Wow. This was obviously a pretty
good score

for Sheriff Melton because what he
did was force

the local drug dealers into the most
famous conundrum in

the history of winning.

It is called, appropriately enough,
the prisoner's dilemma,

and it demonstrates very clearly the
dangers

of falling into a lose-lose
situation

when acting in your own
best interests.

Think of it like this.

Imagine Sheriff Melton has chucked
a couple of shady looking characters

from his local beat into jail.

He has got evidence to charge them
with possession,

but can only get them for dealing
if they rat each other out.

So, he puts them
in two separate cells

and gives them both his
clever flyer.

Our suspects must now consider
whether they should

both keep their traps shut and only

go away for one year each for
possession...

..both rat the other out for dealing

and each get
a three-year sentence...

..or hope that they alone grass
the other up,

getting off scot-free while their
competition gets

a whopping five years - otherwise
known as the sucker's payoff.

So, what to do?

Well, this option is the best.

But there's a risk it could quickly
turn sour if one person decides

to basically betray the other.

Good old Sheriff Melton knows these
two are toerags,

and they know it too.

So, to avoid being screwed over,

the only stable solution for them
is this.

They both must implicate the other.

A win for Sheriff Melton,
but lose-lose for them.

This unhappy scenario is called the
Nash equilibrium.

It's a beautifully simple proof
that was published in 1950 by the

mathematician John Nash, when he was
still in his early 20s.

It won him a Nobel Prize, and it
transformed the analysis of winning.

What Nash proved was that in a
situation

with several possible outcomes,
like this one,

where people either can't or
won't cooperate with each other,

there is always a strategy

which you and everyone else is best
off opting for.

Now, in the case of
the prisoner's dilemma,

paradoxically that strategy ends up
with lose-lose.

Everybody wants to win by ratting
out their competition,

and everyone wants to avoid
the sucker's payoff.

And as a result,
everyone ends up going to jail.

Being uncooperative can cost you
more than you bargained for.

The reason Nash's proof matters so
much

is because these kind of dilemmas

constantly appear in real life
because of the way our individual

interests often clash with those of
others and of society.

Whether you are a drug dealer, or
just out for dinner with your mates,

no-one wants to be the sucker,
right?

I remember the day I was arrested,
then I was locked up for 48 hours.

I remember thinking...

"Oh, THIS is what happens."

If ever there was an example of
Nash's theory in action,

it is in the controversial world
of professional cycling.

The global hero at the time was
Lance Armstrong.

We were really good friends.

I remember him saying, "I got caught
with my hand in the cookie jar".

I knew what Lance was doing.

It was like... Hang on a second.

David is one of the highest profile
riders to talk candidly

about the use of
performance-enhancing drugs
within cycling.

Tell me about the first time that
you realised that cycling

perhaps wasn't squeaky-clean.

Um, my very first pro race in
February, 1997.

My roommate was offered
a cortisone pill.

We all carried around medical bags
and it was omnipresent.

It was white noise, is what I've
always described it as.

For four years, David trained and
raced clean,

but the pressure to remain
competitive took its toll.

Eventually, despite your initial
resistance,

you did decide to give in.

Yeah. I think that is the term -
I gave in.

I didn't decide to join them, I gave
in and thought, "Well, you know,

"I can't fight this any more".

I was an ethical person,
but over time I just went...

It wears you down?

Well, just...the environment
you are in wears you down.

You can put a good apple in a barrel
of bad apples,

it's always going to turn bad.

It's a classic prisoner's dilemma.

In professional cycling,
riders compete to win.

If doping makes winning more likely,

then abiding by the rules risks
the sucker's payoff...

..and so the rational thing to do
is cheat.

Because a faster field and a doping
arms race has become the new norm.

This dilemma unites all
competitive sport.

Though it is a lose-lose scenario
if everyone cheats, nonetheless,

for individuals,
cheating can give you the edge,

IF you can get away with it.

The fundamental reason I was there
was because I wanted to win.

I was very ambitious. If the goals
you want to achieve

are being achieved by the people who
are cheating, why don't I do it?

David was the reigning world
time-trial champion

when he was caught in 2004,
receiving a two-year ban.

But after his punishment,
he returned to racing clean.

David Millar comes up, hits the
line. Best time, 31:15.

Millar is back.

Every time I won, from then on, it
was to prove a point,

that it was possible to win clean.

And you were appealing because you
were clean? Because we were clean.

It actually became a valuable asset
to be clean and win races.

It goes back to that
whole barrel of apples,

make sure it is a barrel of good
apples with one bad apple.

That's easier to control.

These guys will never have to
encounter it because we have

an anti-doping culture
in professional cycling now.

David's experience illustrates the
profound tension between individual

drive to succeed
and the greater good.

Our winning instincts can be both
our greatest asset

and deeply destructive.

This is something that is relevant
to all of us.

If you think about it, how many
times have you been in a situation

where you didn't want to upset the
balance of things

for fear that you might end
up missing out?

Maybe you have had a job
where you ended up staying later

and later at work just because
everybody else was doing it,

and you didn't want to look like
you were lazy.

Or maybe you have failed to call
someone out for a racist or sexist

comment just because
you didn't want to look bad,

you didn't want to make the fuss.

Or maybe, you have waited and waited
to tell someone that you love them,

just because if you said it first,
and it wasn't reciprocated,

you'd end up feeling heartbroken.

Now, all of these situations are
real-life examples

of Nash equilibrium.

So, what can be done about these
traps which are, admittedly,

very logical?

How can we break out of them and
secure that elusive win-win?

Well, I would like to show you one
option,

with the help of my favourite ever
game show.

So I have invited some people along
to a screening

of its dramatic climax.

You each have a golden ball
with the word "split"

written inside. You each have a
golden ball with the word "steal".

If you both choose the split ball,

you split today's jackpot
of £100,150.

If one of you splits and one of
you steals,

whoever chooses the steal ball will
go home with today's jackpot.

If you both choose the steal ball,
you go home with nothing.

I am going to split this.

I am very, very happy
to go home with 50,000.

You're genuinely going to split
with me? If I stole off you,

every single person there would
run over and lynch me.

There's no way I could...

Everyone who knew me would just be
disgusted if I stole.

Sarah, I can look you straight
in the eye and tell you,

I am going to split.
Promise? I swear down to you.

I AM going to split.

Sarah, Steve, choose either
the split or the steal ball now.

Hold it up.

We're going home with 50 grand each.

I promise you that.

Split or steal?

SHOUTING AND GROANING

You never know what's coming
in this game.

Trust me, that never gets
any less painful to watch!

I think we can all agree
that was pretty incredible.

I'm just really shocked that she
would do such a thing.

What would you have done in that
situation, though?

To be honest, I would actually have
stolen as well.

There you are, slight contradiction!

She seemed to be reeling him in
really well

to say, "Are you sure you're
going to split?

"Do you promise me you are going to
split?"

As soon as she knew that,
she could've equally thought,

I'm going to split as well and we're
both going to leave with some money.

Well, if you thought that was
interesting.

I want to show you
another clip which might be

one of my favourite things
of all time.

That's the only introduction
I'm going to give you.

Nick, Ibrahim.

Ibrahim, I want you to trust me.

100%, I'm going to pick
the steal ball.

Sorry, you are going... I'm going
to choose the steal ball.

I want you to do split,

and I promise you that I will split
the money with you.

After you've took the steal?

Yes. You're going to take steal,
I'm going to take split.

Yes. So you take the money...

And I will split it with you.
After the show. Yes.

CHUCKLING

APPLAUSE

Why don't we just both pick split?

I'm not going to pick split,
I'm going to steal, Ibrahim.

Honestly, 100% I'm going to steal.

If you do split,
then I will split the money.

I can't see myself doing that.
OK, well, I'm going to steal, so
we are going to leave with nothing.

You are walking away with no money
because you're an idiot.

That's not true. You're an idiot.
That's what you are.

You're an idiot.
Nick, choose split or steal.

Ibrahim, choose split or steal.
Now, please.

Split or steal?

Yes, congratulations!

You have both split
and each receive £6,800.

I would have split it.
Why did you put me through that?!

Why would you do that to me?!

Let's take a moment to recap
what just happened.

By promising he will steal upfront,

Nick removes two possible outcomes
to the game.

This means Ibrahim can only steal
and be guaranteed nothing,

or split, handing the cash to Nick
in the hope that he will share it.

Nick knows Ibrahim wants the cash,

so despite his ultimatum,
he also splits.

It's a win-win,

thanks to a brilliant way of forcing
cooperation.

I am delighted that we are joined
today by Nick from that video.

Wow! Thank you.
Nick, that was pretty amazing.

How did it come about,
you appearing on Golden Balls?

So, when I initially saw it,

I thought it was a bit horrendous as
a game show

because what happened basically
is you are rewarded for shafting

people. And I just wanted to prove
that if you trust someone, actually,

more often than not,
people will come through for you.

That was the motivation behind it.

Was there any point when you were
worried

that he wouldn't go with you,
that he wouldn't go for split?

If he didn't split, then he'd lost
everything,

so you can either be stupid or
REALLY stupid -

and when I say really stupid,

you'd rather have nothing than
see somebody get something.

You just had one clear strategy
you just needed to stick to.

I tried to sort of remove the
dilemma.

Forced him into a position?

Yes. If you had won the money,

would you have split it with him
outside of the game?

Yes. I REALLY would have done.

It was about proving that if you
trust people,

sometimes they don't always
shaft you,

and that was the philosophy
of why I wanted to do it.

Were you expecting it to get
that much attention?

No, nobody could have foreseen that.

Harvard University teach it
in economics.

UCL teach it... As do I!
Yes! Bath University do.

I've been asked to go to New York
to talk about it.

President Obama's economist has
included me in his book,

it's just a bit insane, really.

Yeah, wow. You did break
the prisoner's dilemma.

It's safe to conclude that having a
strategic genius

and all-round lovely man like Nick
take control

can be a real win for all.

So, like him, look for strategies
to force cooperation.

Strong leadership, incentives
or shared morals and values

underpin equilibria that
work in everyone's favour.

But they are hard won

and we don't need to look far to see
the terrible consequences

of our failure to cooperate.

There are many situations in life,

egotistical behaviour is not only
morally problematic but it is also

strategically unwise.

I think a nice domestic example is
washing dishes.

No-one loves it, OK.

It is a little bit annoying,
you know.

And we all know that it is better
for someone else to do it.

But if you're living
in a shared house,

the problem begins when all the
players decide to adopt my strategy

and then NO-ONE is washing
the dishes.

The outcome is a tower of dirty
plates, and it is not good.

When you are taking into account
only your personal good

and all your thinking is
self-centred,

you don't care at all
about other players,

the result may be a total disaster.

It's so easy to disregard the small
impact we might make

just by ditching stuff
for someone else to deal with.

But many small acts of selfishness
can have huge consequences.

It's a phenomenon known
as the tragedy of the commons.

For example,
the damage to the atmosphere.

The destruction of ocean ecosystems,
rainforest loggings,

these issues are far more important.

And it is really hard to tackle
with them,

even with rules and regulations.

Arguably, the challenge for
government

is to create rules that align the
interests of individuals and society

to find those win-wins.

But like the rest of us,

our leaders have their own political
and economic goals to pursue,

meaning there will always be the
temptation for some to put their own

short-term interests first.

So, in the real conflicts we all
face,

can we ever justify
being uncooperative?

Definitely, I would argue -
on occasion.

Because some people really don't
know what's good for them.

I'd like to suggest we take a
potentially very unstable situation,

taking two small argumentative
children on holiday,

to demonstrate some strategies that
can ensure you win

in a domestic stand-off.

The first thing absolutely NOT to do
is to make a non-credible threat.

Right, that's it.
Holiday's cancelled.

I'm turning the car around,
we're going home.

The kids quickly work out that you
won't do this,

as it harms you just as much as
them. Everybody wants a holiday.

So try a far more credible threat
instead.

If you don't shut up, we're going to
be spending the first day of the

holiday visiting an art gallery.

As long as they know you REALLY like
art galleries

and you know they really hate them,
this one is a much better strategy.

Even better, try a grand gesture
called pre-commitment.

If one of you starts arguing again,
one of you is going to go to bed

at six o'clock all week

and the other one can stay up
as late as they like.

This one is quite a serious
pre-commitment

because you are risking not
being able to pack them off to bed

like normal, but you would just have
to hope that the prospect

of them missing out is enough for
them to be smart and stay quiet.

In order to get what you want,

any adversary has to believe you
have the credibility and commitment

to go through with your threats.

But, in the end,
no matter how winning your tactics,

there is one thing that is
incredibly difficult to deal with.

KIDS: It's not fair!

In any kind of interaction,

our sense of what is and isn't fair
is incredibly powerful.

And in some circumstances, it can
actually make us deliberately lose.

To explore this apparently quite
irrational way of getting what

we want, Haim and I are going to
play something

called the ultimatum game,
and the rules are very simple.

Two players, one is called the
proposer

and the other is called the
respondent.

The proposer gets a sum of money,
for example £100.

Is that what you've got in there?
Yes, yes, yes.

And the proposer has to decide how
to split the money.

And the responder,

the responder must decide
whether to accept or to reject.

If the responder rejects the split,

both players will end up
with nothing.

And it is one short game.
Take it or leave it offer.

OK. The fairest thing to do
obviously is to say 50-50.

50-50, of course.

I could get an extra £10
by saying 60-40.

Easily, I think.
However I decide...

I mean, I do genuinely get
some of the money.

Yes, yes, yes, real money.
A real game. Everything is real.

Now to make some offers to a series
of unsuspecting volunteers.

I think I'm going to split it 70-30.

I get the 70.

Yes. Well, obviously it is really
unfair, but I'm going to accept it.

You have to decide.
I'm going to accept it.

OK. £30.

OK. Are you going to check it?

I'll check it, I'm a mathematician.

Thank you. Thank you.

So, unfair offer number one
works in my favour.

What is your decision? OK, I'm going
to go for

£80 to me and £20 to you.

Yes or no,
take it or leave it offer.

Leave it. No. But hang on,
you came here with nothing.

I did, but I feel like
if you were like, "£50 for you,

"£50 for me,"
I'd be fine with that.

I would've said deal. We both came
here with nothing so we both should

have left with something, and an
equal amount would've been better

than an unequal amount.

Wow. Goodness. OK.

You see, it contradicts all the
economic predictions, yes?

Economics says one is better than
none -

20 is for sure better than none.

Economics says
Sayed here should accept,

but I am denied. Next?

Hi. Hi. Hello.

I quite like money.

So £90 to me and £10 to you.

You know what?
Why not, I'll take £10.

You have £10.

It is yours. Thank you very much.

Hannah, you are now such a rich
person!

Thank you very much.
Are you happy with your decision?

It's pretty unfair, but...
Pretty unfair.

I am a realist and I like £10
at least in my pocket,

so I am at least £10 richer, so...
£10 is better than none.

Yes.
A man after my own logical heart.

After three offers, I've bagged £160
of a possible 240.

So why did I not clean up?

The 20-80 split,

not taking the £20
seems bonkers to me.

The 20, it is approximately the
world average of the split

that people refuse to take.

People seem to show an unwillingness
to accept unfairness and they are

prepared to pay. Even at 80-20?

They are basically being irrational,
right?

People usually behave rationally
from their point of view,

so it is really hard to define
what is rational, you know,

what is not. For example, Sayed,

yes, he paid £20, but to teach you a
lesson,

£20, it seems to me a low price,
you see? Nothing, almost.

Well, it was an expensive lesson
for me.

For you, but not for him.

It might seem like an irrational way
to get what we want, but what we're

looking at here is the long game.

The act of sacrificing a small win
to punish someone means

they may well be less selfish with
us and others in the future.

It's a perfectly rational way to
secure greater collective success.

But most creatures on earth
AREN'T rational

so why do we see cooperative,

even altruistic behaviour
in the animal kingdom,

that seems to benefit others more
than the individual?

Surely this contradicts
the theory of evolution,

based as it is on the struggle for
life

and the survival of the fittest?

When I learned about evolution
at school,

I was under the impression that it
was all about competition.

That every animal was necessarily
out for itself

and the fitter you are,

the more likely you are to
win fights for mates,

for food and for territory.

If you can ace THOSE conflicts, the
more likely you are to pass on your

genes and win at the game of life.

It has been said that nothing in
biology makes sense

except in the light of evolution,

and evolution has been based on
conflict.

It is a struggle for existence.

In animal behaviour,
there exists many examples

where animals fight between

the species, but where they
fight, according almost to rules,

where they seem to restrain
themselves

and don't escalate the conflict
too much.

You could try to explain individuals
avoiding violence as being for the

benefit of the group, but that's not
quite how evolution works.

If there is a single individual
ready to escalate the conflict,

and all others are going
to run away,

when they see that
things become serious,

then this individual will win
everything,

will have many offsprings.

The offspring will win his trait
of escalating a conflict

and this trait
will become more and more frequent.

In this scenario, aggressive
behaviour will always win out.

So there has to be an alternative
explanation.

It only began to emerge in the early
1970s, when British biologist John

Maynard Smith was given a manuscript
to review, written by an unknown

American called George Price.

Now, Price wasn't a mathematician or
a biologist or a game theorist,

but he had read von Neumann

and he had written about
Cold War games and the uses

of deterrence. His paper, titled
Antlers, Intraspecific Combat,

And Altruism, suggested that things
like giant deer antlers weren't

they were clever strategic
accessories

that would help you limit conflict

and avoid the destructive effects
of fighting.

It's just like nuclear missiles,

antlers are the kind of weapon that
you could

parade in front of your enemy,

hopefully without ever
having to actually use them.

Maynard Smith was struck by this

and, together with Price,
created a simple

game to explore how such limited
war strategies could evolve.

And he called it the Hawk-Dove Game.

Picture an imaginary species of bird
that only has two inherited

behavioural strategies.

One is aggressive, or hawkish,

and the other more cooperative,
or dovish.

If two hawks clash over something
like food,

their strategy means total war.

They will fight, risking injury and
no guarantee of food either.

Now, if a hawk and a dove meet,

the dove initially stands up for
itself, but then scarpers.

Finally, if doves meet,
they'll share.

In each interaction,
both birds receive a score.

And if these are added up over time,
it reveals which behaviours are most

likely to benefit individuals, and
so survive down the generations.

On the face of it,

if everyone was displaying dovelike
behaviour,

it looks like it could work,

as well as being genuinely nice
for everyone.

But, unfortunately,

that's unstable because just one
meanie hawk could come along and

immediately have the upper hand
on everybody.

And if that hawkish behaviour really
took off,

that too would be unstable,

because of the constant risk and
cost of violence.

Now, what the maths shows is that a
stable population is possible,

but only if you have one-third hawks
and two-thirds doves.

Now, those exact numbers might
change slightly

if you tweak the payoff,

but the key point here is that this
was mathematical proof that there

was a strategic advantage to
avoiding conflict.

Evolution, it turned out,

is not simply a winner-takes-all
kind of game.

And so, scientists took to this new
evolutionary form of game theory.

The reason? To find the ultimate
long-term winning strategy

for us all.

It was an ingenious American
political scientist

called Robert Axelrod

who, around 1980,
took the next big step.

Axelrod invited economists,
mathematicians,

political scientists,

psychologists and sociologists,

all of whom had written theoretical
papers on co-operation and the

prisoner's dilemma, to compete
in a computer tournament.

The challenge was to design a
computer program

that would play the best combination

of attacking and more cooperative
behaviour.

It was a bold move, considering the
golden age of popular computer games

and coding was still in its infancy.

Researchers from around the world

mailed in their computer programs
via post.

It was all to see which of
their electronic beasts,

some of which were a lot more
cooperative than others,

would emerge the winner.

14 programs were to play 200
rounds of the prisoner's dilemma

against themselves and one another.

As you would expect, cooperating
with your opponent scores well.

But you could get a much higher
payoff

by attacking a co-operator
all of the time.

But attack an attacker,
and your score will suffer.

BEEPING

And so, the tournament ran,

with some players doing better
than others.

One strategy, for example,
was nicknamed "the grudger".

It would co-operate
until it was attacked,

at which point it would get the hump

and never co-operate again
for the rest of the game.

After competing against
everyone else,

the grudger crawled in
in seventh place.

The surprise winner, with 504
points,

was written
in just four lines of code,

and was easily the simplest
program that had been submitted.

It was called tit-for-tat.

It would start off by cooperating

and then would just copy whatever
the opponent did

in the previous round - so if the
opponent either attacked or

cooperated, tit-for-tat
would respond in kind.

Tit-for-tat's behaviour over the
course of the competition

is basically, "You scratch my back,
I'll scratch yours".

So was this the winning strategy
everyone was looking for?

Well, no.

Because, unlike in real life,
these computer programs,

including tit-for-tat,
could play endlessly,

without ever making mistakes.

Imagine if I decided to use
tit-for-tat as my new strategy

for winning at life. So I would
co-operate by default - lovely -

and only retaliate if someone
was really mean to me,

just to teach them a lesson.

But what if, idiotically,

I sort of accidentally was
a bit mean to someone?

Say I just bumped into them.

Oh, sorry.

If they are also playing
tit-for-tat,

they'll have to shove me back -
formerly known as defecting.

And then I'd have to do the same,
as would he.

We'll defect for ever.

Hmm. Not great, is it?

But some scientists weren't quite
ready to give up on tit-for-tat

just yet. Karl Sigmund and his
student Martin Nowak

started experimenting

with a new kind of evolutionary
tournament, but this time,

as in the natural world,

competing strategies could evolve
and make mistakes.

Using computer simulations, they
watched strategies like tit-for-tat
emerge

and compete over thousands of
generations.

After the first 50 or 100 rounds,

it seemed as if everyone was
a defector.

Everyone? Not quite.

There was one little minority
playing something like tit-for-tat,

and this little minority
very slowly increased

and became more and more frequent,

and was actually defeating the
defectors.

The key was to let natural
selection find the winning strategy.

If you wait still longer, then you
will see that another,

more generous form of tit-for-tat is
going to evolve and to take over.

And here it comes,
generous tit-for-tat.

This strategy will always co-operate
first.

But when facing defection...

..around one out of every three
times, it will just ignore it

and co-operate, regardless.

Of all the possible strategies,
and despite its forgiving ways,

generous tit-for-tat consistently
came out on top.

For me it is still...

..one of the fondest remembrances
of my scientific life.

There was no master program
behind it,

no design for forgiveness,
so to speak.

It came out all by itself.

A purely mathematical simulation had
revealed that winning strategies,

in the long run, tend to be
generous, hopeful and forgiving.

Now, this basic moral code
just emerged.

Perhaps you could even take this as
proof of the existence and advantage

of goodness.

So why, then, don't we live

in a wonderful, generous and
forgiving utopia?

The simulations
pointed to an answer.

Over generations of stability,

the main strategy becomes total
cooperation.

But this is fragile because hawkish
defectors can rapidly take over...

..and do their worst.

And yet slowly, thanks to strategies
like tit-for-tat,

cooperation emerges again and again.

Despite its fragility,
there is hope.

Because ultimately cooperation
can't be suppressed.

Thanks to things like altruism,
kindness and reciprocity,

it re-emerges time after time.

And these aren't just codes that are
divined by priests and philosophers.

They have pure mathematics
and evolution itself behind them.

So where does that leave
you and me?

Well, I wanted to try something out.

Starting tonight.

Now, this could work for any kind of
relationship, but let's imagine

that it is your partner. What
I want you to do is to co-operate,

but copy their previous move,
so if they come home one day

with a big bunch of flowers,

you should get to work
on your own romantic gesture.

But if they come home one night
much drunker and later

than they promised,
you get to do something equivalent.

But every now and then, you should
forgive one of their slip-ups

because nobody's perfect, and

you are going to mess up, too,
at some point.

So, there you have it.

Strategies for a happier life and a
better world, all thanks to maths.

I call that a win.