Mathematics and Sex: Clio Cresswell at TEDxSydney

Mathematics and sex are deeply intertwined. From using mathematics to reveal patterns in our sex lives, to using sex to prime our brain for certain types of problems, to understanding them both in terms of the evolutionary roots of our brain, Dr. Clio Cresswell shares her insight into it all.

Yes, I am the mathematician
who's going to get you so laid.

(Laughter)

And to begin I need you
to stare at this equation.

I mean, there's your first orgasm
right there, I know it.

But these are very sophisticated equations

that model a successful marriage.

And they're ground breaking equations

because it was the first time
that truly sophisticated mathematics

was used in the field of romance.

And they predict with 95% accuracy rate

whether newlyweds will be together
in six years time.

And you can see there's the "W" for wife

and the "H" for husband.

So, they modeled newlyweds
talking about areas of contention

like the in-laws or money.

And then they modeled the responses

according to how each partner
was responding to the other.

Body language as well.

And what came out
was this interesting influence factor

at the end there,

which actually revealed that couples

that responded the least to each other

had a better chance
of a successful marriage.

So that means --
(Laughter)

I see some people are like,
"We knew that."

So, couples that compromised the least

ended up being together the most.

This was very interesting

because a lot of therapy
has been based on empathy.

And you laughed before,

so maybe you don't say
when you partner comes home,

"Yes darling, I know. Let me rub your feet
and fix you a martini."

Because what they've actually found
is that might not be the best way forward.

Maybe the best way,
or the mathematics revealed,

that having high standards
and finding ways to reach

for those standards
is in fact the way to go.

So mathematics is the study of patterns.

All the symbols that you see
are in fact patterns.

You know, encapsulating patterns.

And we're very used to seeing

mathematics being used
in physics and engineering.

That's just because
it's been there the most.

You know, E equals mc squared.
That's so early 1900's.

There's actually been an evolution.

Since the 80's
we've seen mathematics venture

into stock market analysis,
risk analysis that was new.

And then since the 1990's or 2000's even

we're seeing mathematics enter
into the sometimes called Softer Sciences

like psychology, sociology,
anthropology, biology.

New mathematics appears every day.

I brought in a few
just to remind you of how that works.

Here's some latest research.

This is looking at antibiotic use

and how to implement antibiotics
for tuberculosis

while getting the patient healthy,

but making sure
that we avoid antibiotic resistance.

That came out a couple of weeks ago.

And this is looking at how an opinion
spreads through a population.

And when will you have the coexistence
of several opinions, or one big consensus.

One of my favorites,
it's older but I couldn't resist.

This one's from 2009 and this is
how to create the perfect chocolate.

One that melts in your mouth
but not in your hand.

And yes, these are very sexy equations,
I'm sure you'll agree.

Mathematics is absolutely everywhere
these days; it's being used everywhere.

It really is no surprise

that now we're seeing
the equations for love.

Now, love sucks.
I know you all know that.

Because, yes, you're excited at first.

But then you're scared.
Oh, my god. I haven't eaten.

You're sitting looking at your phone,
"Please ring!"

Then they send you a two-word text.

And you're like, "Whoo-hoo!
It's on like Donkey Kong."

(Laughter)

And so these equations
look at which personality traits

are more likely to come together

to have a more stable
companionship type love

because some people

they just end up being
up and down continuously.

Imagine being in a relationship
with Charlie Sheen.

That would be like
well, unlike Donkey Kong

and also like this.
(Laughter)

It gets a bit out of control --
mathematically quite fast.

So just to tell you, it's about

one thing to look out for
is if your partner --

if you overestimate
your partner's qualities.

So with partners we can behave
a bit like proud parents.

"He's so smart. He's so sexy."
Everyone's just staring at this guy like

(mumbling)

Anyway, (Laughter)

here's some more mathematics.

Now, men report, on average,
having had sex with two to four times

as many women than women do men.

And this does not make sense.

(Laughter)

It doesn't. (Laughter)

I know you're all thinking,
"But what about prostitutes?"

"But what about my ex?
He's slept with everybody."

No, every time a man
has sex with a woman --

there are averages for other things --

But in a large enough sample space

it's going to be about the same,
not off like this.

So here's an example.

Here's Charlie Sheen.
He's had sex with everyone.

(Laughter)

Then the next guy, only one.
One, one, one.

And that forces, you see,
the outcome for the women.

The first one's had one.
The others have had 2 partners each.

And 2, 4, 6, 8, 9.
9 divided by 5

and on the right 5, 6, 7, 8, 9.
9 divided by 5.

Every time a man has sex with a woman

it's adding to the general tally
of both sides.

Now, why is this discrepancy?

Because the surveys
are confidential and non-identifying,

it turns out, if you ask about kinky things,
people are very honest.

(Laughter)

What we've turned to
is we think it's counting strategy.

Because if you enumerate
you'll be prone to an underestimation.

If you approximate
you'll be prone to an overestimation.

So it seems women are going,
"Justin, Brad,

the guy with the sexy biceps. The end."

And men are going,
"20 a year for the last 5 years."

(Laughter) You know.

My favorite clue in all the data

was that 80% of men's results
were divisible by 5.

(Laughter)

So, of course the mathematicians are like,
"Yeah, no, you're lying."

(Laughter)

Back to some more waves.

Of course, there are waves
in women's hormones.

And these equations look at what kind
of mechanism is in a woman's body --

how does your body know
28 days have gone by?

And it's based on understanding
why women have all their immature eggs

at birth ready to go.

We hear so much about women's hormones,

so I've brought in men's as well.

These are ---
(Laughter)

These are real.
I'm not making them up.

These model the relationship between
the brain and the testes

as the fluctuation happens during the day.

(Laughter)

I promise these are real.

Testosterone, for example,
has a peak in the morning.

And a slump in the evening.

But there's actually
a mini testosterone peak

every 2 to 2.5 hours in between.

So, you know what that means.
Especially women.

If you ask a guy a favor
and he's not responding

just wait half an hour
and ask again, just try and --

(Laughter)

just try and get that slump moment.

It's got its purposes.

Though the peak
has another purpose as well.

Yes, this is all great fun
and I could carry on with fun maths

and sex problems for hours.

But ultimately, what I'm about
is our amazing brain

and the impact of abstract thinking
and the power of abstract thinking.

And so let me turn things
a little bit around on you and say,

What do you think happens
if you think about sex

before doing mathematics?

Because it's actually
not super distracting.

You'll actually become better

at doing certain types of brain processes.

It turns out there's two fundamental types
of brain processes.

You either think globally or locally.

Forest or trees.

And when you're solving a problem,

you often start with the global
kind of analysis

and then you have to dig in deep
and follow leads to solutions.

It turns out that we're now seeing
with the latest research

that this is linked to creative
versus analytical thinking.

And more than that we're finding

that it's actually
very easily manipulated.

So, if you get people to think about love
and then solve problems

they'll be better at the globalization,

the beginning, the creative part.

And if you get people to think about sex

they get better at the process
part of the problem solving.

Easy as that.

And here's the bigger question
that interests me.

What is this thing called mathematics

that's only been going
for about 2,000 years

that popped up independently
across the world

that so many people swear they can't do?

See, there's something
that's not quite reconciling there.

You can't have something
that's developed so recently

with some people
just having an extra brain bit.

No, that doesn't make sense.
It's about finding those right triggers.

Here's a school report card of mine

in French.

My parents are these wild, wild travelers
always looking for wild parties.

I'm actually the conservative offspring
of some crazy wild people.

As you see, we lived in Cannes, whatever.
Great parties there.

But more importantly, you can see
two out of 20 for mathematics.

And my best result was 15
for Travaux Manuels et Technique.

which is woodwork.

(Laughter)

So it's very clear to me
what life is like without mathematics.

Once I found mathematics at 18
when I came to Australia,

it was the first time
that I was connecting to something pure,

to something that was so amazing.

You see, pattern recognition

is right at the core of the animal kingdom.

You see, even reptiles recognize

whether it's something
to eat, fight or have sex with.

Even a jellyfish knows which way is up
and which way is down.

Now the seeds of the number concept

are also very much part
of the animal kingdom.

A pack of animals will recognize

whether another pack
is greater than theirs.

And you can actually teach a rat
to press a lever

an approximate number of times
to get food.

Now, you see how I the word approximate.

That's because the rat doesn't have
self-awareness or a linguistic ability

to capture, tame those innate sensations.

So if the rat is just tapping three times
1, 2, 3 -- it will kind of get it right.

But once it gets to 16,
the poor little rat is tapping away

it doesn't know where it's reaching.
And it's the same with us.

If you do an experiment
where we can't count out

we'll make exactly the same
mistakes as the rat.

We went further.

We went to things like 2 + 5 = 5 + 2.

I can swap the order of things
and still reach the same result.

We went further still.

A + B = B + A

I can substitute
any of the infinite number of numbers

that I'm now aware of in that formula
and it means the same thing.

You see, language is more
than just naming things.

With it, we also got cause and effect
and temporal reasoning.

Mathematics is our most precise use
of this syntactical understanding.

Because with mathematics
at each step that you're creating

the pattern linking discovery,
there's no ambiguity.

It is very precise
what you're doing at each step,

what is in each classification.
True or false. That's it.

In the box or outside the box.
It's very clear, ultimate precision.

And that is why mathematics is so powerful

and being used more
often right through to sex.

And that's why it's so hard
because you're using

the limits of our evolution
right to their extreme.

We're using,
we're taming those innate sensations

with the most ultimate precision we can.

Mathematics as you can see, it's just ---

what's so breath taking is that it emerged
independently across the globe.

And when people came together
in peace or war

they may have clashed when it came
to religion, cultures, languages,

but their mathematics,
or pure pattern recognition just meshed.

You see, mathematics
lies right at the roots of humanity.

Like sex, it transcends human culture.

And now that I've shared that with you,

you are the sexiest ladies in town.

(Laughter)

Thank you very much.

(Applause)