0:00:00.507,0:00:05.176
Today I want to talk to you[br]about the mathematics of love.

0:00:05.200,0:00:06.829
Now, I think that we can all agree

0:00:06.853,0:00:10.162
that mathematicians[br]are famously excellent at finding love.

0:00:10.479,0:00:11.882
(Laughter)

0:00:11.906,0:00:14.873
But it's not just because[br]of our dashing personalities,

0:00:14.897,0:00:19.520
superior conversational skills[br]and excellent pencil cases.

0:00:20.083,0:00:23.826
It's also because we've actually done[br]an awful lot of work into the maths

0:00:23.850,0:00:26.326
of how to find the perfect partner.

0:00:26.350,0:00:30.029
Now, in my favorite paper[br]on the subject, which is entitled,

0:00:30.053,0:00:31.916
"Why I Don't Have a Girlfriend" --

0:00:31.940,0:00:33.347
(Laughter)

0:00:33.371,0:00:36.989
Peter Backus tries to rate[br]his chances of finding love.

0:00:37.013,0:00:39.242
Now, Peter's not a very greedy man.

0:00:39.266,0:00:41.518
Of all of the available women in the UK,

0:00:41.542,0:00:45.037
all Peter's looking for[br]is somebody who lives near him,

0:00:45.061,0:00:46.867
somebody in the right age range,

0:00:46.891,0:00:49.813
somebody with a university degree,

0:00:49.837,0:00:51.819
somebody he's likely to get on well with,

0:00:51.843,0:00:53.786
somebody who's likely to be attractive,

0:00:53.810,0:00:56.116
somebody who's likely[br]to find him attractive.

0:00:56.140,0:00:59.194
(Laughter)

0:00:59.218,0:01:04.008
And comes up with an estimate[br]of 26 women in the whole of the UK.

0:01:04.032,0:01:05.211
(Laughter)

0:01:05.235,0:01:07.268
It's not looking very good, is it Peter?

0:01:07.292,0:01:09.246
Now, just to put that into perspective,

0:01:09.270,0:01:12.550
that's about 400 times fewer[br]than the best estimates

0:01:12.574,0:01:16.275
of how many intelligent[br]extraterrestrial life forms there are.

0:01:16.299,0:01:21.593
And it also gives Peter[br]a 1 in 285,000 chance

0:01:21.617,0:01:23.878
of bumping into any one[br]of these special ladies

0:01:23.902,0:01:25.441
on a given night out.

0:01:25.465,0:01:27.467
I'd like to think[br]that's why mathematicians

0:01:27.491,0:01:29.949
don't really bother[br]going on nights out anymore.

0:01:31.109,0:01:33.365
The thing is that I personally[br]don't subscribe

0:01:33.389,0:01:35.045
to such a pessimistic view.

0:01:35.069,0:01:37.658
Because I know,[br]just as well as all of you do,

0:01:37.682,0:01:40.054
that love doesn't really work like that.

0:01:40.078,0:01:44.928
Human emotion isn't neatly ordered[br]and rational and easily predictable.

0:01:45.396,0:01:47.617
But I also know that that doesn't mean

0:01:47.641,0:01:50.921
that mathematics hasn't got something[br]that it can offer us,

0:01:50.945,0:01:54.691
because, love, as with most of life,[br]is full of patterns

0:01:54.715,0:01:59.141
and mathematics is, ultimately,[br]all about the study of patterns.

0:01:59.165,0:02:03.509
Patterns from predicting the weather[br]to the fluctuations in the stock market,

0:02:03.533,0:02:06.564
to the movement of the planets[br]or the growth of cities.

0:02:06.588,0:02:08.878
And if we're being honest,[br]none of those things

0:02:08.902,0:02:12.064
are exactly neatly ordered[br]and easily predictable, either.

0:02:12.966,0:02:18.144
Because I believe that mathematics[br]is so powerful that it has the potential

0:02:18.168,0:02:21.489
to offer us a new way of looking[br]at almost anything.

0:02:21.513,0:02:24.333
Even something as mysterious as love.

0:02:24.979,0:02:26.651
And so, to try to persuade you

0:02:26.675,0:02:31.368
of how totally amazing, excellent[br]and relevant mathematics is,

0:02:31.392,0:02:38.075
I want to give you my top three[br]mathematically verifiable tips for love.

0:02:38.651,0:02:40.416
(Laughter)

0:02:40.440,0:02:42.080
OK, so Top Tip #1:

0:02:42.104,0:02:44.221
How to win at online dating.

0:02:46.567,0:02:49.938
So my favorite online dating[br]website is OkCupid,

0:02:49.962,0:02:53.550
not least because it was started[br]by a group of mathematicians.

0:02:53.574,0:02:55.319
Now, because they're mathematicians,

0:02:55.343,0:02:56.820
they have been collecting data

0:02:56.844,0:03:00.340
on everybody who uses their site[br]for almost a decade.

0:03:00.364,0:03:02.514
And they've been trying[br]to search for patterns

0:03:02.538,0:03:04.401
in the way that we talk about ourselves

0:03:04.425,0:03:06.484
and the way that we interact[br]with each other

0:03:06.508,0:03:07.852
on an online dating website.

0:03:07.876,0:03:10.801
And they've come up with some[br]seriously interesting findings.

0:03:10.825,0:03:12.423
But my particular favorite

0:03:12.447,0:03:15.803
is that it turns out[br]that on an online dating website,

0:03:15.827,0:03:21.487
how attractive you are[br]does not dictate how popular you are,

0:03:21.511,0:03:25.367
and actually, having people[br]think that you're ugly

0:03:25.391,0:03:27.286
can work to your advantage.

0:03:27.469,0:03:28.619
(Laughter)

0:03:28.643,0:03:30.313
Let me show you how this works.

0:03:30.337,0:03:34.716
In a thankfully voluntary[br]section of OkCupid,

0:03:34.740,0:03:37.541
you are allowed to rate[br]how attractive you think people are

0:03:37.565,0:03:39.850
on a scale between one and five.

0:03:39.874,0:03:42.855
Now, if we compare this score,[br]the average score,

0:03:42.879,0:03:46.020
to how many messages[br]a selection of people receive,

0:03:46.044,0:03:47.567
you can begin to get a sense

0:03:47.591,0:03:51.999
of how attractiveness links to popularity[br]on an online dating website.

0:03:52.023,0:03:55.365
This is the graph the OkCupid guys[br]have come up with.

0:03:55.389,0:03:58.383
And the important thing to notice[br]is that it's not totally true

0:03:58.407,0:04:01.232
that the more attractive you are,[br]the more messages you get.

0:04:01.256,0:04:05.511
But the question arises then[br]of what is it about people up here

0:04:05.535,0:04:09.398
who are so much more popular[br]than people down here,

0:04:09.422,0:04:12.518
even though they have the same[br]score of attractiveness?

0:04:12.542,0:04:16.675
And the reason why is that it's not just[br]straightforward looks that are important.

0:04:16.699,0:04:19.506
So let me try to illustrate[br]their findings with an example.

0:04:19.530,0:04:23.448
So if you take someone like[br]Portia de Rossi, for example,

0:04:23.472,0:04:27.952
everybody agrees that Portia de Rossi[br]is a very beautiful woman.

0:04:27.976,0:04:31.694
Nobody thinks that she's ugly,[br]but she's not a supermodel, either.

0:04:31.718,0:04:36.309
If you compare Portia de Rossi[br]to someone like Sarah Jessica Parker,

0:04:36.333,0:04:40.015
now, a lot of people,[br]myself included, I should say,

0:04:40.039,0:04:44.296
think that Sarah Jessica Parker[br]is seriously fabulous

0:04:44.320,0:04:46.966
and possibly one[br]of the most beautiful creatures

0:04:46.990,0:04:49.380
to have ever have walked[br]on the face of the Earth.

0:04:49.404,0:04:54.169
But some other people,[br]i.e., most of the Internet ...

0:04:54.193,0:04:56.263
(Laughter)

0:04:56.287,0:04:58.673
seem to think that she looks[br]a bit like a horse.

0:04:58.697,0:05:01.486
(Laughter)

0:05:01.510,0:05:05.603
Now, I think that if you ask people[br]how attractive they thought

0:05:05.627,0:05:07.535
Jessica Parker or Portia de Rossi were,

0:05:07.559,0:05:10.467
and you ask them to give[br]them a score between one and five

0:05:10.491,0:05:13.511
I reckon that they'd average out[br]to have roughly the same score.

0:05:13.535,0:05:16.299
But the way that people would vote[br]would be very different.

0:05:16.323,0:05:19.025
So Portia's scores would[br]all be clustered around the four

0:05:19.049,0:05:21.480
because everybody agrees[br]that she's very beautiful,

0:05:21.504,0:05:24.218
whereas Sarah Jessica Parker[br]completely divides opinion.

0:05:24.242,0:05:26.218
There'd be a huge spread in her scores.

0:05:26.242,0:05:28.591
And actually it's this spread that counts.

0:05:28.615,0:05:30.841
It's this spread[br]that makes you more popular

0:05:30.865,0:05:33.041
on an online Internet dating website.

0:05:33.065,0:05:34.253
So what that means then

0:05:34.277,0:05:36.882
is that if some people[br]think that you're attractive,

0:05:36.906,0:05:38.767
you're actually better off

0:05:38.791,0:05:42.738
having some other people[br]think that you're a massive minger.

0:05:43.935,0:05:46.149
That's much better[br]than everybody just thinking

0:05:46.173,0:05:48.236
that you're the cute girl next door.

0:05:48.260,0:05:50.585
Now, I think this begins[br]to make a bit more sense

0:05:50.609,0:05:53.879
when you think in terms of the people[br]who are sending these messages.

0:05:53.903,0:05:56.261
So let's say that you think[br]somebody's attractive,

0:05:56.285,0:06:00.250
but you suspect that other people[br]won't necessarily be that interested.

0:06:00.274,0:06:02.519
That means there's[br]less competition for you

0:06:02.543,0:06:05.325
and it's an extra incentive[br]for you to get in touch.

0:06:05.349,0:06:08.134
Whereas compare that[br]to if you think somebody is attractive

0:06:08.158,0:06:11.375
but you suspect that everybody[br]is going to think they're attractive.

0:06:11.399,0:06:14.604
Well, why would you bother[br]humiliating yourself, let's be honest?

0:06:15.077,0:06:17.470
But here's where the really[br]interesting part comes.

0:06:17.494,0:06:21.674
Because when people choose the pictures[br]that they use on an online dating website,

0:06:21.698,0:06:23.874
they often try to minimize the things

0:06:23.898,0:06:27.136
that they think some people[br]will find unattractive.

0:06:27.160,0:06:31.191
The classic example is people[br]who are, perhaps, a little bit overweight

0:06:31.215,0:06:33.657
deliberately choosing[br]a very cropped photo,

0:06:33.681,0:06:35.032
(Laughter)

0:06:35.056,0:06:36.816
or bald men, for example,

0:06:36.840,0:06:39.788
deliberately choosing pictures[br]where they're wearing hats.

0:06:39.812,0:06:42.402
But actually this is the opposite[br]of what you should do

0:06:42.426,0:06:43.816
if you want to be successful.

0:06:43.840,0:06:45.174
You should really, instead,

0:06:45.198,0:06:48.356
play up to whatever it is[br]that makes you different,

0:06:48.380,0:06:52.531
even if you think that some people[br]will find it unattractive.

0:06:52.555,0:06:55.766
Because the people who fancy you[br]are just going to fancy you anyway,

0:06:55.790,0:07:00.346
and the unimportant losers who don't,[br]well, they only play up to your advantage.

0:07:00.370,0:07:02.923
OK, Top Tip #2:[br]How to pick the perfect partner.

0:07:02.947,0:07:05.600
So let's imagine then[br]that you're a roaring success

0:07:05.624,0:07:07.165
on the dating scene.

0:07:07.189,0:07:11.724
But the question arises[br]of how do you then convert that success

0:07:11.748,0:07:14.299
into longer-term happiness,

0:07:14.323,0:07:19.413
and in particular, how do you decide[br]when is the right time to settle down?

0:07:19.437,0:07:22.245
Now generally,[br]it's not advisable to just cash in

0:07:22.269,0:07:26.392
and marry the first person who comes along[br]and shows you any interest at all.

0:07:26.416,0:07:29.537
But, equally, you don't really[br]want to leave it too long

0:07:29.561,0:07:32.331
if you want to maximize your chance[br]of long-term happiness.

0:07:32.355,0:07:35.819
As my favorite author,[br]Jane Austen, puts it,

0:07:35.843,0:07:38.037
"An unmarried woman of seven and twenty

0:07:38.061,0:07:41.493
can never hope to feel[br]or inspire affection again."

0:07:41.517,0:07:44.182
(Laughter)

0:07:44.206,0:07:45.388
Thanks a lot, Jane.

0:07:45.412,0:07:46.825
What do you know about love?

0:07:46.849,0:07:47.932
(Laughter)

0:07:47.956,0:07:49.865
So the question is then,

0:07:49.889,0:07:52.478
how do you know when[br]is the right time to settle down,

0:07:52.502,0:07:55.130
given all the people[br]that you can date in your lifetime?

0:07:55.154,0:07:58.604
Thankfully, there's a rather delicious bit[br]of mathematics that we can use

0:07:58.628,0:08:01.172
to help us out here,[br]called optimal stopping theory.

0:08:01.196,0:08:03.177
So let's imagine, then,

0:08:03.201,0:08:05.803
that you start dating when you're 15

0:08:05.827,0:08:09.596
and ideally, you'd like to be married[br]by the time that you're 35.

0:08:09.620,0:08:11.062
And there's a number of people

0:08:11.086,0:08:13.583
that you could potentially[br]date across your lifetime,

0:08:13.607,0:08:15.735
and they'll be at varying[br]levels of goodness.

0:08:15.759,0:08:18.424
Now the rules are that once[br]you cash in and get married,

0:08:18.448,0:08:20.878
you can't look ahead to see[br]what you could have had,

0:08:20.902,0:08:23.435
and equally, you can't go back[br]and change your mind.

0:08:23.459,0:08:25.058
In my experience at least,

0:08:25.082,0:08:27.880
I find that typically people[br]don't much like being recalled

0:08:27.904,0:08:33.122
years after being passed up[br]for somebody else, or that's just me.

0:08:33.146,0:08:36.339
So the math says then[br]that what you should do

0:08:36.363,0:08:39.534
in the first 37 percent[br]of your dating window,

0:08:39.558,0:08:43.315
you should just reject everybody[br]as serious marriage potential.

0:08:43.339,0:08:45.489
(Laughter)

0:08:45.513,0:08:49.137
And then, you should pick[br]the next person that comes along

0:08:49.161,0:08:52.130
that is better than everybody[br]that you've seen before.

0:08:52.154,0:08:53.575
So here's the example.

0:08:53.599,0:08:56.466
Now if you do this, it can be[br]mathematically proven, in fact,

0:08:56.490,0:08:58.951
that this is the best possible way

0:08:58.975,0:09:03.304
of maximizing your chances[br]of finding the perfect partner.

0:09:03.328,0:09:07.909
Now unfortunately, I have to tell you that[br]this method does come with some risks.

0:09:08.604,0:09:13.413
For instance, imagine[br]if your perfect partner appeared

0:09:13.437,0:09:16.119
during your first 37 percent.

0:09:16.143,0:09:18.915
Now, unfortunately,[br]you'd have to reject them.

0:09:18.939,0:09:21.628
(Laughter)

0:09:22.129,0:09:24.244
Now, if you're following the maths,

0:09:24.268,0:09:25.901
I'm afraid no one else comes along

0:09:25.925,0:09:28.196
that's better than anyone[br]you've seen before,

0:09:28.220,0:09:32.069
so you have to go on[br]rejecting everyone and die alone.

0:09:32.093,0:09:34.092
(Laughter)

0:09:34.560,0:09:36.076
Probably surrounded by cats ...

0:09:36.100,0:09:37.719
(Laughter)

0:09:37.838,0:09:39.405
nibbling at your remains.

0:09:39.429,0:09:43.398
OK, another risk is,[br]let's imagine, instead,

0:09:43.422,0:09:46.538
that the first people that you dated[br]in your first 37 percent

0:09:46.562,0:09:50.483
are just incredibly dull,[br]boring, terrible people.

0:09:50.839,0:09:53.221
That's OK, because[br]you're in your rejection phase,

0:09:53.245,0:09:54.960
so that's fine, you can reject them.

0:09:54.984,0:09:58.357
But then imagine[br]the next person to come along

0:09:58.381,0:10:01.711
is just marginally less boring,[br]dull and terrible ...

0:10:01.735,0:10:02.834
(Laughter)

0:10:02.858,0:10:04.756
than everybody that you've seen before.

0:10:04.780,0:10:08.375
Now, if you are following the maths,[br]I'm afraid you have to marry them ...

0:10:08.399,0:10:09.454
(Laughter)

0:10:09.478,0:10:12.621
and end up in a relationship[br]which is, frankly, suboptimal.

0:10:12.645,0:10:13.798
Sorry about that.

0:10:13.822,0:10:17.322
But I do think that there's an opportunity[br]here for Hallmark to cash in on

0:10:17.346,0:10:18.928
and really cater for this market.

0:10:18.952,0:10:20.535
A Valentine's Day card like this.

0:10:20.559,0:10:21.715
(Laughter)

0:10:21.739,0:10:24.741
"My darling husband,[br]you are marginally less terrible

0:10:24.765,0:10:26.919
than the first 37 percent[br]of people I dated."

0:10:26.943,0:10:28.573
(Laughter)

0:10:28.597,0:10:31.435
It's actually more romantic[br]than I normally manage.

0:10:31.745,0:10:33.216
(Laughter)

0:10:33.240,0:10:37.901
OK, so this method doesn't give you[br]a 100 percent success rate,

0:10:37.925,0:10:41.360
but there's no other possible[br]strategy that can do any better.

0:10:41.384,0:10:44.814
And actually, in the wild,[br]there are certain types of fish

0:10:44.838,0:10:47.655
which follow and employ[br]this exact strategy.

0:10:47.679,0:10:50.432
So they reject every possible[br]suitor that turns up

0:10:50.456,0:10:53.145
in the first 37 percent[br]of the mating season,

0:10:53.169,0:10:56.920
and then they pick the next fish[br]that comes along after that window

0:10:56.944,0:10:59.099
that's, I don't know, bigger and burlier

0:10:59.123,0:11:01.701
than all of the fish[br]that they've seen before.

0:11:01.725,0:11:06.602
I also think that subconsciously,[br]humans, we do sort of do this anyway.

0:11:06.626,0:11:09.471
We give ourselves a little bit of time[br]to play the field,

0:11:09.495,0:11:13.091
get a feel for the marketplace[br]or whatever when we're young.

0:11:13.115,0:11:17.705
And then we only start looking seriously[br]at potential marriage candidates

0:11:17.729,0:11:19.756
once we hit our mid-to-late 20s.

0:11:19.780,0:11:22.990
I think this is conclusive proof,[br]if ever it were needed,

0:11:23.014,0:11:27.222
that everybody's brains are prewired[br]to be just a little bit mathematical.

0:11:27.450,0:11:29.453
OK, so that was Top Tip #2.

0:11:29.477,0:11:32.706
Now, Top Tip #3: How to avoid divorce.

0:11:33.351,0:11:36.275
OK, so let's imagine then[br]that you picked your perfect partner

0:11:36.299,0:11:40.528
and you're settling into[br]a lifelong relationship with them.

0:11:40.552,0:11:44.538
Now, I like to think that everybody[br]would ideally like to avoid divorce,

0:11:44.562,0:11:48.808
apart from, I don't know,[br]Piers Morgan's wife, maybe?

0:11:48.832,0:11:49.982
(Laughter)

0:11:50.185,0:11:52.605
But it's a sad fact of modern life

0:11:52.629,0:11:55.889
that one in two marriages[br]in the States ends in divorce,

0:11:55.913,0:11:59.705
with the rest of the world[br]not being far behind.

0:11:59.729,0:12:01.563
Now, you can be forgiven, perhaps

0:12:01.587,0:12:05.320
for thinking that the arguments[br]that precede a marital breakup

0:12:05.344,0:12:09.134
are not an ideal candidate[br]for mathematical investigation.

0:12:09.359,0:12:11.141
For one thing, it's very hard to know

0:12:11.165,0:12:14.242
what you should be measuring[br]or what you should be quantifying.

0:12:14.266,0:12:20.449
But this didn't stop a psychologist,[br]John Gottman, who did exactly that.

0:12:20.473,0:12:25.710
Gottman observed hundreds of couples[br]having a conversation

0:12:25.734,0:12:28.040
and recorded, well,[br]everything you can think of.

0:12:28.064,0:12:30.431
So he recorded what was said[br]in the conversation,

0:12:30.455,0:12:32.748
he recorded their skin conductivity,

0:12:32.772,0:12:34.835
he recorded their facial expressions,

0:12:34.859,0:12:36.850
their heart rates, their blood pressure,

0:12:36.874,0:12:43.110
basically everything apart from whether[br]or not the wife was actually always right,

0:12:43.134,0:12:46.325
which incidentally she totally is.

0:12:46.349,0:12:48.998
But what Gottman and his team found

0:12:49.022,0:12:52.037
was that one of the most[br]important predictors

0:12:52.061,0:12:54.543
for whether or not a couple[br]is going to get divorced

0:12:54.567,0:12:59.190
was how positive or negative each partner[br]was being in the conversation.

0:12:59.214,0:13:01.544
Now, couples that were very low-risk

0:13:01.568,0:13:05.837
scored a lot more positive points[br]on Gottman's scale than negative.

0:13:05.861,0:13:08.402
Whereas bad relationships,

0:13:08.426,0:13:11.173
by which I mean,[br]probably going to get divorced,

0:13:11.197,0:13:15.554
they found themselves getting[br]into a spiral of negativity.

0:13:15.578,0:13:17.838
Now just by using these very simple ideas,

0:13:17.862,0:13:20.333
Gottman and his group were able to predict

0:13:20.357,0:13:23.079
whether a given couple[br]was going to get divorced

0:13:23.103,0:13:25.288
with a 90 percent accuracy.

0:13:26.005,0:13:29.294
But it wasn't until he teamed up[br]with a mathematician, James Murray,

0:13:29.318,0:13:31.209
that they really started to understand

0:13:31.233,0:13:35.727
what causes these negativity spirals[br]and how they occur.

0:13:35.751,0:13:37.284
And the results that they found,

0:13:37.308,0:13:41.957
I think, are just incredibly[br]impressively simple and interesting.

0:13:41.981,0:13:46.544
So these equations predict how the wife[br]or husband is going to respond

0:13:46.568,0:13:48.456
in their next turn of the conversation,

0:13:48.480,0:13:50.613
how positive or negative[br]they're going to be.

0:13:50.637,0:13:52.022
And these equations depend on

0:13:52.046,0:13:54.352
the mood of the person[br]when they're on their own,

0:13:54.376,0:13:56.990
the mood of the person when[br]they're with their partner,

0:13:57.014,0:13:58.739
but most importantly, they depend on

0:13:58.763,0:14:01.795
how much the husband and wife[br]influence one another.

0:14:02.115,0:14:04.722
Now, I think it's important[br]to point out at this stage,

0:14:04.746,0:14:08.255
that these exact equations[br]have also been shown

0:14:08.279,0:14:10.474
to be perfectly able at describing

0:14:10.498,0:14:14.232
what happens between two countries[br]in an arms race.

0:14:15.010,0:14:18.098
(Laughter)

0:14:18.300,0:14:21.881
So that an arguing couple[br]spiraling into negativity

0:14:21.905,0:14:23.810
and teetering on the brink of divorce

0:14:23.834,0:14:28.083
is actually mathematically equivalent[br]to the beginning of a nuclear war.

0:14:28.107,0:14:30.997
(Laughter)

0:14:31.021,0:14:33.334
But the really important term[br]in this equation

0:14:33.358,0:14:35.853
is the influence that people[br]have on one another,

0:14:35.877,0:14:39.134
and in particular, something called[br]"the negativity threshold."

0:14:39.158,0:14:40.890
Now, the negativity threshold,

0:14:40.914,0:14:45.541
you can think of as[br]how annoying the husband can be

0:14:45.565,0:14:49.828
before the wife starts to get[br]really pissed off, and vice versa.

0:14:49.852,0:14:54.384
Now, I always thought that good marriages[br]were about compromise and understanding

0:14:54.408,0:14:57.170
and allowing the person[br]to have the space to be themselves.

0:14:57.194,0:15:00.547
So I would have thought that perhaps[br]the most successful relationships

0:15:00.571,0:15:03.851
were ones where there was[br]a really high negativity threshold.

0:15:03.875,0:15:05.668
Where couples let things go

0:15:05.692,0:15:08.463
and only brought things up[br]if they really were a big deal.

0:15:08.487,0:15:12.738
But actually, the mathematics[br]and subsequent findings by the team

0:15:12.762,0:15:15.294
have shown the exact opposite is true.

0:15:15.799,0:15:18.108
The best couples,[br]or the most successful couples,

0:15:18.132,0:15:21.495
are the ones with a really low[br]negativity threshold.

0:15:21.519,0:15:25.153
These are the couples[br]that don't let anything go unnoticed

0:15:25.177,0:15:28.375
and allow each other[br]some room to complain.

0:15:28.399,0:15:33.633
These are the couples that are continually[br]trying to repair their own relationship,

0:15:33.657,0:15:36.400
that have a much more positive[br]outlook on their marriage.

0:15:36.424,0:15:38.492
Couples that don't let things go

0:15:38.516,0:15:43.396
and couples that don't let trivial things[br]end up being a really big deal.

0:15:44.426,0:15:49.684
Now of course, it takes a bit more[br]than just a low negativity threshold

0:15:49.708,0:15:54.076
and not compromising[br]to have a successful relationship.

0:15:54.100,0:15:56.626
But I think that it's quite interesting

0:15:56.650,0:15:59.004
to know that there is really[br]mathematical evidence

0:15:59.028,0:16:02.456
to say that you should never[br]let the sun go down on your anger.

0:16:02.480,0:16:04.164
So those are my top three tips

0:16:04.188,0:16:07.359
of how maths can help you[br]with love and relationships.

0:16:07.383,0:16:09.778
But I hope, that aside from[br]their use as tips,

0:16:09.802,0:16:13.904
they also give you a little bit of insight[br]into the power of mathematics.

0:16:13.928,0:16:18.269
Because for me, equations[br]and symbols aren't just a thing.

0:16:18.684,0:16:23.095
They're a voice that speaks out[br]about the incredible richness of nature

0:16:23.119,0:16:24.905
and the startling simplicity

0:16:24.929,0:16:29.742
in the patterns that twist and turn[br]and warp and evolve all around us,

0:16:29.766,0:16:32.346
from how the world works to how we behave.

0:16:32.370,0:16:34.680
So I hope that perhaps,[br]for just a couple of you,

0:16:34.704,0:16:37.189
a little bit of insight[br]into the mathematics of love

0:16:37.213,0:16:40.510
can persuade you to have[br]a little bit more love for mathematics.

0:16:40.534,0:16:41.733
Thank you.

0:16:41.757,0:16:48.757
(Applause)