So, yes, I'm Hannah Fry, I am a mathematician,

我是漢娜．弗萊，我是個數學家。

and today I want to talk to you about the mathematics of love.

今天我想要和大家談談 關於愛情的數學。

Now, I think that we can all agree

我想大家都同意

that mathematicians are famously excellent at finding love.

數學家在尋找真愛上特別在行。

But it's not just because of our dashing personalities,

但那並不只是因為我們 精力充沛的性格、

superior conversational skills and excellent pencil cases.

超凡的對話技巧， 和炫麗的筆盒。

It's also because we've actually done an awful lot of work into the maths

也是因為我們真的 花了許多時間精力在數學上，

of how to find the perfect partner.

計算如何找到完美的伴侶。

Now, in my favorite paper on the subject, which is entitled,

現在，在此學科中我最愛的論文，名為

"Why I Don't Have a Girlfriend" - (Laughter) -

「為甚麼我沒有女友」 （笑聲）

Peter Backus tries to rate his chances of finding love.

Peter Backus 試著 計算他尋得真愛的機會。

Now, Peter's not a very greedy man.

現在，Peter 不是一個非常貪心的人。

Of all of the available women in the U.K.,

在英國所有適宜的女性對象中，

all Peter's looking for is somebody who lives near him,

Peter 所看的， 就只是那個住在他附近的對象、

somebody in the right age range,

某個處於適宜的年齡階段的女人、

somebody with a university degree,

某個擁有大學文憑、

somebody he's likely to get on well with,

某個他很有可能相處地不錯的對象、

somebody who's likely to be attractive,

某個有魅力的女子，

somebody who's likely to find him attractive.

以及......某個認為 他也富有魅力的對象。

(Laughter)

（笑聲）

And comes up with an estimate of 26 women in the whole of the UK.

結果他估計在全英國 大概有 26 位此類女性。

It's not looking very good, is it Peter?

這看來很不妙，不是嗎，Peter？

Now, just to put that into perspective,

我們好好思考一下這件事，

that's about 400 times fewer than the best estimates

在無數聰明外星 生命形式存在的情況下，

of how many intelligent extraterrestrial life forms there are.

那是少於 400 倍數的估計呀。

And it also gives Peter a 1 in 285,000 chance

那也給了 Peter 一個

of bumping into any one of these special ladies

28 萬 5 千之 1 的機會

on a given night out.

在某晚遇見一個特別的女子。

I'd like to think that's why mathematicians

我想，那就是為什麼數學家

don't really bother going on nights out anymore.

不再怎麼想 晚上出去約會了的原因了吧。

The thing is that I personally

重點是，我個人其實並不同意

don't subscribe to such a pessimistic view.

這種悲觀的看法，

Because I know, just as well as all of you do,

因為我知道，如同你們所有所知道的，

that love doesn't really work like that.

愛情並不是這樣發生的。

Human emotion isn't neatly ordered and rational and easily predictable.

人類的情感不是那樣地秩序井然、 乾淨利落、邏輯清晰，和容易預測。

But I also know that that doesn't mean

但我也知道那並不意謂著

that mathematics hasn't got something that it can offer us

數學無法為我們提供幫助，

because, love, as with most of life, is full of patterns

因為愛情，如同生命中多數的事物一般， 充斥著許多規律，

and mathematics is, ultimately, all about the study of patterns.

而數學最終就是 那研究規律的學說。

Patterns from predicting the weather to the fluctuations in the stock market,

從預測天候，到 預測股票市場的開高走低，

to the movement of the planets or the growth of cities.

到星球的運轉，或都市的發展。

And if we're being honest, none of those things

如果我們對自己誠實的話， 上述那些東西，沒有一個是

are exactly neatly ordered and easily predictable, either.

井然有序以及容易預測的。

Because I believe that mathematics is so powerful that it has the potential

因為我相信，數學的力量非常強大， 以至於它讓我們得以以新方法

to offer us a new way of looking at almost anything.

重新看待任何事物。

Even something as mysterious as love.

就算是和愛情一般神秘的東西也是。

And so, to try to persuade you

因此，為了試著說服你們

of how totally amazing, excellent and relevant mathematics is,

數學的美妙用處，

I want to give you my top three mathematically verifiable tips for love.

我想要給大家三個最重要的 在數學上可以驗證的愛情秘訣。

Okay, so Top Tip #1:

好，首先最重要的秘技一：

How to win at online dating.

如何贏得線上交友的機會。

So my favorite online dating website is OkCupid,

我最愛的線上交友網站是 OkCupid （網站名：好吧，丘比特），

not least because it was started by a group of mathematicians.

這並不僅僅因為這網站 是由一群數學家所架設的。

Now, because they're mathematicians,

因為他們是數學家，

they have been collecting data

他們已經蒐集了

on everybody who uses their site for almost a decade.

近乎這十年來所有 該網站使用者的資料。

And they've been trying to search for patterns

他們試著尋找

in the way that we talk about ourselves

我們在線上

and the way that we interact with each other

談論自己的方式的模式，

on an online dating website.

以及我們和他人互動的模式。

And they've come up with some seriously interesting findings.

他們發現了一些重要的有趣結果。

But my particular favorite

但我特別喜歡的結果之一是

is that it turns out that on an online dating website,

在線上交友網站上

how attractive you are does not dictate how popular you are,

你的魅力程度並無法 預測你的受歡迎程度，

and actually, having people think that you're ugly

事實上，讓人們覺得你很醜

can work to your advantage.

可以讓你擁有優勢。

Let me show you how this works.

讓我向各位展示這是怎麼一回事。

In a thankfully voluntary section of OkCupid,

在 OkCupid 的一個自願欄目中，

you are allowed to rate how attractive you think people are

你可以評價人們的魅力值，

on a scale between 1 and 5.

從 1 到 5 。

Now, if we compare this score, the average score,

現在，如果我們比較這個分數， 平均分數，

to how many messages a selection of people receive,

有多少人收到訊息，

you can begin to get a sense

你就可以開始理解

of how attractiveness links to popularity on an online dating website.

在一個線上約會網站上 魅力指數與受歡迎程度有關。

This is the graph that the OkCupid guy shave come up with.

這是 OkCupid 得到的圖表。

And the important thing to notice is that it's not totally true

一件重要的值得注意的事是

that the more attractive you are, the more messages you get.

並不是越有魅力的人， 收到的訊息越多。

OK, there's maybe a bit of a trend there,

好吧，是可能有那麼一點趨勢，

but it's got an R squared of absolutely naff all, let's be honest.

但這裡有個 R 與絕對空無的平方， 我們誠實地來看待這事吧。

But the question arises then of what is it about people up here

問題是，為什麼上面的這些人

who are so much more popular than people down here,

比下面這些人要受歡迎得多，

even though they have the same score of attractiveness?

即便他們都有相同的魅力值？

And the reason why is that it's not just straight forward looks that are important.

原因是，並不是直觀的外貌是重要的。

So let me try to illustrate their findings with an example.

讓我來談談他們的發現， 以一個案例說明。

So if you take someone like Portia de Rossi, for example,

如果你拿 Portia de Rossi 為例，

everybody agrees that Portia de Rossi is a very beautiful woman.

每個人都同意 Portia de Rossi 是個非常美麗的女人，

Nobody thinks that she's ugly, but she's not a supermodel, either.

沒有人覺得她醜，但她也不是超級名模。

If you compare Portia de Rossi to someone like Sarah Jessica Parker,

如果你拿某個人，比如 Sarah Jessica Parker （譯注：慾望城市女主角）來和她比較

now, a lot of people, myself included, I should say,

許多人，包括我自己，我應該會說，

think that Sarah Jessica Parker is seriously fabulous

Sarah Jessica Parker 魅力極為出眾，

and possibly one of the most beautiful creatures

有可能是地表上

to have ever have walked on the face of the Earth.

最美麗的物種之一。

But some other people, i.e., most of the Internet,

但許多其他人，比如，大多數的網友

seem to think that she looks a bit like a horse. (Laughter)

似乎都認為她看起來像馬。（笑聲）

Now, I think that if you ask people how attractive they thought

如果你問人們他們覺得自己有多美，

Sarah Jessica Parker or Portia de Rossi were,

Sarah Jessica Parker 或 Portia de Rossi

and you ask them to give them a score between 1 and 5,

你要他們給自己打分，從 1 到 5，

I reckon that they'd average out to have roughly the same score.

我猜他們也會大約給一個 和大家都差不多的數字。

But the way that people would vote would be very different.

但是人們投票的方式各自不同。

So Portia's scores would all be clustered around the 4

因此 Portia 的分數會聚集在 4 分左右，

because everybody agrees that she's very beautiful,

因為所有人都同意，她非常美麗，

whereas Sarah Jessica Parker completely divides opinion.

然而人們對 Sarah Jessica Parker 卻有截然不同的意見。

There'd be a huge spread in her scores.

她的分差懸殊很大。

And actually it's this spread that counts.

然而事實上，就是那分差別具意義，

It's this spread that makes you more popular

那差異讓你

on an online Internet dating website.

在交友網站上受歡迎。

So what that means then

所以那意味著

is that if some people think that you're attractive,

如果有些人認為你別具魅力，

you're actually better off

你最好有其他人認為

having some other people think that you're a massive minger.

你很醜。

That's much better than everybody just thinking

那遠優於所有人認為

that you're the cute girl next door.

你是鄰家的可愛女孩。

Now, I think this begins makes a bit more sense

當你們開始思考一下 這些寄送訊息的人的話，

when you think in terms of the people who are sending these messages.

這開始變得合理些了。

So let's say that you think somebody's attractive,

這麼說吧，假設你認為那個人很美，

but you suspect that other people won't necessarily be that interested.

但你同時猜想其他人並不會 和你有同樣的審美觀。

That means there's less competition for you

那就意味著，你的競爭對手略少，

and it's an extra incentive for you to get in touch.

這就給你增加了額外的動機 去與他/她認識。

Whereas compare that to if you think somebody is attractive

與之相對的情況是， 你認為某人很有吸引力，

but you suspect that everybody is going to think they're attractive.

但你猜想所有其他的人 都認為那人很有吸引力，

Well, why would you bother humiliating yourself, let's be honest?

嗯，讓我們面對事實 為什麼要自取其辱呢？

Here's where the really interesting part comes.

這就是最有趣的部分。

Because when people choose the pictures that they use on an online dating website,

因為當人們去選擇他們 在交友網站上使用的照片時，

they often try to minimize the things

他們總是試圖最小化

that they think some people will find unattractive.

其他人認為不吸引人之處的可能性。

The classic example is people who are, perhaps, a little bit overweight

最經典的例子是， 那些體重略重的人

deliberately choosing a very cropped photo,

故意選擇一個 剪裁非常不正確的照片，

or bald men, for example,

例如那些禿頭的男士，

deliberately choosing pictures where they're wearing hats.

故意去選擇他們帶著帽子的照片。

But actually this is the opposite of what you should do

但你的行為是與你的目標相悖的，

if you want to be successful.

如果你想要在網上交友成功。

You should really, instead, play up to whatever it is that makes you different,

你真的應該，去選擇 讓你看起來與眾不同的照片，

even if you think that some people will find it unattractive.

即便你認為某些人會對此失去興趣。

Because the people who fancy you are just going to fancy you anyway,

因為那些喜歡你的人 無論如何都會去喜歡你，

and the unimportant losers who don't, well, they only play up to your advantage.

而那些不重要的路人 只是渲染你的優勢。

Okay, Top Tip #2: How to pick the perfect partner.

好了，最高秘訣 2 號： 如何選擇完美的伴侶。

So let's imagine then that you're a roaring success

讓我們想像你的約會

on the dating scene.

精彩成功，

But the question arises of how do you then convert that success

但問題來了 你如何將那成功的約會

into longer-term happiness and in particular,

轉變成長期的幸福，尤其是，

how do you decide when is the right time to settle down?

你要如何選擇 在哪個時刻安定下來？

Now generally, it's not advisable to just cash in

一般來說， 並不建議人們立刻

and marry the first person who comes along

與第一個出現

and shows you any interest at all.

對你表達好感的人結婚。

But, equally, you don't really want to leave it too long

但是，一般來說，如果你想要 最大化你未來數十年幸福婚姻的機會，

if you want to maximize your chance of long-term happiness.

你也不願等待太久。

As my favorite author, Jane Austen, puts it,

我最喜歡的作家珍．奧斯汀這樣說：

"An unmarried woman of seven and twenty

「一個未婚的 27 歲女子

can never hope to feel or inspire affection again."

就別指望再能感受或觸動愛情了。」

(Laughter)

（笑聲）

Thanks a lot, Jane. What do you know about love?

這太嚴重了，珍， 你對愛瞭解多少呢？

So the question is then,

那麼問題來了，

how do you know when is the right time to settle down

你怎麼知道哪個時刻 是該要安定下來的時刻，

given all the people that you can date in your lifetime?

畢竟生命中你有很多可能的對象？

Thankfully, there's a rather delicious bit of mathematics that we can use

幸好，我們可以運用一點數學

to help us out here, called optimal stopping theory.

來幫助我們計算解決這個問題， 這理論名叫 「最優停止理論」。

So let's imagine then,

那麼讓我們來想像一下，

that you start dating when you're 15

你在 15 歲的時候開始交往，

and ideally, you'd like to be married by the time that you're 35.

理想狀態下，你在 35 歲的時候會結婚。

And there's a number of people

你的人生中

that you could potentially date across your lifetime,

有很多潛在的約會對象，

and they'll be at varying levels of goodness.

他們都有各自的優點。