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The Mathematics of Love | Hannah Fry | TEDxBinghamtonUniversity

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    Today I want to talk to youabout the mathematics of love.
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    Now, I think that we can all agree
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    that mathematiciansare famously excellent at finding love.
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    But it's not justbecause of our dashing personalities,
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    superior conversational skillsand excellent pencil cases.
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    It's also because we've actually donean awful lot of work into the maths
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    of how to find the perfect partner.
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    Now, in my favorite paperon the subject, which is entitled,
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    "Why I Don't Have a Girlfriend" --(Laughter) --
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    Peter Backus tries to ratehis chances of finding love.
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    Now, Peter's not a very greedy man.
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    Of all of the available women in the U.K.,
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    all Peter's looking foris somebody who lives near him,
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    somebody in the right age range,
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    somebody with a university degree,
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    somebody he's likely to get on well with,
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    somebody who's likely to be attractive,
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    somebody who's likely to find him attractive.
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    (Laughter)
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    And comes up with an estimateof 26 women in the whole of the UK.
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    It's not looking very good, is it Peter?
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    Now, just to put that into perspective,
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    that's about 400 times fewerthan the best estimates
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    of how many intelligentextraterrestrial life forms there are.
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    And it also gives Petera 1 in 285,000 chance
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    of bumping into any oneof these special ladies
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    on a given night out.
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    I'd like to thinkthat's why mathematicians
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    don't really bothergoing on nights out anymore.
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    The thing is that I personally
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    don't subscribeto such a pessimistic view.
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    Because I know,just as well as all of you do,
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    that love doesn't really work like that.
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    Human emotion isn't neatly orderedand rational and easily predictable.
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    But I also know that that doesn't mean
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    that mathematics hasn't got somethingthat it can offer us
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    because, love, as with most of life,is full of patterns
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    and mathematics is, ultimately,all about the study of patterns.
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    Patterns from predicting the weatherto the fluctuations in the stock market,
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    to the movement of the planetsor the growth of cities.
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    And if we're being honest,none of those things
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    are exactly neatly orderedand easily predictable, either.
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    Because I believe that mathematicsis so powerful that it has the potential
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    to offer us a new way of lookingat almost anything.
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    Even something as mysterious as love.
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    And so, to try to persuade you
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    of how totally amazing, excellentand relevant mathematics is,
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    I want to give you my top threemathematically verifiable tips for love.
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    Okay, so Top Tip #1:
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    How to win at online dating.
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    So my favorite online dating website is OkCupid,
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    not least because it was startedby a group of mathematicians.
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    Now, because they're mathematicians,
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    they have been collecting data
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    on everybody who uses their sitefor almost a decade.
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    And they've been trying to search for patterns
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    in the way that we talk about ourselves
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    and the way that we interact with each other
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    on an online dating website.
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    And they've come up with someseriously interesting findings.
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    But my particular favorite
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    is that it turns outthat on an online dating website,
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    how attractive you aredoes not dictate how popular you are,
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    and actually, having peoplethink that you're ugly
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    can work to your advantage.
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    Let me show you how this works.
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    In a thankfully voluntarysection of OkCupid,
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    you are allowed to ratehow attractive you think people are
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    on a scale between 1 and 5.
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    Now, if we compare this score, the average score,
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    to how many messages aselection of people receive,
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    you can begin to get a sense
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    of how attractiveness links to popularityon an online dating website.
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    This is the graph that the OkCupid guyshave come up with.
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    And the important thing to noticeis that it's not totally true
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    that the more attractive you are,the more messages you get.
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    But the question arises thenof what is it about people up here
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    who are so much more popularthan people down here,
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    even though they have thesame score of attractiveness?
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    And the reason why is that it's not just straightforward looks that are important.
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    So let me try to illustrate theirfindings with an example.
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    So if you take someone likePortia de Rossi, for example,
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    everybody agrees that Portia de Rossiis a very beautiful woman.
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    Nobody thinks that she's ugly,but she's not a supermodel, either.
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    If you compare Portia de Rossito someone like Sarah Jessica Parker,
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    now, a lot of people, myself included, I should say,
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    think that Sarah Jessica Parkeris seriously fabulous
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    and possibly one of themost beautiful creatures
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    to have ever have walked on the face of the Earth.
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    But some other people, i.e., most of the Internet,
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    seem to think that she looks a bit like a horse. (Laughter)
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    Now, I think that if you ask peoplehow attractive they thought
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    Sarah Jessica Parker or Portia de Rossi were,
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    and you ask them to give them a score between 1 and 5,
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    I reckon that they'd average outto have roughly the same score.
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    But the way that people would votewould be very different.
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    So Portia's scores wouldall be clustered around the 4
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    because everybody agrees that she's very beautiful,
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    whereas Sarah Jessica Parkercompletely divides opinion.
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    There'd be a huge spread in her scores.
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    And actually it's this spread that counts.
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    It's this spreadthat makes you more popular
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    on an online Internet dating website.
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    So what that means then
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    is that if some peoplethink that you're attractive,
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    you're actually better off
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    having some other peoplethink that you're a massive minger.
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    That's much betterthan everybody just thinking
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    that you're the cute girl next door.
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    Now, I think this begins makes a bit more sense
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    when you think in terms of the peoplewho are sending these messages.
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    So let's say that you thinksomebody's attractive,
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    but you suspect that other peoplewon't necessarily be that interested.
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    That means there'sless competition for you
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    and it's an extra incentivefor you to get in touch.
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    Whereas compare that to if you think somebody is attractive
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    but you suspect that everybody is going to think they're attractive.
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    Well, why would you bother humiliating yourself, let's be honest?
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    Here's where the reallyinteresting part comes.
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    Because when people choose the picturesthat they use on an online dating website,
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    they often try to minimize the things
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    that they think some people will find unattractive.
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    The classic example is peoplewho are, perhaps, a little bit overweight
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    deliberately choosing a very cropped photo,
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    or bald men, for example,
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    deliberately choosing pictureswhere they're wearing hats.
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    But actually this is the opposite of what you should do
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    if you want to be successful.
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    You should really, instead, play up to whatever it is that makes you different,
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    even if you think that some peoplewill find it unattractive.
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    Because the people who fancy youare just going to fancy you anyway,
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    and the unimportant losers who don't,well, they only play up to your advantage.
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    Okay, Top Tip #2:How to pick the perfect partner.
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    So let's imagine thenthat you're a roaring success
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    on the dating scene.
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    But the question arises of how do you then convert that success
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    into longer-term happinessand in particular,
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    how do you decidewhen is the right time to settle down?
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    Now generally,it's not advisable to just cash in
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    and marry the first personwho comes along
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    and shows you any interest at all.
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    But, equally, you don't really want to leave it too long
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    if you want to maximize your chance of long-term happiness.
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    As my favorite author, Jane Austen, puts it,
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    "An unmarried woman of seven and twenty
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    can never hope to feel orinspire affection again."
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    (Laughter)
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    Thanks a lot, Jane.What do you know about love?
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    So the question is then,
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    how do you know when is the right time to settle down
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    given all the people that you can date in your lifetime?
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    Thankfully, there's a rather delicious bitof mathematics that we can use
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    to help us out here, calledoptimal stopping theory.
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    So let's imagine then,
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    that you start dating when you're 15
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    and ideally, you'd like to be marriedby the time that you're 35.
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    And there's a number of people
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    that you could potentiallydate across your lifetime,
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    and they'll be at varying levels of goodness.
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    Now the rules are that once you cash in and get married,
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    you can't look ahead to seewhat you could have had,
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    and equally, you can't go backand change your mind.
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    In my experience at least,
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    I find that typically people don'tmuch like being recalled
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    years after being passed up for somebody else, or that's just me.
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    So the math says thenthat what you should do
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    in the first 37 percent of your dating window,
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    you should just reject everybodyas serious marriage potential.
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    (Laughter)
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    And then, you should pick the next person that comes along
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    that is better than everybody that you've seen before.
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    So here's the example.
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    Now if you do this, it can bemathematically proven, in fact,
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    that this is the best possible way
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    of maximizing your chances of finding the perfect partner.
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    Now unfortunately, I have to tell you thatthis method does come with some risks.
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    For instance, imagine if your perfect partner appeared
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    during your first 37 percent.
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    Now, unfortunately, you'd have to reject them.
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    (Laughter)
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    Now, if you're following the maths,
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    I'm afraid no one else comes along
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    that's better than anyoneyou've seen before,
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    so you have to go on rejecting everyone and die alone.
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    (Laughter)
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    Probably surrounded by catsnibbling at your remains.
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    Okay, another risk is, let's imagine, instead,
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    that the first people that you datedin your first 37 percent
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    are just incredibly dull,boring, terrible people.
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    Now, that's okay, because you're in your rejection phase,
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    so thats fine, you can reject them.
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    But then imagine, the nextperson to come along
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    is just marginally less boring, dull and terrible
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    than everybody that you've seen before.
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    Now, if you are following the maths,I'm afraid you have to marry them
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    and end up in a relationshipwhich is, frankly, suboptimal.
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    Sorry about that.
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    But I do think that there'san opportunity here
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    for Hallmark to cash in onand really cater for this market.
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    A Valentine's Day card like this.(Laughter)
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    "My darling husband, youare marginally less terrible
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    than the first 37 percentof people I dated."
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    It's actually more romanticthan I normally manage.
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    Okay, so this method doesn't giveyou a 100 percent success rate,
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    but there's no other possiblestrategy that can do any better.
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    And actually, in the wild,there are certain types
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    of fish which follow andemploy this exact strategy.
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    So they reject every possible suitor that turns up
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    in the first 37 percent of the mating season,
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    and then they pick the next fishthat comes along after that window
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    that's, I don't know, bigger and burlier
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    than all of the fish that they've seen before.
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    I also think that subconsciously,humans, we do sort of do this anyway.
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    We give ourselves a little bit of timeto play the field,
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    get a feel for the marketplace or whatever when we're young.
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    And then we only start looking seriouslyat potential marriage candidates
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    once we hit our mid-to-late 20s.
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    I think this is conclusive proof,if ever it were needed,
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    that everybody's brains are prewired to be just a little bit mathematical.
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    Okay, so that was Top Tip #2.
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    Now, Top Tip #3: How to avoid divorce.
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    Okay, so let's imagine thenthat you picked your perfect partner
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    and you're settling intoa lifelong relationship with them.
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    Now, I like to think that everybodywould ideally like to avoid divorce,
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    apart from, I don't know, Piers Morgan's wife, maybe?
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    But it's a sad fact of modern life
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    that 1 in 2 marriages in theStates ends in divorce,
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    with the rest of the worldnot being far behind.
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    Now, you can be forgiven, perhaps
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    for thinking that the argumentsthat precede a marital breakup
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    are not an ideal candidatefor mathematical investigation.
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    For one thing, it's very hard to know
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    what you should be measuring or what you should be quantifying.
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    But this didn't stop a psychologist,John Gottman, who did exactly that.
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    Gottman observed hundreds of coupleshaving a conversation
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    and recorded, well, everything you can think of.
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    So he recorded what was said in the conversation,
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    he recorded their skin conductivity,
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    he recorded their facial expressions,
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    their heart rates, their blood pressure,
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    basically everything apart from whetheror not the wife was actually always right,
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    which incidentally she totally is.
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    But what Gottman and his team found
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    was that one of themost important predictors
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    for whether or not a coupleis going to get divorced
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    was how positive or negative each partner was being in the conversation.
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    Now, couples that were very low-risk
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    scored a lot more positive pointson Gottman's scale than negative.
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    Whereas bad relationships,
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    by which I mean, probablygoing to get divorced,
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    they found themselves getting into a spiral of negativity.
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    Now just by using these very simple ideas,
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    Gottman and his group were able to predict
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    whether a given couplewas going to get divorced
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    with a 90 percent accuracy.
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    But it wasn't until he teamed upwith a mathematician, James Murray,
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    that they really started to understand
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    what causes these negativity spirals and how they occur.
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    And the results that they found
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    I think are just incrediblyimpressively simple and interesting.
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    So these equations, they predict how the wife or husband is going to respond
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    in their next turn of the conversation,
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    how positive or negativethey're going to be.
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    And these equations, they depend on
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    the mood of the person when they're on their own,
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    the mood of the person whenthey're with their partner,
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    but most importantly, they depend on
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    how much the husband and wifeinfluence one another.
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    Now, I think it's important to point out at this stage,
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    that these exact equations have also been shown
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    to be perfectly able at describing
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    what happens between twocountries in an arms race.
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    (Laughter)
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    So that -- an arguing couplespiraling into negativity
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    and teetering on the brink of divorce --
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    is actually mathematically equivalent tothe beginning of a nuclear war.
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    (Laughter)
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    But the really important termin this equation
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    is the influence that peoplehave on one another,
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    and in particular, something called the negativity threshold.
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    Now, the negativity threshold,
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    you can think of ashow annoying the husband can be
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    before the wife starts to get really pissed off, and vice versa.
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    Now, I always thought that good marriageswere about compromise and understanding
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    and allowing the person to have the space to be themselves.
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    So I would have thought that perhapsthe most successful relationships
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    were ones where there wasa really high negativity threshold.
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    Where couples let things go
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    and only brought things up if they really were a big deal.
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    But actually, the mathematicsand subsequent findings by the team
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    have shown the exact opposite is true.
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    The best couples,or the most successful couples,
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    are the ones with a really low negativity threshold.
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    These are the couples that don'tlet anything go unnoticed
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    and allow each other some room to complain.
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    These are the couples that are continuallytrying to repair their own relationship,
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    that have a much more positiveoutlook on their marriage.
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    Couples that don't let things go
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    and couples that don't let trivial thingsend up being a really big deal.
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    Now of course, it takes bit more than just a low negativity threshold
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    and not compromising tohave a successful relationship.
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    But I think that it's quite interesting
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    to know that there is reallymathematical evidence
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    to say that you should neverlet the sun go down on your anger.
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    So those are my top three tips
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    of how maths can help youwith love and relationships.
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    But I hopethat aside from their use as tips,
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    they also give you a little bit of insightinto the power of mathematics.
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    Because for me, equations and symbols aren't just a thing.
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    They're a voice that speaks outabout the incredible richness of nature
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    and the startling simplicity
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    in the patterns that twist and turnand warp and evolve all around us,
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    from how the world works to how we behave.
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    So I hope that perhaps,for just a couple of you,
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    a little bit of insight intothe mathematics of love
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    can persuade you to have a little bit more love for mathematics.
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    Thank you.
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    (Applause)
Title:
The Mathematics of Love | Hannah Fry | TEDxBinghamtonUniversity
Description:

Dr. Hannah Fry is a mathematician and complexity scientist from University College London's Centre for Advanced Spatial Analysis. Her work revolves around exploring the patterns in human behavior and applying a mathematical perspective to tackle a wide range of problems across our society. Alongside her academic position, Fry is passionate about sharing the abstract beauty of mathematics with others and demonstrating its importance in our modern world. She has a broad portfolio of media and public engagement activities from schools outreach, math-themed stand-up comedy, YouTube videos and public lectures. Fry also regularly presents the Number Hub strand of BBC Worldwide's YouTube channel, Headsqueeze.

In the spirit of ideas worth spreading, TEDx is a program of local, self-organized events that bring people together to share a TED-like experience. At a TEDx event, TEDTalks video and live speakers combine to spark deep discussion and connection in a small group. These local, self-organized events are branded TEDx, where x = independently organized TED event. The TED Conference provides general guidance for the TEDx program, but individual TEDx events are self-organized.* (*Subject to certain rules and regulations)
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Video Language:
English
Team:
closed TED
Project:
TEDxTalks
Duration:
17:43

English subtitles

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