I was one of the founders of OkCupid, a dating website that, over a very unbubbly long haul of 10 years, has become one of the largest in the world. I started it with three friends. We were all mathematically minded, and the site succeeded in large part because we applied that mindset to dating. I have led OkCupid’s analytics team since 2009, and my job is to make sense of the data our users create. Playing with the numbers helps us run our site. But as people bring technology deeper and deeper into their lives, it can show us profound and ridiculous things about who we are as human beings. Here are just a few examples.

1. Women have a very sensible approach to ageing

This table lists, for a woman, the age of men she finds most attractive.

Reading from the top, we see that 20 and 21-year-old women prefer 23-year-old guys; 22-year-old women like men who are 24, and so on down through the years to women at 50, who we see rate 46-year-olds the highest. This isn’t survey data, this is data built from tens of millions of preferences expressed in the act of finding a date, and even from the first few entries, the gist of the table is clear: a woman wants a guy to be roughly as old as she is.



Look more closely, though, and there are two transitions, which coincide with big birthdays. The first is at 30, where the trend of male ages dips below parity, never to cross back. The data is saying that until 30, a woman prefers slightly older guys; afterwards, she likes them slightly younger. Then at 40, a woman’s tastes appear to hit a wall. Or a man’s looks fall off a cliff, if you want to think about it that way. If we want to pick the point where a man’s sexual appeal has reached its limit, it’s there: 40.



2. Meanwhile, men may get older but they don’t really grow up

Here’s how men rate women, the votes going the other way. Whether they are 20, 30, or 50, men think a woman is at her best when she’s in her early 20s.

As you can see, it’s pretty much a unanimous vote for youth. Wooderson, the character played by Matthew McConaughey in the film Dazed and Confused, apparently spoke for all men when he said: “That’s what I love about these high-school girls, man. I get older. They stay the same age.”

3. White people love to talk about their hair

I crunched 3.2 billion words of profile text, looking algorithmically for the most typical ways people describe themselves. Here are the top five phrases for white men and white women:

Men

my blue eyes



blond hair



Ween



brown hair



hunting and fishing

Women

my blue eyes



red hair and



blonde hair and



love to be outside



mudding

Ween (a prog-rock band) and mudding (where you drive a car or four-wheeler through ... mud) are both artifacts of OkCupid’s large American user base. This method looks at the most exceptional words a group uses to talk about themselves; white people’s hair types come up because, by and large, other racial groups don’t have blond or red hair. For comparison, here are the words for a few other large groups on OkCupid:

Black men

dreads



Jill Scott



Haitian



soca



neo soul

Latino men

Colombian



salsa merengue



cumbia



una



merengue bachata

Asian men

tall for an Asian



Asians



Taiwanese



Taiwan



Cantonese



4. Using the same method, these are the 30 ‘most British’ words

Here, I compared Britain’s OkCupid profiles to those from rest of the English-speaking world, and pulled out the words that are algorithmically most British. These are the words people in the UK disproportionately use in talking about themselves.

Newcastle



Bristol



wot



wasters



Camden



Brighton



twat



Portsmouth



Biffy



Clyro



trousers



trainers



Glasgow



feeder



Plymouth



consultancy



bloke



moaning



Haribo



kebab



nan



Ibiza



Essex



lecturer



Stereophonics



bolognese



Yorkshire



housemate



bugger



shite



5. Beauty is an exponential quantity on OkCupid

Every dating site has to have a way to measure how good-looking its users are. This helps keep the site healthy – you’re able to make sure nobody’s getting too much attention, make sure no one’s getting ignored. Unfortunately, despite our efforts, people still gravitate to the best-looking people. Here are messages received each week, versus beauty:

The sharp increase at the right smashes down the rest of the curve, so its true nature is a bit obscured, but from the lowest percentile up, this is roughly an exponential function. That is, it obeys the same maths seismologists use to measure the energy released by earthquakes: beauty operates on a Richter scale. In terms of its effect, there is little noticeable difference between, say, a 1.0 and 2.0 – these cause tremors that vary only in degree of imperceptibility. But at the high end, a small difference has cataclysmic impact. A 9.0 is intense, but a 10.0 can rupture the world. Or launch a thousand ships.



6. Even on a jobs site, women are treated as if they’re looking for a date

Here is data for interview requests on ShiftGig, a job-search site for hourly and service workers, plotted against the attractiveness of the applicants:

Here, the female curve is exponential and the male is linear. Moreover, they hold whether the hiring manager, the person doing the interviewing, is a man or a woman. In either case, the male candidates’ curves are a flat line – a man’s looks have no effect on his prospects – and the female graphs are exponential. So these women are treated as if they’re on OkCupid, even though they’re looking for employment. Male HR reps weigh the female applicants’ beauty as they would in a romantic setting – which is either depressing or very, very exciting, if you’re a sexual discrimination lawyer. And female employers view it through the same (seemingly sexualised) lens, despite there (typically) being no romantic intent.

7. The best questions to ask someone on a first date might surprise you

OkCupid matches people by asking them questions – we ask pretty much everything (from how often you brush your teeth, to whether you believe in God) – and the user answers on average about 300 of them. The site lets you decide the importance of each question you answer, and you can pinpoint the answers that you would (and would not) accept from a potential match.

People tend to run wild with those match questions, marking all kinds of stuff as “mandatory”, in essence putting a checklist to the world: I’m looking for a dog-loving, agnostic, nonsmoking liberal who’s never had kids – and who’s good in bed, of course. But very workaday questions like: “Do you like scary movies?” and: “Have you ever travelled alone to another country?” have amazing predictive power. If you’re ever stumped on what to ask someone on a first date, try those. In about three-quarters of the long-term couples OkCupid has brought together, both people have answered them the same way, either both “yes” or both “no”. That’s much, much higher than the expected rate, since both questions evenly split our user base. In fact, successful couples agree on scary movies – either they both like them or they both hate them – about as often as they agree on the existence of God.

• Dataclysm: Who We Are (When We Think No One’s Looking) by Christian Rudder is published by Fourth Estate

• If you’re looking for love, try Soulmates, the Guardian’s online dating service