I think we can all agree that mathematicians are well known for being extremely popular
with the opposite sex.
But it's not just because of our dashing personalities and superior pencil cases.
Oh no.
It's also because we've have done an awful lot of work in the mathematics of, how to
find the perfect partner.
In my favourite paper on the subject, entitled "Why I don't have a girlfriend", Peter Backus
tries to work out his chances of finding love.
In particular, he is looking for single women who live near him in the UK, are of the right
age range, have an university degree, are likely to be attractive, and he is likely
to get in well with.
And the total he comes up with is 26 in the whole of the UK.
Now to just put that in perspective that's 400 times fewer than the best estimates of
how many intelligent extra-terrestrial life forms there are.
And it gives him a 1 in 285,000 chance of meeting one of these 26 ladies on a given
night out.
It's not looking very good is it Peter?
Now I don't prescribe to this frankly pessimistic view.
I think there is a lot of people you can have a successful relationship with if you want
to.
But given all the people you'll date throughout your life time, how do you know when is the
right time to settle down?
Of course it isn't wise to cash in the first person who shows you any interest, but equally
if you want to be truly happy you can't leave it too long.
As my good friend Jane Austin says "An unmarried woman of seven and twenty can never hope to
feel or inspire affection again."
Yeah, thanks a lot Jane, what do you know about love?
But the thing about dating is that once you've made up your mind, you can't go back and change
it.
Typically people aren't that happy being recalled later after being passed up for somebody else.
So many people should you date before you decide to settle down?
Now, if only there were some kind of a mathematical formula for a dating strategy that we could
use to help us.
Oh wait, there totally is!
And its called optimal stopping theory.
So, let's say you start dating at about 15 years old and ideally you'd like to settle
down at 35.
And the rules are you can't see ahead of what you could've had once you settle down and
you can't go back and change your mind.
So the theory says that in the first 37% (or 1 over e) of your dating time, you should
reject everybody as serious marriage material.
And after that period has passed you should pick the next person that comes along that
is better than everybody else you've seen before.
And if you do that it can be mathematically proven that you're maximising your chances
of picking the perfect partner.
So this method has been observed in the wild.
So certain types of fish will reject any suitor who comes along within the first 37% of the
mating season and then pick the next male fish that comes along that's bigger and burlier
than all of the rest.
But you could also use this strategy when you're looking to buy or rent a house.
Say you got three months in which to look for a house.
You should spend the first month (30% of the time window) just getting a feel for the market,
going to see houses but never cashing in on any of them.
And after that period has passed you then pick the first house that comes along that
is better than everything else you've seen before.
Now this method does come with risks, it doesn't guarantee that you'll get the perfect partner,
it just gives you your best chance of finding them.
You could, for instance, be really unlucky and have your perfect match appear within
that first 37% window when you're rejecting everybody.
And if that's the case, unfortunately the maths says that you'll grow old alone probably
be surrounded by cats.
Or let's say you got really unlucky and the first 37% of the people you dated were just
incredibly dull and boring and terrible people.
And that's ok because you're still rejecting all of those people.
But let's say the next person that comes along is still really dull and boring but marginally
less terrible everybody you'd seen before.
If you're following the maths and marry that person you'd just be in a relationship that
was suboptimal.
Sorry about that.
But if everybody followed this strategy then one in three people who do, they can settle
down in the knowledge that maths says they'd done the very best they can.