Michael Kaplan

Michael Kaplan

Bozo Sapiens

What Are the Odds on Love?

How chance rules the heart.

Posted Apr 29, 2009

True love is like a kick in the head. No, really. It's not just that it 
comes out of nowhere, knocks you sideways and changes your life 
forever. It's statistically like a kick in the head.

Most statistics are about things that usually happen or that most 
people share: prices, salaries, IQs, political opinions. These 
qualities are called "normally distributed": If you chart them, the 
graph they produce is that old favorite, the bell curve.

Love, here as everywhere, is different. True love is rare; we can only 
hope to find it once in a lifetime, and maybe not even then. The curve 
that charts love is very narrow – more like a steeple than a bell. 
It's called a Poisson curve, and its classic example was the chance of 
being kicked to death by a horse while serving in the Prussian cavalry.

The normal distribution was discovered during the 18th century, when confident Age of Enlightenment types assumed that all people, places 
and times were pretty much alike. Statistics that produce a bell curve 
(like, say, the heights of everyone on your street) show a clear 
average, with plenty of readings within a predictable range around that 
average, called a "standard deviation." Common qualities, such as 
height, are easy to forecast.

Simeon-Denis Poisson, though, lived in the more unpredictable 19th century. He was interested in rare events. He wanted to discover how 
well you could predict the chances of one such event occurring during a 
given time (improbable); two events (very improbable); three (like, 
totally improbable); or four (so improbable you can forget about it).

Years of work produced a formula that allowed just such prediction - 
and Poisson's successor, Ladislaus Bortkiewicz, applied it to the 
chances of a given cavalry regiment suffering a death by horse kick in 
a given year. In a triumph of mathematical prediction, the actual 
figures for the German army between 1875 and 1894 matched almost 
perfectly the numbers generated by theory.

While the bell curve describes things we can expect; Poisson's formula predicts things we fear or hope for – things that, though rare, could happen at any time. In World War II, the British used it to predict the 
likelihood of any particular neighborhood in London being hit by a V-2 
rocket. Telephone companies use it to predict the likelihood that any 
particular number is going to ring at a particular moment (it's low, 
although somehow much higher when you're in the bath). The chance that 
the store will run out of your cat's favorite food, that you'll have a 
fender bender on the way home, the chance a war will break out 
somewhere today: If there's an average occurrence of any event over 
time, however low, Poisson's formula can predict a likelihood for the 
here and now.

True love is such an event. It could be today; it could be never. All 
we know is that it happens to some people, sometimes. This makes me 
believe that the hope of meeting the love of your life is also governed 
by the Poisson curve. If so, it suggests some interesting conclusions.

Woody Allen pointed out that being bisexual doubles your chance of a 
date on Saturday night - but, sadly, Poisson shows very little change in response even to this drastic rise in probability.

His curve, applied to finding true love, charts two things: the chance this rare event will happen once, twice, thrice, in a lifetime; but 
also how likely it is to happen at all in progressively more unlikely circumstances. When you move away from the back of the horse, the chance of being kicked to death falls precipitously. Similarly, edging away from the kind of people who are the current focus of your 
affections (in the hope that, say, a Florentine millionaire-poet-ski champion will come knocking at your door) makes the chance of success drop away much more quickly than it would for normally distributed 

This implies that your best chances come from seeking out and 
sustaining friendships with the people you already like most, rather 
than devoting too much time to the mad, bad alternatives. Rare things 
become near-impossible once you compound their rarity – say, by buying 
a lottery ticket only on your birthday.

In probability, we have only two ways to control fate: through standards and through opportunities. If you want to avoid a bad Poisson event (like the fender bender), you maintain high standards by driving as defensively as you can. You steer clear of certain routes at certain times to avoid giving the other idiots too many opportunities to hit you. Finding love, too, demands high standards (this is, after all, the 
person who'll share your whole existence) but you need lots of 

Go speed dating, by all means – remembering that it only selects for a good date, not necessarily a good mate. Get your friends to introduce you to their other friends; you may fit well together. Skew your social life toward those events where you can find out more about potential partners than whether they are just great dancers. Use every experience, good or bad, to refine your vision of that unknown ideal... so that when the one chance comes, you won't let it slip. Every 
step takes you closer to the center of the Poisson curve.

And who am I to tell you this? Someone who knows something about probability; but, more important, the person who went to that dinner party 20 years ago with friends of friends. There across the table was the woman I'd heard about, asked my friends about. Those eyes... that face... that character.... Kabong!