The Mathematics of Love: Patterns, Proofs, and the Search for the Ultimate Equation

by Hannah Fry

Real science is about trying as hard as you can to disprove your own theories. The more you try, and fail, to prove yourself wrong, the more evidence there is to suggest that what you’re saying is right.

Since the 1800s, researchers have known that overlaying images of lots of faces from a particular ethnic group will lead to an average face that is widely considered attractive. Each ethnic group has a different ideal, but essentially, once you’ve ironed out the oversized chins, lopsided ears, and lengthy foreheads, what you’re left with is a completely average (if unexciting) hottie.

As girls go through puberty, their hormones will have a direct impact on how their facial features develop. Women with high levels of estrogen will end up with full lips and a large waist-to-hip ratio, while women with lower levels of androgen, the steroid hormones, will keep their short and narrow jaws from childhood, along with their flatter brows—giving them much larger eyes. And—surprise, surprise—this balance of female hormones is also positively linked to fertility.

Men, on the other hand, need testosterone throughout puberty to develop muscle mass, broader jaws, and defined brow ridges, which will inevitably result in more sunken eyes. And testosterone, the male sex hormone, is also a useful marker for fertility.

For example, it seems that the rules of symmetry only really work on pictures of people’s faces. In real life, many people are also drawn to asymmetrical characteristics. Not only do they show more character, but people who possess them are also perceived to be more sincere.

George Bernard Shaw put it, “Love consists of overestimating the difference between one woman and another.”

If you can handle the occasional cringe-inducing rejection, ultimately, taking the initiative will see you rewarded. It is always better to do the approaching than to sit back and wait for people to come to you. So aim high, and aim frequently: The math says so.

The latest statistics suggest that three-quarters of US singles have tried dating sites, and up to a third of newly married couples originally met online.

By multiplying the values rather than adding them, the geometric mean finds a number in the multiplicative middle

Scientists have known for a long time that our body language will mirror that of someone we are attracted to. Our pupils will become dilated, the words we use in conversation will adjust to mimic the language patterns of the other person, and our laughter will begin to synchronize. All of this happens within a matter of minutes, and all of these signs can be used to quantitatively define a connection between two people.

When choosing a profile picture, you should play up to whatever makes you different—including the things that some people might not like.

These networks are known as scale-free because—unlike normal distributions or Poisson distributions—the underlying power-law doesn’t have a typical parameter (like the mean or standard deviation) that defines its scale.

In relationships where both partners consider themselves as happy, bad behavior is dismissed as unusual: “He’s under a lot of stress at the moment,” or “No wonder she’s grumpy, she hasn’t had a lot of sleep lately.” Couples in this enviable state will have a deep-seated positive view of their partner, which is only reinforced by any positive behavior:

The most successful relationships are the ones with a really low negativity threshold.4 In those relationships, couples allow each other to complain, and work together to constantly repair the tiny issues between them. In such a case, couples don’t bottle up their feelings, and little things don’t end up being blown completely out of proportion.