You’ve probably come across those couples where one partner is significantly more attractive than the other. It’s often fodder for fictional comedy – think of oafish Homer and demure Marge in “The Simpsons,” Peter and Lois Griffin in “Family Guy,” or a fake article in the Onion. In real life, of course, it’s also a source of pain for some couples, who may be hurt and embarrassed to hear that their partner “could do so much better than you.”
While there are all kinds of variations within partners, mixed-attractiveness couples do go somewhat against the grain. We’re often cautioned that real beauty is found within, but good looks are among the more highly rated characteristics in what people say they want in a romantic partner. And in general, couples tend to be more similar in many respects – including their genetics, physical attractiveness and cultural characteristics such as religion, politics and socioeconomic status – than two randomly selected people would be. Scientists call this “assortative mating,” and it’s a principle that has been studied for over a century: As early as 1903, scientists reported similarities in the height and arm length of couples.
There are various theories for why people sort themselves out into similar pairs. One is competition: As individuals contend for the most desirable mates, they end up being constrained by their own characteristics. So someone who is just moderately attractive would love to end up with a supermodel, but competition from other good-looking people means they’ll probably end up with someone whose looks are on the same level. But there are other theories as well, for example, that people just prefer or are more likely to meet others who are more similar to them.