Back in 2022, a spate of articles introduced the wider world to the term “doppelbangers.” A play on “doppelgänger,” the word has long been used by members of the LGBTQ+ community to describe couples who resemble one another. Since then, countless articles have pointed out “celebrity couples that look like siblings” and a popular Instagram account is dedicated to asking whether two people standing together in a photo are “Siblings or Dating.” (It’s harder to tell than you think!) 

It’s not a new phenomenon. People have long mused that couples often look alike. A 1987 study conducted by the University of Michigan even set out to prove the phenomenon, positing that the longer a couple was married, the more likely it was that they would have begun to look the same. Different academics have expounded on that theory since, suggesting that couples’ features begin to merge over time due to a variety of factors, like hobbies, location, happiness, fashion choices, immune systems and age.

But in 2020, a study out of Stanford University found that, in fact, couples don’t start to look more alike as they age. Instead, their research suggested that we tend to be attracted to people who already look similar to us, whether that’s because they’re in the same general level of attractiveness, same friend group, profession or local region. 

Michal Kosinski, a computational psychologist who co-authored the Stanford study, says that it’s natural for people to seek out the simplest explanation to a question, but that in practice, the reason couples tend to look alike is complex and a bit more socially restrictive. “People prefer to hang out with—and marry—similar others,” he explains. “We prefer to listen to and read books by similar others, too, and when we say similar, we mean virtually everything, including age, gender, political orientation, personality, intelligence, religious views, affluence and so on… The same people end up living in similar places, going to similar schools and bars, and going to the same dating websites, where they choose to meet people who are just like them.”¹