It is a truth universally acknowledged, that a single person in possession of a desire to date, is bound to couple up with a series of similar partners—and now, scientists have the data to back it up.
According to new research published today in the journal PNAS, people do, in fact, have a “type” when it comes to their romantic partners, gravitating toward similar personality traits from one relationship to the next. Beyond confirming an old cliché, the study suggests that partnering patterns may be more predictable than once thought—a finding that could someday influence the design of dating app algorithms and more.
The study’s results may not don’t come as a big shock. Humans are, after all, creatures of habit, and make no exception for interpersonal relationships. But in the wake of a breakup, plenty of people might shy away from potential partners that remind them of an ex—an aversion that could easily tip the scales in the other direction, says study author Yoobin Park, a psychologist at the University of Toronto.
Figuring out which of these competing motivations wins out, however, is a pretty daunting task. To accurately compare a person’s current and ex-partners, Park would need to identify individuals in a relationship, gather information from both them and their current partners, then wait for them to break up and find new significant others before repeating the process—an experiment that would probably exceed the length of your garden-variety PhD.
Luckily, such a dataset actually already existed—in the form of the German Family Panel, which has been collecting information on the interpersonal dynamics between couples and families since 2008. Part of the Germany study involved administering a personality test called the Big Five Inventory, a common psychological survey that rates people on five personality traits: openness to new experiences, conscientiousness, extraversion, agreeableness, and neuroticism. Out of more than 12,000 participants, Park identified 332 who had dated two different partners who had also completed the self-assessments between 2008 and 2017. This, she says, was key to the study’s success, because the personality data for each person came from their own self-reflection, rather than a potentially biased partner or ex.
“I don’t know of anyone else who’s used a dataset like this [to answer these questions],” says Margaret Clark, a psychologist studying interpersonal relationships at Yale University who was not involved in the study. “I think what they’ve done here is terrific, and brand new, all because they’ve been able to make very good use of a very unusual dataset.”
When Park compared the personality profiles in each dating triad (one person and two partners), three trends became clear. First, people frequently coupled up with partners who were pretty, well, average. Human beings tend to resemble each other in a lot of ways, and some of the traits people share can just be chalked up to there being such a thing as a “typical” personality, says study author Geoff MacDonald, who oversees Park’s research. Second, individuals often dated others who were similar to themselves—something that’s been shown several times before.
Both of these tendencies could create a false sense of similarity between a person’s ex- and current partners, MacDonald says. But even when Park and MacDonald accounted for these patterns by essentially “subtracting” them from the data, the third and most important finding held true: People’s successive partners still had personality traits in common. It’s a phenomenon the researchers call “distinctive similarity,” and it seems to be a strong indication that, when it comes to personality, humans do have a penchant for dating certain “types.”
At least, that’s the case if you’re careful about defining “type,” says Leigh Smith, a social psychologist at the University of California, Davis who was not involved in the study. While the study’s findings suggest that people’s partners have consistent traits, they don’t imply that the personalities of successive significant others are identical, she says. It’s a bit like indulging in a smorgasbord of desserts that all happen to contain chocolate, even if each dish has a wildly different recipe.
It’s also not yet clear what’s behind this peculiar pattern. Due to the limitations of the data available, the researchers couldn’t make any conclusions about causes, or guarantee that they apply to other countries or cultures. On the whole, though, “humans are cognitive misers,” Smith says. “Having something familiar is more predictable...and gives us a sense of control. We don’t like to put in more work than we need to.”
There is some evidence in the results, however, that suggests people who are more extraverted and open to new experiences were among those less likely to end up with similar partners—possibly because these individuals have wider social circles or are more inclined to branch out from what’s familiar, MacDonald says.
But these patterns probably aren’t just about who people are “choosing” to be with, he adds. Our dating pools are obviously restricted by who’s available to us, and people with a lot in common tend to cluster. Relationships are also about mutual choice, and it could be that similar individuals are picking you, rather than the other way around, he says.
Importantly, the study’s results also have no bearing on whether dating people with similar personality traits is good or bad. While the idea of “types” is often cast in a negative light, dating similar people doesn’t always equate to repeating a mistake, MacDonald says. Nor are these trends foregone conclusions, he says—especially if people have a little more self-awareness when these tendencies manifest.
“Types” could even be a plus for some people, Park says. “If your new partner's personality resembles your ex-partner's personality, you might be able to transfer the skills you learned from the past relationship.” For now, she adds, “it’s really an open question at this moment how much is a minus and how much is a plus.”
Figuring that out will require investigating whether falling into partnership patterns predict satisfaction or wellbeing, Smith says. Still, “knowing that this exists in the first place is a crucial first step...and this study lays the groundwork for that.”