Let’s say you’ve just gotten out of a romantic relationship and are ready to look for someone new. Someone different. Someone who, above all, is the polar opposite of your ex, who by the end of it was frankly driving you a little nuts.
After some false starts you make a match. Things are going great, honestly. You begin telling friends and family and even start thinking long term when, weeks or months into the new relationship, it suddenly hits you: This new partner is eerily similar to the last one.
If you’ve experienced anything like this, you’re not alone, according to new research published in the Proceedings of the National Academy of Sciences. The study, by a pair of psychologists at the University of Toronto, confirms what dating histories have long suggested: When it comes to romantic partners, most people do have a “type,” personality-wise. And it arrives at its conclusions in a novel and slightly terrifying way: via interviews with hundreds of people’s romantic exes.
Psychologists have delved into the topic before, but much of the prior research relied on individuals’ self-reported experiences with their exes. That’s potentially a huge problem, as anyone who’s tried to speak in coldly rational terms about a former lover can probably attest. People may be inclined to cast former partners in a negative light, particularly vis-a-vis their current partners, muddying up the data.
The current study gets around this issue by relying on the German Family Panel study, a representative survey of German adults that’s been ongoing since 2008. That survey involves interviews with both primary survey participants and their romantic partners. If a participant changes partners, the new arrival gets interviewed and that data is added to the primary participant’s file.
Researchers evaluated current and former romantic partners on the Big Five personality inventory, an interview-based tool that social scientists have relied on for years. The inventory assigns scores on five personality traits: extraversion, agreeableness, conscientiousness, neuroticism and openness to new experience.
With those scores in hand, the researchers then compared current and former partners to see how similar (or different) they were. Crucially, they controlled for a couple of potentially confounding factors: since people tend to date people who are broadly similar to them, personality-wise, they controlled for the personality type of the primary survey participant. They also controlled for people’s tendency to characterize themselves in socially desirable terms, to ensure that any similarities weren’t simply an artifact of the way that all humans talk about themselves.
In the final analysis, they found “a significant degree of distinctive partner similarity, suggesting that there may indeed be a unique type of person each individual ends up with,” according to the study. If you’ve dated, say, introverted and neurotic people in the past, you’re likely to date similar types of people in the future.
Interestingly, however, they found that this partner association was weaker, although still present, for people who scored high on extraversion and openness to new experience. If you are an outgoing person who loves trying new things, in other words, you are more likely to date people who are dissimilar to one another.
The findings have “important implications for predicting future partnering behaviors and actions in romantic relationships,” according to the study authors. They envision, for instance, online or app-based dating services that recommend potential partners to people based on their previous romances: Think Netflix recommendations, but for dating. That’s already happening, to an extent, although much of the emphasis tends to be based on what people say they want in a partner, rather than what their experience has shown they want.
For the time being, the results suggest — somewhat disturbingly — that the key to finding happiness in long-term relationships is to find someone who’s a lot like your exes.