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When it comes to dating, many people say they have a "type" they're attracted to. Maybe you're into the brooding loner, the social butterfly, or the quirky artist. While many of us intuitively believe in the idea of having a type, it's actually pretty difficult for researchers who study relationships to verify if people really do consistently choose the same kinds of romantic partners. However, new research by Yoobin Park and Geoff MacDonald just published in The Proceeding of the National Academy of Sciences attempted to answer this question by comparing the personalities of people's current and ex partners.

Most research that assesses what people want in a romantic partner simply asks people about the qualities they find desirable. For example, respondents in these studies will rate how important different qualities are in an ideal partner. These studies show that people's preferences for their ideal partners are relatively stable over time. However, people's actual partner choices don't necessarily line up that well with what they said they wanted in a partner. So the best way to test if people really have a type is to compare their different romantic partners to one another.

The researchers wondered about the dynamic nature of moving from one relationship to another. Do you deliberately seek out someone different than your ex, or do you tend to go for the same type of person over and over? You go to an ice cream shop and try strawberry ice cream, and you end up not liking it as much as you thought you would. When you go to a new ice cream shop, do you try their version of strawberry or opt for another flavor?

One past series of studies did examine multiple ex-partners to determine if people's past partners resemble each other. They found that a particular individual's exes had similar levels of physical attractiveness to one another. However, given that physical attractiveness is a highly valued trait on the dating market and is quite apparent at first meeting, it is likely to be a function of the person's overall desirability rather than a unique preference for physically attractive partners. That research also found that exes resembled each other on socially relevant characteristics (religiosity, intelligence, and educational goals). However, much of this was due not so much to people choosing mates based on those characteristics, but rather due to circumstances – That is, people were just more likely to meet others who shared their education levels or religion.

Do we have a "type" when it comes to personality?

Park and MacDonald took a unique approach by examining similarity in exes' personality traits. Specifically, they examined the Big 5 personality traits: Openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism. Openness refers to the extent to which people are creative, intellectual, and seek out new experiences. Conscientiousness refers to how practical, organized and responsible we are. Extraversion captures sociability, assertiveness, and adventurousness. Agreeableness reflects the extent to which people are warm, generous, and cooperative with others. Finally, neuroticism reflects the extent to which people are anxious, insecure and emotionally volatile.

To test the similarity of ex-partners, Park and MacDonald used data from large study of German adults collected over a span of nine years, in which the respondents and their romantic partners completed questionnaires measuring the Big 5 personality traits. They used data from the 332 respondents who had two different romantic partners during the nine-year period.

There are two potential problems that arise when trying to determine if ex-partners are similar to each other. First, the personality traits examined by this research aren't neutral – Some traits are more socially desirable than others. For example, most people think being warm and kind is desirable and respond positively to warm and kind people. In order to prevent this from contaminating their results, the researchers statistically adjusted for the average ratings of the sample. Thus, they could examine how similar someone's current and ex partner were to each other, regardless of the general tendency for people to rate themselves similarly to one another. A second issue is that people may be choosing partners who are similar to themselves. That is, if you're introverted, you might date other introverts. This is part of your type (you like people who are like you), but the common idea of a "type" goes beyond mere similarity. To prevent this from contaminating their results, they also statistically adjusted for the respondent's own personality. So the researchers statistically controlled for both the average levels of the traits in the sample overall and the respondent's own personality.

So do people have a type when it comes to personality? The results suggest that they do. There was a significant link between the current and ex partner's personalities, even when adjusting for similarity to the respondent themselves. In fact, the results showed that on average, the unique association between your personality and your partner's is as strong as the unique association between your current partner's personality and your ex's personality.

Does everyone have type?

Another question that Park and MacDonald investigated is whether some people are more prone to having a type than others. The results discussed previously were averages across the whole sample. That means that some people have a very consistent type of person they date, whereas others might date many different types of people. To test this out, the researchers examined how the respondent's own personality correlated with how likely they were to have partners who were similar to each other.

They found that those who were high in neuroticism (that is, moody and anxious people) tended to have less desirable partners and to date people who were less similar to themselves. Compared to all of the other Big 5 traits, neuroticism is the one that has been consistently shown to be associated with relationship problems, like conflict, jealousy, and lack of forgiveness. So perhaps highly neurotic people had fewer options for partners, and thus ended up with people who were less desirable or less their type.

The results also showed that people who were high in extraversion or openness were less likely to date someone who was similar to their ex. The researchers suggested that this might be due to the tendency for such individuals to be more open to different kinds of people or their tendency to have wider and more diverse social networks.

Why do we end up with the same type of person?

This research shows that we often do end up dating similar types of people. But it doesn't answer the question of why that happens. One explanation is that we are actively choosing partners who are similar to each other because we have a type. But that's not the only possible reason that our exes resemble each other.

It might happen simply because you're in situations where you meet a particular kind of person, since personality affects what people do. For example, the Big 5 traits are related to participation in sports, interest in joining sororities/fraternities, and what courses people take in college. The researchers claim that similarity to oneself should account for this, but it might not entirely do so if some individuals find themselves in situations that generally attract people who are different from themselves yet similar to each other.

Another possibility is that rather than us liking similar people, a certain type of person tends to like us. For example, imagine that you're an emotionally undemanding person. You might find that people who are emotionally flat or distant find you relatively easy to be around, so you tend to date that kind of person more, even if you don't particularly like those qualities. Or imagine that you're very easy-going and don't mind if your partner makes most of the decisions about your joint activities, like what to have for dinner, or where to go on vacation. People who are more controlling, or just fussy about their activities, might especially like that quality and find you easier to get along with. Again, this wouldn't be because you especially like or seek out controlling or fussy people. In essence, rather than you having a consistent type, you might be that type's type.

Most likely, all three of these factors are at play. We probably end up dating similar kinds of people because we do have a type, because we attract a certain type of person, and because we just happen to be in situations where we encounter a certain type of person more frequently.

Overall, this research probably underestimates how similar our exes really are to each other because the researchers only looked at one set of factors (the Big 5 personality traits). Examining a full range of personality traits, preferences, and demographic variables would probably reveal even more similarity than the researchers discovered in this study. Nonetheless, this research provides some evidence that when it comes to personality, we do have a "type."