How Alike Do You and Your Partner Need to Be?

For most of us, an important life task is finding a partner. Whom we end up with may depend on who is available and willing, whom we want, or any number of other things.

But whatever the reason, are we likely to settle with a partner who is similar to us? And if yes, which traits are most often shared by partners?

For example, we may find a similar partner because we tend to hang around with similar people. Many find their partner at the university or by engaging in the same leisure activities.

Or we may actively seek others like us. Perhaps being with a like-minded person is easier than working around differences.

The Similarity of Partners’ Personality Traits

Personality traits such as the Big Five summarize many psychological characteristics. This makes them useful to learn about partners’ psychological similarities.

Pulling together data from many thousands of couples, Tanya Horwitz and Matthew Keller found a small statistical trend. On average, partners’ Big Five personality traits are slightly more similar than strangers'. The most typical correlation among partners’ trait scores is 0.13.

But this small trend says almost nothing about any given couple. This graph shows why.

Correlation 0.13 between partners' personality trait scores.

Source: René Mõttus

Suppose both partners complete a Big Five personality test and get feedback about their traits: low, medium, or high. This correlation means that partners get similar feedback in only 37 percent of couples (the green hearts), while 63 percent of couples don’t have matching trait levels (red hearts).

Because even strangers’ feedback would be similar in 33 percent of cases, being someone’s partner raises the likelihood of personality trait similarity by 4 percentage points. This is not a lot.

So, one partner’s personality traits tell us very little about the traits of the other partner. For example, being a highly extraverted, agreeable, or conscientious person, we are almost equally likely to partner with someone low, medium, or high in those traits.

Politics and Religiosity Are Better Match-Makers

Partners are more often similar in their political views and religiousness, with correlations just below 0.60 between partners’ values in these traits.

For example, if we split people equally into left, moderate, and right in their political orientation, both partners would hold similar views in about 53 percent of couples. About the same would be true for religiousness.

Because 33 percent of strangers would be similar by chance, being someone’s partner raises the similarity in religiosity and political orientations by 20 percentage points. This is not a huge increase, but five times more than for personality traits.

Compared to personality traits, the somewhat stronger partner similarity for political and religious views is not surprising. Being non-religious, it may often be challenging to live life with a highly religious person, and ideological arguments can often be too bruising to continually put up with. It may be easier for an extravert to be with an introvert—someone’s got to do the listening, after all.

And yet, many couples are different, even in religiosity and politics.

Other Traits Are Somewhere In Between

Horwitz and Keller also calculated typical partner similarity for a range of other traits, such as how much people drink, whether they smoke or how they score on intelligence tests.

In these traits, typical partner similarity was somewhere in between personality trait similarity on the one hand and religiosity/politics on the other. That is, partners are somewhat more likely to be similar than strangers, but being different is also very common.

The same goes for education. Sharing a higher or lower educational level makes it somewhat more likely for people to become partners, but it is far from uncommon for partners to have stopped their education at different stages.

Typical partner similarity was quite low in physical traits, such as height and body weight. For example, someone with an average height is almost equally likely to have a tall, short, or medium-height partner.

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One Less Thing to Worry About

People with certain personality trait levels like high Agreeableness may be particularly attractive for long-term relationships, but there simply aren’t enough of them for everyone to partner with. And, as it now appears, settling with someone who has similar personality traits isn’t that common either.

Is this bad? Is this perhaps one reason that breaking up is so common? Indeed, many studies have asked whether partners’ dissimilarity contributes to how unsatisfied they are with their relationships.

But there is little evidence yet for a clear link between partners’ personality trait similarity and relationship satisfaction. Although some studies have found a link, others haven’t. So, even if a statistical trend exists, it is probably not strong enough to matter for individual couples.

This means one less thing to worry about. For most of us, a relationship can be satisfying regardless of how similar our partner’s personality traits happen to be to ours.

Facebook image: Sv Svetlana/Shutterstock