From romance novels to romance novels, there’s a common trope when it comes to love: opposites attract.
But is it really true? In fact, it’s the opposite in real life: A wealth of research over the past few decades has shown that people tend to date people who are more like themselves. People with shared traits are also more likely to have the long-term attraction needed for lasting relationships.
“When people talk about opposites attracting, it’s like, ‘Oh, I know this couple; they got together and don’t have much in common”. But it tends to be the exception to the rule.” Erica Slottera psychologist at Villanova University in Pennsylvania, told Live Science. “Similarity is still a powerful predictor of attraction.”
In fact, similarity plays a key role in all stages of relationship formation. Researchers examine a person’s stated preferences, or the attributes people say they look for in another person.
“Most of the time, people say they want people who are like them,” Slotter said. This applies to all kinds of attributes, such as socio-economic status, religion, political orientation and hobbies.
When we look at the data on people in long-term relationships, similarity also seems to reign supreme. Tanya Horwitza researcher at the University of Colorado Boulder, led a study on these trends by analyzing past literature and large-scale demographic data sets. The results, published in the journal Nature Human behavior in 2023, concluded that up to 89% of traits between partners were positively correlated, meaning that if, say, one person exercises a lot, their partner likely does too. This applies to politics, health habits, substance use and more. “We analyzed the raw data with 133 features,” Horwitz said. “It was surprising how unusual it is to see a trend where people are less alike.”
So does this mean you are destined for someone who is your carbon copy? Not exactly.
One trait that tends to differ between partners is how they take charge in social interactions, also known as social dominance. If both individuals in a pair are dominant, “they tend to stick their heads out,” Slotter said. In contrast, two submissive and neutral people may never deal with problems in a relationship. People with opposite social dominance tend to be happier than those with similar outcomes, Slotter added.
Two people who are different on paper may be attracted to each other for another reason as well: chemistry. For example, studies on speed dating have found that what we say we want in a partner doesn’t always match what we’re physically or emotionally attracted to. How this works is still a bit of a mystery. Slotter said that’s partly because when we talk to someone face-to-face, we’re still looking for similarities, but in a more holistic way. She added that increased holistic similarity has been found to be associated with better romantic chemistry.
Even if they start out very different, partners can become more similar over time — a phenomenon called convergence, Horwitz said. Spending time together can change things like habits and lifestyle. This can also increase attraction as a relationship grows, Horwitz added.
Finally, who we think we are and our impressions of our partner can also affect lasting attraction. For example, a 2000 study in Journal of Experimental Social Psychology found that it did not matter whether strangers or friends thought the individuals in a pair were similar. Instead, love, as well as relationship satisfaction, depended on whether people in relationships thought their partner was similar to them.
“It’s really about that … subjective judgment you do,” Slotter said. “If you feel like this person is similar to you, go for it. Because… that seems to matter more.”