In many TV dramas, two very different people fall in love. But is this true in real life? In 2023, researchers studied data from about 80,000 couples.

In most things, partners were similar. They often had similar political ideas, similar education and similar drinking habits. Opposite pairs were rare. One small example was morning people and night people. So "opposites attract" is mostly a myth.

Many stories say that opposites attract, but large studies suggest otherwise. In 2023, researchers combined 199 earlier studies and also analyzed up to about 80,000 couples in a British database. For most traits, partners were similar. They were especially alike in political and religious views, education, smoking and drinking habits, and birth year.

Personality traits such as extraversion were only slightly similar. Only a few traits showed an opposite pattern, such as being a morning person or a night person, and even this effect was weak. However, these results do not prove that people choose similar partners. Couples may meet at the same schools or workplaces, and their habits may become similar after living together.

In 2023, a team from the University of Colorado put the romantic notion that opposites attract to a large-scale test. They first ran meta-analyses of 199 studies covering 22 traits.

Then they examined 133 traits in up to roughly 80,000 male-female couples from the UK Biobank. For the vast majority of traits, partners were positively correlated. The strongest similarities showed up in political and religious attitudes, educational attainment, smoking and drinking habits, and birth year. Personality traits such as extraversion showed only weak similarity.

Negative correlations were rare and small; one example was chronotype, with morning types slightly more likely to pair with evening types. These correlations say nothing about why partners resemble each other. Couples often meet through shared schools, neighborhoods or social classes, and they may grow alike after years together.

The UK Biobank also tends to attract healthier volunteers. Earlier work had come at the question from other angles. Experiments by Donn Byrne suggested that people like strangers whose attitudes resemble their own, though they relied on artificial questionnaires. And a 2008 meta-analysis found that in existing relationships, perceived similarity predicted attraction more strongly than actual similarity.