The old adage “opposites attract” is well-worn when it comes to relationships, but according to a new study, “birds of a feather flock together” is more appropriate.
The findings were published in the journal Nature Human Behaviour — in an article with the decidedly unromantic title, “Evidence of correlations between human partners based on systematic reviews and meta-analyses of 22 traits and UK Biobank analysis of 133 traits.”
The short story from that long title is that people in heterosexual couples tend to couple up with people like themselves, from education level, religious beliefs and political affiliations.
Even smoking and drinking habits tend to bind people together, the researchers found.
The researchers found that it’s not even close: The percentage of couples whose partners had similar traits was as high as 89% compared to the 3% who were found to be “substantially different.” Scientists have a decidedly clinical term for linking with someone like you: assortative mating.
And the data went way back: The study crunched the numbers from nearly 200 research papers on partnership dating back to 1903 and cross-referenced that with information from nearly 80,000 opposite-sex couples who took part in the U.K.’s Biobank initiative.
Same-sex couples, the researchers noted, will be part of another study.
The scientists did note, however, that psychological traits had less of an impact — so, for example, introverts can and do find themselves with extroverts and vice versa.