Contrary to the popular adage that in love “opposites attract”, a new study of over 80,000 heterosexual British couples has found that individuals tend to partner with those exhibiting similar qualities.
“Our findings demonstrate that birds of a feather are indeed more likely to flock together,” study first author Tanya Horwitz said.
The study, published in the journal Nature Human Behaviour, found that for between 82 per cent and 89 per cent of traits analyzed – ranging from political leanings to age of first intercourse to substance use habits – partners were more likely than not to be similar.
In only one part of their analysis, and for only 3 per cent of the traits, individuals were found to partner those who were different from them.
The new findings, according to scientists, have important implications for the field of genetic research.
“A lot of models in genetics assume that human mating is random. This study shows this assumption is probably wrong,” study senior author Matt Keller said.
In the study, researchers conducted both a review of previous research as well as analysis of their own original data.
In the research review, they looked at 22 traits across 199 studies including millions of male-female co-parents, engaged pairs, married pairs or cohabitating pairs with the oldest study conducted in 1903.
Scientists also used the UK Biobank data set to study 133 traits across almost 80,000 opposite-sex pairs in the UK.
Researchers say they are currently exploring data on same-sex couples separately.
Their research in heterosexual couples found that traits such as political and religious attitudes as well as level of education showed particularly high correlations.
Traits related to substance use also showed high correlations, scientists said, adding that heavy smokers, heavy drinkers and teetotalers strongly tending to partner up with those with similar habits.
Height, weight, medical conditions, and personality traits showed far lower but still positive correlations, they said.
“People have all these theories that extroverts like introverts or extroverts like other extroverts, but the fact of the matter is that it’s about like flipping a coin: Extroverts are similarly likely to end up with extroverts as with introverts,” Dr Horwitz said.
The review, however, did not find any “compelling evidence” on any trait that opposites attract.
“These findings suggest that even in situations where we feel like we have a choice about our relationships, there may be mechanisms happening behind the scenes of which we aren’t fully aware,” Dr Horwitz said.
However, researchers caution that the correlations in the study were “fairly modest” and should not be overstated or misused to promote an agenda.