This article was originally posted by Arti Patel on globalnews.ca
No, it’s not just in your head — there could be a scientific reason why some couples look alike.
According to a recent report from the Boston University School of Public Health and the University of California, it could have something to do with genetics.
“Until recently, most people picked a spouse from within their local community, and that person often had the same ancestry. Over many generations, this affinity for similar mates has created a genetic structure in the population which has the potential to bias the results of genetic studies.” researchers said in a statement.
The report, which was published in PLOS Genetics on April 6, analyzed three generations of white people from the Framingham Heart Study (FHS). The FHS study, which started in 1948, originally followed 5,209 men and women between the ages of 30 and 62 in the town of Framingham, Mass.
Using genome-wide genotype data (or the study of genetics) to analyze 800 pairs of couples, the goal was to characterize their genetic ancestry, Yahoo reports.
“By examination of spouse-pairs, we observed that individuals of Northern/Western European, Southern European and Ashkenazi ancestry preferentially chose spouses of the same ancestry, however, the degree of endogamy decreased in each successive generation, especially between Northern/Western and Southern Europeans,” researchers wrote in the journal.
Opposites don’t always attract
One 2010 study from the University of Michigan found that overtime, more couples tended to look alike, according to Live Science, and it had nothing to do with genetics.
Psychologist Robert Zajonc analyzed photos of couples when they first got married and photos of them 25 years later.
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As years passed, spouses looked more and more like each other, and Zajonc believed this was because they mimicked each other’s facial expressions. For example, if your partner had a good sense of humour, both of you will likely develop lines around your mouth.
Sometimes it’s in the face
But looking similar could also have to do with the selection process.
According to a 2010 report from Personality and Social Psychology Bulletin, people are attracted to others who look like their parents or themselves, Psychology Today reports.
In two separate studies, participants were shown pictures of strangers: one which was preceded by a photo of their own opposite-sex parent or stranger, and another which was a morphed photo of a stranger and a participant.