I’m married to someone who’s an identical twin, and that’s given me some personal insight into the nature-nurture discussion. My wife and her sister are genetic clones. But they don’t look exactly alike, their tastes and hobbies are different and their moods traverse on very different time tables. James Fowler would expect that’s partly because they grew up in different places with different circles of friends.
Fowler is a rare specimen among academics since he’s a professor of political science and medical genomics at UC San Diego. He studies social networks and the how genes influence behavior.
Fowler and his research partner, Nicholas Christakis of Harvard Medical School, have published research telling us the influence of social networks can make us obese and cause us to sleep badly. They’ve concluded that genes can make us liberal or conservative. Now, they published an article that says we choose our friends based on genetics.
Fowler examined data from two medical surveys that included thousands of people. He studied six gene types in those populations and found that two of them were very commonly shared among groups of friends.
“I always heard people say, 'Birds of a feather flock together,'" said Fowler. “So this is one of the first scientific questions I was really interested in when I was a child.”
Another bit of folk wisdom he heard growing up was that “opposites attract.” Though it would seem to contradict the "birds of a feather" theory, Fowler claims his latest paper proves this as well. He found people with a gene type linked to "open personality" typically befriended people who lacked that gene.
So why is this important? Fowler responds by saying our genes are greatly affected by the environments we live in - as proven by the differing natures of identical twins - and a big part of that environment is the people who surround us.
“We live in a sea of the genes of others,” said Fowler. “We’re not just a product of our own genes, we’re a product of the people in our environment. And that’s not just true of the people we marry and have children with, it’s true of our friends.”
Fowler says that social environment may play a big role in human evolution. He’s just not yet sure exactly how. Maybe that’s the next paper he and Christakis will write.
