Do Our Genes Decide Whether To Make Us Popular Or Shy?

By Margarita Nahapetyan

A new study has found that it is genes that might be responsible to determine whether a person is sociable or shy.

The researchers Nicholas Christakis from Harvard University and Christopher Dawes and James Fowler from University of California in San Diego, compared the social behavior of two types of twins, identical and fraternal. 1,110 twins were studied in a population of more than 90,000 people. What researchers discovered was a greater similarity in social behavior of identical twins, who come from the same egg and have the exact same genes, than those of fraternal twins, whose genes slightly vary, as they are separately fertilized. Identical twins often found themselves in the same position within a group - whether as social outcasts or the center of attention.

Indications of popularity, such as the way people make friends and interact with them, as well as indicators like if an individual likes to be at the center of attention, or at the edge of a social group, were measured by scientists. Some people are the life of any company, butterflies, naturally drawing attention to them. Others tend to be in a shadow - social wallflowers, like some will call them. According to the study, genetics put all of them in their places to a significant, measurable extent.

James Fowler called the finding revolutionary and added, "There has been a simple model for the metabolic, neural and Internet networks, and the same model is applied to human beings -- that all parts of the network are identical and interchangeable." This he said no longer could be said about people's social network interactions. "There are inherent characteristics that govern where we [as individuals] gravitate to in the social network."

There may be an evolutionary explanation for this genetic influence and the tendency for some people to be in the center of attention while others are at the edges of the group, the researchers said. If a deadly germ is spreading through a community, individuals at the edges are least likely to be exposed. At the same time, to gain access to important information about a food source, being in the center of the group is hardly considered as a benefit.

The findings also put light on a previously unknown limitation of existing social network models, which speculated that all members behave as interchangeable cogs. To address these essential differences in people that lead to the formation of social networks, the researchers have created a new mathematical model, called the "attract and introduce" model, which closely simulates actual human social networks. "We find that how interconnected your friends are depends on your genes. Some people have four friends who know each other and some people have four friends who don't know each other. Whether Dick and Harry know each other depends on Tom's genes," Nicholas Christakis said in a telephone interview.

The role of genes in forming and configuring social networks is the latest surprising discovery by Fowler and Christakis. Last year, the experts published a paper reporting that joy is infectious, spreading like a virus from one happy person to another. In another study, they found obesity to be similarly contagious. If your friend, or someone close to your friend has gained weight, don't be surprised, but you would, too. The same way it is easier to quit smoking if people around you, known or unknown, are doing the same thing. Fowler said it is already a known fact that certain genes are associated with certain behaviors or health outcomes, such as smoking and obesity. "Social networks might be the conduit between genes and these health outcomes."

"What will be interesting to see is how social networks act as a conduit to explain why genes are associated with these health outcomes." A better understanding, the researchers said, could help health authorities create more effective anti-obesity or anti-smoking programs. An international team of physicists even suggested that the knowledge of networks intersections might lead to more efficient vaccination programs. "Instead of inoculating everyone during an epidemic, they said, "health officials could concentrate on vaccinating the most highly connected people to prevent them from infecting their friends, colleagues and neighbors."

Of course, the new insights will not help wallflower to turn into to a social butterfly, and vise versa. The scientists said that this is not likely to happen, in part, because "genetic engineering is very difficult," but mostly because social behavior stems from the interplay of genetics and upbringing.

The report was published in the latest edition of the Proceedings of the National Academy of Sciences.