We sit near people who look like us

The next time you're in an audience, turn to the person sat next to you and take a good look. That's what you look like, that is. Scary eh? Sean Mackinnon and his research team have shown that people sit next to people who resemble themselves. The effect is more than just people of the same sex or ethnicity tending to aggregate - a phenomenon well documented by earlier research. The new finding could help explain why it is that people so often resemble physically their friends and romantic partners (known as "homophily") - if physically similar people choose to sit near each other, they will have more opportunities to forge friendships and romances.

Mackinnon's team first noted the seating positions of hundreds of different students in a 31-seat computer lab 21 times over 3 months, and whether or not they were wearing glasses - a simple proxy for physical similarity. The students, it was found, sat next to someone who matched them on glass-wearing status far more often than would be expected if they were randomly distributed (the effect size was .63).

A second study of 18 university classes involving over two thousand students expanded this finding to show people were more likely to sit next to someone who matched them on glass-wearing, hair colour and hair length, than would be expected by chance. This held true even focusing just on females or just on Caucasians, thus showing the physical similarity effect is more than mere aggregation by sex or race.

But what if people sit next to physically similar others simply as a side-effect of tending to sit near to friends or partners who, as prior research has shown, tend to be physically similar? A third study addressed this concern by seeing how close participants sat to a stranger. Seventy-two participants took part in what they thought was a study into non-verbal behaviours, part of which involved pulling a chair up to an unfamiliar co-participant (a role played by an actor) so as to interview each other. As expected, participants who more closely resembled the young lady (a 20-year-old brown-haired Caucasian) tended to choose to sit closer to her.

Why do we choose to sit near people who look like ourselves? Clues come from Mackinnon's final study. One hundred and seventy-four participants looked at photos of eight individuals and rated how much they liked them, how much they perceived them to have similar attitudes, and thought they would be accepted by them. They also said how close they would choose to sit near each person. Consistent with the earlier studies, participants said they'd sit nearer those individuals who resembled them (based on similarity ratings provided by independent judges). They also thought these physically similar individuals would share their attitudes, they liked them more, and they expected to be accepted by them, as compared with their judgments about physically dissimilar others. The shared attitudes factor was the strongest. A further possibility is that seeking proximity to physically similar others is an evolutionary hang-over - an instinct for staying close to genetically similar kin.

"Though perhaps appearing innocuous on the surface, the simple process of choosing to sit beside people who are similar to us can have broad implications at the macro level," the researchers said. " ... [S]egregation may occur, which can result in myriad prejudices and misunderstandings. Of course, this tendency is merely one portion of the overall processes that contribute to segregation and homophily more generally, but given the implications for racial and ethnic segregation, it is certainly a phenomenon with profound implications worthy of further pursuit."
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Mackinnon, S., Jordan, C., and Wilson, A. (2011). Birds of a Feather Sit Together: Physical Similarity Predicts Seating Choice. Personality and Social Psychology Bulletin, 37 (7), 879-892 DOI: 10.1177/0146167211402094

This post was written by Christian Jarrett for the BPS Research Digest.