School Size and Self Segregation

Here's a good example of research that puts some numbers behind what everybody already believes:

Being able to choose friends from larger populations discourages friendships with people from other races, finds a study examining the mathematical underpinnings of self-seeking behavior and group size.

If you only see ten people every day, you can't be really picky about which ones you hang out with. But if you are regularly around thousands of people -- say, in a suburban high school with 3,000 students -- then you can choose to hang out only with people who look and act exactly like you. And this is what American high school students do: sort themselves into small groups of people who listen to the same music, wear the same clothes, take the same classes, and are the same race. Sure, there are exceptions, but by and large, the bigger the school, the less likely you are to see students hanging out in mixed race (or mixed any other way) groups. And this is why segregation is not disappearing from America: in a mass society, people sort themselves according to every available metric, and race is one available way to distinguish who is who.