Excerpt from Us and Them by David Berreby, plus links to reviews, author biography & more

In 1969 Honduras and El Salvador went to war over a soccer match. Today gangs of "soccer hooligans" shadow games in Europe, where they maim and occasionally kill each other in the name of their teams. A study of such violence in Holland found that these soccer tribes were racially mixed and drew poor, working class, and higher-income men. In other words, members' devotion to their teams wasn't a stand-in for some supposedly more serious loyalty to class or race. The human kind for which they risked their lives was the soccer gang.

As sports wars go, these recent instances are unremarkable compared to combat between "fans of the green team in the chariot race" versus "fans of the blue." The fighting over those two kinds of person spanned centuries in the Byzantine Empire, as the opposed groupings grew into political, cultural, and organized-crime institutions. One of these outbreaks of mass violence, at Constantinople in 532 C.E., killed thirty thousand people.

A human kind need not acquire tribal myths, as "Aryan" did, nor gather people under team colors, as sports fans do. Banal, practical human kinds have also been made fatal. One way to be targeted during the Cambodian genocide of 1975-79, for example, was to be the kind of person who wears eyeglasses.

This was not because the country's traditional human kinds were forgotten. The Yale historian Ben Kiernan has documented how the Khmer Rouge's genocidal policies hit - and were intended to hit - Vietnamese, Chinese, and Cham people harder than Cambodian Khmers. Nonetheless, more than 1 million Khmer perished out of approximately 1.7 million people killed in this atrocity; being Khmer was not in itself enough to protect anyone. To be spared, one had to be the right sort of Khmer. To wear glasses was to show the sign of being the wrong sort - a person who had received an education under the old regime. A happenstance human kind became a means to sort the living from the doomed.

Many don't want to believe people kill, or die, for a mere mental pigeonhole. So they turn to the other levels of explanation: wars over soccer games and chariots must "really" have been about other, respectably economic and political matters.

Certainly soccer wars and chariot races did not blot out Salvadoran thoughts or Byzantine schemes. But people belong to many human kinds at once; he who is proudly Dutch in many circumstances may nonetheless die fighting other Dutchmen, in the name of Rotterdam's team. In that moment, in that place, it is not nation or race that determines who is murdered, but soccer fandom. In that moment, it's the warrior's belief that counts. An economist may find causes for mob violence that the mob never heard of; the fact remains that the people killing and dying in ancient Antioch were talking chariots, not economics.

So kind-mindedness is not "really" something else in disguise. It is itself - the mind's guide for understanding anyone we do not know personally, for seeing our place in the human world, and for judging our actions. This human-kind psychology is a source, not just a consequence, of institutions: national governments, religious authorities, promoters of ethnic, racial, class, or gender pride. We care about today's political tribes only because these entities have learned how to speak to the human-kind faculty in its language.

Speaking the right human-kind language, you can make any happenstance collection of people feel tribal, even one like "women on the 8:15 ferry." In fact, a documentary filmmaker made a movie about just that group - women who spent their morning commute together chatting, putting on makeup, and relaxing in the ladies' room of the 8.15 Staten Island Ferry. When the film came out, the women told reporters their membership in that particular human kind meant a lot to them. And their earliest response to the filmmaker had been to wonder who this outsider was and why she was hanging out in their territory.

Copyright © 2005 by David Berreby.  No part of this book maybe reproduced without written permission from the publisher.