Us and Them: Understanding Your Tribal Mind

Natural History, Feb, 2006 by Laurence A. Marschall

Us and Them: Understanding Your Tribal Mind by David Berreby Little, Brown and Company, 2005; $26. 95

The stereotype," as the journalist and political commentator Walter Lippmann wrote in his 1922 book, Public Opinion, "saves time in a busy life," enabling all of us to quickly establish how we should relate to others. Does the woman in the maroon coat mean well or ill? Is she an employee or a customer, a student or a teacher, a police officer or a shoplifter? A second's glance often suffices to tell. The downside, of course, is that people are not always what they seem at a glance: the tattooed man in the motorcycle jacket may well be chairman of the board; that earnest, clean-cut chap may be a serial killer. In its worst form, stereotypical thinking leads to hate crimes and acts of terrorism. At its very least, writes Lippmann, the stereotype "tends to preserve us from all the bewildering effects of trying to see the world steadily and see it whole"

David Berreby's book is an eloquent effort to view the world steadily and whole. Human "kind-mindedness" as Berreby sees it, however strongly it may seem linked to social and political experience, is ultimately rooted in behavioral genetics. No animal can survive for long without being able to distinguish members of its own species from predators, and nature rewards individuals that can effortlessly tell the nutritious bugs from the poisonous ones. Socially speaking, natural selection favors the ability to distinguish kin ("our family") from strangers, because our genes profit from helping our blood relatives survive.

That tendency is particularly apparent in primates, whose social world is notably convoluted and complex. The seminal work of Frans B.M. de Waal, a primatologist at Emory University in Atlanta, for instance, has demonstrated that chimpanzees have elaborate protocols for dealing with unfamiliar individuals. Not only do the chimpanzees react to apes outside their social group, but when they interact with people, they also view with suspicion any person they don't recognize as part of the group they see every day. When we humans divide the world into "us" and "them;' we're just doing what comes naturally.

Berreby suggests that a little science might help people overcome such primate tendencies toward Manichean thinking. By its strict rules of evidence and its insistence on expressing differences not as yes-or-no statements but as degrees of confidence and uncertainty, science provides an effective antidote to false perceptions of "us" versus "them." For example, according to Berreby, DNA analysis gives the lie to commonsense ideas about race:

Genetically, almost all variations in human DNA are found in all races. As the chemistry of ink on your money gives no clue to its economic value, so human genetics doesn't support today's notion of race.

Nor does science recognize any genetic or physiological basis for divisions of people by nation, class, ideology, or religion--a fact that perceptive individuals have known for centuries.

Berreby argues for diversity and tolerance, hardly a novel position, but one resonant with the insights and sentiments of wise men since the dawn of civilization. What makes his argument powerful is the wealth of information he has marshaled, from disciplines as diverse as molecular genetics, neurobiology, quantitative history, and social psychology. But what makes his book so poignant is that despite the wealth of data pointing in his direction, so much political capital is being spent these days in accentuating and perpetuating our differences, instead of in trying to understand, accommodate, and eventually overcome them.