But what exactly is this seemingly natural tendency to sort others into "kinds"? This question forms the core of Us and Them, which explores the conscious and unconscious ways in which people classify one another--and more important--why. How humans can use this propensity constructively, rather than destructively, remains a central issue of our time, argues David Berreby, a veteran science journalist. Although this penchant may be hardwired into our brains, ultimately we choose how to live. Religious strife, political conflict and clan rivalries boil down to individual behavior.
Berreby says the sciences of brain and mind offer "a new way to look at love of country, at culture, at religion (and at hatred too)." Researchers are starting to understand "how and why people think and feel in tribes, and why all of us are capable of both tribal good and tribal evil." Advances are allowing scientists to grapple with such questions as "Why can't we all get along?" Berreby investigates the social, psychological and neurological mechanisms that move humans to categorize. For example, he considers how codes in the nervous system predispose us to organize perceptions, including ones that help us feel how other people feel. Science's assault on our beliefs about race, religion and nationalism has shown that even much of "common sense" is both blind and cruel. Berreby reminds us that not long ago North Americans held by common sense that slavery was natural, women should not vote and only heterosexuals deserved respect. "Good riddance to all that," he says. Still, attitudes die hard. "A white person and a black person in today's New York City can agree over coffee that race is `all in your mind,'" Berreby contends. "But when they leave Starbucks and raise their hands to hail a taxi, the white person is more likely to get a cab. In that moment, race is as real as gravity."
Given our drive to categorize, Berreby reflects thoughtfully on how to do so responsibly. "The Us-Them code does not own you," he concludes. "You own it."