BIGOTRY IS CAUSED by being human. That may seem like an awfully simplistic explanation for a multifaceted issue, but it sums up the problem in a nutshell: Prejudice, according to many social scientists, is an innate human trait.

Recently, a group of scientists conducted an experiment. In the experiment, white people were shown pictures of other people, both white and black. Then they were shown another set of pictures of only black people (including some whose pictures they had just been shown) and asked to identify individuals whose pictures they had seen. They also were asked to identify individual white people whose pictures they had seen.

What the scientists found was that the whites were much worse at recognizing black faces than at recognizing white faces. The reason for these results, according to Daniel Levin of Kent State University, is...