Any theory of racism has to explain a big puzzle in America. On the one hand, the overwhelming majority of black Americans think they suffer from prejudice – and they have ample evidence of discrimination in police stops, job interviews, and jury decisions. On the other hand, very few white Americans will admit to being racist. The dominant explanation among political scientists recently has been that this is due, in large part, to widespread implicit prejudice. White Americans may mean well, this theory goes, but they have a subconscious bias, which influences their treatment of black Americans.