In a classic study on race, psychologists staged an experiment with two photographs that produced a surprising result.
They showed people a photograph of two white men fighting, one unarmed and another holding a knife. Then they showed another photograph, this one of a white man with a knife fighting an unarmed African-American man.
When they asked people to identify the man who was armed in the first picture, most people picked the right one. Yet when they were asked the same question about the second photo, most people -- black and white -- incorrectly said the black man had the knife.
Even before the Ferguson grand jury's decision was announced, leaders were calling once again for a "national conversation on race." But here's why such conversations rarely go anywhere: Whites and racial minorities speak a different language when they talk about racism, scholars and psychologists say.