Some students begin by forming an opinion ... and it is not till afterwards that they begin to read the texts. They run a great risk of not understanding them at all, or of understanding them wrongly. What happens is that a kind of tacit contest goes on between the text and the preconceived opinions of the reader; the mind refuses to grasp what is contrary to its idea, and the issue of the evidence of the text but that the text yields, bends, and accommodates itself to the preconceived opinion.

If we take people as they are, we make them worse. If we treat them as if they were what they ought to be, we help them to become what they are capable of becoming.

But once a negative bias begins, out lenses become clouded. We tend to seize on whatever seems to confirm the bias and ignore what does not. Prejudice, in this sense, is a hypothesis desperately trying to prove itself to us. And so when we encounter someone to whom the prejudice might apply, the bias skews our perception, making it impossible to test whether the stereotype actually fits. Openly hostile stereotypes about a group - to the extent they rest on untested assumptions - are mental categories gone awry.