How should cognitive mechanisms in general go about producing sound beliefs? Part of the answer, it seems, is that they should be free of bias. Biases have a bad press, in part because a common definition is “inclination or prejudice for or against one person or group, especially in a way considered to be unfair.” However, psychologists often use the term in a different manner, to mean a systematic tendency to commit some specific kind of mistakes. These mistakes need not have any moral, social, or political overtones.