There is a tendency to identify individuals or groups with general, impersonal terms that allow one to simplify the process of trying to understand each individual as a separate entity. A stereotype is a mental picture of different groups, on the basis on which individuals are evaluated. People are "rightists", "vegetarians", "liberals" and so on, according to the group into which they most conveniently fall for the labeller. The catastrophe of this device is that it completely blocks for many people the possibility of ever knowing the other individual or group for the unrepeatable specificity that they are. One actually no longer experiences the other, but experiences only what the label leaves visible. One of course also gradually ceases to experience the self as well.
A sociotype is a stereotype empirically verifiable for the bulk of a population or group.
In its worst or most inaccurate form, a stereotype takes the form of a universal syllogism that prevents undifferentiated thinking and exceptions. For example, all white American males are unethical; John is a white American male; therefore John is unethical.