“Stereotypes” have a bad name, and everybody hates stereotypes. But what exactly is a stereotype?

What people call “stereotypes” are what scientists call “empirical generalizations,” and they are the foundation of scientific theory. That’s what scientists do; they make generalizations. Many stereotypes are empirical generalizations with a statistical basis and thus on average tend to be true. If they are not true, they wouldn’t be stereotypes. The only problem with stereotypes and empirical generalizations is that they are not always true for all individual cases. They are generalizations, not invariant laws. There are always individual exceptions to stereotypes and empirical generalizations. The danger lies in applying the empirical generalizations to individual cases, which may or may not be exceptions. But these individual exceptions do not invalidate the generalizations.

An observation, if true, becomes an empirical generalization until someone objects to it, and then it becomes a stereotype. For example, the statement “Men are taller than women” is an empirical generalization. It is in general true, but there are individual exceptions. There are many men who are shorter than the average woman, and there are many women who are taller than the average man, but these exceptions do not make the generalization untrue. Men on average are taller than women in every human society (and, by the way, there are evolutionary psychological explanations for this phenomenon, known as the sexual dimorphism in size, but that’s perhaps for a future post). Everybody knows this, but nobody calls it a stereotype because it is not unkind to anybody. Men in general like being taller than women, and women in general like being shorter than men.

However, as soon as one turns this around and makes a slightly different, yet equally true, observation that “Women are fatter than men,” it becomes a stereotype because nobody, least of all women, wants to be considered fat. But it is true nonetheless; women have a higher percentage of body fat than men throughout the life course (and there are evolutionary reasons for this as well). Once again, there are numerous individual exceptions, but the generalization still holds true at the population level.

Stereotypes and empirical generalizations are neither good nor bad, desirable nor undesirable, moral nor immoral. They just are. Stereotypes do not tell us how to behave or treat other people (or groups of people). Stereotypes are observations about the empirical world, not behavioral prescriptions. One may not infer how to treat people from empirical observations about them. Stereotypes tell us what groups of people tend to be or do in general; they do not tell us how we ought to treat them. Once again, there is no place for “ought” in science.

As empirical generalizations borne of the observations and experiences of millions of individuals, most stereotypes are on the whole true. If they are not true, they cannot survive long as stereotypes. Nonetheless, theory and research in have overturned a few stereotypes and shown them to be false. For some reason that I cannot quite fathom, all the stereotypes that have been shown to be false so far have to do with people’s physical appearances. In the next few posts, I will discuss each of these stereotypes which evolutionary psychological theory and research have shown to be false.