There are some bona fide cultural attributes that can be found in a given culture. For example, in business Americans are generally taught that it’s important make strong eye contact, especially for things like being interviewed for a job. My understanding is that in Japan, this is considered rude or aggressive (I have not been to Japan). These seem to be real cultural behaviors. Americans as a culture tend to be more conservative about public display of naked bodies–advertising is constantly sexy but never nude–whereas some other Western cultures don’t find nudity shocking.
But there are plenty of stereotypes that probably stem from a very small but conspicuous segment of people, or maybe they stem from someone’s imagination as though cut from whole cloth. I don’t know where they come from.
But where do you draw the line between a genuine cultural trait vs. a stereotype? The loud American raising his voice to a French waiter because he thinks if he speaks louder, the waiter will understand English better–is that a reflection of American culture, or is it a baseless stereotype?
I think it’s not a question of what the trait is, or even whether the generalization is accurate. I think that stereotyping is an attitude. Let us stipulate for the sake of argument that (relatively speaking) many Americans, as a national trait, tend to speak loudly and assertively. It becomes stereotyping when it is treated as an assumption that any American that we encounter will be like that; or when American character and culture is oversimplified as defined solely by brash assertiveness.
There might be some bias for a given group to act in a certain way but that it a loooong way from being able to predict what any given individual might do. As such you should not pigeon-hole someone merely because they are part of “X” group.
There are over six billion individuals in the world. Stereotypes are far too blunt to be able to discern how any given person will act.