Erving Goffman's Asylums , in its four essays, identifies the creation of social roles and related rituals as the raw material of the social institution. In this case the institution was a real mental hospital.
My take on the kind of psychological experiment under discussion is that by studying an artificial social situation they have already failed. The petri dish of a very small mock prison on a campus just doesn't tell us anything very useful. Yet we can see eye catching results being amplified and then becoming part myth and part morality tale. However, the belief that human agency is contingent and flawed, that we often don't know how we know the things we know, or whey we do the things we do remains.