Ethnology (the discipline, not the magazine of that name) is "the science which treats of races and people, and of their relations to one another, their distinctive physical and other characteristics." It is practiced by sociologists and anthropologists and you've probably been exposed to at least some of it through the works of people such as Margaret Mead. Ethnology tends to examine the relationships among individuals and their culture, with some emphasis on how people fit into that culture. One of the tenets of ethnology is that cultures tend to develop models of appropriate roles for its members, with some classic examples being the shaman, the warrior, the clan mother, etc.