I assume that the proper study of interaction is not the individual and his psychology, but rather the syntactical relations among the acts of different persons mutually present to another.
By definition, of course, we believe the person with a stigma is not quite human. On this assumption we exercise varieties of discrimination, through which we effectively, if often unthinkingly, reduce his life chances.
There is a close meshing with the ritual properties of persons and with the egocentric forms of territoriality.