High Quality Content by WIKIPEDIA articles! Social Dominance Theory (SDT) is a multilevel theory of group conflict which attempts to explain the stability of group-based social hierarchies and group-based inequalities in the world. According to the theory, individual people differ on the extent to which they desire group-based inequality, which is an individual difference variable called "Social Dominance Orientation" (SDO). The theory was developed in the 1990s, but the related concepts are much older.