From the 1980s, however, the Bielefeld school was increasingly challenged by proponents of the "cultural turn" for not incorporating culture in the history of society, for reducing politics to society, and for reducing individuals to structures. Historians of society inverted the traditional positions they criticized (on the model of Marx's inversion of Hegel). As a result, the problems pertaining to the positions criticized were not resolved but only turned on their heads. The traditional focus on individuals was inverted into a modern focus on structures, and traditional emphatic understanding was inverted into modern causal explanation.