Kelly reviews the literature for concepts relating to regression and the superego. In Freud's original concepts the superego was characterized by its resistance to change. Subsequently, Freud recognized that the superego reacts to regressive changes in the id and ego. More recently, various authors have conceptualized the superego itself as the site for regressive change and have asserted that the superego, being a later structure, was 'more fluid and less stable than the ego'. Kelly points out the contradiction between this later concept and Freud's earlier thoughts about the durable quality of the superego. The problem remains: is the superego subject to regressive change? If so, how are we to understand its resistance to change?