Quoting Blanck and Blanck "As thought processes develop, involving delay of drive discharge, intelligence serves the ego by aiding the organization of percepts and memory traces, making meaningful action possible. This organization of the inner world -- the world of internalizations -- is the very process of structuralization. As this proceeds, certain forms of behavior change in function. A process, which had originated as a defense -- for example, the essential mechanism of reaction formation in toilet training -- acquires adaptive autonomy when the purpose changes to maintenance of hygienic habits and orderliness. With change in function, the activity becomes pleasurable in its own right; whereas when it is still in its archaic defensive form it counteracts pleasure. The end result of change in function is attainment of secondary autonomy."