THE FUNCTION OF AGGRESSION AND THE REGULATION OF AGGRESSIVE DRIVE.

Preliminary to the development of a stimulus-mediating response model of aggressive drive, formal definitions are given of instrumental aggressive acts and aggressive drive-mediated behavior. In defining aggressive drive, a distinction is made between expressive aggression and hostile aggression which is illustrated in the difference between the desire to "hit" and the desire to "hurt." Hostile aggression is assumed to be a learned drive whose primary antecedents are past exposure to punishment and present threats to self-esteem. Several procedures for reducing aggression other than performance of an aggressive response are described and the function of diverse measures responsive to changes in expressive aggression, aggressive drive, and aggressive response strength, particularly when evaluating the consequences of an aggressive act, are analyzed. The general problems to which this paper is addressed are the functional properties of an aggressive act and the mechanisms by which aggression is reduced. We will be particularly concerned with the following hypothesis which is central to the theoretical analysis presented by Dollard, Doob, Miller, Mowrer, Sears, Ford, Hovland, and Sollenberger (1939) in the frustration-aggression monograph: "The expression of an act of aggression is a catharsis that reduces the instigation to all other acts of aggression [p. 53]." There are three terms or phrases in this hypothesis which require further explication in order to ascertain its theoretical implications and the empirical operations which would be appropriate to a test of this hypothesis. We must establish what constitutes an "act