Buss (1961) differentiated between angry aggression and instrumental aggression. The former is based on emotion (anger) where the latter does not have a strong emotional basis and yet can be extremely violent. Buss purposely excluded verbal aggression because he believed that ‘it renders the term fuzzy and imprecise… [and] it is preferable to avoid the notion of a bruised or wounded ego’ ( Buss 1961 p. 6). Buss proposed that all aggression subsumes a large number of responses that share two characteristics: (1) the delivery of noxious stimuli; and (2) an interpersonal context.
Buss (1961) excluded the concept of intent from his definition because he believed that the crucial issue is not the premeditation but the reinforced consequences of the outcome. He proposed that angry aggression is motivated by the desire to inflict pain or discomfort, where instrumental aggression is motivated by acquisition of some external reinforcement or the cessation of the noxious stimuli. Instrumental aggression, he argued, is a means to some desired end that is not motivated by intent to do harm.