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.