Social and agonistic interactions are composed of a range of species-typical acts, postures, displays and other communicative signals that follow characteristic patterns. Descriptive and analytic methods permit an assessment of the temporal and sequential features of highly probable patterns of agonistic interactions. Analysis of the intervals that separate consecutive attacks by a resident mouse or rat toward an intruder identifies bursts or epochs of attacks. Amphetamine (1.25, 2.5 mg/kg), but not diazepam or alcohol, alters the burst pattern of attack behavior. Higher doses of alcohol, but not diazepam, in either resident male rats or in lactating rats confronting an intruder, reduce the sequences of aggressive acts and postures with high transition probabilities as identified by lag sequential analysis. These results suggest that temporal and sequential patterning mechanisms may be differentially altered by amphetamine- and alcohol-type substances. These neural for many types of behavior.