The hope that functionally unitary brain circuits will be discovered for global concepts such as altruism and aggression remains unrealistic. Those labels are only class identifiers for diverse behavior patterns that may share outward similarities but that arise from several distinguishable neural systems.

Only preliminary biological understanding of altruism and aggression can be distilled from existing knowledge concerning emotive systems of the brain. We know approximately which brain circuits are essential for elaborating several forms of aggression (i.e., predatory, rage, and competitive). All run through the hypothalamus, interconnecting higher and lower areas of the visceral brain. As the available information has been reviewed extensively (e.g., see Adams, 1979; Moyer, 1976; Valzelli, 1981), those systems receive little further attention here.

No comparable circuits for altruistic behaviors have yet emerged from brain research. Indeed, the concept of altruism remains troublesomely vague in the study of animal behavior, and the diverse helping behaviors that could be subsumed under this concept (depending on one's definition) may be less directly coupled to activities of hard-wired emotional circuits than the above-mentioned aggressive tendencies. Whereas circuits for several distinct emotions, including anger–rage, anxiety–fear, separation–panic, and curiosity–expectancy appear to be wired into the visceral brain by the genetic heritage of mammals (albeit the behavioral competence of this heritage is refined by experience) (for review, see Panksepp, 1981a, 1982), altruistic tendencies may be linked more integrally to learning processes coupled to changing levels of activity in such emotive systems.