Integrating the behavioral ecology, social psychology, and neurobiology of aggression

Pervasive aggression among animals, including humans, determines social status, reproduction, and survival. Species-typical tactics of threat, attack, defense, and quitting (i.e., submission/escape) are distally shaped over evolutionary time. However, the behavioral processes are proximally controlled by nervous systems reacting to intraspecific challenges for resources balanced against energy and injury costs. Behavioral ecology (BE) examines this balance in assessing evolutionarily stable strategies (ESS) of aggression that apply across species. Human social psychology (HSP) analyzes different aggressive motivations and also defensive emotions, while behavioral neuroscience (BN) investigates the neural structures and systems that plan, execute, or inhibit aggression. All three disciplines distinguish between offensive/proactive and defensive/reactive types of aggression and, importantly, now recognize that each is motivated by central states that persist over time, generating and scaling behavior sequences (e.g., threat-to-attack escalation). Each discipline contributes to the overall understanding of aggression, but interdisciplinary sharing of viewpoints has been limited. HSP and BN recognize that offensive/proactive aggression is sometimes positively reinforcing, while BE has yet to reckon with the consequent implications. BE raises important questions about, e.g., resource valuation and quit decisions that could be answered by BN, while BN might provide brain-based constraints on function that could increase the physiological realism of BE model-building and reduce variance in the data. The BE concept of resource holding potential is similar to HSP “formidability,” while BE “retaliation cost” efficiently captures the constraint that formidability imposes on human aggression. Conversely, human personality and cultural variations challenge the inclusivity of BE modeling. Here, we propose typological equivalences between animal and human aggression, review evidence characterizing their respective central motivational states, and note the behavioral phenomena they may explain, including aggression contagion, redirection, and motivational override. We describe the neural instantiation of states as mathematical “attractor” functions that account for state persistence and scalability within a subcortical core modulated by cortical networks. We then apply these findings to BE modeling, drawing widely on observations of different taxa as befits a concern with pan-species ESS. Crosstalk among the three disciplines will hopefully enrich the understanding of aggression, leading to its amelioration among our species and animals held in captivity.