Forms and functions of aggression

This chapter provides an introduction to aggression research. To this end, historical trends, sex differences, and lifetime trajectories of aggression are detailed. Regarding subtypes of aggression, different categorizations have been used, such as direct versus indirect aggression, and distinctions between verbal, relational, and physical aggression. The differentiation between reactive (RA; hot-blooded, impulsive, and in retaliation to perceived provocation) and proactive (PA; cold-blooded, deliberate, and with a goal other than harming the victim) functions of aggression however, remains the most empirically validated-and forms the focus of the current chapter. Studies have demonstrated differential correlates for RA and PA in at least six different areas: behavioral and emotional control, psychopathology, social information processing, social adjustment, brain function, and genetic influences. Suggestions for clinical application of this empirical data are discussed. Finally, assessment methods for aggression are addressed, including both self-report (such as the Reactive Proactive Questionnaire) and behavioral methods (such as the Competitive Reaction Time Task).