Trait Aggression

Some people are more aggressive than others. Does nature endow some people with more aggressive personalities than others? Or does nurture, in which factors within one’s environment shape aggressive tendencies, also matter? Early psychological research on aggression often focused on situational factors, ignoring the role of trait aggression. Indeed, a massive host of environmental variables that affect aggression have been identified, such as temperature, noxious odors, physical pain, and alcohol intoxication. Despite the profound effects that these external influences can have on an individual’s aggressive behavior, other work has suggested that aggression is also reliable over time in the same individuals. In a powerful demonstration of this concept, L. Rowell Huesmann and colleagues (1984) conducted a 22-year longitudinal study, tracking the aggressive tendencies of individuals from 8 years old to 30 years old, their offspring, and their parents. The authors of this study found that childhood aggression predicted antisocial behavior, such as serious criminal behavior and intimate partner violence, in adulthood. Whereas the durability of aggressive tendencies across ages was substantial, it was even more powerful across generations within the same family unit, with a profound degree of similarity among the aggressive tendencies of participants, their parents, and offspring at comparable ages. This intrafamily aggressive similarity suggests that an aggressive disposition may have a strongly heritable aspect, a topic addressed later in this entry. Such research has demonstrated that aggressive tendencies are, in fact, stable enough to be considered a personality trait, defined as an enduring and pervasive characteristic that predicts future outcomes and behavior. This now-accepted conceptualization of trait aggression has redefined the way researchers approach the topics of hostility, anger, aggression, and violence. This entry discusses the measurement of aggression, models and theories pertaining to trait aggression, and implications for media violence research.