▪ Abstract Media violence poses a threat to public health inasmuch as it leads to an increase in real-world violence and aggression. Research shows that fictional television and film violence contribute to both a short-term and a long-term increase in aggression and violence in young viewers. Television news violence also contributes to increased violence, principally in the form of imitative suicides and acts of aggression. Video games are clearly capable of producing an increase in aggression and violence in the short term, although no long-term longitudinal studies capable of demonstrating long-term effects have been conducted. The relationship between media violence and real-world violence and aggression is moderated by the nature of the media content and characteristics of and social influences on the individual exposed to that content. Still, the average overall size of the effect is large enough to place it in the category of known threats to public health.

Normative beliefs have been defined as self-regulating beliefs about the appropriateness of social behaviors. In 2 studies the authors revised their scale for assessing normative beliefs about aggression, found that it is reliable and valid for use with elementary school children, and investigated the longitudinal relation between normative beliefs about aggression and aggressive behavior in a large sample of elementary school children living in poor urban neighborhoods. Using data obtained in 2 waves of observations 1 year apart, the authors found that children tended to approve more of aggression as they grew older and that this increase appeared to be correlated with increases in aggressive behavior. More important, although individual differences in aggressive behavior predicted subsequent differences in normative beliefs in younger children, individual differences in aggressive behavior were predicted by preceding differences in normative beliefs in older children.

Although the relation between TV-violence viewing and aggression in childhood has been clearly demonstrated, only a few studies have examined this relation from childhood to adulthood, and these studies of children growing up in the 1960s reported significant relations only for boys. The current study examines the longitudinal relations between TV-violence viewing at ages 6 to 10 and adult aggressive behavior about 15 years later for a sample growing up in the 1970s and 1980s. Follow-up archival data (N = 450) and interview data (N = 329) reveal that childhood exposure to media violence predicts young adult aggressive behavior for both males and females. Identification with aggressive TV characters and perceived realism of TV violence also predict later aggression. These relations persist even when the effects of socioeconomic status, intellectual ability, and a variety of parenting factors are controlled.