Short-term and long-term effects of violent media on aggression in children and adults.
OBJECTIVE
To test whether the results of the accumulated studies on media violence and aggressive behavior are consistent with the theories that have evolved to explain the effects. We tested for the existence of both short-term and long-term effects for aggressive behavior. We also tested the theory-driven hypothesis that short-term effects should be greater for adults and long-term effects should be greater for children.


METHODS
Meta-analysis.


METHODS
Children younger than 18 years and adults.


METHODS
Violent media, including TV, movies, video games, music, and comic books.


METHODS
Measures of aggressive behavior, aggressive thoughts, angry feelings, physiological arousal (eg, heart rate, blood pressure), and helping behavior.


RESULTS
Effect size estimates were combined using meta-analytic procedures. As expected, the short-term effects of violent media were greater for adults than for children whereas the long-term effects were greater for children than for adults. The results also showed that there were overall modest but significant effect sizes for exposure to media violence on aggressive behaviors, aggressive thoughts, angry feelings, arousal levels, and helping behavior.


CONCLUSIONS
The results are consistent with the theory that short-term effects are mostly due to the priming of existing well-encoded scripts, schemas, or beliefs, which adults have had more time to encode. In contrast, long-term effects require the learning (encoding) of scripts, schemas, or beliefs. Children can encode new scripts, schemas, and beliefs via observational learning with less interference and effort than adults.
Vrije Universiteit, Amsterdam, the Netherlands. bbushman@umich.edu
Brad J
BJ
Bushman
L Rowell
LR
Huesmann
D000328:Adult; D017677:Age Distribution; D000374:Aggression; D000375:Aging / Q000523:psychology*; D002648:Child; D003146:Communications Media / Q000706:statistics & numerical data; D006801:Humans; D007389:Internal-External Control; D013997:Time Factors; D014754:Violence / Q000706:statistics & numerical data