This article presents a brief overview of existing research on the effects of exposure to violent video games. An updated meta-analysis reveals that exposure to violent video games is significantly linked to increases in aggressive behaviour, aggressive cognition, aggressive affect, and cardiovascular arousal, and to decreases in helping behaviour. Experimental studies reveal this linkage to be causal. Correlational studies reveal a linkage to serious, real-world types of aggression. Methodologically weaker studies yielded smaller effect sizes than methodologically stronger studies, suggesting that previous meta-analytic studies of violent video games underestimate the true magnitude of observed deleterious effects on behaviour, cognition, and affect.