"In their narrative review of the empirical literature, Dill and Dill (1998) concluded that short-term exposure to violent videogames increases aggression. Similarly, Bensley and Van Eenwyk (2001) conclude there is evidence that playing violent videogames can increase short-term aggression in young children. Meta-analyses conducted on the research on violent videogames have also supported an effect of game play on aggression. The first such comprehensive study was conducted by Anderson and Bushman (2001). Across all studies included in their meta-analysis, the authors found that exposure to violent videogames was positively associated with increased levels of aggression. Anderson (2004) recently updated with original meta-analysis and concluded that when only those studies with the soundest methodological approaches were used, results showed even stronger effect sizes, suggesting that methodologically weaker studies actually underestimate the true effects of exposure to volent videogames. Another meta-analysis by Sherry (2001) using 25 studies found evidence for a small effect of videogame play on aggression. However, Sherry also found that effect sizes have increased over time, with more current studies producing stronger effects, presumably due to the greater realism of today's games. Game type was also important, as games classified as human violence or fantasy violence were found to be more strongly related to aggression than sports games."