Media Violence and Aggression
Effects of media violence on aggression for different types of studies. Diamond widths are proportional to the number of independent samples. There were 46 longitudinal samples involving 4975 participants, 86 cross-sectional samples involving 37,341 participants, 28 field experiment samples involving 1976 participants, and 124 laboratory
experiment samples involving 7305 participants. Red lines indicate the mean effect sizes. Blue lines indicate a 95% confidence interval. Note that zero (dashed line, indicating no effect) is excluded from all confidence intervals.
[source: C. A. Anderson and B. J. Bushman (2002), SCIENCE vol 295, pp. 2377-2379]