The study asked 607 eighth and ninth grade students to to complete a survey that reported their habits, knowledge of video games, school performance, demographic data, hostility, and favorite video games. The data collected was entirely self-reported.
Students were asked how often they played video games and how much they prefer violent games. They were asked to estimate their average school grade. Students were also asked to answer how often they have arguments with a teacher and if they were involved in a physical fight in the past year. 62% of respondents considered their favorite video games violent.
The average time spent playing video games was 9 hours, which the average for males being 13, and the average for females being 5. 68% of boys preferred violent video games and 22% of girls preferred violent video games.
The authors found that the amount of time playing and exposure to violent video games have a positive correlation with hostility, poor grades, arguments with teachers, and whether or not they have been involved in a fight in the past year. Hostility was strongly correlated with violent video game exposure and the amount of violence they like in video games.
Douglas Gentile, Paul Lynch, Jennifer Linder, and David Walsh. 2004. “The effects of violent video game habits on adolescent hostility, aggressive behaviors, and school performance.” Journal of Adolescence 27, no. 1: 5-22.
https://doi.org/10.1016/j.adolescence.2003.10.002