Hasan, Y., Bègue, L., Scharkow, M., & Bushman, B. J. (2013). The more you play, the more aggressive you become: A long-term experimental study of cumulative violent video game effects on hostile expectations and aggressive behavior. Journal of Experimental Social Psychology, 49(2), 224-227. doi:10.1016/j.jesp.2012.10.016

It is well established that violent video games increase aggression. There is a stronger evidence of short-term violent video game effects than of long-term effects. The present experiment tests the cumulative long-term effects of violent video games on hostile expectations and aggressive behavior over three consecutive days. Participants (N = 70) played violent or nonviolent video games 20 min a day for three consecutive days. After game play, participants could blast a confederate with loud unpleasant noise through headphones (the aggression measure). As a potential causal mechanism, we measured hostile expectations. Participants read ambiguous story stems about potential interpersonal conflicts, and listed what they thought the main characters would do or say, think, and feel as the story continued. As expected, aggressive behavior and hostile expectations increased over days for violent game players, but not for nonviolent video game players, and the increase in aggressive behavior was partially due to hostile expectations. (PsycINFO Database Record (c) 2013 APA, all rights reserved)