Past research has provided abundant evidence that exposure to violent video games increases aggression and aggression-related variables. In contrast, little is known whether and why video game exposure may also decrease aggressive behavior. In fact, two experiments revealed that playing a prosocial (relative to a neutral) video game reduces aggressive behavior. Mediational analyses showed that differences in both aggressive cognition and aggressive affect underlie the effect of type of video game on aggressive behavior. These findings are in line with assumptions of the General Learning Model and point to the importance of the cognitive and affective routes in predicting how aggressive behavior is affected by exposure to video games. Copyright © 2011 John Wiley & Sons, Ltd.