A recent development in video games is that players can design and personalize their own in-game characters. it was predicted that this innovation could lead to elevations in the intensity of the psychological effects of video games. The present study confirmed this hypothesis, revealing that participants who played an aggressive video game using their own, personalized character exhibited higher levels of aggressive behavior than participants who played an aggressive game with a non-personalized character. The aggressive behavior levels of the own-character players also exceeded those of individuals who played a non-aggressive game, regardless of whether or not they used a personalized character. Process analyses revealed that participants playing a violent video game with a personalized game character experienced more arousal and self-activation than they did when playing with an impersonal, default game character, which in turn increased aggressive responses. (C) 2009 Elsevier Inc. All rights reserved.