A widely reported analysis by the American Psychological Association's Task Force on Violent Media reviewed 170 studies on how playing violent video games might affect aggressive tendencies in gamers. The Task Force members concluded last year that "the research demonstrates a consistent relation between violent video game use and heightened aggressive behavior, aggressive cognitions, and aggressive affect and reduced prosocial behavior empathy and sensitivity to aggression."

Now a new study in the Journal of Experimental Social Psychology asks, "Does playing video games with violent content temporarily increase aggressive inclinations?" Short answer: No. From the abstract:

The current study tested whether participants who played a violent video game (VVG) would exhibit increased aggressive inclinations relative to those who played a non-violent video game (NVG). Participants (N = 386) were randomly assigned to play a VVG or a NVG prior to presumably interacting with another (non-existent) participant. We then measured participants' aggressive inclinations: Participants reported how many pins they would like to stick into a "voodoo doll" representing their interaction partner, and participants reported how likely they would be to actually harm their interaction partner. We did not detect any differences between conditions for several outcomes: the amount of aggressive inclinations displayed during the interaction, the number of pins participants chose to stick into a representation of their interaction partner, and participants' self-reported likelihood they would harm their interaction partner. Thus, the hypothesis that playing a VVG would increase aggressive inclinations was not supported in this study.

As interesting as such experimental work is, the point made by 230 psychological researchers in an open letter when the Task Force was launched seems more salient:

During the video game epoch, youth violence in the United States and elsewhere has plummeted to 40-year lows, not risen as would have been expected if the 2005 APA resolution were accurate. Although we do not assert video games are responsible for this decline (such would be an ecological fallacy), this decline in societal violence is in conflict with claims that violent video games and interactive media are important public health concerns. The statistical data are simply not bearing out this concern and should not be ignored.

In any case, more and more evidence from psychological experiments and the real world point in the direction that playing violent video games is mostly harmless.