The precedents
Before discussing their own results, the authors cite several other studies that have explored the video game-aggression link on a correlational level. Three of the studies showed a correlation; one did not. The authors note, however, that none of these studies distinguished between a violent and non-violent video game. To quote the article, "[t]hus, none test the hypothesis that violent video games are uniquely associated with increased aggression."

The authors also cover the existing experimental studies in this area. A few brief quotes:

The extant experimental studies of video games and aggression have yielded weak evidence also . . . Two additional experimental studies of violent video games and aggression found no effect of violence . . . . In sum, there is little experimental evidence that the violent content of video games can increase aggression in the immediate situation.

Four experimental studies cited in the article showed a possible link between violent videogames and aggression. However, even the authors discount these studies, because "none of these studies can rule out the possibility that key variables such as excitement, difficulty, or enjoyment created the observed increase in aggression." They then sum up the results of the previous studies as follows: "There are methodological shortcomings in many of these studies, which, when combined with the mixed results, suggest that there is little evidence that short-term exposure to violent video games increases aggression-related affect."

The first study: squeezing a truism from a rock
The authors' own studies begin with a survey of six separate scales. They were irritability, aggression, delinquency, video game preferences, world view, and academic achievement. The first five scales were obtained via survey, the last through the participant's college GPA. All of the participants were college students.

There are some interesting results here. First, 91% of the students surveyed (comprised of 88% of the females and 97% of the males) played video games. Of those surveyed who did play video games, one third played video games described by the authors as violent/aggressive. Interestingly, the authors seemed eager to classify "Super Mario Brothers" as a violent game, which would push the percentage to 44%. I will leave it to the reader to decide if Super Mario Brothers is in fact a violent video game.

I think the above results are interesting because of the percentages involved; if approximately 30% of all college students are playing violent video games, and video games cause aggressive behavior as the authors later suggest, where is the huge outpouring of violence on our college campuses?

The argument could be made that because the subjects in question are college students, they might be more intelligent, have had more opportunities, and are thus less prone to the supposed aggressive side effects of video games. Assuming that at least 30% of junior high or high school students play these same games, however (a fairly safe assumption in this anecdotal context at least; after all, college students have beer!), there should be at least the same level of violent incidents in our middle and high schools, as well. In terms of numbers, it's just not there.

The article goes on to point out that VGV (the article's acronym for Video Game Violence) "was positively and significantly related to aggressive behavior. . ." Additionally, "[v]iolent video game play and aggressive personality separately and jointly accounted for major portions of both aggressive behavior and nonaggressive delinquency."

The authors then state "The positive association between violent video games and aggressive personality is consistent with a developmental model in which extensive exposure to violent video games (and other violent media) contributes to the creation of an aggressive personality." Strong words, but remember, correlation does not equal causation.

Indeed, after stating the above, the authors admit that "[t]he cross-sectional nature of this study does not allow a strong test of this causal hypothesis". The authors later state:

the correlational nature of Study 1 means that causal statements are risky at best. It could be that the obtained video game violence links to aggressive and nonaggressive delinquency are wholly due to the fact that highly aggressive individuals are especially attracted to violent video games.

Thus, the first study yields only this result: violent individuals play violent video games. Based on this study alone, it's impossible to say whether 'violent games make violent individuals' or simply 'violent games attract violent individuals.' Without clinical experimental data to establish causation, the correlation means no more than the connection between crime and ice cream.