The question of whether media depictions of violence, whether in video games, movies, TV shows, narrative, or comic books, is an old one. It is a question that concerns many different people, from parents to teachers to politicians. And it is also a question that persists despite the fact that no studies have found conclusive evidence that this media has a negative impact on people who engage with it.

There are some studies that have found evidence that violent video games lead to a reduction in empathy and an increase in aggression, but these studies have mostly investigated only the short-term effects of playing violent video games. Participants in previous studies played these games just before, or even during, the experiments.

But a new study has expressly avoided this, focusing on men who played “first-person shooter” games like Call of Duty or Counterstrike for at least two hours a day for four or more years. The study had male subjects because men are much more likely to play violent video games than women are. In order to avoid any short-term effect on empathy, they forbade the subjects from playing those games for at least three hours before the experiment.

Between questions and fMRI scans, they found that the gamers and the control group, who had little experience with video games and did not play violent games, showed “no differences in measures of aggression and empathy.” If there are negative effects associated with playing violent video games then, they exist only briefly, during and immediately after playing.

While this study is unlikely to end the discussion about violence in the media, it does open some interesting new avenues of study. The question of whether violent video games have an impact on people has to include questions of how long any such impact might remain.

The team acknowledges that more research is needed to determine what, if any, long-term effects violent video games might have on empathy and aggression.

“We hope that the study will encourage other research groups to focus their attention on the possible long-term effects of video games on human behavior,” said Dr. Gregor Szycik of the Hanover Medical School, one of the authors of the paper. “This study used emotionally provocative images. The next step for us will be to analyze data collected under more valid stimulation, such as using videos to provoke an emotional response.”