Watching violent films or playing violent video games decreases helping behavior towards people in need of assistance, according to a study conducted by researchers from the University of Michigan.

In one experiment, participants are playing a violent or non-violent video game when a loud and apparently physical fight breaks out in the hallway just outside their room, resulting in one person being injured. In a second experiment, participants are exiting a movie theater after watching either a violent R-rated film or a non-violent PG-rated film when they encounter an injured woman who has dropped her crutches and is struggling to pick them up. In both experiments, researchers timed how long it took for the participant to help the person in need and, in both cases, those who were exposed to violent media took longer to help than those exposed to non-violent media.

Researchers attribute the delay in helping to desensitization, suggesting that exposure to violent media causes people to become numb to the pain and suffering of others, leading to less helpful behavior. Of the two experiments, the video game experiment seems fairly sound, but there are some problems with experiment two, the movie experiment.

For one, the sample population is non-random. In order to address this issue, researchers had some people encounter the woman before they went in the theatre. In this case, there was no difference in reaction time between the two groups in terms of their helping behavior. This certainly points to the possibility that the behavioral difference was a result of the violent movie, but I would suggest that this doesn’t, however, completely rule out that there was something systematically different about the population attending the violent film. Maybe the decrease in helping behavior for people choosing to attend the violent film is context-dependent, only surfacing after exposure to a prime (the violent film), whereas this behavioral change wouldn’t surface in people who choose more benign, and less violent, movie fare.

I would also posit that its not impossible that some element other than violence in the violent film might have primed people to be less helpful, or that some element in the non-violent film primed people to be more helpful. For the record, the violent and non-violent movies which served as independent variables were “The Ruins” and “Nim’s Island,” respectively. I’ve seen neither film so can’t posit a guess as to which moderating variables could be responsible, but given the fact that we’re talking about two feature-length Hollywood movies and not films carefully constructed so that the only difference between them is the level of violence, its not hard to imagine that such variables might be present.

Experiment 1, as I mentioned earlier, is on more solid ground. It seems unlikely that helping behavior was primed by the video games in the non-violent condition, which included titles like Tetris and 3D Pinball, although its remotely possible that the decrease in helping behavior in the violence condition was moderated by some variable other than violence. An additional strength of Experiment 1 is that participants were randomly assigned to either condition,

Although published as a package deal, I see these two experiments as addressing slightly different questions. In experiment one, participants are playing instrumental roles and actually initiating much of the violent behavior to which they’re exposed. Those watching a movie, on the other hand, are passively involved in the experience, which would seem to require far less active attention and, not incidentally, no active role or involvement in the violence portrayed.

Pre-testing nonwithstanding, both the non-randomness of the population attending the violent film, and the possibilty of some systematic difference in this population, and also the possibility that some other variable primed the decrease in helping behavior, or an increase in helping behavior in the non-violent condition, suggests some problems with the claim that passive exposure to violent media leads to a decrease in helping behavior. The researchers suggest that either active participation in or passive exposure to violent media lead to a decrease in helping behavior but I would suggest that, for the reasons mentioned above, a strong claim can only be made for the former and not the latter.