A recent series of opinion pieces in the New York Times resurrected the debate on whether media violence causes actual crime or violence. One article dredged up a discredited claim that the link between media violence and actual violent behavior is “on par with the correlation of exposure to secondhand smoke and the risk of lung cancer” (the original claim involved “first hand” smoking). This confusion arises in part from a misunderstanding of “effect sizes” and how this concept differs in social science research vs. medical research.
Is media violence “linked” (a weasel word for maybe-caused-by-but-possibly-not) to real-life violence? Let’s reframe this issue by looking at how scientists prove cause and effect, using the example of cigarettes and lung cancer.
- Lung cancer was an obscure disease before smoking became common; now it’s the leading cause of cancer deaths. Aggressive behavior was hardly rare before electronic media became popular.
- Lung cancer rates increase as smoking rates go up, and decrease as they go down. For the overall population as well as for subgroups, the more smoking, the more cancer. We see nothing like this relationship when we look at violent media and measures of real-world violence. According to FBI statistics, violent crime has dropped dramatically since the 1990s, as access to violent video games and other media increased.
- There is a well-understood physiological mechanism for how cigarette smoke triggers cancer. How media violence might promote or trigger actual violence is still in the realm of speculation.
- There’s a dose-response relationship between smoking and lung cancer. While genetics and environmental toxins play a role, in general the more one smokes, the higher her risk of lung cancer. We don’t know whether greater exposure to violent media (More hours or years of play? Picking extra-gory games or movies?) is related to greater effects on children.
- Lung cancer is a clearly defined set of diseases; we know it when we see it, and experts pretty much agree on diagnostic methods and results. But experts don’t even agree on the meaning of harmful “aggression,” let alone how to measure it in lab settings or on playgrounds.
- Also, the reliability (consistency) of measurement over time is different. Cancerous cells will still be present three hours later, while aggressive thoughts or behavior may have gone away.
- Finally, smoking causes cancer, not the other way around. But research suggests that children with aggressive personalities may preferentially seek out violent media programs and games.
While linking violent media content with real-world violent behavior is easy for politicians and pundits, the science to support such claims just isn’t there.