Teens and young adults who watch more than 3 hours of TV a day are more than twice as likely to commit an act of violence later in life, compared to those who watch less than 1 hour, according to a new study. The authors of this and similar studies say the causal link between TV and aggressive behavior is now nearly as strong as the link between smoking and lung cancer. Yet other experts say the issue isn't quite that cut and dried.
Psychologists have worried about the effects of TV as long as the tube has been around. Most early research addressed short-term behavior, finding that violent TV made children more aggressive. Only a few investigated long-term effects, and even fewer tried to disentangle the effects of TV from confounding psychological and environmental factors that could create violent tendencies.
The new study, published in the 29 March issue of Science, fills an important gap by addressing TV viewing during adolescence and controlling for confounding factors. Psychologist Jeffrey Johnson of Columbia University in New York City and colleagues used information on the TV viewing habits of 707 14- and 22-year-olds who participated in an earlier study. They quizzed the same people and their mothers about violent behaviors. Even after making statistical allowances for factors such as psychiatric disorders, economic status, and prior violent acts, they found that those who watched 1 to 3 hours of TV per day were about 60% more likely to get in a serious fight, threaten someone, or use a weapon to commit a crime than those who watched less than an hour a day. More than 3 hours of TV more than doubled the risk.
Johnson says the causal connection between TV and violence is now ironclad, and he hopes it will galvanize parents and the TV industry to respond. "The size of the relation is no smaller than the relation between smoking and lung cancer," says Leonard Eron, a University of Michigan psychologist who co-authored a similar study in 1986 with L. Rowell Huesmann. But some observers say that's putting it too strongly. Jonathan Freedman, a psychologist at the University of Toronto, doesn't find the new evidence persuasive. The study can't rule out the possibility that "television is just a marker" for some unmeasured environmental or psychological influence on both aggression and TV habits.