That's the conclusion of a ground-breaking research, which uncovered a significant link, particularly in males, between the amount of time spent in front of the tube during adolescence and early adulthood and violent behavior later in life.
The most startling example from the study, which tracked New York kids along with crime data for a 17-year period, involved 14-year-olds who watched more than three hours of TV a day. Those 14-year-olds were more likely to commit assaults, robberies, threaten to injure someone or use weapons to commit a crime at ages 16 or 22.
On the other hand, those youths who watched less than one hour of television a day appeared less likely to engage in aggressive acts against other people.
In general, the study, which appears in tomorrow's issue of the journal Science, says that those adolescents who watched an hour or more a day were more likely to be aggressive in their late teens and early 20s.
The relationship between TV viewing and violence appeared to hold true even after compensating for such factors as childhood neglect, family income, neighborhood violence, parental education, psychiatric disorders and previous television viewing as a child. Some of these factors appeared to contribute to the amount of time spent watching television.
"There've been hundreds of studies that have looked at this association in children, but fewer studies in adolescents," says Jeffrey Johnson, lead author of the study and an assistant professor of clinical psychology at Columbia University's College of Physicians and Surgeons in New York City.
"This is the first study to follow a sample of adolescents into adulthood and investigate whether violent television during adolescence is associated with risk for aggressive behavior all the way into adulthood," Johnson adds. "It's also the first study to examine if television viewing at 22 [years of age] is associated with a risk for aggressive behavior over a substantial eight-year period."
Leonard Eron, a professor of psychology at the University of Michigan and author of an influential study on kids and television in the 1960s, says he was surprised and enlightened by the new study results.
"Most of the research [on television viewing and aggressive behavior] was done with young children and showed that children are influenced by violent television. But I never knew that this applied to adults and adolescents," Eron says.
In the new study, researchers followed 707 individuals in northern New York state over a 17-year period. The mean age of the participants at the start of the study was 5.8 years; at the conclusion, it was 30 years. They were interviewed in 1975, 1983, 1985-86 and again in 1991-93. The researchers also relied on crime data from New York state and the Federal Bureau of Investigation.
Perhaps the most striking example of the relationship could be seen in those 14-year-olds who watched more than three hours of TV a day, says John P. Murray, professor of developmental psychology at Kansas State University, who was not involved in the study.
"You get a linear increase in aggression particularly for males," Murray says.
It's not clear why the females exhibited less-aggressive behavior, but the study authors speculate that it could have something to do with the types of shows the genders were watching.
An average hour of prime-time television depicts three to five violent acts, according to the study authors. An average hour of children's television, particularly cartoons, shows 20 to 25 violent acts. Even cartoon violence could have an impact on future aggression, Eron notes.
"You think that this is an appropriate way of behaving, that this is the way problems are solved, the way you get what you want and reduce frustrations," Eron explains. "Everybody's doing it so it's OK and you get permission that way to do it."
Johnson adds, "There's a child inside of everybody. Even an adult has a tendency to do some things that are childlike or irrational. And when a person sees a certain kind of behavior being enacted on TV, one might have the tendency to want to try it out. Even adults can be very impressionable at times."
The new study and others like it may also help to answer some of the questions surrounding the rash of school shootings in recent years, experts says.
"There have always been fights in school. But now, with easier access to guns, the lethality of the break-outs and the frequency is increased because you have a culture that says, 'Hey, if someone disses you, take them out,' " Murray says.
What To Do
For a wealth of information, including studies on how TV viewing affects the brain, visit Prof. Murray's Web site.