Young people exposed to violent media are more likely to lash out violently themselves, new research published in Pediatrics shows.

"Our findings add to the growing evidence that violence in the media is related to aggressive behavior, including seriously violent behavior among youths," Dr. Michele L. Ybarra of Internet Solutions for Kids in Santa Ana, California and her colleagues report. "Reduction in youths' exposure to violent media should be viewed as an important aspect of violence prevention."

Many studies have examined exposure to violent media and violent behavior among young people, Ybarra and her team note in their report. In fact, they point out, the American Academy of Pediatrics calls media violence "the single most easily remediable contributing factor" to youth violence.

The researchers examined the relationship between media violence and "seriously violent behavior," defined as shooting or stabbing someone, robbing someone, or committing aggravated assault or sexual assault, in a survey of 1,588 young people 10 to 15 years old. The average age was 13 years old and 48 percent were girls.

Five percent of those surveyed reported having engaged in some type of seriously violent behavior over the past year, while 38 percent said they had visited at least one type of violent Web site. With each additional type of violent Web site a study participant reported viewing, the likelihood of violent behavior increased by 50 percent.

Young people who said that "many, most or all" of the Internet sites they frequented featured "real people fighting, shooting or killing" were five-times more likely than their peers who didn't visit violent Web sites to engage in seriously violent behavior.

The odds of violent behavior also rose with the number of types of violent media a young person consumed, but the effect of violent TV, movies, music, games or Internet cartoons was much smaller than that of Internet violence depicting real people.

The interactive nature of the Web may be behind its apparently more powerful influence when compared with types of violent media, Ybarra and colleagues suggest.

But the current study doesn't answer the question of whether violent media is turning kids violent, whether violence-prone youth are more likely to seek out violence on the Internet, or "more probably," whether a bit of both is going on, the researchers say.