BOSTON (The Boston Globe) -Just as MTV said it would censor the new music video by Madonna, a sweeping new survey of research on media violence, sex and risky behavior over the past 10 years concludes that what children watch can directly influence their behavior.

The survey by a Johns Hopkins University psychiatrist, published Tuesday, reflects the growing concern of mental-health experts about the impact on youngsters of the sexually suggestive, violent and aggressive content that frequently permeates television today.

The classic studies linking TV violence and aggression and youth behavior were done in the 1970s and 1980s, "with material that wasn't very violent" by today's standards, said Dr. Susan Villani.

But now, "it's more violent and more graphic and more sexual," she said. "Children are being exposed to more graphic content at younger and younger ages."

Villani proposes that health-care professionals treating disturbed children compile a "media history" of what they've watched as well as the traditional medical history.

Concerns about television sex and violence have led to a fierce debate about the government's role in regulating content, a voluntary ratings system to warn viewers about subject matter and increasing sensitivity about content among some networks and producers. But for the most part, networks have been reluctant to concede that their shows influence behavior.

Tuesday, however, the popular music video network MTV, which was embroiled in controversy over its animated series "Beavis and Butthead" when several young viewers allegedly mimicked risky behavior depicted on the show, said it would broadcast the new music video by pop star Madonna only once, late at night, and include a warning about its content. The video for "What it feels like to be a girl," shows the singer in a fantasy as an angry woman on a violent crime spree that the network believes is too strong for prime-time viewers.

Though anecdotal evidence abounds, the real link between televised sex and violence and actual behavior has been difficult to prove. Villani said the research in the past decade has strengthened previously reported links between television violence and increased aggressive behavior in preschoolers. Risky behavior depicted in entertainment media has been associated with increases in sexual activity, drinking, smoking and drug use, she said.

One major study cited by Villani showed that viewers of violent TV content learned aggressive behaviors and attitudes, became desensitized to violence and became fearful of being victimized.

Villani's review of a decade's worth of research on the media's impact on children and adolescence is published in the April issue of the Journal of the American Academy of Child and Adolescent Psychiatry.

Researchers in the 1990s have probed the impact of rock music and music videos, she finds. In one study, patients in a hospital for mentally ill offenders became less likely to get embroiled in assaults after a television showing MTV music videos was removed from the ward.

Other research linked a preference for heavy-metal music in the 1990s to reckless behaviors such as stealing, driving fast, using drugs and being sexually promiscuous in groups of adolescents. Again, cause and effect could not be proved.

Even children's cartoons are becoming violent, said Kimberly Thompson of the Harvard School of Public Health. She studied G-rated animated films from 1937 to the recent past, and found that depictions of violence increased steadily - to the point that Thompson believes children could be disturbed.

Currently, Thompson said she's studying the content of video games. Villani, in her survey, said there's been little research to date on the negative or positive impacts of video games. But she did mention studies in Japan that found little support for the theory that video games cause aggressive behavior. Still, Thompson said she has concern about the kind of games reportedly watched by some adolescents who carried out school shootings, because those games are repetitive simulations of killing.

Harvard researcher Jay Winsten, who heads the Center for Health Communication at the school of public health, cautioned that media exposure is only one factor shaping behavior, and that some children are more vulnerable because they live in an abusive or unsupportive family.

"We have to be cautious in interpreting these studies" that show an association between media content and behavior, he said.

Winsten said his concerns are not so much about prime-time network television shows but focus more on feature films shown on cable TV that contain a lot of violence. Winsten's center has developed ways to use the media to shape behavior positively.

Villani believes parents should spend more time monitoring what children are watching and protecting them having their values shaped in negative ways.

One trend she applauds is the development of "media literacy" programs in schools. In these programs, teachers highlight the messages that are being conveyed in movies and TV shows and music videos. With this information, children are better able to be critical and resist the messages, said Villani.

In a study published in the journal Pediatrics earlier this year and cited by Villani, researchers gave one group of California schoolchildren instruction in media literacy, and saw their violent behaviors decrease in comparison to a similar group that didn't receive the instruction.

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