Study links TV viewing among kids to later violence

WASHINGTON (CNN) -- Adolescents who watch more than three hours of TV daily are more likely to engage in aggressive behavior as adults, a new study says.

"We found that teenagers who, at mean age 14, watched more than three hours a day of television were much more likely than those who watched less than one hour a day of television to commit subsequent acts of aggression against other people," said Columbia University's Jeffrey Johnson, lead researcher for the study published Thursday in Science magazine.

Johnson said the aggressive acts include assaults, fights that sometime lead to injuries, use of a weapon to commit a crime and other serious behaviors.

Researchers tracked about 700 boys and girls for 17 years. Even accounting for factors such as family income, childhood neglect or psychiatric disorders, the link between watching violent television and behaving aggressively as an adult remains, the study said.

EXTRA INFORMATION Teen violent behavior and TV viewing  Violent adolescent warning signs

An editorial accompanying the Science article suggests the study "probably underestimates the effects of TV violence."

Johnson said that at age 14 males appear to be more vulnerable than females to acting out after viewing excessive television.

But his research turned up a surprising twist as males and females grow older.

"At mean age 22, the females seem to be more affected by television, by extensive television viewing," said Johnson, who added that further studies must be done to confirm this finding.

He theorizes the difference between sexes may be explained because females don't begin watching violence on television as early as males.

In response to the study, Marc Osgoode Smith, spokesman for the National Cable & Telecommunications Association, wrote: "We have long advocated responsible television viewing and supported that advocacy with numerous public affairs initiatives."

Research shows the average hour of television viewing has four to five acts of violence, according to Daphne White, executive director of the Lion & Lamb Project, a Bethesda, Maryland, organization created in 1995 to reduce violence in the media. Children's programming, such as cartoons, average 20 to 25 violent acts every hour, White said.

"If you add it up, the average child, with those statistics has seen 100,000 acts of violence by the time they leave elementary school on television," White said, "and 8,000 murders."

The nation's first major study on the effects of TV violence was a 1972 U.S. surgeon general's report that said, "Televised violence, indeed, does have an adverse effect on certain members of our society."

Professional health organizations such as the American Academy of Pediatrics, American Psychological Association and American Medical Association have concluded data show at least a casual link between extensive TV viewership and aggression in children.

"We have to start looking as a culture at this laissez-faire attitude of letting children consume so much violence on television," White said.

She said she thinks society is sending confusing messages to children.

On the one hand, many schools have zero tolerance policies, White said, but the tolerance for violence in the media goes virtually unchecked.

"Kids are getting suspended for incredibly minor violations ever since Columbine," White said, "and yet in the media that they see every day, violence is shown as the way to solve problems."