"In fact, they got quite a bit more violent over time," said Dr. Robert Hancox, the study's senior author from the University of Otago in Dunedin, New Zealand.

The concern, according to Hancox and his colleagues, is that children may watch these and other popular movies, and be exposed to an increasing amount of violence.

One researcher, who was not involved with the new work, said there is clear evidence that exposure to violent content is linked to aggressive and violent behavior in children and teens.

"So when this content shows up in films kids are seeing, it can be problematic," said Amy Bleakley, a senior research scientist at the Annenberg Public Policy Center at the University of Pennsylvania in Philadelphia.

To test whether popular movies that are accessible and marketed to children and teens are showing more violent acts, Hancox and his colleagues analyzed the Bond movie series, which includes 23 films spanning the last 50 years.

The newer Bond movies, according to the researchers, are rated PG-13, which means children and teens are not required to go to the theater with their parents.

For the new study, published in the Archives of Pediatrics & Adolescent Medicine, researchers watched each Bond movie and counted the number of violent acts, such as one character trying to shoot or punch someone else.

They found the number of violent acts shown on the screen during the first Bond film in 1962 - Dr. No - and the latest film they analyzed in 2008 - Quantum of Solace - more than doubled from 109 to 250, respectively.

The increase didn't come from trivial violence, such as a character slapping someone else. Instead, "The change has been in the portrayal of severe violence," said Hancox, referring to any character punching, kicking or using a weapon.

Severe violence increased from 77 acts in the first film to 219 in 2008.

But while the movies tended to show more violent acts over time, each movie had a different number of violent acts.

For example, 1997's movie Tomorrow Never Dies contained about 400 violent acts, which is nearly twice as many as 1999's The World Is Not Enough.

Metro-Goldwyn-Mayer Studios, which co-owns the copyright to Bond films with Eon Productions, had no comment on the new research.

SHOULD PARENTS BE DR. NO?

Bleakley told Reuters Health that the results of the new research jibe with a study she published earlier this year of top-grossing films between 1950 and 2006.

In that study, she and her colleagues found movie characters were increasingly involved with violent acts.

"The main point of this is that it's not just Bond," said Hancox. "It's about what's happening in movies and media in general, and that they tend to be getting more violent."

Bleakley said she thinks parents should follow - as best they can - the American Academy of Pediatrics recommendations, which suggest limiting screen time for movies, television, video games and the computer to one or two hours per day.

The recommendation also suggests parents make thoughtful media choices, watch programs and movies with their children, use parental controls on televisions, avoid violent video games and keep children's bedrooms media free.

"I think parents should think very carefully about whether it is a good idea if their children should be watching this amount of violence," said Hancox.

SOURCE: bit.ly/TS91cK Archives of Pediatrics & Adolescent Medicine, online December 10, 2012.

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