He may be known to many children as a comic book friend, but a Purdue University professor warns the new "Dark Knight" Batman is a much more violent reincarnation of the classic character.Glenn Sparks, a professor of communication, studies the effects of scary movies, particularly on children."The danger with a film like this is its history in the Batman comic book series and cartoons. People think of this hero as fun and entertaining, so parents may even take very young children to see what they believe is a family film. Instead, they may be jarred by the film's explicit level of violence," he said."Dark Knight," which is rated PG-13, opened July 18 and broke box office records during its opening weekend.Sparks said the level of violence in the movie can be especially upsetting for children ages 6-10 as they try to comprehend why bad things happen to people."At the same time, children at this age don't have experience coping with explicit images of violence or understanding the likelihood that something will happen," Sparks said.The latest interpretation of Batman's longtime nemesis the Joker can also be confusing to younger children, Sparks said, because of the distorted, violent image of a clown.Sparks said he recommends that parents research films in advance by viewing descriptions of their violent content at the Web site Kids In Mind. Run by an Ohio-based company, the site also ranks sex, nudity and profanity in movies.Sparks said parents, especially now, need to be aware of what's really in the movies their children are watching."Ultimately, filmmakers are trying to appeal to multiple markets and ages. Violence in films like these has been a trend. For example, the Harry Potter movies have been getting darker and more explicit, as well as Indiana Jones," Sparks said. "Hollywood is really pushing the envelope because our culture is saturated with violent images. Hollywood probably senses the need to up the ante if they want to keep people's attention."