Some researchers say the debate is over--that children are undeniably harmed by media violence. Others maintain the jury is still out.
But almost every parent already knows that it's a lot more complex than yes, they're hurt, or no, it's just a movie.
For instance, one mother said her 8-year-old would shrug off blood-splattered scenes in the R-rated "Die Hard" but is too frightened to see the PG-rated "Ghostbusters"--as is her 13-year-old.
Some 10-year-olds were terrified by the rapacious dinosaurs in "Jurassic Park," while others were fascinated by the special effects.
Some parents thought "Andre" would be safe--until their 3-year-olds started screaming during a scary storm scene.
Experts who fault the Motion Picture Assn. of America's film rating system for being of little use say that in order for parents to better judge which movies might be harmful, they need much more information than PG, PG-13 and R.
For instance, UC Santa Barbara researcher Barbara Wilson said that not only do individual children vary greatly--regardless of age--in their abilities to evaluate what they're seeing, but children between 8 and 12 differ markedly from 3- to 7-year-olds in how they respond to media portrayals.
Younger children have more trouble separating reality from fantasy and depend more on surface appearances. Some were frightened by the way the alien E.T. looked, despite his kind nature. They perceive Ninja Turtles to be human as long as they act human.
Older children are better at drawing conclusions, forming opinions and recognizing consequences.
Surprisingly, some depictions are actually more problematic for older than for younger children, she said. Older children, for instance, were more upset by "The Day After," a movie about nuclear holocaust, than younger children who didn't understand it.
"One mother said 'Charlotte's Web' upset her (preschool) child a lot more," Wilson said.
Preteen viewers are more interested in motives and role models and are more inclined to imitate behaviors portrayed by actors around their age. Young children are more likely to be influenced by child actors such as Macaulay Culkin.
In both groups, movies that feature young perpetrators cause more problems than those with violent adults, she said.
Moreover, she said, context is crucial and often more significant than volume or explicitness. While violence portrayed in "Schindler's List," for example, was presented as despicable, that shown in hero-action movies such as "Rambo: First Blood" is often glorified.
Portrayals in which violent characters benefit from their actions or are not punished for antisocial acts can encourage aggressive attitudes and copycat behavior, Wilson said.
Younger children are particularly susceptible to violence that appears to be justified--such as acts committed by the Teenage Mutant Ninja Turtles.
If the punishment is delayed until the end of the movie, younger children are more likely to see the violence as acceptable.
Wilson said it is thought that scenes of horror, street language and erotic sex can be analyzed similarly, although ethics have prevented researchers from using control groups to study the effects of sexual portrayals on children.
Reformers such as Wilson are calling for a new ratings system, based on child development and devised by an independent group of parents, researchers and teachers. This summer, the American Medical Assn. also called for a new rating system based on context and broken down for ages 3-7, 8-12 and 13-17.
Meanwhile, said Wilson: "Many studies suggest one of the most important things a parent can do to mediate these effects is to watch with children, to help them interpret images and make sense of what they're seeing."