How much film violence for kids? Parents losing their compass, study says

Regardless of the order in which they viewed the scenes, the parents started off relatively conservatively, saying on average that a child should be about 17 years old before he or she watched the movie in question. With each succeeding clip, though, the parents reduced this age judgement. By the last clip, parents set an average age of 13.9 for watching the violent movies and 14 years for the movies that included the sex scenes. 

“We expected there to be a certain amount of what we call desensitization,” says Dan Romer, associate director of the Annenberg Public Policy Center and the lead author on the study. “But what was so stunning was how clear the pattern was and how dramatic it was.”