Since 2000, the Federal Trade Commission (FTC) has repeatedly investigated the marketing practices of the major entertainment industries to determine whether they target children for violent material that their ratings say is inappropriate for children. The first investigation was conducted at the request of President Clinton following the school shootings in Columbine, Colo., which began a national conversation about the role of violent media in these tragedies. The last one, completed in 2009, reached the same conclusion as earlier ones, that the movie industry routinely advertises films to children that are rated as inappropriate for them.

The irony here is only too apparent because the industry's trade group, the Motion Picture Association of America (MPAA), prides itself on advising parents about which movies are suitable for their children. It also assumes responsibility for monitoring the advertising practices of its members so that they remain within the dictates of their ratings.

All of this would be concerning enough if the ratings that the MPAA assigns to films were based on an objective standard that parents could understand. But here things get really fuzzy, because over the past few decades, the ratings for violent movies have become progressively more tolerant. Movies once rated R for violent content are now rated as acceptable for anyone over age 12. And no restrictions are in place to prevent anyone under that age from seeing those films in theaters.

ADVERTISEMENT

This situation is win-win for the industry. By labeling films with intense violence as PG-13, it can claim to protect younger children. At the same time, because of lax enforcement over advertising for those films and the fact that anyone can walk into a theater and see a PG-13 film, it can generate traffic among audiences of any age.

But wait — you might say that parents are informed about the content of those PG-13 films and can decide for themselves whether to allow their children to view them. In a study published online in October in Pediatrics, we tested the idea that parents can tell the difference between the violence in PG-13 and R-rated movies.

Our survey of 1,000 parents across the United States found that when parents were shown scenes of violence from PG-13 and R movies, there was no difference in how they regarded those films as appropriate for adolescents. In both cases, after viewing the first scene, parents felt, on average, that those movies were appropriate only for children older than 16. However, the more of those scenes they viewed, the less they were bothered – until, after a half-dozen scenes, the parents judged them suitable for 14-year-olds.

This suggests that parents can become desensitized to the violence that once appeared in R-rated movies and that now commonly appears in PG-13 movies. Indeed, parents who routinely viewed more movies were more lax about their assessments of age-appropriateness. This suggests that the increasing violence that has appeared in films has eroded parents' sense of what their children can tolerate. And it means that almost anything labeled PG-13 may increasingly be seen as acceptable for adolescents.

Recent history supports this scenario. Movies labeled PG-13 now dominate box office sales. In 1980s and '90s, R-rated films such as the "Die Hard" series were top-grossing movies, but over time — and especially since 2000 — PG-13 films have dominated. At the same time, parents have become less concerned about violence and sex in movies, as documented in Kaiser Family Foundation surveys.

What this all indicates is that we're involved in a cycle of increasing exposure to violent entertainment that any child can view in a movie theater and, even more likely, without parental oversight, on the Internet and television.

We don’t know the effects of this massive change in exposure to violent entertainment. For most youth, the effects may be minimal. But just as we are warned about drugs that can have side effects for some users, the same is likely to be the case for violent entertainment, especially when taken in large doses. Research published in the most prestigious journals finds that heavy exposure to violent media during childhood is linked to aggressive behavior in youth. Long-term studies of people who watched lots of violent TV as children find that they are more likely to be rated as violent by peers as they age, and in one study were more likely to be arrested.

This brings us back to the FTC and its repeated warnings against advertising movies to children under the age recommended by its ratings. The agency has taken the stand that all it can do is document its findings and encourage better behavior by the industry. The FTC may not have the regulatory authority to judge the rating system. But perhaps it is time for the agency to think about stronger measures to bring the industry in line with its own ratings system. It appears that the system is primarily useful for the industry itself, and not for the country or its parents.

Romer, Ph.D., is associate director of the Annenberg Public Policy Center of the University of Pennsylvania and director of the center's Adolescent Communication Institute.