But that assumes that parents can and will control what movies their children will see, an increasingly dubious proposition in the Internet age. If anything, advertising that a movie has "grisly violence" or "strong sexual content" could make teenagers want to see it more. As a child, I remember scanning the content descriptions beneath cable movie listings to see whether any had enough adult content for it to be worth my while. The MPAA's new labels will not stop anyone from seeing movies with adult content; it will only save children the trouble of squinting.

Historically, movie studios only make serious moves towards self-regulation when Congress forces them to, and in in many ways, this latest cosmetic tweak is a proportionate response. President Obama has done little to make good on his promise to include violence in the media as part of the post-Newtown discussion. His comprehensive gun violence package, the centerpiece of which failed in the Senate on Wednesday, included only a $10 million allocation to the Centers for Disease Control and Prevention to study the link between video games, television, and movies, and real-life violence. This is the definition of token, especially since numerous studies already exist on this topic. Congress has done even less. Senator Patrick Leahy, as chair of the Senate Judiciary Committee, promised to bring studio executives to Washington for hearings on violence in the media. But so far, Leahy has not called a single witness from the Hollywood community to testify, a fact that makes it hard to forget he has close ties to the industry (his two biggest campaign contributors are Disney and Time Warner, and he has even appeared in several Batman movies).

The idea that movie violence and real-life violence are linked is, to say the least, controversial. But it's a link that polls have shown much of the public holds. And interestingly, even many people in the industry seem like they are up for discussing it. After the shooting in Aurora, influential producer Harvey Weinstein called for an industry-wide summit to discuss the effect movie violence may have on real-life bloodshed. Just a day after the tragedy in Newtown, Jamie Foxx said that Hollywood cannot say that "violence in films...doesn't have a sort of influence." This is noteworthy because both Weinstein and Foxx are closely linked with writer/director Quentin Tarantino, who has exploited movie violence with more glee—and more success—than any filmmaker working today. Further, the trade paper Variety issued in January a substantive special report on the issue of violence in the media, featuring multiple viewpoints on the issue and artful collages of still photographs from famous violent movies juxtaposed with gruesome real-life violence. In the issue's introduction, editor-in-chief Timothy M. Gray urged filmmakers to "think about every word and action and whether they devalue human life" and noted that there is "a fine line between catering to the public and pandering to their basest instincts."