What prompted that Gun Violence Trends In Movies study I reported on yesterday? The one in which American and Dutch university researchers discovered that over a 20-year period gun violence in PG-13 films has more than tripled and that in 2012, there was more violence in PG-13 films than in R movies, which often gets that rating because of depictions of sex and nudity?

Here’s a closer look.

Co-author of the study, Dan Romer, a psychologist at the Annenberg Public Policy Center, tells me his team initiated its research after the massacre at Sandy Hook Elementary School in Connecticut last year, which unfortunately has been several massacres ago. The study predicts that “youth will be more interested in acquiring and using guns after exposure to gun violence in films.” I grew up in New Jersey and had my fair share of exposure to guns, but there aren’t as many guns here. That doesn’t mean that we haven’t seen incidents in Europe: in Norway in 2011, a gunman killed 69 people at a summer camp on the island of Utøya, and in 2010 in Britain a lone gunman killed a dozen people before turning the gun on himself. Last year in Toulouse, France, a lone perpetrator killed seven people in a series of three attacks. Meanwhile, in Marseille, the death toll in what is seen as an ongoing battle between drug dealing gangs, has just this week reached 18. Still, that is a pittance compared with the U.S., where semi-automatic weapons are so prevalent. According to reports, there have been 9,900 gunshot deaths since the Sandy Hook massacre.

I asked Romer his conclusions about why actual gun violence is less prevalent in Europe, even though we see the same movies as our Americans counterparts. He acknowledged that was a “counter-example” that’s often brought up since the same effects don’t seem apparent in other countries where Hollywood films are widely consumed. “We have a huge number of guns in America that are stored in homes where kids can get access to them,” he said. In Europe and elsewhere, Romer surmises, “It’s less of a problem because there is not as much access to firearms.”

One other big difference here is that in some parts of Europe, movies are given harder ratings for violence. In the U.S., the MPAA ratings board seems to be more concerned with the depiction of nudity and sex. In the UK, the classifications board rated The Dark Knight a 12A, which brought an outcry that the knife violence was too graphic, a reaction that came after a spate of stabbings on the streets. When the UK gave Nicolas Winding Refn’s ultra-violent Only God Forgives an 18 rating (the equivalent of an NC-17), France gave it a -12 rating, which means it was deemed appropriate for any teenager. It did hold a special warning that it included “scenes that could shock a young audience.” France gave Django Unchained the same rating, while the UK gave Quentin Tarantino’s violent slave saga an 18. Filmmakers are given a chance to trim for a desired rating. It wasn’t until The Hunger Games lost seven seconds of violence that it was given a 15 certificate. 

Romer’s big focus is on the U.S. and he feels the study should give the MPAA cause to consider giving more films the R rating for overt gun violence, and encourage them to give greater weight to gunplay than sex and cussing. Romer sent the study to the MPAA, but has yet to hear back. “We’d like them to reconsider if there’s a lot of gun violence,” he said, “but we’re not particularly optimistic. There’s been some talk about introducing a PG-15 category.” If that were to come to pass, it would be the first time a major category had been added to the system since PG-13 was added in 1985. As society continues to ponder the cause and effects of real violence, and the glorification of violence presented to young audiences in movies, TV and videos, some of it just seems to come down to common sense: “There is evidence that tobacco in movies gets kids to smoke, and that drinking gets kids to drink,” Romer said. “So what does gun violence get kids to do?”