One study that did find a link between movies and violence, for example, was Gordon Dahl and Stefano DellaVigna's paper "Does Movie Violence Increase Violent Crime?" The authors looked at patterns of violent crimes during evenings that violent movies were shown. In their words:
We find that violent crime decreases on days with larger theater audiences for violent movies. The effect is partly due to voluntary incapacitation: between 6PM and 12AM, a one million increase in the audience for violent movies reduces violent crime by 1.1 to 1.3 percent. After exposure to the movie, between 12AM and 6AM, violent crime is reduced by an even larger percent. This finding is explained by the self-selection of violent individuals into violent movie attendance, leading to a substitution away from more volatile activities. In particular, movie attendance appears to reduce alcohol consumption.
The main viewers of violent films are young men. Young men are also disproportionately responsible for violence. If large numbers of young men are sitting and watching a violent film, they aren't going to be committing robberies or vandalism or hooliganism or murder. They also aren't going to be drinking alcohol, which can lead to violence. So, Dahl and DellaVigna show, the immediate result of violent films is to reduce violent crime. If Weinstein wants to reduce violence, shelving Tarantino films is exactly the wrong way to do it.
So, violent films lead to less violence? Well, not exactly. In his memoir A Long Way Gone, Ishmael Beah, who was forced to become a child soldier in the terrible Sierra Leone civil war of the 1990s, writes about how violent media was part of his training regimen. Rambo: First Blood, Rambo II, and Commando were screened in constant rotation, a supplement to the drugs the children were given to encourage them in battle. "We all wanted to be like Rambo; we couldn't wait to implement his techniques," Beah writes. In one incident, Beah's friend Alhaji says he wants to practice his Rambo moves, then sneaks into an enemy camp and starts slitting the throats of the guards. Violent films here inspired real-life violence. They were part of a deliberate system that turned children into killers.
Media violence doesn't just affect children. Just as Beah and his friends learned from Rambo, so did lawyers at Guantanamo take information from 24's Jack Bauer. According to military lawyer Lieutenant Colonel Diane Beaver, 24 was "hugely popular" among personnel at Guantanamo, and "gave people lots of ideas" for novel ways to interrogate prisoners. Philippe Sands, who interviewed Beaver, said that the lawyer "believed the series contributed to an environment in which those at Guantánamo were encouraged to see themselves as being on the frontline—and to go further than they otherwise might."