One could analyze this predicament (someone needs to watch these videos; they yield valuable information about a territory closed to outsiders) as a human-resources issue. How does an employer protect its workers from trauma? One set of tips, quoted by Allam, includes the suggestion that the viewer lessen the effect of the snuff films by turning off the sound, changing the color settings to monochrome, or “taking a deep breath.” These techniques may well help, but they suggest a narrow perspective on the issue.

Simon Cottee: What the media won’t tell you about ISIS

I first watched a terrorist beheading video in 2002, when Pakistani al-Qaeda members beheaded the Wall Street Journal correspondent Daniel Pearl, and I was too young to know better than to click on the video. A couple of years later, the progenitor of the Islamic State, Abu Mus’ab al-Zarqawi, beheaded Nicholas Berg on camera, inaugurating a new era in decapitation videos. I was in the company of U.S. marines at Al Asad Air Base, in Iraq, when a burly corporal walked into the room and announced that he had found a “sick video” depicting the execution of a British contractor, Kenneth Bigley. I suggested that the marines not watch the video, but I knew that marines tend to do whatever they damn well please, and that friendly admonitions from non-marines tend to backfire. So out came the laptop. They watched the video, and although they didn’t shudder, and even laughed, I knew that it had wounded them. In a small way, they had participated in an act of supreme inhumanity.

These were men—no women were in the room—more used to violence than most: They were trained and deployed to kill. One might add that they came from a culture soaked in violence, where cinemas countrywide are packed every weekend with audiences watching violent movies, and more people are shot per capita than anywhere else in the developed world. But I promise that when you watch the real thing—an actual murder, filmed in high definition—the difference becomes immediately apparent. You can never see a Hollywood or grind-house movie again without recognizing the violence for the comic-book fantasy that it is. Hostel (memorably praised by Jeffrey Goldberg as “the most repulsively violent movie I’ve ever seen twice”) contains scenes superficially reminiscent of ISIS videos, but it is no longer the violence that repels me; it’s the repulsively boring story, characters, and dialogue. Compare it with, say, certain Werner Herzog films, which shock you by being unmistakably real, with actors really frightened by real explosions, and magical scenes that could not possibly have been faked.

Read: What ISIS really wants

But back to ISIS. The whole point of those videos is to terrify their viewers, and to nibble away at the mental health of people like those marines and other enemies of the Islamic State. Jihadists often quote the scriptures that commend terrorizing certain enemies of Islam. They interpret verses to mean that terrorism in the defense of Islam is no vice, and that anything that scares the bejesus out of the infidel is a blessing. So, to be direct: Is this concern about the mental toll of these videos a sign that they were successful? Are the researchers traumatized by these videos casualties of war?