Mass Shootings in America Are Spreading Like a Disease

If it seems like the shootings are becoming more frequent, it might be because mass murder can catch on like an epidemic.

A hand holding a candle at a nighttime vigil
A vigil for victims of the mass shooting in Sutherland Springs, Texas (Darren Abate / AP)

Twenty-six people shot dead in Sutherland Springs, November 5.

Fifty-nine people shot dead in Las Vegas, October 1.

Forty-nine people shot dead in Orlando, June 12 of last year.

These are three of the five worst mass shootings in modern U.S. history. All happened in the past two years. Two occurred within the same two months.

Is there a connection?

Several years ago, Malcolm Gladwell wrote an article in The New Yorker positing that national school shootings might spread like a disease. He cited the models of Mark Granovetter, a Stanford University sociologist whose theory of social-influence “thresholds” explained the gathering force of a riot. Imagine an avalanche, where the first tranche of snowpack to move might be quite unsteady, but as the wave of snow gathers force, it becomes powerful enough to dislocate even the most stable trees and houses. Similarly, a riot might begin with one wild rebel throwing a rock through a window just to get a rush. It becomes a public movement when the momentum is powerful enough to move even the relatively stable people nearby to join in the rock hurling.

In this way, a spate of mass shootings might behave like “a slow-motion … riot,” such that each murderous event normalizes, or encourages, new participants to join the movement.

At the time, Gladwell’s conjecture was mocked for its suggestiveness. After all, there wasn’t much evidence to support the claim that Granovetter’s threshold theories applied to mass shootings that were separated by many months and committed by strangers who had had no chance of meeting.

But according to a 2015 paper out of Arizona State University, “Contagion in Mass Killings and School Shootings,” there are some data that mass shootings often occur in bunches, which indicates that they “infect” new potential murderers, not unlike a disease. “We find significant evidence that mass killings involving firearms are incented by similar events in the immediate past,” the authors wrote. Suicide and terrorism, too, have been found to be likewise contagious. (Interestingly, the authors found “no significant association” between the rate of school and mass shootings and the state’s prevalence of mental illness.)

Diseases spread among individuals, but the contagion of mass shootings seems to spread through broadcast media. In an interview with The Atlantic in 2015, Sherry Towers, the ASU paper’s lead author, hypothesized that television, radio, and other media exposure might be the vectors through which one mass shooting infects the next perpetrator. Like a commercial, each event’s extraordinary coverage offers accidental advertising for depravity. One reason why mass-media coverage of shootings might inspire more shootings is that public glorification inspires some mass murderers. Eric Harris, the central planner of the Columbine murders, wrote Ich bin Gott—German for “I am God”—in his school planner.

It’s hard to say what lessons the news community should take from such findings. Mass shootings have inherent and unambiguous news value. It is absurd to suggest that the media ignore them entirely. But perhaps journalists should cover such events with an awareness that even noble coverage can advertise. Some media critics endorse a “Don’t Name Them” method, whereby mass shooters are deliberately left anonymous. But readers and viewers are fascinated by the motives and details of mass shootings, and it’s unlikely that they’d tolerate such an approach. With that in mind, Mother Jones has suggested minimizing the use of the perpetrator’s name, limiting head shots, and banning outright any potentially aggrandizing photos.

The mass-shooting-contagion paper ought not to be the final word on the effect of mass media on gun violence. The United States spends millions of dollars tracking other causes of disasters, such as tornadoes, which have been about as deadly as mass shootings in the past half-century. But research on mass shootings is relatively sparse.

That might explain why there aren’t standard methodologies, definitions, or even conclusions about their frequency or causes. For example, an analysis by Mother Jones starting in 2012 found that mass shootings killing four or more people have become more frequent in the past few decades. But a separate analysis by Grant Duwe, the research director at the Minnesota Department of Corrections, found that while the mass-shooting rate has not increased since the 1970s, the number of victims has grown steadily since the early 2000s. Duwe supposes that the rising deadliness of mass shootings might be most responsible for the growing perception that these events are becoming more common, since the number of casualties is the strongest predictor of media coverage. It’s a scary story, no matter which side is correct. Given the contagion research, one can imagine a sinister feedback loop that might explain the recent spate of murderous sprees. If more victims mean more media coverage, and more coverage means more inspiration, it implies that historically violent mass shootings might be the most contagious.

Mass shootings are often committed by lonely and unrooted men, suffering from both grandiose aspirations and petty grievances. The postmortem descriptors are practically rote: He was cold, weird, withdrawn, a loner (and, one must note, always “he”). It’s astonishingly rare to read the antonyms: He is almost never warm, welcoming, the most popular kid in school. Even when mass shootings are not, strictly speaking, terrorism, they still seem to adhere to a sort of dark and nearly invisible ideology of oppressive self-aggrandizement, a bid for greatness that requires the destruction of others. Just because there is no formal institution like ISIS to symbolize this strain of white rage doesn’t mean that the rage isn’t ideological. It’s possible that many instances of white-male mass-shooting violence are, in fact, driven by a media-inspired religion of grievance and greatness—a mass-distributed sickness for which male outcasts are most vulnerable to infection.

“This isn’t a guns situation,” President Donald Trump claimed on Sunday in a brief address from Tokyo. But the statistics offer no doubt. There are more gun deaths in America because, simply, there are more guns. The American rates of firearm homicide, child-firearm mortality, and gun-related suicide are far higher than in any other industrialized country. The United States, home to 5 percent of the industrialized world’s population under 15 years old, accounts for 87 percent of its unintentional firearm fatalities involving that age group, according to a 2003 paper. Mass killings are an epidemic that so many leaders refuse to name, or even to see. If America cannot amend the laws that facilitate such violence, it should at least commit more resources to studying why this seems to be a paradoxical age of historically low crime, yet contagious mass murder.