Gary Slutkin, a renowned epidemiologist and physician, believes violence is a contagion that requires medical intervention. It is an unorthodox point of view he’s been developing for years, influenced by his work fighting infectious diseases in places like Uganda, where he ran the country’s AIDS program in the late eighties and early nineties, and helped reverse the epidemic there. The spread of violence, he likes to say, mirrors the spread of Tuberculosis or HIV, and can only be combated by going into the most infected areas and stopping the sickness at its source.

In 2000, Slutkin, a professor at the University of Illinois at Chicago, began to put his ideas about violence into practice, starting an organization called CeaseFire Chicago with the hope of reducing homicides and shootings in the city. The group’s efforts revolve around “interrupters,” people with a deep knowledge of a particular neighborhood who are trained as community health workers. Their job, according to Slutkin, is to “prevent shootings by identifying (before violence occurs) and mediating potentially lethal conflicts in the community, and following up to ensure that the conflict does not reignite.” Among other things, they respond to every shooting in their area, working with locals and victims to “cool down emotions and prevent retaliations.”

In the summer of 2007, it was CeaseFire’s interrupters who stepped in when Martin Torres, a former Chicago gang leader who was then 38, sought to avenge the shooting death of his 17-year-old nephew. Once he believed he had tracked down the killer, Torres obtained two handguns. But before he could use them, he received a call from another former gang member named Zale Hoddenbach, who knew Torres from a stint in prison and had heard he was plotting revenge. Ultimately, Hoddenbach persuaded Torres to return his weapons and let it go.

The program, now called Cure Violence, has since been implemented in other cities such as Baltimore and New York and has helped reduce violence in some urban neighborhoods by 40 to 70 percent. Eric Holder, the former Attorney General under President Obama, has called Cure Violence “the kind of approach that this Administration is dedicated to pursuing and supporting.” In the wake of another violent summer, with shootings on the rise in a number of major U.S. cities, The Trace spoke with Slutkin about how to halt a deadly epidemic.

What does it mean to “cure” gun violence?

The first part is for people to understand that violence is a health issue rather than an issue of morality, of people being good or bad. Years ago when people contracted the plague, they were thought of as “bad” people. In time, as science developed, society understood that the plague was a virus, contracted through exposure. A person wasn’t bad if they had the plague. They had a virus.

It’s the same thing with violence. Why? Because it’s acquired through transmission, and can be treated in the way we treat all infectious problems. “Curing” means reducing the violence by many levels so it’s a much less prevalent problem. It means “cure” in the community sense.

And what makes violence contagious?

People act because of the way they were treated by others — i.e., they pick up these behaviors in subconscious ways — and the brain is hardwired to copy other behaviors. Contagion means that something is contagious if it produces more of itself. Flu begets more flu, for example. The same principle is also true for violence, though it’s not true for everything: High blood pressure, for example, doesn’t cause other people to have high blood pressure. With violence, it’s just what we empirically see in nature — the greatest predictor of violence is exposure to a preceding event of violence. We also know there’s an underlying process that causes this to happen: There are neurons on the brain that cause copying, which is the principle way people pick up all kinds of behavior. Violence is a very powerful type of behavior for copying because it’s so electric and emotional that it actually causes even more copying. These are predicable biological processes.

But it isn’t possible to detect violence in the brain before the act is carried out.

No, there is not a biomarker in the brain per se. But there are proxies: history of prior exposure and victimization. The more you’ve had to deal with one of those things, the more likely you are to commit an act of violence. Understanding violent behavior in this way allows us to explain things that weren’t explainable before.

For instance: Why someone who was abused as a child abuses their own child — a third of abused people abuse their own children. Or why people who saw combat in a war sometimes continue the violence when they get home. In theory, that would make no sense, because you’re supposed to do violence against the enemy, not your family or your community. But it’s not about that; it’s that something has been acquired. It’s an epidemic pattern, and the more people who are exposed — i.e., the larger the dose — the more it continues.

So the conclusion is that people who are exposed to acts of gun violence are more likely to commit acts of gun violence?

It doesn’t have that specificity, really. If someone slept with your girlfriend or owes you money and it’s normative in your friend or peer group or neighborhood to respond with violence, you could use a gun or not — the norm is only that something violent be done.

Can a person’s brain be prevented from codifying violent behavior?

The brain is the manager of behaviors, but this is not seen or treated as a “mental health” issue. Rather, it is an issue of normal brain processes. While at first we need to have “interrupters” to help high-risk people off the hook socially, or go against the norms of their community, longer term it requires the expectations of a person’s [peer] group to change, and subconsciously driven behaviors will follow. So when someone says they’re going to retaliate violently, their group says, “You’re gonna do what?” You need to make a nonviolent response the group’s norm.

What sort of success have you had in changing a group’s behavior?

The Johns Hopkins evaluation of Baltimore’s adaptation of the Cure Violence health approach shows that norms among the highest risk are indeed changing in response. High-risk people in the neighborhood, beyond those who Cure Violence reached directly, were shown to be changing their behaviors according to confidential surveys. The study showed people were less likely to shoot or use violence in circumstances in which they previously would have. In fact, interviews of people in the next neighborhood over also showed that they were being influenced by the program, further disseminating the new norms. Control neighborhoods did not see this change in norms.

Can mass shootings be contagious?

There’s no doubt about it. Suddenly, for example, there have been several shootings in movie theaters, and the number of shootings of four or more persons at a time has increased quite a bit over the past couple years. The media, without a doubt, has a role in facilitating more events. There is research that shows that fewer headlines can equal fewer incidents and vice versa. The repeated nature of the showing of the event serves to spread or accelerate the transmission of the behavior.

But the media has a responsibility to cover these tragedies.

There needs to be some way of discussing it without causing a recurrence of visuals. The most responsible journalism would avoid showing photos and videos of graphic violence, and instead be more objective and informative.