School shootings are, thankfully, rare events. But when they do occur, they often do so in otherwise peaceful small towns or suburbs. Places like Newtown, Connecticut. Is this just random chance? Or is there a reason for it?

Julio Cortez/AP

A decade ago, at the urging of the National Research Council, sociologist Katherine Newman and a team of researchers looked into this very question. They examined 18 small-town school shootings since 1970 and spent years studying two extensively — one at Heath High School in Kentucky, the other at Westside Middle School in Arkansas. And in her 2004 book, Rampage: The Social Roots of School Shootings, Newman concluded that many of these small-town massacres followed a few striking patterns. 

One thing they discovered was that it was often boys at the margins of society who carried out these shootings. They weren't loners. But they were often socially awkward and struggling to fit in. And the atmosphere of small towns could exacerbate the problem. "In a small town," Newman says, "there often aren't that many options, it's hard to find a place where you can feel socially comfortable. These smaller towns are extremely stable — that's what makes them such wonderful places to raise a family. But that very stability can often feel like a death sentence to those at the margins."

So why attack schools? "Think about what the shooter wants to accomplish — trying to get the attention of their peers, trying to change how people around them think about them," Newman says. "If you're looking to attack a community and change the way people think about you, the school is the place where you'll have the most devastating impact."

Let's pause for a second and add a note of caution here. There's still a whole lot we don't know about Adam Lanza, the 20-year-old who shot 26 people in Sandy Hook Elementary School last Friday. Newman cautions that Lanza may not fit the general pattern she described in her book. "For one," she says, "[Lanza] wasn't part of that school community" — as the shooters she studied usually were. While there are often "family resemblances" between shootings, no two are ever exactly alike.

But even if school shootings are often wildly different, is there anything that can help prevent them?

Newman points out that the two policies most often discussed — stricter gun laws and better access to mental health — could conceivably help at the margins. "The vast majority of young people who ever think about doing something like this are ambivalent and don't really have the drive," she says. "And if it's harder to get their hands on a gun, they won't do it. But for the truly dedicated, they're much harder to stop."

Better access to mental-health services, meanwhile, would be invaluable for the millions of Americans suffering from depression and other disorders. But would it stop school shootings? That's less clear. Again, these are rare events that are extremely difficult to predict. Some shooters come from good families, some from bad ones. They are nearly impossible to profile. The FBI, for one, has given up trying.

Many schools have tried to improve their security systems. That might have helped in the case of Adam Lanza, who reportedly forced his way into Sandy Hook. But that could be an exception, not the rule. "In the cases we studied," Newman cautions, "better security systems wouldn't have worked." School shooters are typically people who are supposed to be in school. And most shootings start and finish very quickly—before security officers or the police can react.

There was, however, one policy that Newman's team found might help. "In most of the cases we studied, there was ample evidence that the shooters had made a lot of veiled threats before the shooting," Newman says. "Often the threats are extremely difficult to interpret. They're vague statements like, 'You'll see who lives or dies on Monday' or 'I'm going to be running from the cops.'" Even so, there are frequently other students who do pick up on the threat.

"One thing that's absolutely critical is for schools to make it easier for kids who hear threats to come forward," she says. "Very often they don't. They often perceive social risks to coming forward. Often they don't feel like the adults will do anything." In many of the cases Newman studied, students didn't trust that adults would keep what they said confidential, often with good reason.

Newman's team did find that in schools with school resource officers — typically retired police officers providing security — students were often much more willing to come forward with threats they'd heard. "Kids do seem more comfortable with them because they're not part of the school hierarchy," she said. (Interestingly, it's typically girls who are most likely to come forward.) In recent years, however, many schools have cut back on these officers, thanks to tight budgets.

But would any of this have helped in the Newtown shooting? Probably not. After all, unlike in many past shootings, Adam Lanza wasn't a member of the school community. There's little evidence that he tried to issue threats or boast about his crime beforehand. And, while many schools have tried to invest in anti-bullying programs to help social outcats, there's nothing to suggest that Adam Lanza was bullied either. 

Which means that the Newtown shooting may well be yet another special case. A better understanding of the social roots of school shootings might be able to help prevent some future tragedies. But not all of them.

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