"When a mass killing occurred, it temporarily increased the probability of a similar event occurring in the near future."
Sherry Towers
As homicide rates in Hartford and other cities across the country spike, some are asking whether one high-profile shooting can breed another.
Sherry Towers was supposed to have a meeting at Purdue University back in 2014. But the meeting was canceled because of a school shooting there that day.
"And it occurred to me that day that that was, I believe, something like the third school shooting that I had heard about in a about a ten-day period," Towers said on WNPR's Where We Live. "And I thought, is this just a statistical fluke that there has been this many over about a week long period?"
So Towers, a research professor and statistician at Arizona State University, decided to study the question. Using data from the Brady Campaign to Prevent Gun Violence and from USA Today, she found that, for some shootings, there was in fact a spillover effect.
Towers said that big, high-profile shootings may in fact inspire follow-ups, causing them to spread like a contagious disease.
"If you looked at higher-impact events, where there were many more people killed, or if it was a school shooting, then those tended to get national media attention -- those showed evidence of contagion," Towers said. "They showed that there was evidence that, when a mass killing occurred, it temporarily increased the probability of a similar event occurring in the near future."
Hank Schwartz is psychiatrist-in-chief at Hartford Hospital’s Institute of Living. He said that Towers's data makes sense.
"The contagion, I think, is fueled by disinhibition," Schwartz said. "Which is to say that, the more an individual sees these kinds of incidents, and we're seeing them all the time, the more the incident becomes acceptable."
Towers also said that per-capita rates of school and mass shootings are far higher in states that have a higher prevalence of firearm ownership.