According to Campus Safety Magazine, since the two mass shootings in El Paso, TX and Dayton, OH, police have reported at least 30 people have been detained on threats of mass shootings, with one of the most recent resulting in the arrest of a student at High Point University. This comes as no surprise to researchers who study mass shootings, including Sherry Towers, a faculty research associate at Arizona State University. Towers had spent most of her career modeling the spread of infectious diseases and began using the same mathematical model to see if violence spread contagiously. In an interview with NPR, Towers said, "what we found was that for the mass killings, so these are high-profile mass killings where there's at least four people killed, there was significant evidence of contagion. We also found significant evidence of contagion in the school shootings." These shootings tend to receive national and even international media coverage, which creates a window when a shooting is most likely to lead to more incidents, typically about two weeks. Towers' findings were published in 2015 and similar patterns were confirmed by Jillian Peterson, a criminologist at Hamline University in Minnesota and founder of the nonpartisan think tank,  The Violence Project, funded by the National Institute of Justice.

 

Peterson has found similarities between mass shooting contagion and suicide contagion (see our previous article on suicide contagion). She has conducted interviews with living mass shooters in prison and found that these people often start out feeling suicidal. Peterson is quick to clarify that a small minority of people considering suicide go down the path of violence toward others and people with any kind of mental health problems aren't more likely to be violent than others.

 

Economists Michael Jetter and Jay Walker, of the University of Western Australia and Old Dominion University, respectively, also concluded that media plays a heavy role in contagion. In a working paper they published in 2018, the findings "consistently suggest a positive and statistically significant effect of coverage on the number of subsequent shootings, lasting for 4-10 days. At its mean, news coverage is suggested to cause approximately three mass shootings in the following week."

In addition to traditional media coverage, social media coverage soars both during and after a mass shooting event. One communications student at Elon University analyzed (PDF) the differences in social media use between Columbine, Virginia Tech, and Parkland. Understanding the evolution of social media and how it is used today to convey intense moments from a live active shooter incident is a dramatic departure from even 10 years ago.

 

In an interview with Wired, Michael Jetter explained, "Many of these people (shooters) want fame. In manifestos by some of these shooters, they say, 'I want to be famous, and I want to be recognized, I want to be feared.' We found a way to test for that empirically, and the results seem to confirm that if you give them that room in the media, then you just encourage others."

 

Some media outlets have made concerted efforts to limit naming shooters or showing their photos, rather focusing on victims and their stories. Pennsylvania State University behavior analyst Jonathan Ivy suggests several guidelines for reporting on mass shootings including:

The answer to media coverage is undoubtedly complex since the media has a public safety duty, and this does include communication via social media. It is likely additional research on mass shooting contagion will continue as more connections are revealed. As always, it remains crucial for students, faculty, staff, and community members to inform law enforcement of anything suspicious. The See Something, Say Something campaign applies to mass shooting prevention, not just international terrorism prevention.