Mass Shootings Sometimes Occur Close Together, But The Reason Why Remains A Mystery

Coronavirus is not the only public health concern running rampant in the U.S. as the nation's attention has been renewed to the frequency of mass shootings amid the violence in Boulder, Colorado and Atlanta, Georgia that killed a combined 18 people over the past week.

The recent tragedies are the latest chapter in the U.S.' long history of mass shootings, which begs the question if this violent phenomenon is an epidemic itself. More than 100 mass shootings have happened in 2021 alone, according to data from the Gun Violence Archive (GVA).

"In the world of psychology, we have very few phenomena that are due to one thing or one idea. It's really always a recipe with several ingredients," psychologist and Temple University professor Frank Farley told Newsweek, who is also a past president of the American Psychological Association (APA), in regards to the prevalence of mass shootings.

The GVA defines a mass shooting as four or more people shot, not including the shooter, with 2020 having 611 and 2019 having 417. A few of these instances occurred within 24 hours of each other, such as the 2019 El Paso, Texas mass shooting on August 3 followed by the Dayton, Ohio mass shooting on August 4.

Some prior research into mass shootings has pointed to a possibility of a contagious effect and how they could lead to more occurring.

The published 2015 study "Contagion in Mass Killings and School Shootings," written by data scientist Sherry Towers and a few others, used a mathematical contagion model to determine if "contagion" was evident in mass killings and school shootings.

After analyzing data from USA Today and the Brady Campaign to Prevent Gun Violence, the study found that mass killings involving firearms and school shootings can be "contagious" and likely to inspire similar events within a 13 day period. The data from USA Today covered mass killings between 2006 to 2013 and school shooting data from the Brady Campaign between 1998 and 2013.

The research acknowledged that this contagious effect could be potentially due to widespread media coverage of mass killings and school shootings.

"Columbine became so salient in our consciousness," Farley said of the April 1999 Columbine High School shooting in Littleton, Colorado. He mentioned that Columbine was the first mass shooting sensationally covered by the media and inspired the actions of some of those that followed.

In 2012, the Newtown, Connecticut Sandy Hook Elementary school shooter, Adam Lanza, who killed 20 children and six others, was obsessed with Columbine, according to the official report from the Connecticut State Division of Criminal Justice.

In 2015, authorities discovered that two female teenagers, Sienna Johnson and Brooke Higgins, were planning an attack on their Mountain Vista High School in Highlands Ranch, Colorado. After their plans were discovered, Johnson, while in custody, told detectives she was inspired by Columbine, according to Denver's

Farley said he understands how the word "contagion" can be used to understand the prevalence of mass shootings. However, he said it could be explainable by various psychological factors.

In the case of inspired events, such as those incentivized by Columbine, Farley points to the potential element of imitative modeling behavior where a person may copy others. However, he notes when an act of violence occurs and then is imitated, it may have been a "tipping" point for the imitator who was already headed in that direction emotionally and psychologically.

"One of the problems is we often will tend to oversimplify and we'll say, 'it's contagion,' or 'it's mental illness,'" Farley said while also noting the difficulty in deciphering a mass shooter's psychology and motives.

In the case of the shooting in Boulde, the lawyer of suspected shooter Ahmad Al Aliwi Alissa, who is being charged with 10 counts of first-degree murder, said in court Thursday that Alissa has a mental illness.

Colorado mass shooting
A SWAT team member runs toward a King Soopers grocery store where a gunman opened fire on March 22, 2021 in Boulder, Colorado. Chet Strange/Getty Images

However, Farley argued that mentally ill people tend to commit very few of these kinds of crimes

When mental health or illness is an alleged factor for a mass shooting, Farley said that standard approaches to mental health, such as the APA's Diagnostic and Statistical Manual of Mental Disorders (DSM-5), are important to consider.

"I don't know of any mass shooters or serial killers who were studied as part of developing the DSM-5 diagnostic system. They're just not there," he said. "If you generalize from our standard diagnostic system in psychology and psychiatry to a mass shooter, you're going away beyond the data in hand. They are way beyond the basis for a diagnostic system."

Farley mentioned another avenue of psychological theory known as the controversial weapons effect, "the idea that the mere presence of a weapon potentiates aggressiveness," he said.

This idea ties into another key factor he mentioned outside the realm of psychology to understand mass shootings — is easy access and ownership of guns in the U.S.

To provide an example, Farley said U.S. and Canadian culture are similar, but Canada has a vastly lower mass shooting rate.

"There's lots of guns here, but a lot of restrictions," Farley, who grew up in Canada, said. "It's a hunting culture, but they don't hunt each other."

Canadian Prime Minister Justin Trudeau banned assault weapons two weeks after a mass shooting in Nova Scotia in April 2020. The attack left 22 dead, and is the worst mass shooting rampage in Canadian history.

Alongside multiple psychological reasonings and how accessible guns are in the U.S., there's also the possibility of the role chance plays, Farley said, which is often downplayed in psychology.

"We want to go for a motive," Farley said. "Sometimes in some cases, it just was a chance event. I add that to the mix as a potential ingredient in the recipe in trying to understand this whole horrendous phenomenon."