A rule of thumb in the firearm industry is that when Democrats are in office, gun owners buy more guns because they’re worried that politicians will “take their guns away.”

But as with so much else in 2020, the last year of President Donald Trump’s tenure, that rule did not seem to apply.

The total number of guns purchased each year in the United States is hard to come by. But the number of FBI background checks, which represents a substantial portion of efforts to acquire firearms, reached a record 39.7 million in 2020 — a 40% jump from the year before. The surge began during the early months of COVID-19, and it picked up steam in the summer after the murder of George Floyd and its consequences.

In a new study exploring the psychology behind these purchases, Rutgers University researchers found that when compared with other gun owners, those who purchased firearms in 2020 seemed more sensitive to perceived threats and had less control over their emotions and impulses.

“What we’re showing is that these people who are purchasing firearms during the 2020 surge are different from typical firearm owners,” said Taylor R. Rodriguez, one of the study authors. “There’s something unique about this group of people.”

The findings come amid a renewed debate over gun safety, sparked by record rates of homicides in Philadelphia and other cities in 2021, the Kyle Rittenhouse trial, and other high-profile cases.

Published in the journal Social Science & Medicine, the study was based on a survey of 3,500 U.S. adults, selected to correspond with demographic characteristics from the 2010 census. Participants included gun owners who said they purchased a firearm in 2020, those who did not, and non-gun owners.

When asked a series of questions designed to measure sensitivity to threats, gun owners who did not purchase a new firearm in 2020 scored the lowest of the three groups. Those who did purchase firearms in 2020 were warier of threats, scoring about the same as non-gun owners.

In a second series of questions designed to measure “disinhibition,” those who purchased a firearm in 2020 scored far higher than either of the two other groups, meaning they had lower impulse control.

The mind-set that prompts people to purchase firearms has received little study, so the new findings represent a valuable contribution to the field, said Nick Buttrick, a postdoctoral research associate at Princeton University’s School of Public and International Affairs.

Buttrick, who was not involved with the Rutgers study but has studied the topic, said more work is needed to sort out cause and effect in the psychology of the 2020 purchasing surge.

Were those people prompted to buy guns because of how they view the world? Or did the purchase itself alter their mind-set in some way?

“We aren’t sure whether they were that way beforehand, or whether having bought a gun, it’s sort of sensitizing them to be more aware of threats,” he said.

Likewise, prior research has found that owning a firearm is associated with more willingness to take risks. But that doesn’t necessarily mean one factor causes the other. Men in general have a higher tolerance for risk.

Other studies suggest there are two primary motivations behind firearm purchases — sport shooting and hunting, and the belief that the weapon is needed for self-protection, Buttrick said. There can be overlap between the two, but it is likely that those who purchased firearms in 2020 fell more into the “protection” category, he said.

Rodriguez agreed that more research was needed, calling the study a first step. She said she and her coauthors, who work at the New Jersey Gun Violence Research Center, undertook the study in part to guide violence-prevention messaging.

“If you can tailor it to the specific group you’re working with — what’s important to them, what’s driving them to this behavior — then you can know what to target,” she said. “You can know how to talk to them.”

With gun purchases still brisk in 2021, the researchers may now have to broaden their scope. By the end of October, the FBI had recorded 33 million background checks, already higher than any year before — except for 2020.