A new Public Religion Research Institute survey out Thursday finds that two-thirds of Americans say that mass shootings are a "critical" issue facing the country today, with 75 percent saying the same about terrorism. And the shooting in San Bernardino last week represents something of a perfect confluence of those issues: Islamic State-inspired extremists walk into a staff gathering and begin murdering people with assault-style rifles.

Data from Google shows that Americans are dealing with these anxieties in the most quintessentially American way: interest in concealed carry gun permits has exploded to unprecedented levels this month.

Concealed carry permits allow people to carry loaded handguns on them in public, hidden from sight, typically for self-defense. The practice has become more widespread over the past decade as gun rights advocates have pushed for more states to allow it. Researcher and gun advocate John Lott estimates that there are about 12.8 million concealed carry permit holders in the U.S. as of 2015, up from 4.6 million in 2007.

As the chart above shows, the previous peak in search interest in the subject came in the immediate aftermath of the Newtown school shooting. But so far this month, interest in concealed carry is roughly 66 percent higher than it was then. People may be heeding the advice of Jerry Falwell Jr., president of Liberty University, who said in response to the San Bernardino shooting that "if more good people had concealed-carry permits, then we could end those Muslims before they walked in and killed them."

This line of reasoning has become increasingly accepted among the public. A recent Gallup poll found that 56 percent of Americans say the country would be safer if more people carried concealed firearms. The only problem is that the research generally doesn't back up this notion. Social scientists are finding that more guns lead to more gun crime. Loosening concealed carry restrictions is associated with an increase in assault, rape and murder. And most people are shockingly bad at effectively using their guns in a self-defense situation.

You don't need to be a gun policy expert to understand that if more people are walking around carrying firearms, some will use them to nefarious ends. People with concealed carry permits are more likely to commit mass shootings than to stop them.

To be fair, a certain number of "good guys with guns" will be able to use them in self-defense to prevent crime. But for every criminal killed in self-defense, 34 innocent people die. And simply having a firearm in the house is a risk factor for both homicide and suicide.

It's a well-established fact that Americans buy more guns in response to mass shootings. The New York Times released a fantastic interactive Thursday that poignantly shows what national events proceed spikes in gun sales. The typical explanation is that anticipation of stricter gun control laws prompt people to get a weapon, as criminologist Gay Kleck explained to me earlier this year.

But the chart above suggests that fear and a desire for self-defense is another factor in rising gun sales in response to tragedies, and that those are certainly a big driver of interest in concealed carry permits. But the research suggests that our instinct toward self-preservation via firearm may actually be putting us in more danger.

More from Wonkblog: