If we knew that AK-47-wielding terrorists were destined to kill 1,000 people in the U.S. in 2016—a thinkable possibility—then we should be afraid . . . albeit 1/10th as afraid of other homicidal gun violence (which kills more than 10,000), and 1/30th as fearful of riding in a motor vehicle, where more than 30,000 Americans die each year. Yet several recent surveys indicate we are much less fearful of the greater, everyday threats than of the dreaded horror.

The hijacking of our rationality by fears of terrorist guns highlights an important and enduring piece of scientific news: we often fear the wrong things.

Shortly after 9/11, when America was besieged by fear, I offered a calculation: If we now flew 20 percent less and instead drove half those unflown miles, then—given the greater safety of scheduled airline flights—we could expect about 800 more people to die on our roads. A German colleague, Gerd Gigerenzer, later checked that prediction. He reported that, actually, in the year after 9/11 “an estimated 1,500 Americans died on the road in the attempt to avoid the fate of the [246] passengers who were killed in the four fatal flights.” Long after 9/11, the terrorists were still killing us.

Why? Why do we fear flying, when, for most of us, the most dangerous part of our trip is the drive to the airport? Why do terrorist fears so effectively inflate our stereotypes of Muslims, inflame us/them thinking, and make many of us Christians forget the ethics of Jesus (“I was a stranger and you welcomed me”)?

Underlying our exaggerated fears is the “availability heuristic”: We fear what’s readily available in memory. Vivid, cognitively available images—a horrific air crash, a mass slaughter—distort our judgments of risk. Thus, we remember—and fear—disasters (tornadoes, air crashes, attacks) that kill people dramatically, in bunches, while fearing too little the threats that claim lives one by one. We hardly notice the half-million children quietly dying each year from rotavirus, Bill Gates once observed—the equivalent of four 747s full of children every day. And we discount the future (and its future weapon of mass destruction, climate change).

If only such deaths were more dramatic and immediate. Imagine (to adapt one mathematician’s suggestion) that cigarettes were harmless—except, once in every 25,000 packs, for a single cigarette filled with dynamite. Not such a bad risk of having your head blown off. But with 250 million packs a day consumed worldwide, we could expect more than 10,000 gruesome daily deaths (the approximate actual toll of cigarette smoking)—surely enough to have cigarettes banned.

News-fed, cognitively available images can make us excessively fearful of infinitesimal risks. And so we spend an estimated $500 million per U.S. terrorist death but only $10,000 per cancer death. As one risk expert explained, “If it’s in the news, don’t worry about it. The very definition of news is ‘something that hardly ever happens.’”

It’s entirely normal to fear violence from those who despise us. But it’s also smart to be mindful of the realities of how most people die, lest the terrorists successfully manipulate our politics. With death on their minds, people exhibit “terror management.” They respond to death reminders by derogating those who challenge their worldviews. Before the 2004 election, reported one research team, reminders of 9/11 shifted people’s sympathies toward conservative politicians and antiterrorism policies.

Media researcher George Gerbner’s cautionary words to a 1981 congressional subcommittee ring true today: “Fearful people are more dependent, more easily manipulated and controlled, more susceptible to deceptively simple, strong, tough measures and hard-line postures.”

Ergo, we too often fear the wrong things. And it matters.