Bird Box was the first breakout film of the new year. The post-apocalyptic thriller was watched by more than 26 million people over its first week on Netfilx, a record for the streaming service. It comes on the heels of last year's A Quiet Place, which was one of the top-grossing films of 2018.

Movies such as these have a single mission: To terrify their viewers. But why do so many people choose to spend two hours in perpetual fear?

New research provides a clear answer: We are evolutionarily wired to seek out such material. A research team led by Mathias Clasen of Denmark's Aarhus University argues horror movies, novels, and video games fall into the category of "benign masochism."

"Horror movies tend to imaginatively transport consumers into fictional universes that brim with dangers," the researchers write. "Through such imaginative absorption, people get to experience strong, predominantly negative emotions within a safe context. This experience serves as a way of preparing for real-world threat situations."

The study, in the journal Evolutionary Behavioral Sciences, featured 1,070 Americans recruited online. All completed surveys designed to measure their personality traits, propensity for sensation-seeking, and belief in paranormal phenomena.

They also reported how much they enjoy horror movies, books, and games; how frequently they were exposed to such material; and whether they prefer such films to be intensely or merely moderately scary.

As recent successes like Bird Box suggest, horror is far from a niche market, and more than 54 percent of the study's participants either agreed or strongly agreed with the statement "I tend to enjoy horror media." Only 14 percent strongly disagreed.

Echoing earlier research, the study found that horror-movie appeal peaked in adolescence and decreased with age. This pattern makes sense from an evolutionary perspective, in that the teen years are typically a time of angst-filled exploration — experience that produce emotions similar to those evoked by horror movies.

In terms of personality, those who scored high on "intellect/imagination" were most likely to report enjoying the genre. In the researchers' words, such people have "a proclivity for imaginative activity, including cognitive exploration and intellectual stimulation," and thus enjoy entering alternative worlds.

Surprisingly, the study found these films did not typically produce emotional catharsis (which Aristotle famously wrote was the ultimate purpose of drama). "A small majority reported being more scared after having used horror media, and 42 percent reported no change in anxiety level," the researchers report. "Only 5.6 percent reported being less scared."

But fans of the genre reported that, beyond mere fear, watching such films produced "higher levels of several types of positive emotions: joy, trust, anticipation, and surprise." These pleasant experiences "apparently more than compensated for the high level of expected fear."

These findings suggest that, at least for horror devotees, "such media provide a stimulus for greater mastery of initially [terrifying] situations," the researchers conclude. "With exposure, one builds up a certain level of coping competence."

Like so many traits that can be traced back to the early days of our evolutionary history, this one would seem to have limited usefulness in the modern world. Unless you're in motel management, it's hard to see how watching Psycho prepares you for the admittedly scary challenges of the modern workplace.

But we all feel terror at times, and, for horror fans, that potentially overwhelming emotion is reassuringly familiar. Having processed such emotions in the safety of a movie theater, or a living-room sofa, we may be better able to keep our wits about us when actual terror strikes.

Perhaps those of us who are petrified by presidential pronouncements need to spend more time binge-watching The Walking Dead.

This story originally appeared as How humans evolved to love horror movies on Pacific Standard, an editorial partner site. Subscribe to the magazine's newsletter and follow Pacific Standard on Twitter to support journalism in the public interest.