Your pulse pounds. Your eyes widen. Your white knuckles grip tightly.

At first blush it sounds like something you might want to avoid, but those are the opening lines for an ad promoting Six Flags Great Adventure's new drop ride, Zumanjaro: Drop of Doom.

At 415 feet, Zumanjaro is the tallest drop ride in the world. The 30-second trip to the top gives riders sprawling views of New Jersey as the ground gets farther and farther away.

"Once you get to the top, there's a very short delay. But there's no warning – just let you go," said Six Flags corporate engineer Michael Reitz, who was part of the team that built Zumanjaro.

Suddenly, the drop.

Roughly 250 feet without brakes. Ninety miles per hour straight down.

"And that entire time you are very aware that the ground is getting much closer. Quickly!" laughs Reitz.

On a recent morning I rode Zumanjaro, and it is as terrifying as it sounds. I remember thinking that if my harness gave out at any time, it could have pretty quickly turned into a skydiving trip.

And yet the only conclusion I could come up with after it was all over was: man, that was awesome.

My fellow riders offered similar reasons for why they chose to be hoisted 415 feet in the air and dropped without warning—the thrill, the adrenaline rush, the payoff after overcoming their fears about the ride.

"I believe that we, for some reason, we love controlled fear," said Reitz. "We want to be afraid, we want to push ourselves to the limit. But we want to know that we're safe."

So, how is it that we can take an emotion as devastating as fear can be, and get intense enjoyment out of it? It turns out that has a lot to do with how our brains work.

New York University neuroscientist Dr. Joseph LeDoux found that when our bodies receive information from our senses in a threatening situation, like the sound of screeching tires, that information follows two different pathways in the brain.

The first, quicker pathway—known as the "low road"—runs directly to a part of the brain called the amygdala, which produces protective defensive responses. So you might react to those screeching tires by screaming or jumping out of the way before you're even aware of what's happening.

The second, longer pathway—known as the "high road"—sends the sensory information first to the cerebral cortex, then to the amygdala. That lets the brain figure out in more detail what's going on. This pathway would tell you that the sound of those screeching tires came from a few blocks away and that you're safe.

"The low road sets up what may be a dangerous situation. The high road will confirm or deny that," said LeDoux.

This is evolution acting an over-protective parent. Even if we consciously know that a threatening situation is actually harmless, like riding a roller coaster, our unconscious brains will respond to it by deploying our body's defenses anyway.

In a matter of milliseconds, blood will rush to our legs in case we need to run, our arms in case we need to fight.

This is why you might feel that shiver go up your spine during a scary movie. "Your skin cools because it doesn't have blood to warm it," said LeDoux, "so you get a chill."

The difference between a good scary experience and a bad scary experience rests in how we process those instinctual responses.

"It's all in the meaning-making we do," said Dr. Margee Kerr, a University of Pittsburgh sociologist who studies fear. "Once that arousal, or threat response happens, that next part is all the cognition. And the thinking about, you know, what it feels like and whether you're in real danger."

For those of us who like being scared, that burst of feeling can be fun if we process it the right way.

But even if most thrill-seekers after the rush in a scary situation, there are other benefits to feeling fear. Take, for example, the psychological boost we get after making it through a terrifying experience.

On a fact-finding trip for her upcoming book, SCREAM: Adventures in the Upside of Fear, Kerr visited the CN Tower in Toronto, Canada. For $175, you can walk around on a narrow ledge near the top of the tower, 1,168 feet off the ground.

"As soon as I walked out there I was terrified. Everything in me was saying 'this is a really bad idea. You can't fly. And you're gonna die.'"

The "low road" sounded alarms. But Kerr pushed aside her fears and completed the walk anyway, feeling like a million bucks afterward. Her brain took note.

"When we engage in these safe thrilling experiences," Kerr said, "it helps us build a kind of distress tolerance. So when we experience situations that are threatening and they're not our choice, we can get through them a little bit more easily."

And all of that is to say nothing of the social bonds we form when experiencing fear or horror in a group.

Kerr, who is also the resident sociologist at ScareHouse, a series of extreme haunted houses in a converted Pittsburgh Elks lodge, has seen this firsthand.

"People who are standing in line together, for example, they may not know each other. And by the end of the ride they're high-fiving, they're giving each other hugs. And you see this kind of bonding that happens in these moments when our bodies are in this high arousal state. We're just kind of connecting more strongly, and building great memories usually. If the experience is good."
It turns out fear can really work to our advantage, as long as we can convince ourselves to take the leap.

So next time you sit down to watch a slasher flick with your friends, remember there are good reasons for choosing to be scared. Just don't let your brain tell you otherwise.