Every year, a few people bail out at the entryway to the "Haunted Basement" in southeast Minneapolis.

They've paid their $20, hoping for a good scare, then get cold feet. Some even call from home, pleading for a refund.

But there are no refunds at the Haunted Basement, says Lillian Egner, one of the hosts.

After all, if they're too afraid to set foot in the door -- well, mission accomplished. It's no accident that people feel their courage start to drain when they walk into the elaborate haunted houses that flourish at this time of year. The creators readily tap into the psychology of fear, using techniques that are known to manipulate people's emotions.

At the same time, experts say, visitors' reactions may depend as much on brain chemistry as on any sense of bravado, which helps explain why some people love a good thrill and others avoid it at all costs.

"Everyone has their threshold for stimulation and titillation," said Marc Mooney, an assistant professor of psychiatry at the University of Minnesota. "Some people are kind of predisposed to be scared."

Let the games begin

Will Grant, a lead designer of the Haunted Basement, says the goal is to play on people's primal fears. "The big thing is fear of the unknown," he said.

Grant and his team design everything -- sound, smells, lighting -- to build a sense of dread from the moment the customer walks in, and before.

"Many of these people have never been here; they're kind of scared of the building," said Egner, program manager at the Soap Factory, which hosts the Haunted Basement in a rugged-looking 19th-century brick warehouse near St. Anthony Main.

The psychological gamesmanship begins at check-in, when customers (who must be 18 or older) sign a waiver in case of harm. "It's a legitimate waiver," said Egner. But, she acknowledged, it also gets "the jitters going."

Thanks to some strategically placed holes in the floor, new arrivals can hear screams drifting up from below. Egner coaches the staff, mostly volunteers, to keep customers in the waiting area at least 10 or 15 minutes. "That's when the anticipation builds," she said. Then there's what Grant calls "total sensory overload" -- near or total darkness, weird smells and "massive amounts of audio." Plus roaming bands of actors who "can insert themselves in your group," sight unseen.

What Hitchcock knew

The haunted-house experience has a parallel in horror movies and roller coasters, says Robert Silberman, who teaches film studies at the University of Minnesota.

"It's exciting, and just scary enough to give you a little edge," he said.

The best fright houses, he said, take a cue from director Alfred Hitchcock, who famously preached the cinematic difference between surprise and suspense.

"Surprise is: We're watching two people talking and then a bomb blows up," said Silberman. "Suspense is: We're watching two people talking, and we know there's a bomb there." Then you can keep up the suspense, Silberman said, "until people just about burst."

For horror moviegoers, he added, "it can be a test. It can be a challenge." It's the same way with a fun-house, he said. You keep telling yourself it's make-believe, and "you sort of take that walk on the wild side."

In effect, they're trying to trick the brain, said Mooney, a clinical psychologist.

"We want to con ourselves into thinking we're in danger," he said. That causes what thrill-seekers often refer to as an "adrenaline rush." Literally, the brain signals the body to release adrenaline and another chemical messenger, noradrenaline, which together cause the heart to race and trigger the famous "fight or flight" response. Among other things, he said, the rush gives you the energy you'd need to fend off a life-threatening danger and shifts blood away from nonessential tasks, such as digesting food.

Risk-seekers

Mooney said some people seek out that kind of thrill because they crave dopamine, the pleasure chemical in the brain. "They need to seek out stimulation in order to feel good," he said.

They tend to be extroverts, he said -- the kind of people who join the military, or police or fire departments. "They have to find unusual risky situations for them to sort of feel alive."

But obviously, not everyone would call that fun. "Some people are just kind of keyed up and apprehensive," he said. "They're never really relaxed in any setting." And chances are, they won't find themselves at a haunted house or horror film. "They're the ones who, if they go to the multiplex, they'll go to the chick flick," he said with a laugh.

What about those who lose their nerve in the middle of the Haunted Basement? Once they start, customers are told, there's only one way to get out before the end: Cry "Uncle."

Last year, more than 200 people did, out of 8,000 customers.

Lest you think it was mostly women, Egner says it was closer to 50/50. "The two people who vomited last year were both men," she added helpfully.

Mooney sympathizes.

"If you reach a point where you're super-scared, you should cash out," he said. "There's no shame in getting out once you've gotten as scared as you can get."

Maura Lerner • 612-673-7384