Halloween is the holiday of haunted houses, horror movies and scaring the pants off people. While some love the thrill of terror, others detest the iconic dark hallways and demons. The reason could be personal chemistry.

Fear is caused by a chemical reaction within the brain, according to Jeff Wise, licensed psychologist and author of “Extreme Fear: The Science of Your Mind in Danger.” Fear is something we are born with, and has been ingrained in our brains since we were “tiny creatures,” Wise said.

“When we’re in a dangerous situation, we have this primitive, reflexive response called the ‘fight or flight’ response, which is where the sympathetic nervous system comes into play,” he said.

The body then releases adrenaline, among other things, which your body recognizes positively because the chemical makes you stronger and more aware, according to Rob Dobrensky, also a licensed psychologist and author of “Crazy: Notes On and Off the Couch.” Wise said this release of chemicals can create effects similar to drugs such as heroine and marijuana.

Dobrensky and Wise agree that the difference between taking pleasure in terror and being just plain scared is the knowledge that you’re not actually getting hurt.

“You’re in a haunted house and somebody jumps out from behind the wall,” Wise said. “This primitive part of your brain is like, ‘Oh crap, I’m potentially about to die.’ Instantly, another part of your brain says, ‘You’re not in mortal danger.’ So you’ve got these invigorating chemicals, but not the unpleasant feeling of, ‘I’m about to get eaten.’”

Nick Smith, writer and director of the horror film “Munger Road” and a Columbia alumnus, said the horror-movie business has tapped into this differentiation, making scary movies more realistic in order to scare viewers more.

“As the horror genre changed, you had this idea of, ‘What if it’s real?’” Smith said. “‘Scream’ was one of the first mainstream movies to really be terrifying to audiences because it was one of those movies that, looking at it, two everyday guys could go bats–t insane one day and start killing their classmates in high school.”

Wise said people who enjoy terror often enjoy life more than others and are better in touch with their emotions.

“I think people who enjoy the spectrum of emotions feel more full and complete,” Wise said. “When you’re avoiding stuff, it’s hard to be truly happy in a lot of ways.”

Chad Savage, who works at Zombie Army Productions, a production company aimed at the sinister, said he was born with the inherent inclination toward terror.

“I’ve been wired this way from day one,” Savage said. “I always liked Halloween better than Christmas.”

In the debate of nature versus nurture pertaining to fear, Dobrensky and Wise think it’s a combination of the two.

“There’s probably something in our hard-wiring that makes us feel that way, and then some people are brought up with positive experiences with Halloween and scary stuff,” Dobrensky said. “The nature-nurture debate always comes down to both—it just depends on how much on each side.”

Smith said enjoying being scared also has to do with gender.

“It seems that [terror] hits women a lot harder than guys,” he said.

Smith also pointed to the artistic value of the horror genre. He said that scary movies go beyond just trying to keep you up at night and people averse to the genre should try to keep an open mind.

“You have this great mixture of storytelling,” Smith said. “I think at the very root of [the horror genre], that’s what people really enjoy. Some of the storytelling behind what is scary is great stuff.”