Psychologist Farley said that some people are wired to be thrill-seekers and others are not. "The brain is involved and we don't know all the processes," he said.
How a person reacts to fear is based on three factors, according to Farley -- biology, psychology and social influences.
"Anybody who studies kids can line them up and see those who are risk takers and those who aren't," he said. "In part, it's genetic. But the amount of thrill-seeking is not totally genetic. It's false science to say it's heritable."
Thrill seeking can also be learned. "There is no question we are a learning animal," he said. "Genetics and biology are important, but thousands of years of culture and learning override all sorts of things. In other species, you take away their habitat and they die. We create a new one."
Communities and societies can also reinforce risk-taking behavior. Americans tend to "push the envelope and explore life," perhaps because of years of immigration.
"Immigrants going to a new life experience risk-taking even when uncertainly is guaranteed. They tend to take risks and be classic envelope pushers."
Sally Reed, director of communications for a nonprofit from Groton, Mass., doesn't like to be spooked. "The Twilight Zone scared the crap out of me," she said.
In high school she went to see the film, "Wait Until Dark" with an older date from Yale. That, however, turned humorous.
"There's a scene where the entire screen goes black and then after suitable suspense, horrible Alan Arkin lunges out of the dark at poor blind Audrey Hepburn," she said. "My date ... screamed a terrified falsetto girly scream and jumped into my lap.
"When I got home I howled with laughter," she said.
If Halloween horrors are any example, humor and laughter also seem closely aligned with fear. Such is an example of so-called gallows humor, according to Farley.
"Right when you are near death, you can crack a joke and laugh," he said. "Somebody says something and there is emotional facilitation or emotional contagion. At the extreme of human emotions, you get this mixture of the dark side and the funny side."
Such was the case with one of Debbie's pajama party guests.
"I don't think we had much to be afraid of, so telling scary stories at pajama parties was popular," said Kathy Varone, a former tennis pro from Hampton, N.H. "I'll bet kids don't do that much anymore – they use Internet games instead.
"The scariest thing I remember doing was driving through the cemetery at night and when the headlights hit a certain monument, it glowed like a ghost. It was always about the dare to do it."