Fear factor: Why we're more scared of the unlikely

One of the most common of all fears: spiders.

Julie McKinney almost didn't talk to us for this story.

Not because she was worried about what she'd reveal or that she was nervous to see herself in print. But because of what she might see: a picture of a snake.

McKinney is scared of snakes — has been since she was was a little girl. If she did see even an image of a snake on our pages, she'd likely throw down this edition. And we, of course, don't want that to happen.

"I can't look at pictures. I can't look at the TV when they're on it," said McKinney, a 24-year-old Federal Hill resident. "I'm not like that with anything else."

When McKinney was 7, her family had a blacksnake problem. Snakes lived under her family's front porch in Franklin, Pa., and it seemed as though every time she went outside they were waiting for her. Some were 6-footers.

"My dad got tired of my sisters and I never playing outside, so he took care of them in a snake-killing rampage," she said. He hooked up a hose to his truck's exhaust pipe, smoked out the suckers and then killed them one by one.

Problem solved. Sort-of. McKinney now lives with her fear. If she saw a snake in person, she'd run away until she "felt safe." "I may never buy a house with land," she said.

McKinney knows that a lethal snake bite — or even encountering a snake on a regular basis — is unlikely. And yet her fear of snakes is common. So is a fear of spiders. Less common are fearing situations that are more likely to occur — car accidents, for example, or falling down stairs. Why? We have our ancestors to thank.

We need fear to survive (it's what makes us react to a car's honking horn as we're crossing the street, for example). Our ancestors needed it, or we likely wouldn't be here. Fear originates from one of the oldest parts of the brain, the limbic system, which goes hyperactive when people are faced with frightening situations, said Ashwini Nadkarni, a resident physician in psychiatry at Boston Medical Center. Since the limbic system is so old, scientists have hypothesized that fear "may have been evolutionarily necessary in prehistoric times for humans to survive threats such as predators," she said.

Nadkarni said that although today we experience fear toward "unlikely" situations (snake bites), what we fear most is not random. "They tend to be the things that could threaten our survival because fear of these situations is hardwired in us," she said. "In this sense, fear is a biological benefit for survival."

Fears, Nadkarni said, become phobias when they are excessive or impair one's functioning. And they are fairly common. According to a 2005 study published in the Archives of General Psychiatry, 12.5 percent of Americans will have a specific phobia in their lifetime.

But why we fear the likely (car crash) versus the unlikely (snakebite) depends on a variety of factors, including exposure, environment and previous experiences. One factor is "vicarious learning," said Jason Prenoveau, an assistant professor of psychology at Loyola University Maryland.

"You learn through seeing other's responses," said Prenoveau. "In research with primates raised in labs, they can see on video another primate responding fearfully to a snake. And that fear becomes enduring to them personally."

Why one might fear unlikely things also depends on the development of inhibition. It's far more likely that you'll die in a car crash compared to a plane crash, but "if you have prior exposure, it makes it difficult for that thing to be fear-inducing," said Prenoveau. "You can have thousands of positive experiences with a car, and you feel deep within you that this is something that should be safe. You develop that latent inhibition."

It's also all relative. If you fear walking around midnight in a metro area ridden with crime, that would be considered rational, said Nadkarni. Conversely, if you are in a neighborhood that has had no crime, the same fear would probably be considered irrational.

"The irrationality of a fear, or the improbability, is often dependent on an incongruency between the actual threat and a perceived threat," she said.

Additionally, prior exposure to a fearsome event also affects behavior. "And then, someone may have had a traumatic personal experience or observed someone else having an experience."

Complicating matters is that the brain is awfully good at maintaining fear. According to a study this year in the journal "Molecular Psychiatry," new neurons in the brain's emotional center, the amygdala, work with another part of the brain, the hippocampus, to remember fear. And yet our brains are also good at knowing when fear is temporary.

That's important, since many of us actively seek to be frightened for pleasure, whether it's going to a haunted house or flooding the theater to take in "Paranormal Activity 3." That has to do with how the brain's reward system responds not just to the experience, but to the the anticipation of future experiences, said Scott Huettel, an associate professor at Duke University's department of psychology and neuroscience, whose research focuses on brain mechanisms underlying social decision-making.

"People are not attracted to all types of fear, specifically real-world situations. We're afraid of the consequences," he said. "But with a movie, you have the ability to leave at any time and you know it's temporary. We know it's not real and we can push it away or talk about it to friends to release the fear."

Even real-world situations that include similar consequences as temporary-fear events can cause more fearful alarm. "People love roller coasters for the scary sensation, and it's physically jarring," Huettel said. "But how many people love turbulence in airplanes? Even though a roller coaster is jerking you around more, you perceive the roller coaster as controlled. It will end soon."

But such "safe" fear-inducing situations aren't attractive for all. McKinney would still have problems there if she saw a snake on screen."If I closed my eyes and closed my ears, I could handle it," she said. "I think."

Jordan Bartel is assistant editor at b. Email him at or follow him on Twitter, @jordanbartel

A look at some (very specific) phobias

Androphobia:fear of men

Biennophobia: fear of slime

Caligynephobia: fear of beautiful women

Cathisophobia: fear of sitting

Ebulliophobia: fear of bubbles

Genophobia: fear of sex

Omphalophobia: fear of belly buttons

Panphobia:fear of everything

Pogonophobia:fear of beards

Scopophobia: fear of being seen or stared at

Percentage of people who will have an anxiety- or fear-related diagnosis in their lifetime

4.7%: Panic disorder

12.5%: Specific phobia

12.1%: Social phobia

5.7%: Generalized anxiety disorder

6.8%: Posttraumatic stress disorder

1.6%: Obsessive-compulsive disorder

5.2%: Separation anxiety disorder

28.8%: Any anxiety disorder