By Peter M. Vishton, PhD, William & Mary
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily
What’s the difference between a phobia and a warranted fear? Professor Vishton explains with a story from his childhood about an overzealous llama and a psychology experiment on perception of heights.

Phobias and Llamas
A phobia is an extreme or irrational fear of or aversion to something. “When I was about six years old, my parents took me to the Philadelphia Zoo,” Professor Vishton said. They visited the petting zoo, which featured a llama.
“I had a lot of brownish, blond hair,” Professor Vishton said. “This particular llama apparently thought it looked like straw or something else worth trying to eat.”
It lowered its head, placed its considerable mouth around the top of his head, and tried to take a bite.
“My memory gets a bit blurry at that point,” Professor Vishton said. “I presume I screamed, and I think I cried a lot. If you’ve ever spent time with a llama, you’ll know that they don’t have any sharp teeth. And the llama jaw is just not built for crushing anything firmer than a wad of dry hay.”
He was never in any danger, and he wasn’t physically injured in any way. There were no scrapes or blood. When he was 20 years old, he visited that zoo again with some friends.
“When we walked by the petting zoo, I glanced over and saw a llama,” Professor Vishton said. “In all likelihood, it was a different llama. It had been 14 years since the initial incident. But it sure looked like the same llama.”
Professor Vishton knew, by age 20, that llamas are not an aggressive or man-eating species. His rational mind told him that he was in no danger from this creature.
“But the fight or flight response that rushed through my body was intense,” Professor Vishton said. “My heart pounded. I began sweating and breathing heavily. The hair on my arms stood straight up. I was gripped by fear. All of this for a kindly llama that lived in the petting zoo.”
What Is a Phobia?
Irrational, unwanted fear reactions like this, called phobias, are relatively common. A library of scientific terms has been invented to describe them. Arachnophobia—the fear of spiders; acrophobia—the fear of heights; aerophobia—the fear of flying; glossophobia—the fear of public speaking.
These are all relatively common, but there are a lot of unusual, less common fears. Trypophobia—the fear of holes; monophobia—the fear of being alone; ornithophobia—the fear of birds; alektorophobia—the fear of chickens.
“I should note that fear, in and of itself, isn’t necessarily a bad thing,” Professor Vishton said. “Most people have at least some fear of heights, but there’s a reason for that. When you’re up high, there is a danger of falling and getting injured—maybe even dying.”
Healthy Fears
Actually, a functional fear of heights is built into the human visual system. Dennis Proffitt and his collaborators have documented a fascinating depth perception illusion. They discovered this while they were standing on a balcony in the psychology building at the University of Virginia.
This particular balcony is about 20 feet above the ground and extends for much of the length of the building. Proffitt asked one experimenter to go down to the ground and stand below the balcony.
The study participant stood directly above that experimenter, where she could look down and see the first experimenter. A second experimenter stood on the balcony on the right side of the student participant. The job of the participant on the balcony was to ask the second experimenter to move gradually farther away until the distance between the participant and the balcony experimenter matched the distance between the participant and the ground experimenter.
When the participant felt that the vertical distance matched this horizontal distance, the experimenters would measure those two distances and compare them. For virtually every participant, they dramatically overestimated the distance to the ground. When they repeated the process from the ground—that is, now the participant is on the ground, looking up at the balcony experimenter—the effect went away.
When you look down from a height, your visual system seems to know that vertical distances are something that require great caution. Whatever the distance actually is, your automatic, unconscious visual system takes that value and multiplies it before passing the information on to your conscious perceptual system.
This overestimation of vertical distances is greater for people who report that they have a fear of heights, but even those who say they don’t really have that fear still show a strong effect here. Your unconscious visual system is afraid of heights.
This is a fear—and a sensible, functional one. It doesn’t really rise to the level of a phobia, however. In order to be a phobia, something has to be irrational before we would call it that.
Irrational Fears
While fear of some things can be functional and important, many people report having fear responses to things that aren’t inherently sensible. For example, elevators, on the whole, are almost perfectly safe, but some people fear them so intensely that they will insist on walking dozens of flights of stairs to avoid anxiety about falling or being trapped inside.
Traveling in a commercial jet is eminently safe. The odds of being injured during a drive to the airport are small, but even those small odds are substantially greater than the odds of being injured during the flight itself. Regardless of this fact, essentially no one fears driving down a highway, while many people experience substantial fear of flying.
Giving a speech or toast in front of a large group is another common fear. Many people suffer from at least some general social anxiety, experiencing fear when meeting people or even, in some cases, pondering meeting them.
There are dozens of miscellaneous phobias that people describe—you know that there is no real danger associated with them, but your body and mind respond as if there is.
Even if it doesn’t prevent you from doing the things you want to do, irrational fear is still distracting and annoying. It can sap the joy right out of a situation.
It would be nice if it could go away. Thankfully, it can. Stay tuned for strategies in tomorrow’s article.

Peter M. Vishton is an Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.