FRIDAY, Feb. 24 (HealthDay News) -- People with an intense fear of spiders perceive the creatures to be larger than they actually are, a new study has found.

While a warped perception of spiders likely won't interfere with daily living, other types of phobias could prove debilitating or even harmful, according to the Ohio State University researchers.

For example, people who are afraid of needles and perceive them to be larger than they actually are may avoid shots and put their health at risk.

In this study, 57 people with a fear of spiders were asked to undergo five encounters with tarantulas and then estimate the size of the spiders. The more afraid participants were of spiders, the larger they estimated the spiders' sizes to be, according to the study published in a recent issue of the Journal of Anxiety Disorders.

"If one is afraid of spiders, and by virtue of being afraid of spiders one tends to perceive spiders as bigger than they really are, that may feed the fear, foster that fear and make it difficult to overcome," lead author and professor of psychology Michael Vasey said in a university news release.

"When it comes to phobias, it's all about avoidance as a primary means of keeping oneself safe. As long as you avoid, you can't discover that you're wrong. And you're stuck. So to the extent that perceiving spiders as bigger than they really are fosters fear and avoidance, it then potentially is part of this cycle that feeds the phobia that leads to its persistence," he explained.

Learning more about how a phobia affects a person's perception of a feared object may help lead to more effective treatments for people who want to overcome their fears, the researchers said.

More information

The American Psychiatric Association has more about phobias.