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Why Are Humans Afraid of Spiders?


Layne is an active freelance writer. She enjoys staying up-to-date on trends, media, and emerging topics.

Why are humans afraid of spiders?

Why are humans afraid of spiders?

The Evolutionary Advantage of Arachnophobia

Arachnophobia is described as an intense and irrational fear of arachnids or eight-legged insects like spiders and scorpions. The word itself comes from the Greek words for spider, arachne, and phobos, meaning fear. For many, such a phobia includes common symptoms of anxiety disorders such as dizziness, nausea, elevated heart rate, sweating, shaking, hyperventilation, and a general feeling of loss of control.

Whereas certain cultures have a high regard for spiders and consider them to be symbols of good luck, deities, or a common food staple, the use of spiders in popular culture, especially Western, has fed into arachnophobia. But of the 63,000 species of spiders in the world, only 2% are actually dangerous to humans1.

Why Are People Scared of Spiders?

Interestingly, science reveals that a fear of spiders might be evolutionary or genetic. Various studies have been carried out throughout the last few decades to investigate this hypothesis. Most of these studies reveal some commonalities about what exactly scares people the most—e.g., watching one crawl across the ceiling, finding one in the bed, having one drop down from the ceiling while you're sleeping, or putting on a shoe and being bit. Some people especially dislike fat spiders, furry spiders, and those with long, arch-legged, but for others, it's ones that jump.

Many individuals describe a feeling of disgust when they see a spider. In one such survey, participants ranked what they felt was most trigger about their encounters. From most-fear-inducing to least, the answers follow2:

  • Legginess
  • Sudden movement
  • Speediness
  • Hairiness
  • Crawliness
  • Size
  • Skin contact
What is it about spiders that scare people the most?

What is it about spiders that scare people the most?

Scientific Studies Link Arachnophobia to Instinctual Survival

Of the various studies carried out of the course of a few decades, many reveal that there is a genetic component to arachnophobia.

Studies in Babies

A study performed by the Max Planck Institute for Human and Cognitive Brain Science in Germany on a group of six-month-old babies concluded that human babies have a natural fear response to arachnids. In this study, the babies sat on their parent's lap and were exposed to images of flowers, fish, spiders, snakes and more. Pupillary dilation was measured to gauge activation of the fight-or-flight response (linked to the hormone norepinephrine), otherwise known as the stress response. It was hypothesized that children six months of age couldn't have possibly learned the danger of spiders yet, so the results of the study concluded that a heightened fear response to snakes and spiders is evolutionary origin3.

It's possible that our ancestors learned to fear certain venomous and poisonous species for survival. According to the American Psychiatric Association, 1 in 10 people have a phobia, and 40% of these are related to insects, followed by mice, bats, and snakes2.

Studies in Adults

Another interesting study conducted by Graham Davey at the City University of London in 1991 revealed that 75% of undergraduate students who were interviewed and reported a fear of spiders also had family members that shared a similar phobia, although they could not confirm an actual time, place, or event in which this response and reaction developed (like a bite). These individuals described themselves as disliking the movement of spiders in particular, which might be linked to disease-avoidance models or predator defense models4. This finding suggests that the response is a conditioned one that can also be unlearned.

Studies in Twins That Are Geographically Separate

Yet another interesting study was conducted in 2003 by The Virginina Institute for Psychiatry on twins that were geographically separated. This study revealed that there was a genetic influence to arachnophobia, as both shared similar fears despite different conditioning and influences that would have shaped a separate response over the course of their lifetime2.

Studies in Children

One study conducted in 1997 by Peter Muris supports the notion of conditioning in children. Participants in the study were given a checklist of things that they could be fearful of. The data revealed the following, ranked in order of of most-fear-inducing to least-fear-inducing5:

  • Spiders
  • Being kidnapped
  • Predators
  • The dark
  • Frightening movies
  • Snakes
  • Being hit by a car/truck

Evolutionary Biology

The cumulation of such studies reveal that arachnophobia is both evolutionary (of a genetic component) and also conditioned-learned, which means it can also be unlearned. Similar to what is demonstrated in primates, humans developed instincts to react quickly to perceived threats–either those that are dangerous (e.g. fear of venomous species) or disgusting; this stress reaction is a mechanism of survival.

How to Stop Being Afraid of Spiders

There are various steps that you can take to stop being afraid of spiders. The same techniques generally work for phobias of snakes and other species:

Cognitive Behavior Therapy

Cognitive behavior therapy is very effective for changing one's perception and emotions around objects or events and the automatic thinking that comes from programming. Desensitization techniques can be used in tandem to not only train the individual to calm themselves when they encounter their trigger, but repeat exposure in neutral situations can lead to decreased arousal. With these combined therapies and techniques (and with he help of a professional), an individual can change their response to spiders.

Virtual Reality Therapy

Like the above-mentioned, virtual reality therapy can also help via exposure therapy and desensitization. Seeing and feeling nearness to your phobia, over and over again without a negative outcome, can help to recognition the brain into perceiving it as less of a threat.


Educating yourself about the important role spiders play in the ecosystem is a good place to start in understanding why these species are necessary for life on this planet. Spider bites are actually rare and most only result in an allergy (similar to a bad mosquito bite). Again, only 2% of spider species are actually venomous.

Black widows and brown recluses, which are notorious for inducing fear in humans due to their venomous bite, generally keep to themselves and bite out of self-defense. There are ways to avoid encounters with these species depending on where you are located geographically.

What Role Do They Play in the Ecosystem?

Reframing the way you perceive spiders might also include education around the important role that spiders play in the ecosystem. Spiders are responsible for maintaining insect populations, like mosquitos, which introduce disease, and flies, moths, cockroaches, fleas, and more. They also serve as an important source of food for other species such as birds and lizards. Biodiversity is important for the health of the planet, and each species plays a significant role in keeping our complex food chains balanced.

Spiders play an important role in maintaining a healthy ecosystem.

Spiders play an important role in maintaining a healthy ecosystem.

How to Deal With a Severe Fear of Spiders

If you are so afraid of spiders that you are missing out on life, you will want to consider working with a professional to overcome your phobia. Some individuals experience such trauma around exposure to spiders that they will avoid fun activities like hiking, going camping, or participating in outdoor actives. In such cases, anti-depressants or anti-anxiety medication might be considered.

How to Avoid Spiders

There are certain steps you can take to spider-proof your house and to avoid spider bites in general. Here are some tips:

  • Don't leave shoes or boots outside; if you do, make sure to tap them together and shake them upside-down before putting them on.
  • Don't leave piles of wood or debris alongside your house. If you do have to handle piles of wood or debris, wear gloves.
  • Wear long sleeves and a hat when working in the yard.
  • Make sure your windows have tight screens. You can build screens for your house by watching an easy DIY video and buying a kit online.
  • Clean your house often—vacuum up cobwebs in the high ceilings and behind and underneath furniture.
  • Keep trees and bushes trimmed away from your house (yes, spiders and insects can easily get into the house through chimneys and vents if they have a tree or bush to cling to and climb down from).
  • Rescue them don't kill them: To easily remove a spider from your home, grab a clear cup and trap them with it against the wall or on the floor. Slide a piece of paper or rigid paper (like a card) under the cup and carefully carry them outside.


  1. Arachnophobia fear of spiders, Psycom.net
  2. Why We Are Afraid of Spiders, TheConversation.com
  3. Characteristics of Individuals With Fear of Spiders
  4. Why Are We Afraid of Spiders? RealClearScience.com
  5. Common childhood fears and their origins, ScienceDirect.com

© 2020 Laynie H

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