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What Makes Spiders Frightening to People?

Spiders are one of the most abundant and diverse orders of arthropods with nearly 50,000 known species. Data from few assessed species show, however, that habitat loss, urbanization, invasive species, pet trade, climate change, pollution, intense farming, and global insect abundance decline are major causes for the alarming loss of spiders species worldwide.

Although spiders play a key role in food webs ecosystem by regulating the density of other invertebrate herbivores and predators, their popularity with humans is low. Furthermore, the prevalence of spider phobia (extreme innate fear of spiders) varies cross-culturally between 2.7 and 9.75%; it is considered as one of the most common animal phobias, particularly in women. Spiders increase perceptual and attention processes in humans from childhood. These processes do not seem to be generalized responses to small arthropods, since spiders are perceived as being more dangerous and disgusting than beetles, wasps, and butterflies.

Some researchers suggest that the fear of spiders can be explained in terms of biological preparedness. More efficient search for threat-relevant objects, such as fears of spiders, suggests that our ancestors responded quickly to dangerous animals, which ultimately enhanced their fitness; however, this explanation is problematic, because, unlike snakes, only a few species of spiders are dangerous to humans. Some studies suggest that spiders are associated with attitudes of disgust and with survival strategies practiced in the Middle Ages.

Brain activity measured by using the early posterior negativity (EPN) turned out to be larger for snake pictures compared with spider pictures, which suggests that early attention to spiders is lower than attention to snakes. Finally, fast detection and rapid learning in non-human primates are limited to snakes, but no similar evidence has been found for spiders. These arguments seem to indicate that fear of spiders in human may have different roots than fear of snakes.

Because the evolutionary origin of fear of spiders in humans is still unclear, further research is needed to understand the main reasons as to why spiders are frightening and disgusting animals to most people. In this study, we used a representative sample of Slovak people to examine which specific cues make spiders unpopular animals. We submit that this approach can contribute to an improvement in human-spider interactions. Conservation initiatives may improve their communication with the general public by avoiding cues, which were considered frightening or disgusting by people. Human emotions toward animals greatly influence their willingness to protect them; thus, research focused on public perception of undesired animals, such as spiders, is necessary.


Participants and Procedure

This study was implemented online during the spring semester of 2021. Participants in the study consisted of N = 1,015 Slovak citizens with ages ranging between 18 and 69 years; they were recruited by the authors via online networks (Google Forms, Facebook) and through private e-mails; the research study was also advertised on the university web page. In all cases, and prior to assent to participate, each individual was informed that the focus of the research study was on the traits that humans find disgusting and dangerous in spiders. The participants were presented with 15 pairs of spider images that had some body traits manipulated (only one image was modified to create the 15 pictures); they were asked to choose one image from each pair that in their views was perceived as disgusting. The same images were presented randomly a second time, the task was to choose images that were perceived as frightening.


We modified several parts of the spider body, legs, eyes, hair, chelicerae, and abdomen


Cues triggering fear/disgust of spiders have long been a topic of interest to researchers in this field. Previous research has shown that “legginess,” spider movement, spider size, and hairiness or perceived danger are prominent cues associated with fear and disgust of spiders. In this article, we used a forced-choice paradigm and a representative non-clinical sample of participants to examine which of the visual stimuli elicits these two emotions.

Chelicerae and abdomen were the scariest body traits in spider. Female participants perceived enlarged chelicerae as more frightening than their male counterparts. In contrast, the abdomen of the spider elicited more disgust, while enlarged chelicerae, hairiness, and enlarged legs also contributed to the perception of spiders as disgusting animals. Female respondents considered hairiness more disgusting than males.

Often, animal weapons that can potentially threaten humans come in the form of straight objects; thus, it is not surprising to find out that humans have an evolutionary predisposition to pay attention to potentially harmful objects, such as sharp teeth, claws, animal spikes, and horns.

Enlarged abdomen significantly contributed to the rating of fear and disgust; however, this trait seemed to play a more prominent role in the perception of disgust than fear. We suggest that the abdomen of spider plays a dual role in perceived fear and disgust. An enlarged abdomen may visually enlarge the body of the spider, and the larger the size of an animal, the more likely it is perceived as a threat for humans. This may be a simple mechanism as an enlarged abdomen can increase perceived fear. Enlarged abdomen, however, may also superficially resemble a tick or other blood-eating ectoparasites that can transmit serious infections to humans.

The presence of body hair seems to be significantly associated with both fear and disgust of spiders. We suggest that the rationale for this perception (fear of hairiness) is that body hair (or fur) when standing up in many mammals occur when the animal is threatened. The elevated body hair strategy makes the animal appear bigger than its original size. Body hair can be therefore perceived as a cue of fear.

In general, women are more feared of spiders than men, and it is possible that certain gender differences, in this study, could be the result of greater fear among female participants. In particular, spider chelicerae were significantly more associated with the fear of spiders in females than in the male group. Furthermore, hairiness was also more associated with disgust by females than by male respondents. Regarding the former, female participants reported greater fear of predators than male participants.

The long legs feature is thought to promote fear of spiders, and results in this study partly support this idea; however, this trait is not a prominent factor in eliciting fear and disgust. Contrary to these findings, spider eyes did not show any significant influence on ratings of fear or disgust.

In this study, participants with a background in biology were less fearful of snakes and spiders than those without training in this discipline. Compared with the non-biologists group, we found that biologist participants rated hairy spiders less frightening and less disgusting.

If you have a fascination with spiders, TISOVN has a course that's on sale for the month of January only - Certificate In Arachnology. Go to for detils.

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