Now I think it's fair enough to invoke explanations arising from evolutionary psychology ("poisonous") or about learned behaviour, and I respect that, but couldn't we consider the most obvious explanation: that spiders are just horrible-looking little bastards?
"Movies starring the superhero Spiderman may rake in millions at the box office, but the humble spider inspires fear and loathing quite unlike that of other creepy-crawlies. A third of women and a fifth of men admit to being scared of spiders. And an obvious explanation is that we have evolved a dread of spiders because they can be poisonous. However, psychologist Georg Alpers at the University of Würzburg, Germany, and his team believe that if this theory is correct, we would be just as afraid of stinging insects such as bees and wasps.
"To find out if this was the case, Alpers's team asked 76 students to rate photos of spiders, wasps, bees, beetles, butterflies and moths on three counts: how much fear and disgust they inspired and how dangerous the students felt they were. It transpired that spiders triggered far greater fear and disgust than any of the other creatures and were believed to be more dangerous (Evolution and Human Behaviour, DOI: 10.1016/j.evolhumbehav.2008.08.005).
"Stuart Hine, an entomologist at London's Natural History Museum, thinks fear of spiders is probably a learned behaviour. You only have to see someone standing on a chair screaming 'Spider! Spider!' to pick up on that fear, he explains. 'It stems back to the days of plagues when people suspected anything that crawled out of the thatch as carrying disease.'"
I'd post a picture of a spider to prove my point, but as a recovering arachnophobic I don't think it would be a good idea. After years of screaming and screeching after sighting one of the little blighters, what to speak of being paralysed with fear, I'm pleased to report that I overcame my fear (somewhat) after a school trip to London Zoo. It really is quite amazing what group cohesion in the form of "dares" can do, but suffice it to say that we all forced ourselves to go and look at frightening tarantulas and the like in the Insect House. The first thing I noticed when I saw them is how small they are in reality. Many images available in books and other media tend to be close-ups and enlargements which may account for sudden shock reactions. But seeing them in reality gives one the impression that it is the fear itself which is overblown in the face of their diminutive size. If tarantulas represent an extremity in terms of fear, what more could we say about the even smaller stature of house spiders?
Since that visit to the zoo, my own fear of spiders significantly diminished from hysterical reactions to mild observations. I still exhibit a modicum of fear when I see them, but depending on my mood I may choose to squish them into oblivion or I might catch it and throw it outside.
But why do spiders provoke such extreme reactions? I downloaded and quickly read through the actual paper. Alpers et al. hypothesised that similar reactions should be exhibited with respect to bees and wasps, which could be true except that they seem to pose more of an annoyance than a fear. After all, how many apiphobics or spheksophobics do you know? I'd be more surprised if you've even heard those terms. Reading through the introduction to the study, there is much to be said for the evolutionary perspective in terms of fight-or-flight responses but too much is said about their venomous nature as well as the venomous qualities of other arthropods. Quote: "The disgust hypothesis postulates that emotional responses to spiders are culturally transmitted because these animals were historically associated with disease and infection from medieval times onward. However, it is unclear why mainly spiders, and not other 'creepy crawlies,' have been considered to be responsible for infections and disease."
Hello? Could it be because they look horrible? And could it be because they tend to move very quickly and their eight-legged appearance gives off an unnerving impression? I'm sure that much could be said for visual representation in connection with disgust hypotheses and I'm pretty sure that studies have been carried out along those lines, but you'll have to forgive me for being too lazy to dig them up right now. The researchers go on, this time suggesting that fear of spiders could be down to cultural transmission: "Other arthropods that are comparable in terms of venomousness, appearance, or behavior to spiders may elicit similar reactions, but cultural transmission may exert strong biases on verbal labeling. Individuals who report being afraid of spiders may stick with a cultural stereotype ('fear of spiders is common'), although their fears may be much less specific than commonly thought. A variety of arthropods may elicit fear or disgust (e.g., beetles), but 'fear of spiders' may merely be a culturally accepted verbal label for a wide spectrum of animal fears."
Hello? Did you ever consider that their horrific looks may account for fear??
It's no wonder that the results of the experiments suggested that "spider fear is in fact spider specific". Aside from being venomous, the study gives rise to a more interesting evolutionary question as to why spiders accounted for the highest ratings of fear in both emotional and dangerous contexts as compared to bees/wasps. One explanation provided by the authors relates to the honey-creating capacity of bees that formed part of Early Man's diet. Frequent interactions with bees due to honey obtainment and the very real possibility of being stung regularly may have contributed to an adaptive response on the human part with the result of lessening fear. In other words, surviving bee stings would be worth the trouble of obtaining the honey necessary to eat (reward). In spite of the relative rarity of spider stings, interaction with them offers no evolutionary advantage and this leads to a general lack of information about them. Which in turns contributes to informational fear acquisition that is culturally transmitted through generations, often taking the form of myths.
Another explanation relates to their unpredictable and uncontrollable behavior that could be gleaned from their rapid or abrupt movements (aha, now we're finally getting there!). Earlier studies suggest that this could be down to the inability of humans to exert control or influence upon the movements of animals, but many other animals and insects move as fast (or faster than) spiders and this is insufficient to explain spider-specific fear. After some more discussion of other points, the authors recognise one of the limitations of their study in showing static pictures to the participants as opposed to animated, or even 'live' images, and thus responses to spider/insect mobility couldn't be obtained and tested. Whereas spiders tend to be detected extremely quickly in search tasks (and where some say this is observable for other animals), the elevated fear and digust ratings in this study allow the researchers to recognise the 'specality' of spider fear. Very generously, they also recognise that existing explanations for these responses (venomousness and so on) aren't sufficient or well-founded to properly explain them.
They could start by studying reactions to sudden spider appearances, and to what extent this is moderated by their looks!
Thankfully (and at long last!) the researchers do end up suggesting two specific ways to deeply analyse the origin of animal (spider?) fear and disgust; first through detailed cross-cultural studies, and secondly by analysing the morphological and behavioural traits that trigger the fear and disgust responses.
Hallelujah! It was a long ride but they got there in the end! And I think when that kind of study is carried out and published, it will be a worthwhile read.
A GERDES, G UHL, G ALPERS (2008). Spiders are special: fear and disgust evoked by pictures of arthropods☆ Evolution and Human Behavior DOI: 10.1016/j.evolhumbehav.2008.08.005