Arachnophobia in four acts
Act 1: A conditional fear of spiders?
Davey (1991) wrote a truly fascinating paper titled “Characteristics of individuals with fear of spiders”. Based on a series of surveys, Davey’s goal was to assess the shared characteristics of people who have a fear of spiders, and to understand (and challenge) what is the classical ‘conditioning’ view of Arachnophobia (i.e., some kind of direct experience with spiders instilled a life-long fear of arachnids). One of Davey’s surveys involved asking 118 undergraduate students about their fears of spiders, and of that number, 85 had, at one point in time been afraid of spiders or were presently afraid of spiders. 75% of the people sampled were either mildly or severe afraid of spiders! Of the total that were currently afraid of spiders, over 55% of the female respondents were arachnophobic where only 18% of the male respondents were scared of spiders (this gender bias in Arachnophobia has been subsequently supported many times over). There was also an effect of family: those people fearful of spiders reported having a family member with similar fears (but the study was unable to separate genetic- versus environmentally-based fear). In contrast to conditioning fear, Davey reports little effect of any specific ‘spider trauma’ as the reason for Arachnophobia.
What makes spiders so fearful? Surely it’s the threat of being bitten? Thankfully, Davey presents results about this as well. I was pleased to see that this sample reflects my experience also - it’s not so much a fear of being bitten, but rather the seemingly erratic movements of spiders, and their ‘legginess’ (as an aside, that extra set of legs is reported to affect entomologists, too, as reported by Vetter in 2013). In sum, Davey’s excellent paper more-or-less provides support "...that animal fears may represent a functionally distinct set of adaptive responses which have been selected for during the evolutionary history of the human species”.
Act 2: What about the children?
A criticism of Davey’s work is that perhaps ‘conditioning’ can’t be so easily dismissed because the ‘spider trauma’ may have occurred during childhood, and a specific spider event may be buried deep within memories. It’’s therefore quite fascinating to read the work by Muris et al. (1997), who tried to figure out what children in the Netherlands are afraid of. Not surprisingly, if you give kids a list of things that might be scary for them, the vast majority check off things like “not breathing”, “getting hit by a car”, “bombs”, “fire" or “burglars” as quite important. Interestingly, if you give them a ‘free option’ to tell researchers what sorts of things they fear the most, both boys and girls report “spiders” as their top fear (the second fear is "being kidnapped", third is “predators” and fourth is “the dark”). This is truly stunning: of ALL the things that kids might report, they list spiders as the number one fear. In contrast to Davey’s work, Murius et al. find that the kids that were most fearful of spiders could relate that fear to specific events. Stated another way, conditioning was the likely pathway to arachnophobia.
Act 3: Genetics or environment?
I was quite excited to read the paper by Hettema et al (2003) which has significantly furthered our understanding about whether there is a genetic basis to Arachnophobia. In this work, the authors used a ‘twin study’ (i.e., comparisons of reactions between twins allows for the understanding genetic underpinnings given the genetic similarity among the twins) and looked at conditional fear responses to ‘fear-relevant’ images (spiders, snakes) compared to ‘fear-irrelevant’ images (circles, triangles). The authors document that there was “substantial genetic influences, with additive genetic effects accounting for between 34% and 43% of the total variance in our best fit models”. I find this quite astounding, and I think it helps to explain both the high prevalence of arachnophobia in the general population, and why this arachnophobia persists. Again, there is support for the theory of some evolutionarily, adaptive basis for arachnophobia, and this is heritable: you need not necessarily experience spiders to be fearful of them.
Act 4: What to do about arachnophobia?
It’s hard to draw many generalities from the literature on Arachnophobia, although quite clearly conditioning is likely important in some children, spiders elicit strong responses in many people, there is likely some genetic basis to arachnophobia, and females tend to be more fearful of spider than males. There are some interesting clinical approaches to deal with arachnophobia, and you could argue that sharing images and stories about spiders may help reduce arahnophobia. Good: I’ll keep on writing about spiders on this blog!
American Psychiatric Association (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington: American Psychiatric Association.
Davey (1991) Characteristics of individuals with fear of spiders, Anxiety Research, 4:4, 299-314, DOI: 10.1080/08917779208248798
Muris et al. (1997) Common childhood fears and their origins. Beh. Res. Ther. 35(10): 929-937