Spiders, Scorpions, and Snakes, Oh My!

I just spent the last few minutes reading about the basis of specific types of fears, such as fear of snakes and spiders. 

Why is it that so many humans seem to fear certain types of animals, such as snakes and spiders?

One cause of a phobia is experiential.  You have a negative encounter with an animal and you learn to fear it.

My own fear of wolf spiders, for example, is experiential.  While living in Australia I went to stay at a friend's country house.  I was taking a leisurely shower one evening when something caught my eye.  On the opposite side of the shower was the largest, hairiest, ugliest spider I'd ever seen.  Rather than screaming, I froze.  Somewhere in the back of my little brain, a voice was telling me not to scream or make a sudden movement, because wolf spiders are aggressive and respond to wild reactions.  In reality, I'm not sure I could have screamed - the breath had been completely knocked out of me.

Keeping my eyes on the spider, I pressed my back against the wall of the shower and made a very slight movement towards the shower curtain.  That slight movement was all it took for the spider to pounce.  It LEAPT the distance of the shower and was suddenly on my naked flesh.  It was at this point that I screamed bloody murder while leaping out of the tub.   Unfortunately, I slipped and fell out of the tub, ripping the shower curtain off of its hooks.  I tumbled onto the floor, tangling myself in the shower curtain.  Like a fish out of water, I flailed and flopped helplessly on the floor trying to rid myself of the curtain and the spider - which I was sure was crawling over my entire body all at once.  It was in this shrieking, flopping state that my friend and her three brothers found me. Naked and wet, wrapped in a curtain on the floor, trying to jump out of my skin.  It was not a highpoint in my life.

Personally, I find my dislike of spiders, especially the wolf variety, quite understandable.

But I digress. 

Fortunately, most people don't have to experience such traumatic experiences with snakes, scorpions, or spiders to fear them.  Rather, they often develop phobias of these animals without ever having seen them (or having heard horror stories about them on blogs).

So why the phobias?  And why are some phobias more common than others?  Fear bunny rabbits or puppies and people might think you're a bit off.  But few people would think twice if you feared snakes. 

One popular theory is that natural selection has historically selected for people who innately fear certain threatening animals, such as snakes and spiders.  The basic gist of the argument is that individuals with these fears were more likely to survive long enough to reproduce (and thus pass on the fear trait to offspring).  Humans who lacked a fear of these animals were more likely to be bitten or stung by them and die before reproducing.   

However, recent studies suggest that humans don't innately fear these animals.  Rather, it appears that humans have an innate ability to quickly recognize threatening animals.  

In a meta-study conducted by researchers at Rutgers University, fear experiments were conducted on 70 small children.  In one experiment, researchers showed 48 infants between 7-9 months and 16-18 months two videos side-by-side.  One video showed a clip of a snake, while the other showed a video of (what is thought to be) a non-threatening animal, such as an elephant.  While the videos were playing, the researchers played an audio clip with either a happy or fearful voice.  The infants spent more time looking at the snake video when the fearful voice played, but showed no visible signs of fear while watching the video.

In another experiment, 24 toddlers and 24 adults were asked to look at nine pictures and identify a target picture among the 9 pictures, such as a flower, a mushroom, a cockroach, or a spider.  Similar to the adults, the toddlers detected images of snakes and spiders more quickly than other images (flowers, frogs, caterpillars, mushrooms, etc.).  While the toddlers identified the pictures of spiders and snakes as quickly as adults, not a single toddler showed a fear response.


If humans aren't innately fearful of these animals, then how does fear develop?   The answer might lie in two linked findings:  As the above studies and many others suggest, humans are predisposed to pay more attention to certain stimuli - in this case, threatening stimuli.  As other evidence suggests, humans also learn to fear these animals more quickly than they learn to fear other things. 

For example, in a U.S. study, lab-raised monkeys did not express any innate fear to snakes; however, the same monkeys learned to fear the snakes much more quickly than they learned to fear flowers or rabbits. In a Swedish study, people were taught to associate a small electric shock with photos of spiders, snakes, flowers, and mushrooms.  While an associated fear effect was produced for all four images, the fear effect lasted significantly longer with the snakes and spiders than with the flowers or mushrooms. 


Interesting stuff.

Why post it on the blog?

As you know, I don't like mice or scorpions (or spiders), especially when they're in my house.  Actually, my fear of spiders (save wolf spiders) has diminished substantially since living here.  It's simply not pragmatic to fear spiders here.  If I freaked out every time I saw a spider in the house my sympathetic nervous system would be completely shot.  And spiders, unlike mice or scorpions, seem to earn their keep and serve a purpose on Earth.  They kill lots of other insects and generally stay out of my way.  Unlike the mice, they don't poop all over the house (or, rather, I can't see their poop), invade our food stuffs, drown in our toilet, or explode under our pillows.  Unlike scorpions, spiders don't crawl into our bed, our shoes, or our clothing.

My revulsion towards scorpions increased last week after one stung Kaia while she was sleeping in her bed (experiential).  We were not impressed.  On the positive side, the venom seemed to make Kaia drowsy - she fell asleep snuggled between us in our bed, belly to the sky, legs splayed in a very unlady-like manner, and snoring.

Despite my fear of most things "threatening", snakes have never scared me.  In fact, I find them fascinating, provided they don't startle me and I'm a safe distance from them.  The other night Ernesto and I were watching a movie in bed when I took a pee break.  For some reason, I thought to turn on the light in the entryway, which was a good thing, since there was a snake camping out on the floor.  , I didn't even bat an eye as I walked by it, did my business, and then told Ernesto we had a snake in the house.  We swept it outside and went back to our movie. 

The day prior to this, we saw a much larger snake lying in the middle of the road, mouth wide open, trying to swallow something with cute little hind legs - maybe a frog or a bird.  It was pretty cool.

I suppose my lack of fear towards snakes supports the larger research findings.  Or, it might just be that I'm a maladapted dud that shouldn't reproduce.