Afraid of snakes and spiders? That fear may be innate, study finds

close-up of rattlesnake's head [Credit: pixabay]

Most cottagers have had to grapple with the fear of creepy-crawlies at one time or another. Dock spiders, garter snakes, and even the occasional rattler are just a reality of lakeside living. And now science has shown that our creeped-out feelings when we encounter these creatures may be something we were born with.

And a new study in the journal Frontiers in Psychology has shown that even infants respond with fear to snakes and spiders. The study examined the reactions of six-month-olds to “ancestral threats” like spiders and snakes. The babies showed physiological arousal when shown photos of spiders and snakes, as compared to pictures of less threatening species, indicating that our fear may be hardwired into us.

“When we showed pictures of a snake or a spider to the babies instead of a flower or a fish of the same size and colour, they reacted with significantly bigger [eye] pupils,” lead researcher Stefanie Hoehl, a neuroscientist at MPI CBS and the University of Vienna, said in a statement. “. . . [T]his change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions. Accordingly, even the youngest babies seem to be stressed by these groups of animals.”

Dock spider on dock.
Dock spiders generally aren’t harmful to humans, yet sights like these often strike fear into cottagers’ hearts. [Credit: Gord Gibb]
The statement notes that other studies have shown that infants do not show a similar fear response to images of dangerous animals like rhinos and bears. Scientists believe this is because snakes and spiders have coexisted with humans for much longer — 40 to 60 million years — and we’ve co-evolved, developing a practical fear of these potentially harmful organisms.

“We conclude that fear of snakes and spiders is of evolutionary origin,” Hoehl said.

So if you’re one of those people who runs away screaming whenever you see a snake or spider, at least now you have an excuse: it’s in your DNA.

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