Inborn fears and aversions - Why we fear spiders and snakes

Fear of spiders and snakes is innate in humans

Many people feel disgust, discomfort or even fear when they see a spider. This feeling is usually more pronounced when looking at snakes. So far, it has been controversial whether these are learned behaviors or whether we follow an innate instinct. A team of researchers from the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and Uppsala University (Sweden) has now proven that these fears are inherent in us from birth.

Six-month-old babies react stressed when they see snakes and spiders, the scientists report. This was "long before they could have learned this reaction." So it clearly seems to be an innate instinct. However, this can take extremely different forms in the further course of life. The study results were published in the specialist magazine "Frontiers in Psychology".

Fear of spiders and snakes is common

Although there are (almost) no poisonous spiders and snakes in Germany and people rarely come into contact with the animals, the fear of snakes and spiders is also widespread in Germany. The extent to which it concerns learned fears or an innate aversion remains controversial. The researchers at the Max Planck Institute for Human Cognitive and Brain Sciences have now investigated this in six-month-old babies.

"Most people in Germany have probably never encountered a poisonous spider or snake in the wild" and "there are simply no spiders in this country that could be dangerous to humans", reports the MPI CBS. Only two native species are poisonous in snakes, but so rare that you can hardly find them. The aversion to these animals remains widespread and "hardly anyone gets nervous about the thought that a spider, no matter how harmless, can crawl up its trouser leg," the scientists report.

Impending development of anxiety disorders

It is not uncommon for fear to develop into a real anxiety disorder (phobia), which can severely restrict those affected in their everyday lives. Affected people are constantly on the alert and, for example, do not enter a room with a spider phobia until it has been declared "spider-free". Or they don't go into nature with a snake phobia, for fear they might encounter a snake. About one to five percent of the population are affected by a phobia towards these animals, the experts report.

According to the researchers, previous studies have mainly examined what behavior is learned and which is innate in adults or older children. However, this can hardly be separated from one another with increasing age. So far, it has only been tested in children "whether they can spot spiders and snakes faster than harmless creatures and objects, but not whether they show a direct physiological fear reaction."

Reaction in babies examined

In their current study, the scientists were able to prove that a stress reaction is triggered in babies as young as six months old when they see snakes or spiders. This was an age when they were still very immobile and had little opportunity to learn that these two groups of animals could be bad. "When we showed the little ones pictures of a snake or spider instead of a flower or a fish of the same color and size, they reacted with significantly enlarged pupils," reports the neuroscientist Stefanie Hoehl from the MPI CBS.

Stress reaction noticeable

According to the researchers, the enlarged pupils are "when the lighting conditions remain the same, an important signal that the so-called noradrenergic system is activated in the brain, which is linked to stress reactions." The babies react stressed to the sight of the animals. It should therefore be assumed that “the fear of snakes and spiders has an evolutionary origin.” Obviously, with us, and also with other primates, mechanisms were anchored in the brain from birth, through which we very quickly identify objects as “spiders” or Identify "snake" and react to it.

The innate stress reaction in combination with other factors can lead to real fear or even a phobia, the scientists explain. "A strong, panicked aversion of the parents or the genetic predisposition to an overactive amygdala, which is important for the assessment of dangers, can quickly lead to a real anxiety disorder from increased attention towards these animals," reports Stefanie Hoehl.

Evolutionary development of fears

Interestingly, the babies did not show a stress reaction when they saw pictures of rhinos, bears or other animals that could theoretically also be dangerous to us. The researchers therefore suspect that “the special reaction when looking at spiders or snakes is related to the fact that potentially dangerous reptiles and arachnids have been coexisting with humans and their ancestors for 40 to 60 million years - and thus significantly longer than with us today dangerous mammals. ”The innate response to certain groups of animals has been anchored in the brain over a long evolutionary period. (fp)

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Video: Fear Friday Why you Shouldnt Be Afraid Of Spiders (January 2022).