It is striking that when more than half of the world’s population already lives in cities, where the possibility of encountering a poisonous snake or spider is practically reduced to zero, most of us continue to have a severe fear of these creatures, above the rest of the fauna. In fact, between 1 and 5% of the inhabitants of developed countries suffer from a phobia (that is, a panic already considered a mental disorder) for both animals .
But where does this aversion come from? Is it innate or learned? Until now it was not very clear, especially since the studies carried out in this regard have been based on the behavior of adults or older children, which made it impossible to determine when or how they acquired fear. Furthermore, experiments with children were only done to find out if they detected a snake or spider faster than a harmless animal and not so much to examine the physiological reactions triggered by its presence.
In order to fill this gap, researchers from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, and the University of Uppsala, Sweden have studied the reactions of infants and concluded that that fear of spiders and snakes is deeply programmed into the brain , regardless of experiences and learning. According to his experiments, individuals as young as six months of age already experience fear for them, when they could hardly know that they can harm them . When they were shown photos of both animals, the pupils of the small study subjects dilated, which did not happen if they were looking at, for example, a fish or a flower. And that physical change is a clear sign that the stress system in the brain has been activated.
From repelus to phobia
“ We believe that the fear of spiders and snakes has an evolutionary origin . As with primates, our neural circuits allow us to identify an object as a ‘spider’ or ‘snake’ and to react very quickly, ”says Stefanie Hoehel, lead author of the research. Various factors, such as an overactive amygdala (region of the brain linked to basic emotions), can cause simple inborn fear to lead to phobia.
It is known from other studies that babies, however, are not so upset when they see photos of rhinos, bears or other potentially dangerous animals . “The explanation could be that the coexistence between the ancestors of humans and poisonous snakes and spiders dates back between 40 and 60 million years, while the appearance of harmful mammals is much more recent,” Hoehl surmises.
The same could be said of dangerous objects such as plugs or knives : as they have recently been invented, the brain has not had time to develop biopsychological defense mechanisms. Or put another way, that we are disgusted to see them. And that is why parents have to insist so much to their young children not to approach them.
