Evolution Of Aversion: Why Even Children Are Fearful Of Snakes

Evolutionarily speaking, early humans who were capable of surviving the dangers of an uncivilized society adapted accordingly. And the same can be said of the common fear of certain animals, such as spiders and snakes: The ancestors of modern humans were either abnormally lucky or extraordinarily capable of detecting and deterring the threat of, for example, a poisonous snake.

Psychologists Vanessa LoBue and Judy DeLoache were able to show this phenomenon by examining the ability of adults and children to pinpoint snakes among other nonthreatening objects in pictures.

“We wanted to know whether preschool children, who have much less experience with natural threats than adults, would detect the presence of snakes as quickly as their parents,” LoBue explained. “If there is an evolved tendency in humans for the rapid detection of snakes, it should appear in young children as well as their elders.”

Preschool children and their parents were shown nine color photographs on a computer screen and were asked to find either the single snake among eight flowers, frogs or caterpillars, or the single nonthreatening item among eight snakes. As the study surprisingly shows, parents and their children identified snakes more rapidly than they detected the other stimuli, despite the gap in age and experience.

LoBue and DeLoache also found that both children and adults who don't fear snakes are just as good at quickly identifying them as children and adults who do fear snakes, indicating that there may be a universal human ability to visually detect snakes whether there is or is not a fear factor based on a learned bias or experience.

LoBue and DeLoache explain that their study does not prove an innate fear of snakes, only that humans, including young children, seem to have an innate ability to quickly identify a snake from among other things. One of their previous studies indicated that humans also have a profound ability to identify spiders from among non-threatening flora and fauna. Lobue has also shown that people are very good at quickly detecting threats of many types, including aggressive facial expressions.

The results, which appear in the March 2008 issue of Psychological Science, a journal of the Association for Psychological Science, may provide the first evidence of an adapted, visually-stimulated fear mechanism in humans.