Oct 29, 2013 12:13 PM EDT
Fear of Snakes May be Hard-Wired in the Brains of Monkeys and Humans
Ophidiophobia, or fear of snakes, may not be so uncommon and also could be an innate quality shared by all humans, thanks to neurological evolution.
The fear of snakes is among the top phobias for humans and also for monkeys, according to new research, the Los Angeles Times reported. In a new study, published online Monday in the journal Proceedings of the National Academy of Science, scientist discovered a neurological development in monkeys that heightened their alert upon seeing a snake.
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Researchers placed probes into the brains of Japanese macaques monkeys and found the neurological reaction when seeing a snake was stronger than most other reactions to various sights. The response was determined to be motivated by fear of being prey, or a survivalist reaction.
"The characteristics we have help us to see them better than other mammals can see them," said study co-author Lynne Isbell, an evolutionary biologist at UC Davis. "Mammals in general are really good at picking up movement. But snakes lie in wait. They don't move very much, so it's crucial to see them before they see us and to avoid them."
Isbell said she did not believe the fear of snakes was innate, or naturally developed by the mind, but rather built-in by evolution. The spike in attention, or the increase in neurological activity, associated with seeing a snake leads to avoidance motivated by fear.
"[Monkeys] were actually prey," Isbell said "And the first of the modern predators of primates, and the most persistent, that continued to this day - and that look the same as they did 100 million years ago - are snakes."
Study co-author Hisao Nishijo, of Toyama University in Japan, has previously studied the causes of fear in macaques monkeys and said the new research could explain the true reason behind it.
"The results show that the brain has special neural circuits to detect snakes, and this suggests that the neural circuits to detect snakes have been genetically encoded," Nishijo said in a news release.
In the experiment, the monkeys - with probes in their brains - were placed in a walled-off community and put in contact with a real snake for the first time in their lives.
"I don't see another way to explain the sensitivity of these neurons to snakes except through an evolutionary path," Isbell said.