Study on Monkeys May Help Explain Our Fear of Snakes
Scientists are close to explaining one of the top of human's fear - ophidiophobia - that is, fear of snakes. This has been made possible thanks to the study performed on monkeys. That's because fear of snakes is one of the many things we have in common with our primate cousins.
One thing the researchers have found is that the fear of snakes is not something humans are born with, but we surely develop pretty early.
As part of the study, scientists plucked probes into the brains of Japanese macacques and discovered that neurons in an area of their brain that controls visual attention were more strongly and quickly activated in response to images of snakes, versus other objects.
The study, which results were published online in the journal Proceedings of the National Academy of Sciences, supports a theory that early primates developed advanced perception as an evolutionary response to being prey, not as an adaptation that may have made foraging or hunting easier.
According to Lynne Isbell, an evolutionary biologist from UC Davis and one of the authors of the paper, although fear of snakes may not be innate, noticing them more than other phenomena may be hard-wired by evolution.
"That heightened attention," she said, "can lead to early and resilient learned behavior, such as fear-mediated avoidance. In other words, getting out of the way of snakes."
Isbell added that the characteristics we have help us to see them better than other mammals can see them. Mammals in general, she said, 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."
An old scientific belief established that developing new additions to the brain would have given ancestor primates an advantage. Many scientists assumed the advantage had to do with catching insects for food. But Isbell shook that view of primate evolution in 2006, eventually elaborating on it in a book, "The Fruit, the Tree and the Serpent: Why We see So Well." An arms race between predator and prey is what selected for bigger-brained primates, Isbell argued.
"They were actually prey," Isbell explained. "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."