Most people have never encountered a snake, so why are are most people afraid of them? The answer, according to a recent study, may be in our genes.

Psychologists have found that both adults and children could detect images of snakes among a variety of non-threatening objects more quickly than they could pinpoint frogs, flowers or caterpillars. The researchers think this ability helped humans survive in the wild.

"The idea is that throughout evolutionary history, humans that learned quickly to fear snakes would have been at an advantage to survive and reproduce," said Vanessa LoBue, a post-doctoral fellow in psychology at the University of Virginia. "Humans who detected the presence of snakes very quickly would have been more likely to pass on their genes."

"This feeling is really common," LoBue told LiveScience. "We don't see snakes all the time. There's really no reason for this overwhelming disgust or hatred of snakes."

While babies and very young children do not usually fear snakes, they are unusually skilled at detecting them and show a predisposition to learn to fear snakes if they have bad experiences or even if they are exposed to negative portrayals of them in the media, the scientists found.

To learn more, the psychologists showed adults and 3-year-old children images of a snake surrounded by objects of similar colors, such as frogs, caterpillars and flowers. Then they showed them pictures of a frog or a flower surrounded by snakes. Both groups were able to identify the hidden snake faster than the other hidden objects.

"We also did a study with spiders and found the same effect," LoBue said. Although the team has not tested other phobias, they don't think these predispositions would necessarily apply across the board.

"It would have to be something widespread, that you could encounter on a day-to-day basis," she said. "That's why you don't see lion and tiger and bear phobias as often. It would also have to be something that was around and dangerous while humans were evolving. Things that are dangerous right now, like guns, we haven't had enough time to develop a predisposition to detect really quickly."

(Xinhua/Agencies March 6, 2008)