Sunday, March 30, 2008

Snakes on the Brain

New research by psychologists suggests we're born ready to look for snakes. As this ScienCentral News video reports, a series of experiments showed that people–even toddlers–tend to recognize and locate a snake faster than other plants and animals.

Interviewee: Judy DeLoache
University of Virginia
Length: 1 min 24 sec
Produced by Chris Bergendorff
Edited by Chris Bergendorff
Copyright © ScienCentral, Inc.

Scary Serpents

Snakes inspire disgust in many people, and downright terror in others. In fact, snake phobia, or ophidiophobia, is the one of the most common phobias on earth. Now psychology researchers studying toddlers say that avoiding snakes may be an evolutionary adaptation that's slithered its way into our genes. The University of Virginia's Judy DeLoache says her own personal snake fear led her to this research. "I have a very intense fear of snakes. In fact, I would pretty much say I have a snake phobia. I always have, ever since I can remember."

DeLoache, an expert on how children see and interpret symbols, began with the theory that spotting a snake is a survival skill that may have been passed on in peoples' genetic code. This skill most likely extends far back into our evolutionary past. As DeLoache explains, "any human that could quickly detect the presence of a snake and thereby avoid being bitten by one and possibly poisoned, would have been more likely to survive, would have been more likely to pass on their genes to their offspring." Because snakes are found all over the globe, this adaptation would have continued to be useful to our ancestors as they settled in different areas of the world.

If humans truly do have an inherited tendency to quickly locate snakes in their environment, they may also readily fear snakes as well. A threatening object, like a snake, would elicit more of a response than a non-threatening object, like a tree or a rock. Eventually, this could make it more likely for some people to develop an irrationally intense fear of snakes.

DeLoache and her colleague Vanessa LoBue first tested for the snake spotting ability in adults. They measured people's speed at locating pictures of snakes among pictures of flowers, and also the reverse. The results supported the evolutionary theory. "Adults are much more quickly to visually find a picture of a snake among other kinds of pictures," says DeLoache, "than they are to, say, find a flower among a whole bunch of different kinds of snakes."

But what about young children who've never seen a snake? The researchers reasoned that if the ability to see snakes more quickly than other objects really is an adaptation common to all humans, then it should show up in young children, even if they've never had experience with snakes. DeLoache and LoBue set up a new series of experiments that were, in many ways, extensions of the previous one.

They asked a group of young children, and their parents, to repeat the procedure from their former study. They found that both age groups were able to spot snakes among flowers faster than flowers among snakes, reinforcing the previous results. However, they also tested both groups with two other sets of pictures: frogs and caterpillars. The researchers wanted to make sure that their participants were truly spotting snakes faster due to an inborn ability, and not for any other reason. They included pictures of frogs, because frogs and snakes share many physical characteristics, including skin texture and coloring. They also included caterpillar pictures, because those insects most closely resemble the elongated body shapes of snakes.

The researchers wrote in the journal Psychological Science that their tests with toddlers suggest spotting snakes really is an inborn ability. As DeLoache says, "Three, four, and five year old children, and their parents who came into the lab with them, all detected the presence of a snake more rapidly than all sorts of other kinds of pictures that we showed them."

DeLoache points out that if that ability is inborn, then it isn't going anywhere. However, she says, treating phobias is still a poorly understood area of psychology. She hopes a better understanding may help ease the fears of those, like her, who have snakes on the brain.

Original here

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