Scientists experimenting with images of tarantulas have concluded that the human brain responds differently to threats based on proximity, direction and how scary people expect something to be. While those conclusions are totally obvious, the recent experiments are revealing specifically what parts of the brain are involved in identifying and magnifying human fear.
Researchers in Cambridge, England used functional magnetic resonance imaging (fMRI) to track brain activity in 20 volunteers as they watched a tarantula placed near their feet.
"We've shown that it's not just a single structure in the brain, it's a number of different parts of the fear network and they are working together to orchestrate the fear response,” Dean Mobbs, who led the study, tells Reuters News. "It seems that when a spider moves closer to you, you see a switch from the anxiety regions of the brain to the panic regions."
Volunteers were actually watching an elaborately rigged video of a tarantula which they believed was near their foot, since getting the spider to do the same thing for each volunteer would have been impossible.
The scientists also asked volunteers beforehand how scared they thought they might be of the tarantula. They found that those who thought they would be most scared had a false impression afterwards of how large the spider was. This so-called "expectation error" could be the key to people developing a phobia ~ an irrational, intense and persistent fear of certain things, people, animals or situations.
"This may be one cognitive mechanism by which people acquire phobias," said Mobbs.
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Click here for a Business Week article on the topic.