Do We Worry About the Right Things?

May 7 -- War and terrorism, anthrax and SARS, the stock market and the job market — if any of those things have really shaken you up, that's your amygdala talking to you.

The amygdala (pronounced ah-MIG-da-la) is a region of the brain that, as one researcher put it, tells you if new sights and sounds are "relevant" to you — whether you need to respond quickly to them. The amygdala can generate powerful emotions — the so-called fight-or-flight response.

Another region of the brain, the prefrontal cortex, is the center of reflection, the section the brain uses to make reasoned responses. Still other regions help one recall an experience, or calculate its importance.

The problem is that when one needs to react quickly to something traumatic, the amygdala wins out. And that means, sometimes, that people worry about the wrong things.

"We all make poor decisions at times because we don't have enough information, or we react impulsively," says Jordan Grafman of the National Institute of Neurological Disorders and Stroke.

Knowing Your Risks

Grafman's research includes extensive work with a Vietnam veteran he calls Michael. Michael was a very levelheaded man, until a war injury damaged his prefrontal cortex.

After that, says Grafman, he became an uncontrolled risk-taker. He was impulsive. He married a prostitute, then an underage woman. Signals from his amygdala, Grafman theorizes, went unchecked. Only after extensive therapy has Michael been able to hold down a job.

Michael's experience is an extreme case, but Grafman says it shows us how the human brain is designed to react first and reason later.

"It's our natural tendency to look toward things that in essence turn us on, appeal to us or sometimes make us quite fearful," says Grafman. "But that very design often distorts the actual risk of the circumstance."

Behavioral scientists say because of the brain's structure, perfectly healthy people may overreact to upsetting circumstances. Many Americans went and bought duct tape — even though they knew, on an intellectual level, that their personal odds of dying in a terrorist attack were far smaller than the risk from auto accidents or heart disease.