The Science of Risk-Taking

The pursuit of a thrill can make us take crazy chances: bungee-jumping, say, or skydiving. And then there's paying for a prostitute when you're a public figure the whole world is watching. In all such cases, excitement is involved--so why does it seduce some of us while leaving others cold?

The answer may start with brain chemistry. In the 1990s, Israeli researchers identified what they thought of as a risk gene, a bit of behavioral coding that changes the reabsorption of the neurotransmitter dopamine, making it easier for some people to respond to stress or anxiety. The higher your threshold for those feelings, the higher your tolerance for risk. But that accounts for only 10% of thrill-seeking behavior. A later University of Delaware study suggested that another neurotransmitter, serotonin, plays a role as well. The chemical helps inhibit impulsive behavior, and it could be in short supply in people who take chances. (See the top 10 scientific discoveries of 2008.)

Some scientists point to high testosterone levels combined with low monoamine oxidase inhibitors, which regulates dopamine. The role of testosterone may also implicate evolution. When giant beasts stalked the earth, men took big risks to hunt big game. That could explain why males seem more likely to take chances than females do.

Not all risks have to be serious ones. Marvin Zuckerman, psychologist and professor emeritus at the University of Delaware, says risk-taking can mean seeking sensory experiences through food or travel or the more primal thrills of sex--as may be the case with Eliot Spitzer. The problem is, he says, that "high-sensation seekers tend to underestimate the risk."

None of this means Spitzer was a blameless victim of chemistry. Sometimes hubris is just hubris. But humans habituate to thrills, which means needing more and more to get the same buzz. "You want to re-create the high, so you up the ante," says neuropharmacologist Candace Pert. And as Spitzer learned, when you risk everything, you can lose it too.

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