It's the Dopamine

Time | Dopamine is responsible for making us feel satisfied after a filling meal, happy when our favorite football team wins, or really happy when we use stimulating drugs like amphetamines or cocaine, which can artificially squeeze more dopamine out of the nerve cells in our brain. It's also responsible for the high we feel when we do something daring, like skiing down a double black diamond slope or skydiving out of a plane. In the risk taker's brain, researchers report in the Journal of Neuroscience, there appear to be fewer dopamine-inhibiting receptors — meaning that daredevils' brains are more saturated with the chemical, predisposing them to keep taking risks and chasing the next high: driving too fast, drinking too much, overspending or even taking drugs.

"This is one of those situations where the data came out essentially perfectly," he says. "The results were exactly as we predicted they would be, based on the animal data." That is, like the rats, humans who were more spontaneous and eager to take risks had fewer dopamine-regulating receptors than those who were more cautious.

The findings support Zald's theory that people who take risks get an unusually big hit of dopamine each time they have a novel experience, because their brains are not able to inhibit the neurotransmitter adequately. That blast makes them feel good, so they keep returning for the rush from similarly risky or new behaviors, just like the addict seeking the next high.

"This finding is really interesting," says Dr. Bruce Cohen, director of the Frazier Research Institute at McLean Hospital in Boston and a professor of psychiatry at Harvard Medical School. "It's a piece of the puzzle to understanding why we like novelty, and why we get addicted to substances ... Dopamine is an important piece of reward."