In some ways, extroverts are lucky; buzz has a delightful champagne-bubble quality. It fires us up to work and play hard. It gives us the courage to take chances. Buzz also gets us to do things that would otherwise seem too difficult, like giving speeches. Imagine you work hard to prepare a talk on a subject you care about. You get your message across, and when you finish the audience rises to its feet, its clapping sustained and sincere. One person might leave the room feeling, "I'm glad I got my message across, but I'm also happy it's over; now I can get back to the rest of my life." Another person, more sensitive to buzz, might walk away feeling, "What a trip! Did you hear that applause? Did you see the expression on their faces when I made that life-changing point? This is great!"
But buzz also has considerable downsides. "Everyone assumes that it's good to accentuate positive emotions, but that isn't correct," the psychology professor Richard Howard told me, pointing to the example of soccer victories that end in violence and property damage. "A lot of antisocial and self-defeating behavior results from people who amplify positive emotions."
Another disadvantage of buzz may be its connection to risk—sometimes outsized risk. Buzz can cause us to ignore warning signs we should be heeding. When Ted Turner (who appears to be an extreme extrovert) compared the AOL–Time Warner deal to his first sexual experience, he may have been telling us that he was in the same buzzy state of mind as an adolescent who's so excited about spending the night with his new girlfriend that he's not thinking much about the consequences. This blindness to danger may explain why extroverts are more likely than introverts to be killed while driving, be hospitalized as a result of accident or injury, smoke, have risky sex, participate in high-risk sports, have affairs, and remarry. It also helps explain why extroverts are more prone than introverts to overconfidence—defined as greater confidence unmatched by greater ability. Buzz is JFK's Camelot, but it's also the Kennedy Curse.
This theory of extroversion is still young, and it is not absolute. We can't say that all extroverts constantly crave rewards or that all introverts always brake for trouble. Still, the theory suggests that we should rethink the roles that introverts and extroverts play in their own lives, and in organizations. It suggests that when it comes time to make group decisions, extroverts would do well to listen to introverts—especially when they see problems ahead.
In the wake of the 2008 crash, a financial catastrophe caused in part by uncalculated risk-taking and blindness to threat, it became fashionable to speculate whether we'd have been better off with more women and fewer men—or less testosterone—on Wall Street. But maybe we should also ask what might have happened with a few more introverts at the helm—and a lot less dopamine.
Several studies answer this question implicitly. Kellogg School of Management Professor Camelia Kuhnen has found that the variation of a dopamine-regulating gene (DRD4) associated with a particularly thrill-seeking version of extroversion is a strong predictor of financial risk-taking. By contrast, people with a variant of a serotonin-regulating gene linked to introversion and sensitivity take 28 percent less financial risk than others. They have also been found to outperform their peers when playing gambling games calling for sophisticated decision-making. (When faced with a low probability of winning, people with this gene variant tend to be risk-averse; when they have a high probability of winning, they become relatively risk-seeking.) Another study, of sixty-four traders at an investment bank, found that the highest-performing traders tended to be emotionally stable introverts.
Introverts also seem to be better than extroverts at delaying gratification, a crucial life skill associated with everything from higher SAT scores and income to lower body mass index. In one study, scientists gave participants the choice of a small reward immediately (a gift certificate from Amazon) or a bigger gift certificate in two to four weeks. Objectively, the bigger reward in the near but not immediate future was the more desirable option. But many people went for the "I want it now" choice—and when they did, a brain scanner revealed that their reward network was activated. Those who held out for the larger reward two weeks hence showed more activity in the prefrontal cortex—the part of the new brain that talks us out of sending ill-considered e-mails and eating too much chocolate cake. (A similar study suggests that the former group tended to be extroverts and the latter group introverts.)
