Сьюзан Кейн - Quiet [The Power of Introverts in a World That Can't Stop Talking]

A reward-sensitive person is highly motivated to seek rewards—from a promotion to a lottery jackpot to an enjoyable evening out with friends. Reward sensitivity motivates us to pursue goals like sex and money, social status and influence. It prompts us to climb ladders and reach for faraway branches in order to gather life’s choicest fruits.

But sometimes we’re too sensitive to rewards. Reward sensitivity on overdrive gets people into all kinds of trouble. We can get so excited by the prospect of juicy prizes, like winning big in the stock market, that we take outsized risks and ignore obvious warning signals.

Alan was presented with plenty of these signals, but was so animated by the prospect of winning big that he couldn’t see them. Indeed, he fell into a classic pattern of reward sensitivity run amok: at exactly the moments when the warning signs suggested slowing down, he sped up —dumping money he couldn’t afford to lose into a speculative series of trades.

Financial history is full of examples of players accelerating when they should be braking. Behavioral economists have long observed that executives buying companies can get so excited about beating out their competitors that they ignore signs that they’re overpaying. This happens so frequently that it has a name: “deal fever,” followed by “the winner’s curse.” The AOL–Time Warner merger, which wiped out $200 billion of Time Warner shareholder value, is a classic example. There were plenty of warnings that AOL’s stock, which was the currency for the merger, was wildly overvalued, yet Time Warner’s directors approved the deal unanimously.

“I did it with as much or more excitement and enthusiasm as I did when I first made love some forty-two years ago,” exclaimed Ted Turner, one of those directors and the largest individual shareholder in the company. “TED TURNER: IT’S BETTER THAN SEX,” announced the New York Post the day after the deal was struck, a headline to which we’ll return for its power to explain why smart people can sometimes be too reward-sensitive.

You may be wondering what all this has to do with introversion and extroversion. Don’t we all get a little carried away sometimes?

The answer is yes, except that some of us do so more than others. Dorn has observed that her extroverted clients are more likely to be highly reward-sensitive, while the introverts are more likely to pay attention to warning signals. They’re more successful at regulating their feelings of desire or excitement. They protect themselves better from the downside. “My introvert traders are much more able to say, ‘OK, Janice, I do feel these excited emotions coming up in me, but I understand that I can’t act on them.’ The introverts are much better at making a plan, staying with a plan, being very disciplined.”

To understand why introverts and extroverts might react differently to the prospect of rewards, says Dorn, you have to know a little about brain structure. As we saw in chapter 4, our limbic system, which we share with the most primitive mammals and which Dorn calls the “old brain,” is emotional and instinctive. It comprises various structures, including the amygdala, and it’s highly interconnected with the nucleus accumbens, sometimes called the brain’s “pleasure center.” We examined the anxious side of the old brain when we explored the role of the amygdala in high reactivity and introversion. Now we’re about to see its greedy side.

The old brain, according to Dorn, is constantly telling us, “Yes, yes, yes! Eat more, drink more, have more sex, take lots of risk, go for all the gusto you can get, and above all, do not think!” The reward-seeking, pleasure-loving part of the old brain is what Dorn believes spurred Alan to treat his life savings like chips at the casino.

We also have a “new brain” called the neocortex, which evolved many thousands of years after the limbic system. The new brain is responsible for thinking, planning, language, and decision-making—some of the very faculties that make us human. Although the new brain also plays a significant role in our emotional lives, it’s the seat of rationality. Its job, according to Dorn, includes saying, “No, no, no! Don’t do that, because it’s dangerous, makes no sense, and is not in your best interests, or those of your family, or of society.”

So where was Alan’s neocortex when he was chasing stock market gains?

The old brain and the new brain do work together, but not always efficiently. Sometimes they’re actually in conflict, and then our decisions are a function of which one is sending out stronger signals. So when Alan’s old brain sent its breathless messages up to his new brain, it probably responded as a neocortex should: it told his old brain to slow down. It said, Watch out ! But it lost the ensuing tug-of-war.

We all have old brains, of course. But just as the amygdala of a high-reactive person is more sensitive than average to novelty, so do extroverts seem to be more susceptible than introverts to the reward-seeking cravings of the old brain. In fact, some scientists are starting to explore the idea that reward-sensitivity is not only an interesting feature of extroversion; it is what makes an extrovert an extrovert. Extroverts, in other words, are characterized by their tendency to seek rewards, from top dog status to sexual highs to cold cash. They’ve been found to have greater economic, political, and hedonistic ambitions than introverts; even their sociability is a function of reward-sensitivity, according to this view—extroverts socialize because human connection is inherently gratifying.

What underlies all this reward-seeking? The key seems to be positive emotion. Extroverts tend to experience more pleasure and excitement than introverts do—emotions that are activated, explains the psychologist Daniel Nettle in his illuminating book on personality, “in response to the pursuit or capture of some resource that is valued. Excitement builds towards the anticipated capture of that resource. Joy follows its capture.” Extroverts, in other words, often find themselves in an emotional state we might call “buzz”—a rush of energized, enthusiastic feelings. This is a sensation we all know and like, but not necessarily to the same degree or with the same frequency: extroverts seem to get an extra buzz from the pursuit and attainment of their goals.

The basis of buzz appears to be a high degree of activity in a network of structures in the brain—often called the “reward system”—including the orbitofrontal cortex, the nucleus accumbens, and the amygdala. The job of the reward system is to get us excited about potential goodies; fMRI experiments have shown that the system is activated by any number of possible delights, from anticipation of a squirt of Kool-Aid on the tongue, to money, to pictures of attractive people.

The neurons that transmit information in the reward network operate in part through a neurotransmitter—a chemical that carries information between brain cells—called dopamine. Dopamine is the “reward chemical” released in response to anticipated pleasures. The more responsive your brain is to dopamine, or the higher the level of dopamine you have available to release, some scientists believe, the more likely you are to go after rewards like sex, chocolate, money, and status. Stimulating mid-brain dopamine activity in mice gets them to run around excitedly in an empty cage until they drop dead of starvation. Cocaine and heroin, which stimulate dopamine-releasing neurons in humans, make people euphoric.

Extroverts’ dopamine pathways appear to be more active than those of introverts. Although the exact relationship between extroversion, dopamine, and the brain’s reward system has not been conclusively established, early findings have been intriguing. In one experiment, Richard Depue, a neurobiologist at Cornell University, gave an amphetamine that activates the dopamine system to a group of introverts and extroverts, and found that the extroverts had a stronger response. Another study found that extroverts who win gambling games have more activity in the reward-sensitive regions of their brains than victorious introverts do. Still other research has shown that the medial orbitofrontal cortex, a key component of the brain’s dopamine-driven reward system, is larger in extroverts than in introverts.