INTROVERTS are especially vulnerable to challenges like marital tension, a parent’s death, or abuse. They’re more likely than their peers to react to these events with depression, anxiety, and shyness. Indeed, about a quarter of Kagan’s high-reactive kids suffer from some degree of the condition known as “social anxiety disorder,” a chronic and disabling form of shyness.

...true self-esteem comes from competence, not the other way around.

Now that you're an adult, you might still feel a pang of guilt when you decline a dinner invitation in favor of a good book. Or maybe you like to eat alone in restaurants and could do without the pitying looks from fellow diners. Or you're told that you're "in your head too much", a phrase that's often deployed against the quiet and cerebral. Or maybe there's another word for such people: thinkers.

As a young boy, Charles Darwin made friends easily but preferred to spend his time taking long, solitary nature walks. (As an adult he was no different. “My dear Mr. Babbage,” he wrote to the famous mathematician who had invited him to a dinner party, “I am very much obliged to you for sending me cards for your parties, but I am afraid of accepting them, for I should meet some people there, to whom I have sworn by all the saints in Heaven, I never go out.”)

INTROVERTS are especially vulnerable to challenges like marital tension, a parent’s death, or abuse. They’re more likely than their peers to react to these events with depression, anxiety, and shyness. Indeed, about a quarter of Kagan’s high-reactive kids suffer from some degree of the condition known as “social anxiety disorder,” a chronic and disabling form of shyness.

Persistence isn't very glamorous. If genius is one percent inspiration and ninety-nine percent perspiration, then as a culture we tend to lionize the one percent. We love its flash and dazzle. But great power lies in the other ninety-nine percent.

Psychologists usually offer three explanations for the failure of group brainstorming. The first is social loafing: in a group, some individuals tend to sit back and let others do the work. The second is production blocking: only one person can talk or produce an idea at once, while the other group members are forced to sit passively. And the third is evaluation apprehension, meaning the fear of looking stupid in front of one's peers.