Some introverts are perfectly comfortable with public speaking; I'm not one of them.

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.

We don't need giant personalities to transform companies. We need leaders who build not their own egos but the institutions they run.

In the first study, Grant and his colleagues analyzed data from one of the five biggest pizza chains in the United States. They discovered that the weekly profits of the stores managed by extroverts were 16 percent higher than the profits of those led by introverts—but only when the employees were passive types who tended to do their job without exercising initiative. Introverted leaders had the exact opposite results. When they worked with employees who actively tried to improve work procedures, their stores outperformed those led by extroverts by more than 14 percent.

Indeed, your biggest challenge may be to fully harness your strengths. You may be so busy trying to appear like a zestful, reward-sensitive extrovert that you undervalue your own talents, or feel underestimated by those around you. But when you’re focused on a project that you care about, you probably find that your energy is boundless.

Jealousy is an ugly emotion, but it tells the truth. You mostly envy those who have what you desire.

But when the group is literally capable of changing our perceptions, and when to stand alone is to activate primitive, powerful, and unconscious feelings of rejection, then the health of these institutions seems far more vulnerable than we think.