Any time people come together in a meeting, we're not necessarily getting the best ideas; we're just getting the ideas of the best talkers.

I worry that there are people who are put in positions of authority because they're good talkers, but they don't have good ideas. It's so easy to confuse schmoozing ability with talent. Someone seems like a good presenter, easy to get along with, and those traits are rewarded. Well, why is that? They're valuable traits, but we put too much of a premium on presenting and not enough on substance and critical thinking.

Your tendency to be inward-directed or outward-directed is huge; it governs every part of the way you live and work and love.

I'm continually amazed by how many people who appear to be extroverts are actually introverts.

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.

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.

America had shifted from what influential cultural historian Warren Susman called a culture of character to a culture of personality, and opened up a Pandora's box of personal anxieties of which we would never recover.