Change your mind about something significant every day.

The poorer children were, to her mind, often better behaved, less whiny, more creative in making use of their own time, and have a well-developed sense of independence.

Economists often talk about the 80/20 Principle, which is the idea that in any situation roughly 80 percent of the “work” will be done by 20 percent of the participants. In most societies, 20 percent of criminals commit 80 percent of crimes. Twenty percent of motorists cause 80 percent of all accidents. Twenty percent of beer drinkers drink 80 percent of all beer. When it comes to epidemics, though, this disproportionality becomes even more extreme: a tiny percentage of people do the majority of the work.

Take a random group of 8-year-old American and Japanese kids, give them all a really, really hard math problem, and start a stopwatch. The American kids will give up after 30, 40 seconds. If you let the test run for 15 minutes, the Japanese kids will not have given up. You have to take it away.

Occasions when you can change your mind should be cherished, because they mean you're smarter than you were before.

Living a long life, the conventional wisdom at the time said, depended to a great extent on who we were-that is, our genes. It depended on the decisions we made-on what we chose to eat, and how much we chose to exercise, and how effectively we were treated by the medical system. No one was used to thinking about health in terms of community.

Clear writing is universal. People talk about writing down to an audience or writing up to an audience; I think that's nonsense. If you write in a way that is clear, transparent, and elegant, it will reach everyone.