Of those who had at some time in their lives been diagnosed with a major psychiatric disorder, 74 percent had smoked at some point, and 14 percent had quit smoking. Of those who had never been diagnosed with a psychiatric problem, 53 percent had smoked at some point in their life and 31 percent had managed to quit smoking.

Gore Associates,

But we need to remember that small changes in context can be just as important in tipping epidemics, even though that fact appears to violate some of our most deeply held assumptions about human nature.

Ideas and products and messages and behaviors spread just like viruses do.

Of those who have ever tried cocaine, less than one percent—0.9 percent—are regular users.

It takes only the smallest of changes to shatter an epidemic’s equilibrium.

Character, then, isn’t what we think it is or, rather, what we want it to be. It isn’t a stable, easily identifiable set of closely related traits, and it only seems that way because of a glitch in the way our brains are organized. Character is more like a bundle of habits and tendencies and interests, loosely bound together and dependent, at

“The Magical Number Seven.” This is the reason that telephone numbers have seven digits. “Bell wanted a number to be as long as possible so they could have as large a capacity as possible, but not so long that people couldn’t remember it,” says Jonathan Cohen, a memory researcher at Princeton University. At eight or nine digits, the local telephone

Psychologists tell us much the same thing: that when people are asked to consider evidence or make decisions in a group, they come to very different conclusions than when they are asked the same questions by themselves.