Charles Duhigg

One set of neurological patterns—her old habits—had been overridden by new patterns. They could still see the neural activity of her old behaviors, but those impulses were crowded out by new urges. As Lisa’s habits changed, so had her brain.

By focusing on one pattern—what is known as a “keystone habit”—Lisa had taught herself how to reprogram the other routines in her life, as well.

“However, there’s new activity in this area”—he pointed to the region closest to her forehead—“where we believe behavioral inhibition and self-discipline starts. That activity has become more pronounced each time you’ve come in.”

“All our life, so far as it has definite form, is but a mass of habits,” William James wrote in 1892.

One paper published by a Duke University researcher in 2006 found that more than 40 percent of the actions people performed each day weren’t actual decisions, but habits.

Each chapter revolves around a central argument: Habits can be changed, if we understand how they work.

In some sense, he said, a community was a giant collection of habits occurring among thousands of people that, depending on how they’re influenced, could result in violence or peace.

“I’m telling you, if a hick like me can learn this stuff, anyone can. I tell my soldiers all the time, there’s nothing you can’t do if you get the habits right.”

It would help spark a scientific revolution that today involves hundreds of researchers who are learning, for the first time, to understand all the habits that influence our lives.

Habits aren’t destiny. As the next two chapters explain, habits can be ignored, changed, or replaced. But the reason the discovery of the habit loop is so important is that it reveals a basic truth: When a habit emerges, the brain stops fully participating in decision making. It stops working so hard, or diverts focus to other tasks. So unless you deliberately fight a habit—unless you find new routines—the pattern will unfold automatically.