The same process that makes AA so effective—the power of a group to teach individuals how to believe—happens whenever people come together to help one another change. Belief is easier when it occurs within a community.

Rather, to change a habit, you must keep the old cue, and deliver the old reward, but insert a new routine.

Habits, scientists say, emerge because the brain is constantly looking for ways to save effort.

Once people learned how to believe in something, that skill started spilling over to other parts of their lives, until they started believing they could change. Belief was the ingredient that made a reworked habit loop into a permanent behavior.

Cravings are what drive habits. And figuring out how to spark a craving makes creating a new habit easier.

What studies say the number one best way to start an exercise habit is to give yourself a reward that you genuinely enjoy.

The cooperation of NASCAR - or any other system, it turns out - persists only when everyone believes he has the opportunity to win.