The Power of Habit: Why We Do What We Do in Life and Business

by Charles Duhigg

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

This process within our brains is a three-step loop. First, there is a cue, a trigger that tells your brain to go into automatic mode and which habit to use. Then there is the routine, which can be physical or mental or emotional. Finally, there is a reward, which helps your brain figure out if this particular loop is worth remembering for the future:

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.

Every McDonald’s, for instance, looks the same—the company deliberately tries to standardize stores’ architecture and what employees say to customers, so everything is a consistent cue to trigger eating routines. The foods at some chains are specifically engineered to deliver immediate rewards—the fries, for instance, are designed to begin disintegrating the moment they hit your tongue, in order to deliver a hit of salt and grease as fast as possible, causing your pleasure centers to light up and your brain to lock in the pattern. All the better for tightening the habit loop.

Particularly when all it takes is a quick brush with Pepsodent?

First, find a simple and obvious cue. Second, clearly define the rewards.

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

“Self-discipline predicted academic performance more robustly than did IQ. Self-discipline also predicted which students would improve their grades over the course of the school year, whereas IQ did not.… Self-discipline has a bigger effect on academic performance than does intellectual talent.”

However, when a group of psychology PhD candidates at Case Western—including one named Mark Muraven—discovered those studies in the mid-nineties, they started asking questions the previous research didn’t seem to answer.

“When you learn to force yourself to go to the gym or start your homework or eat a salad instead of a hamburger, part of what’s happening is that you’re changing how you think,” said Todd Heatherton, a researcher at Dartmouth who has worked on willpower studies. “People get better at regulating their impulses. They learn how to distract themselves from temptations. And once you’ve gotten into that willpower groove, your brain is practiced at helping you focus on a goal.”

About a year after Pole created his pregnancy prediction model, a man walked into a Minnesota Target and demanded to see the manager. He was clutching an advertisement. He was very angry. “My daughter got this in the mail!” he said. “She’s still in high school, and you’re sending her coupons for baby clothes and cribs? Are you trying to encourage her to get pregnant?” The manager didn’t have any idea what the man was talking about. He looked at the mailer. Sure enough, it was addressed to the man’s daughter and contained advertisements for maternity clothing, nursery furniture, and pictures of smiling infants gazing into their mothers’ eyes. The manager apologized profusely, and then called, a few days later, to apologize again. The father was somewhat abashed. “I had a talk with my daughter,” he said. “It turns out there’s been some activities in my house I haven’t been completely aware of.” He took a deep breath. “She’s due in August. I owe you an apology.”

In 2009, a British soldier admitted to raping a teenage girl, but said he was asleep and unconscious while he undressed himself, pulled down her pants, and began having sex. When he woke, mid-rape, he apologized and called the police. “I’ve just sort of committed a crime,” he told the emergency operator. “I honestly don’t know what happened. I woke up on top of her.” He had a history of suffering from sleep terrors and was found not guilty.