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PROLOGUE: The habit cure

The power of habit summary

Is it possible to turn around a messy life in a relatively short period of time?

Lisa Allen, 34 years old had struggled with obesity her entire life.

She had started smoking and drinking when she was sixteen. Worse, she was $10,000 in debts.

Most people wouldn’t recover from such a situation. Yet, Lisa now completely changed. She looks a decade younger, she’s run a marathon and she just bought a home.

Charles Duhigg begins with this striking example to illustrate the power of habit.

After a divorce, Lisa hit bottom rock. As she traveled, she decided to trek through the Sahara desert, working towards something to rebuild her life.

To achieve this challenging goal, she soon realized that she needed to quit smoking.

According to the author, that one small shift triggered a series of changes “that would ultimately radiate out to every part of her life”.

Charles calls it a “keystone habit”.

Lisa’s decision to quit smoking pushed her to exercise more, to start jogging, to care more about her life including her diet, sleep and finances. She also decided to start a master’s degree.

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

“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”

“This book draws on hundreds of academic studies, interviews with more than three hundred scientists and executives, and research conducted at dozens of companies”

The power of habit highlights that it’s possible to change our habits. But we first need to understand how they work.


the power of habit


1- THE HABIT LOOP: How habits work

They lost their memory

Think about a person who can’t remember his parents and friends.

Eugene would wake up, walk into the kitchen, prepare bacon and eggs then get back to his bed and turn on the radio. Less than an hour later, he would do the exact same thing: get up, cook bacon and eggs, climb back into bed and fiddle with the radio. As if it was not enough, he would do that again and again throughout the day.

Just like Eugene, Henry Molaison’s memory had been removed after an accident. He would introduce himself dozens of times to the medical staff each day.

But not their habits

What’s fascinating is that Eugene has kept his old habits. He lost part of his memory but he still performed his past routines.

“Whenever we gave him a cup of water or complimented him on a particularly detailed answer, Eugene would thank the person and offer a compliment in return. Whenever someone entered the room, Eugene would introduce himself and ask about their day. But when we asked Eugene to memorize a string of numbers or describe the hallway outside the laboratory’s door, the doctor found his patient couldn’t retain any new information for more than a minute or so. When someone showed Eugene photos of his grandchildren, he had no idea who they were.”

It’s a challenge to live with someone who lost his memory. You will be asked the same questions over and over in an endless loop.

To Beverly, Eugene’s wife, the only solution was to walk him outside. They took the same route every day.

One day, Beverly woke up and realized that Eugene was nowhere to find. Panicking, she called the doctor, looked around and even got back home to call the police. To her surprise, she found Eugene sitting in the living room watching quietly the television.

When asked where he went, Eugene got confused and said he didn’t remember leaving. Surprisingly, Beverly saw a pile of pinecones on the table just the ones they found on their way when they usually walk outside.

Eugene took the same route alone without getting lost. Actually, he never got lost as he did this several times.

Even with a loss of memory, how did Eugene absorb this information? Why wasn’t he lost on his way back home?

Basal ganglia

The basal ganglia is a central part of the brain and it holds most of our habits.

“Toward the center of the skull is a golf ball–sized lump of tissue that is similar to what you might find inside the head of a fish, reptile, or mammal. This is the basal ganglia, an oval of cells that, for years, scientists didn’t understand very well, except for suspicions that it played a role in diseases such as Parkinson’s”.

Scientists discovered that “animals with injured basal ganglia suddenly developed problems with tasks such as learning how to run through mazes or remembering how to open food containers”

While we acquired a new routine, we got a lot of mental activities. But over time, the basal ganglia kicks in and we think less and less because the action became a habit.

When you first learn how to drive a car; your brain works at full power. You focus on the break, the gas and the wheel. With continuous practice, the brain activity decreases to a point where you barely need to think at all.

“When a habit emerges, the brain stops fully participating in decision making. It stops working so hard, or diverts focus to other tasks.”

As you develop a habit, your basal ganglia takes over.

“The basal ganglia was central to recalling patterns and acting on them. The basal ganglia, in other words, stored habits even while the rest of the brain went to sleep.”

Eugene survived because his habits were so deeply ingrained in him. He was even still learning new habits despite his loss of memory.

Three-step loop

There are three steps for a habit to form: cue, routine and reward.

“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: Over time, this loop—cue, routine, reward; cue, routine, reward—becomes more and more automatic.”

The habit loop

The power of habit: the habit loop

The habit loop

In the image above, MIT researchers conducted an experiment about habits forming. Laboratory rats were placed in a maze where a door opens after a loud click sounded. At first, they had hard times finding their way through the maze. They couldn’t even find the chocolate on the left side. But then again, through their learnings, their behavior became virtually automatic, less brain activity was involved.

Over time, the cue: “the loud click sound” triggered an automatic behavior in the rats. As soon as the rats heard the click, they easily, almost automatically found their way to the chocolate: a new behavior was created, following the three steps in the habit loop: cue, routine, reward.

loud click

When the rats heard the loud click sound, they adopted an automatic behavior.

Conversely, the right cue will trigger in you a formed habit. If you see a chocolate cake on the table, you would immediately eat half of it: that’s the basal ganglia in action. “The problem is that your brain can’t tell the difference between bad and good habits, and so if you have a bad one, it’s always lurking there, waiting for the right cues and rewards.”

Our basal ganglia is responsible for over hundreds of habits we do every day. Since this morning, you didn’t have to think about how to breathe, which hand to brush your teeth or which shoe to tie first: it’s all automatic.

“As long as your basal ganglia is intact and the cues remain constant, the behaviors will occur unthinkingly”

A habit can be an advantage or a curse.

It is possible to change our habits and it’s the central tenet of the power of habit.

2- THE CRAVING BRAIN How to Create New Habits

Claude Hopkins revolutionized marketing. He is well-known to have defined a series of rules to create new habits among customers.

If millions of American –for instance- never brushed their teeth before, Claude Hopkins changed that habit simply by creating a cue and a reward.

That principle of cue and reward became so famous that it’s now applied in food companies, hospitals and to other thousands of industries.

What really changed was how Claude cultivated and grew new habits.

To power the habit loop, there was a missing piece, and it’s what Hopkins discovered: craving.

Only with enough craving will cues and rewards work. Without craving, you can’t form a habit.

In the power of habit by Charles Duhigg, we can take the example of Pepsodent. Millions of people changed their habits because Hopkins advertised a cue, which was the mucin plaques on our teeth and a reward: “to have a prettier smile, to be more beautiful”.

hopkin's conception of the pepsodent habit loop

From the book: The power of habit

The missing ingredient to create a habit

If Hopkins claimed that cue and reward were enough to form a habit, Charles Duhigg maintains that there is a third rule that must be satisfied.

Companies lost millions of dollars and thousands of hours because they dismissed that third rule. Let me explain.

Julio the Monkey

Wolfram Schultz is a professor of neuroscience at the University of Cambridge. He explains why some cues and rewards have more power than others. Also, he explains why some companies lost millions even if they applied Hopkins’ theories about cues and rewards.

He conducted an experiment on monkeys, especially a famous one: Julio the monkey. Schultz wanted to “decipher how rewards work on a neurochemical level”.

“One day, Schultz positioned Julio on a chair in a dimly lit room and turned on a computer monitor. Julio’s job was to touch a lever whenever colored shapes—small yellow spirals, red squiggles, blue lines—appeared on the screen. If Julio touched the lever when a shape appeared, a drop of blackberry juice would run down a tube hanging from the ceiling and onto the monkey’s lips. Julio liked blackberry juice.”

At the beginning of the experiment, Julio wasn’t that interested in what he saw on the screen. But as he received his first reward, the blackberry juice, he became more focused. Julio associated touching the lever with a reward (blackberry juice) hence his great interest.

The third element: Craving

As he carried on his experiment, Schultz modified one thing.

If Julio previously received the juice as soon as he touched the lever, he would now erratically be offered the rewards.

The monkey got all upset as he’s not offered any reward, or at least, unpredictably so. A new pattern emerged in Julio’s brain: craving.

Anticipation of rewards without rewards created more frustration and got Julio to focus even more. It’s a bit like gamblers at casinos who will play slots long after they lost their winnings.

Habits are powerful because they create neurological cravings.

It’s only with a craving that new habits are formed. Hence the new cycle: cue, routine and reward which is cultivated by a craving.

“Scientists have studied the brains of alcoholics, smokers, and overeaters and have measured how their neurology—the structures of their brains and the flow of neurochemicals inside their skulls—changes as their cravings become ingrained. Particularly strong habits, wrote two researchers at the University of Michigan, produce addiction-like reactions so that “wanting evolves into obsessive craving” that can force our brains into autopilot”

Why runners run

I remember when I first started working out. It wasn’t really on a whim as my roommate inspired me to do so. I realized that I formed the habit thanks to the great feelings right after the work-out.

It wasn’t easy at the beginning but the release of endorphins and other neurochemicals got me hooked. My brain craved for more and the habit formed over time. There would be moments when stopping to work out created a discomfort in me. This happened because of the craving.

In a similar fashion, researchers at New Mexico State University studied 266 individuals who worked out as often as three times a week. The scientists wanted to know why these people do what they do.

“What they found was that many of them had started running or lifting weights almost on a whim, or because they suddenly had free time or wanted to deal with unexpected stresses in their lives. However, the reason they continued—why it became a habit—was because of a specific reward they started to crave. In one group, 92 percent of people said they habitually exercised because it made them “feel good”

Craving used in marketing

Pepsodent created a craving with the toothpaste’s fresh taste alongside with a tingling sensation on the tongue when we brush our teeth.

Many consumers immediately realized that they hadn’t brushed their teeth because they missed the “cool, tingling sensation in their mouths”. “They expected—they craved—that slight irritation. If it wasn’t there, their mouths didn’t feel clean.”

Conversely, companies now used foaming to create a craving in customers’ minds. A brand manager confided that they now use foaming chemicals within shampoos because people expect it as they wash their hair. I also realized that I chose a particular laundry detergent brand because I liked how foamy it is.

“Once the customer starts expecting that foam, the habit starts growing.” Cravings are what drive habits. And figuring out how to spark a craving makes creating a new habit easier. It’s as true now as it was almost a century ago.

3 – THE GOLDEN RULE OF HABIT CHANGE: Why Transformation Occurs

The Golden rule of habit change

This rule states that “you can’t extinguish a bad habit, you can only change it”.

Concretely, how do we change a habit then? The power of habit suggests using the same cue and providing the same reward but insert a new routine.

This golden rule helped fight against alcoholism, obesity and other destructive behaviors. If you understand it, you can change any bad habits you’re dealing with.

AA’ example

Over 10 million people achieved sobriety through Alcoholics Anonymous’ program and group. AA applies the golden rule of habit which consists first of identifying the cues and rewards and later finding new behaviors.

“But to change an old habit, you must address an old craving. You have to keep the same cues and rewards as before, and feed the craving by inserting a new routine.”

“AA forces you to create new routines for what to do each night instead of drinking,” “You can relax and talk through your anxieties at the meetings. The triggers and payoffs stay the same, it’s just the behavior that changes.”

The power of habit: insert a new routine

The importance of belief in habit changing

So far, we’ve seen that we cannot get rid of a habit, instead we can only replace it with a new one.

To change a habit, the Golden rule states that we keep the same cue and the same reward but have to insert a new routine.

One important part of habit changing however is belief. People have to believe that it’s possible to change, only then will they keep their new formed habits. Believing that you can change will sustain the new habit.

To implement that new belief, the author of the power habit, Charles Duhigg recommends finding a support group. A community can help you change your beliefs with shared experience and group dynamics. To permanently change a habit, you must believe in the first place that change is possible.

“Your odds of success go up dramatically when you commit to changing as part of a group. Belief is essential, and it grows out of a communal experience, even if that community is only as large as two people.”



Paul O’Neill was a former government bureaucrat who became Alcoa’s CEO in 1987.

He shocked everyone in the room with his first speech as a CEO. To him, Alcoa’s priority should be safety. According to Paul O’Neill, the company should aim for zero injuries.

His speech didn’t reassure key people who invested millions of dollars in Alcoa stock. Some ordered to sell their stocks right after the speech.

But “within a year of O’Neill’s speech, Alcoa’s profits would hit a record high. By the time O’Neill retired in 2000, the company’s annual net income was five times larger than before he arrived, and its market capitalization had risen by $27 billion. Someone who invested a million dollars in Alcoa on the day O’Neill was hired would have earned another million dollars in dividends while he headed the company, and the value of their stock would be five times bigger when he left. What’s more, all that growth occurred while Alcoa became one of the safest companies in the world.”

So what changed and what explains such a growth?

Keystone habits

Paul O’Neil focused on one single thing. In his research, he looked for habits that would disrupt and spread throughout the entire company.

To him, there are habits that create a ripple effect, a butterfly effect or a domino effect; which are habits that matter more than the others.

It’s what Charles Duhigg calls “Keystone habits” in the power of habit. They can influence all the other areas of one’s life: “how people work, eat, play, live, spend and communicate.”

“Keystone habits start a process that, over time, transforms everything. Keystone habits say that success doesn’t depend on getting every single thing right, but instead relies on identifying a few key priorities and fashioning them into powerful levers. This book’s first section explained how habits work, how they can be created and changed. However, where should a would-be habit master start? Understanding “keystone habits” holds the answer to that question: The habits that matter most are the ones that, when they start to shift, dislodge and remake other patterns.”

“Keystone habits explain how Michael Phelps became an Olympic champion and why some college students outperform their peers. They describe why some people, after years of trying, suddenly lose forty pounds while becoming more productive at work and still getting home in time for dinner with their kids. And keystone habits explain how Alcoa became one of the best performing stocks in the Dow Jones index, while also becoming one of the safest places on earth.”

Read my article: The one thing by Gary Keller

Example of keystone habits

The power of habit 1: Exercise

Exercise is one of the best examples of keystone habits. Countless studies from the past decade examined the impacts of exercise on daily routines.

“When people start habitually exercising, even as infrequently as once a week, they start changing other, unrelated patterns in their lives, often unknowingly. Typically, people who exercise start eating better and becoming more productive at work. They smoke less and show more patience with colleagues and family. They use their credit cards less frequently and say they feel less stressed. It’s not completely clear why. But for many people, exercise is a keystone habit that triggers widespread change. “Exercise spills over”

“There’s something about it that makes other good habits easier. “

The power of habit 2: Having dinner together

“Studies have documented that families who habitually eat dinner together seem to raise children with better homework skills, higher grades, greater emotional control, and more confidence.

The power of habit 3: Making your bed

“Making your bed every morning is correlated with better productivity, a greater sense of well-being, and stronger skills at sticking with a budget. It’s not that a family meal or a tidy bed causes better grades or less frivolous spending. But somehow those initial shifts start chain reactions that help other good habits take hold. If you focus on changing or cultivating keystone habits, you can cause widespread shifts. However, identifying keystone habits is tricky.”

Small wins

“Keystone habits offer what is known within academic literature as “small wins.” They help other habits to flourish by creating new structures, and they establish cultures where change becomes contagious.”

In the book “Essentialism The disciplined pursuit of Less”, Georg McKewon shares Michael Phelps’ routines that would act as keystone habits:

“For years before the Olympic swimmer Michael Phelps won the gold at the 2008 Beijing Olympics, he followed the same routine at every race. He arrived two hours early.1 He stretched and loosened up, according to a precise pattern: eight hundred mixer, fifty freestyle, six hundred kicking with a kickboard, four hundred pulling a buoy, and more. After the warm-up he would dry off, put in his earphones, and sit—never lie down—on the massage table. From that moment, he and his coach, Bob Bowman, wouldn’t speak a word to each other until after the race was over. At forty-five minutes before the race he would put on his race suit. At thirty minutes he would get into the warm-up pool and do six hundred to eight hundred meters. With ten minutes to go he would walk to the ready room. He would find a seat alone, never next to anyone.”

In “The power of habit”, Charles Duhigg highlights: “Once Bowman established a few core routines in Phelps’s life, all the other habits—his diet and practice schedules, the stretching and sleep routines—seemed to fall into place on their own“

“At the core of why those habits were so effective, why they acted as keystone habits, was something known within academic literature as a “small win”

“Small wins are exactly what they sound like, and are part of how keystone habits create widespread changes. A huge body of research has shown that small wins have enormous power, an influence disproportionate to the accomplishments of the victories themselves. “Small wins are a steady application of a small advantage,” one Cornell professor wrote in 1984. “Once a small win has been accomplished, forces are set in motion that favor another small win.”

“Small wins fuel transformative changes by leveraging tiny advantages into patterns that convince people that bigger achievements are within reach. And it all began with one small win“

5- STARBUCKS AND THE HABIT OF SUCCESS: When Willpower Becomes Automatic

Travis Leach is a young boy who was destined to fail. None of his past would predict his success. He had trouble controlling his emotions and he easily got upset.

Being a school dropout, fired from McDonald’s, he later admitted that Starbucks’ training changed his entire life.  At 25, “Travis is the manager of two Starbucks where he oversees forty employees and is responsible for revenues exceeding $2 million per year. His salary is $44,000 and he has a 401(k) and no debt. He’s never late to work. He does not get upset on the job. “

Travis said that from his training, he learned how to live, how to focus and how to master emotional intelligence. Most importantly, the training taught him willpower.

The power of habit: Willpower

“Dozens of studies show that willpower is the single most important keystone habit for individual success”

“Students who exerted high levels of willpower were more likely to earn higher grades in their classes and gain admission into more selective schools. They had fewer absences and spent less time watching television and more hours on homework.”

Just like a muscle, it is actually possible to strengthen willpower. And to do that, you need to make it into a habit.

Angela Duckworth, a researcher at the University of Pennsylvania underlined that people with great self-control seem not to be working hard, but the truth of the matter is, they simply made it automatic.

The Marshmallow experiment

In the 1960s, scientists at Stanford University conducted what would be called the Marshmallow experiment. They planned to test the willpower of a group of four-year-old kids. The children were given two choices: they could have one marshmallow immediately, or they could have two if they waited for fifteen minutes. Some of the kids waited for five to six minutes then gave up; most of them immediately chose to eat the one marshmallow. Only 30 percent exercised their willpower and managed to wait for fifteen minutes for a second treat.

Now here comes the good part.

The scientists traced down the study’s participants. As the kids are now at high-school, “they discovered that the four-year-olds who could delay gratification the longest ended up with the best grades and with SAT scores 210 points higher, on average, than everyone else.”

“They were more popular and did fewer drugs It was as if the marshmallow ignoring kids had self-regulatory skills that gave them an advantage throughout their lives.”

Twenty years after the study, in the 1980s, it was generally accepted that willpower is a learnable skill.

The power of habit: willpower as a muscle

Willpower can be depleted

We also discovered that willpower is a finite resource. The more we use willpower and the more it gets depleted. It’s like money; so you need to wisely allocate it.

If you plan to work out in the evening but end up using all of your willpower with petty tasks during the day, you’re unlikely to achieve what you initially planned to do.

“There have been more than two hundred studies on this idea since then, and they’ve all found the same thing. Willpower isn’t just a skill. It’s a muscle, like the muscles in your arms or legs, and it gets tired as it works harder, so there’s less power left over for other things.”

Willpower can become stronger

The more you use willpower, the more it will spill into other areas. Just like a keystone habit, using willpower to go to the gym can enhance other areas of your life: you’re likely to smoke fewer cigarettes, drink less alcohol and eat healthier.

This is why rich kids are encouraged to learn piano or martial arts at an early age. They might not become musicians or stars but they will learn to strengthen their willpower, which in return will yield in more success later when they grow up.

Training willpower at Starbucks

Starbucks has a full curriculum that focuses on increasing employee’s willpower. Part of the training involves showing up on time, to master one’s emotions and to serve everyone with a smile. It’s even better if the trainee can remember the customer’s orders and their names.

One of the most important parts of the training is dealing with inflection points. The trainees and future employees need to learn how to act when a situation goes awry. For this, they need “to follow a routine when their willpower muscles went limp”

“So the company developed new training materials that spelled out routines for employees to use when they hit rough patches. The manuals taught workers how to respond to specific cues, such as a screaming customer or a long line at a cash register. Managers drilled employees, role-playing with them until the responses became automatic. The company identified specific rewards—a grateful customer, praise from a manager—that employees could look to as evidence of a job well done. Starbucks taught their employees how to handle moments of adversity by giving them willpower habit loops.”

Willpower habit loop in action

Let’s say a customer yells at an employee, it’s a cue. The routine well-implemented will be something that they learned earlier during the training, for instance, the LATTE method:

“One of the systems we use is called the LATTE method. We Listen to the customer, Acknowledge their complaint, Take action by solving the problem, Thank them, and then Explain why the problem occurred.”

LATTE method

The employees learn dozens of routines like the LATTE method especially during stressful inflection points.

In conclusion, it’s a wise decision to keep your willpower for the most important task of the day. It is even better to start your day working on those important tasks as your willpower is at its maximum.

The Power of habit by Charles Duhigg: Conclusion

The rest of the book focuses on organizational and societal habits so I didn’t consider it useful to include them in this summary.

In summary, habits are powerful. They can lift you up or tear you down. Without even being aware of it, our bad habits can lead us to failure.

As we’ve seen, any habit is composed of three-step loop:

  •         The cue or the signal that triggers an automatic pattern, you get on auto-pilot mode.
  •         The routine is the actual habit in response to the cue. It can be physical, emotional or mental.
  •         The reward reinforces a habit because it satisfies a craving. The absence of a reward weakens a habit.

The power of habit highlights that the combination of a cue, a routine and a reward will create a new habit, especially if we add a craving in the loop.

It is possible to change a habit and it is our responsibility to become more aware of their effects in our lives.

The power of habit, as the title implies explains mostly why habits are powerful. It doesn’t really give a clear framework on how to change a habit.

I loved the anecdotes, studies and data revealed in this book. The author took time to give as many details as possible on how habits are formed, how to change them or how they implemented habits change in organizations.

To go further, and if your goal is really to create or change a habit, I invite you to read another great book about habit changing: “Atomic habits” by James Clear. I find this book more practical than the power of habit by Charles Duhigg.

Until next time, Sitraka