Charles Duhigg’s “The Power of Habit”: Book Review, Notes + Analysis

Poor Ash’s Almanack > Book Reviews > Effective Thinking > Psychology

Overall Rating: ★★★★★★ (6/7) (standout for its category)

Per-Hour Learning Potential / Utility: ★★★★★★ (6/7)

Readability: ★★★★★★★ (7/7)

Challenge Level: 1/5 (None) | 285 pages ex-notes (400 official)

Blurb/Description: Pulitzer Prize winning journalist Charles Duhigg explores the cue-routine-reward habit feedback loop that subconsciously drives up to 40% of our daily actions.

Summary: Having read more broadly since my initial couple reads of this book, I’m perhaps more attuned than I once was to some of the flaws – but it is a very good book on the whole.

Providing a variety of relatable and thought-provoking examples, this book explores how habits are formed, reinforced, and broken for people and organizations alike.  Most importantly, the book is very practical and always ties discussions back to how we can apply these concepts in our lives.

Highlights: Duhigg is an engaging writer and this is one of the easiest-reading serious / scholarly nonfiction books you’ll ever encounter.  It’s a quick read, both because it’s not overly lengthy, and because of the reader-friendly writing.

The stories are generally well-told (sometimes too well told) and integrated with relevant research findings on the topic.

This is a profoundly important topic and while there are other books that cover it from different angles – Laurence Gonzales’s “ Deep Survival” (DpSv review + notes) and Stephen Covey’s The 7 Habits of Highly Effective People (7H review + notes), The Power of Habit is still a great read on the mechanisms of habit formation – and how we can use those to our own advantage.

Lowlights: Like many psychology books, this one suffers from occasional man-with-a-hammersyndrome: in several instances (discussed in the notes), I feel that Duhigg overfocuses on habitwhen other mental models, such as  activation energy, are at play.

Additionally, I don’t feel Duhigg does a great job of tying together some of the “obvious” takeaways: he applauds willpower and cites Duckworth’s profoundly, inexcusably awful “ Grit ( Grit review) even as he points out that willpower is finite, that it takes less willpower to do things we don’t want to do, that it’s not sufficient to overcome embedded habits like substance abuse, and that habit-forming operations like Starbucks are actually a structural problem-solving way to reducewillpower usage (based on Duhigg’s own citation of reduced brain activity during habits).

In other words, the adaptivity of willpower is dose-dependent, but you could come away from this book believing “more is better” (which isn’t always true).  Willpower doesn’t really seem like a “ habit” to me, and I question Duhigg’s presentation of it as a “keystone habit.”

Finally, some of the examples toward the end are overly lengthy and you’ll have gotten the point already.

Mental Model / ART Thinking Points:  habittrait adaptivitymemoryagencysample sizedisaggregationfeedbacknonlinearityutilityman with a hammerstructural problem solving,activation energysalienceinversion,

You should buy a copy of The Power of Habit if: you want to learn the easy way, rather than the hard way, to positively modify your behavior (and those of people you interact with).

Reading Tips: don’t skip the prologue or afterword, which are both great.  Do consider skimming Chapter 8, about Saddleback Church and Rosa Parks, as it’s overly lengthy and the idea is pretty intuitive if you understand the  social proof mental model.

Pairs Well With:

Deep Survival” by Laurence Gonzales (DpSv review + notes).  Another fascinating exploration – more broadly, of  cognition / intuition / habit / stress – using very different language and very different context, but hitting the same neurological processes.

The Autobiography of Benjamin Franklin ( ABF review + notes).  It’s never a bad time to check out the original champion of habit.

The 7 Habits of Highly Effective People” (7H review + notes).  I’ve made a  habit out of Stephen Covey’s 7 Habits, and boy do they work.

Reread Value: 3/5 (Medium)

More Detailed Notes + Analysis (SPOILERS BELOW):

IMPORTANT: the below commentary DOES NOT SUBSTITUTE for READING THE BOOK.  Full stop. This commentary is NOT a comprehensive summary of the lessons of the book, or intended to be comprehensive.  It was primarily created for my own personal reference.

Much of the below will be utterly incomprehensible if you have not read the book, or if you do not have the book on hand to reference.  Even if it was comprehensive, you would be depriving yourself of the vast majority of the learning opportunity by only reading the “Cliff Notes.”  Do so at your own peril.

I provide these notes and analysis for five use cases.  First, they may help you decide which books you should put on your shelf, based on a quick review of some of the ideas discussed.  

Second, as I discuss in the memory mental model, time-delayed re-encoding strengthens memory, and notes can also serve as a “cue” to enhance recall.  However, taking notes is a time consuming process that many busy students and professionals opt out of, so hopefully these notes can serve as a starting point to which you can append your own thoughts, marginalia, insights, etc.

Third, perhaps most importantly of all, I contextualize authors’ points with points from other books that either serve to strengthen, or weaken, the arguments made.  I also point out how specific examples tie in to specific mental models, which you are encouraged to read, thereby enriching your understanding and accelerating your learning.  Combining two and three, I recommend that you read these notes while the book’s still fresh in your mind – after a few days, perhaps.

Fourth, they will hopefully serve as a “discovery mechanism” for further related reading.

Fifth and finally, they will hopefully serve as an index for you to return to at a future point in time, to identify sections of the book worth rereading to help you better address current challenges and opportunities in your life – or to reinterpret and reimagine elements of the book in a light you didn’t see previously because you weren’t familiar with all the other models or books discussed in the third use case.

Page xii: the book starts discussing a small sample size study (seems like a few dozen participants) – ex-smokers, compulsive shoppers, etc – who had:

“remade their lives in relatively short periods of time.”  

Duhigg, and the researchers, ask: how?

Page xiv: a change in habits starts with agency –

“the conviction that she *had* to give up smoking to accomplish her goal”

and leads to actual neurological changes:

“[Neurologists] 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.”

Focusing on one habit is the first step.

Of course, Benjamin Franklin discovered this a few centuries earlier.  As he states in The Autobiography of Benjamin Franklin ( ABF review + notes): he didn’t try to establish all of his famous “virtues” at one time, but rather took them sequentially, one per quarter,

“like him who, having a garden to weed, does not attempt to eradicate all the bad herbs at once, which would exceed his reach and strength, but works on one of the beds at a time, and, having accomplished the first, proceeds to a second,”

Page xvi: Duhigg cites a 2006 Duke study that found that 40% of our actions are habits, not decisions.

Page xvii: Duhigg calls the military a “habit-forming organization.”

Of course, these habits, like anything else, are  adaptive traits that will be less adaptive in a different context – see the story about the Army Ranger in Laurence Gonzales’s Deep Survival (DpSv review + notes).

Pages 5 – 6: discussing Eugene Pauly (EP), who suffered from  memory loss after viral encephalitis, Duhigg notes that:

“[professor Larry] Squire’s studies would show that even someone who can’t remember his own age or almost anything else can develop habits that seem inconceivably complex – until you realize that everyone relies on similar neurological processes every day.”

See also Gonzales on learning.

Page 9: EP is like the dude from Memento.  He doesn’t even remember that he has amnesia!

Page 12: to the point on pages 5-6, EP has no clue where the kitchen is, but when he’s hungry, he can find the jar of peanuts… see Gonzales on emotional bookmarking.  EP can find the bathroom, too.

It’s worth noting – for some context – that in Surviving Survival by Laurence Gonzales (SvSv review + notes), Gonzales cites research by a few scientists about learning in people without the ability to form new memory.  

He notes that sleep (specifically, REM sleep – dreaming) helped them learn.  See, of course, Dr. Matthew Walker’s phenomenal “ Why We Sleep ( Sleep review + notes) for more on this.

Pages 14 – 15: the basal ganglia is apparently correlated with habit-forming activity.  Reviewing research on rats in mazes, Duhigg explains:

“Rats stopped sniffing corners and making wrong turns.  Instead, they zipped through the maze faster and faster […] as the route became more and more automatic, each rat started thinking less and less.”

Page 18: Duhigg here discusses “chunking,” which I typically think of in terms of  memory but it’s also involved in  habit formation.  Duhigg cites the example of driving; we don’t consciously think about the process of reversing.  We just do it.

Duhigg cites habits as an  adaptive trait because they’re energy-conserving… it also allows for smaller brains, which fit through the birth canal more easily.

See also Jennifer Ackerman’s “ The Genius of Birds ( Bird review + notes), which includes this interesting observation about just how energetically expensive cognition is.  From p 43 there:

“Brain tissue is heavy and metabolically expensive, the most expensive in the body, second only to the heart.  Neurons may be small, but they’re costly to make and maintain, consuming about ten times more energy relative to their size than other cells.”

In humans, this is one of the drivers of habit and other effort-saving cognitive biases (I believe it accounts for contrast bias as well).  The human brain accounts for roughly 2% of our weight but 20% of our caloric consumption.

Duhigg here also notes that we can’t walk around on autopilot all day, otherwise we’d miss stuff, so our brain uses chunks to do habits.

Page 19: on how habits work:  cue (tells you to go into habit), routine (the automatic action), reward: (what happens at the end)

Page 20: Duhigg on  disaggregation:

“Simply understanding how habits work – learning the structure of the habit loop – makes them easier to control.  Once you break a habit into its components, you can fiddle with the gears.”

Additionally, scientist Ann Graybiel of MIT notes that:

“Habits never really disappear.  They’re encoded into the structures of our brain.”

Which makes good habits really good, and bad habits, well.

Page 22 – 23: some more proof of habit-based learning; Eugene could learn which items were “correct” (via cue/routine/reward) without actually committing them to  memory.

Pages 25 – 26: here, Duhigg notes that habits are so strong that they can:

“cause our brains to cling to them at the exclusion of all else, including common sense.” 

Cross-reference, again, Gonzales in Deep Survival on fighter pilots (down is safe), army guys (needing help is shameful), people who are lost, etc…

Also, importantly, citing the example of eating fast food, Duhigg notes that:

“habits emerge without our permission.”

Pages 28 – 29: the brief little anecdote here about praising E.P., appealing to his ego (“you’re doing something important for science!”) and having nurses dote on him are all Carnegie-approved (“ How to Win Friends and Influence People – HWFIP review + notes).  Wonder if there’s some sort of two-track mechanism here…

Page 34, Pages 56 – 59: Despite rampant dental problems, hardly anyone brushed their teeth in the early 1900s.  How did Claude Hopkins manage to change this?

He knew well the power of cues that pop up often – “a hint of fatigue, for example.

(Cross reference hormone advertisements – do you feel tired?  Do you wish you were stronger?  Do you wish your libido was as strong as it was when you were 19?  See Jerome Groopman in “ How Doctors Think ( HDT review + notes) for more on this.)

In the case of toothpaste, Hopkins identified the “film” that forms on teeth as a cue.  What created the craving / reward?  The tingling ingredients, which have nothing to do with clean teeth.

Tracy Sinclair, a brand manager for Oral-B and Crest Kids toothpaste:

“Consumers need some kind of signal that a product is working […] as long as it has a cool tingle, people feel like their mouth is clean.  The tingling doesn’t make the toothpaste work any better.  It just convinces people it’s doing the job.”

This is a good example of clear  feedback – Duhigg goes on to note that sunscreen has no similar feedback:

“while everyone brushes their teeth, fewer than 10 percent of Americans apply sunscreen each day.”

Habit doesn’t even have to be involved: see Sunstein/Thaler’s Nudge (Ndge review + notes) and Don Norman’s The Design of Everyday Things (DOET review + notes) for a lot of good examples on how clear feedback can influence behavior.

Page 43, Pages 53 – 55: on  contrast bias: when you’ve had pets around for a long time, you don’t notice their smell, which means there’s no “cue” to use Febreze… this was solved by adding perfume, so that there was a reward, which creates a craving.

Also, I like Duhigg’s A/B storytelling… switching back and forth keeps the suspense.  I should get better at this.

Pages 46 – 47: In The Up Side of Down (UpD review + notes) – which also discusses feedback really well – Megan McArdle discusses our dopamine levels rising in anticipation of a reward.  Duhigg goes into this here: in a monkey experiment where the monkey (Julio) was trained to associate a certain shape on a screen with a reward, eventually, his brain flashed with pleasure “before the juice arrived.”

What happened when the experiment changed?

“When the juice didn’t arrive or was late or diluted, Julio would get angry and make unhappy noises, or become mopey […] when Julio anticipated juice but didn’t receive it […] desire and frustration erupted inside his skull […] that joy became a craving that, if unsatisfied, drove Julio to anger or depression.”

Interesting parallels to  loss aversion and defensive pessimism (discussed in the  margin of safety mental model).

Duhigg doesn’t really go into that angle, but anyway, for his purposes, he notes that habits create cravings.

Page 50: How strong are habits?  Stronger than incentives, often.  Duhigg cites two researchers at the University of Michigan:

“Particularly strong habits produce addiction-like reactions so that ‘wanting evolves into obsessive craving’ that can force our brains into autopilot, ‘even in the face of strong disincentives, including loss of reputation, job, home, and family.”

Again, see Gonzales on fighter pilots, etc.

Page 61: Duhigg starts to get into  cognition vs. intuition here in the context of sports, citing Tony Dungy, whose approach as coach of the Tampa Bay Buccaneers was to get players to react automatically, habitually rather than thinking about it.

It’s counterintuitive, but makes sense: again, I think Gonzales does a good job of exploring, in “ Deep Survival ( DpSv review + notes), why cognition is too slow for a lot of life-and-death tasks.

Page 63: Duhigg’s “Golden Rule of Habit Change” is to keep the cue and reward the same, and change the routine.

Pages 68 – 69: Alcoholics Anonymous is a “giant machine for changing habit loops.”


f course, there’s a lot of stuff that goes into AA –  social proof, etc.

Page 69: Duhigg’s footnote here on addiction is phenomenal.  See also Brene Brown on taking the edge off” in Daring Greatly ( DG review + notes).

Page 71: On AA: Duhigg discusses the idea of  disaggregation again (creating a list of drinking triggers), as well as  mindfulness (being aware of why you’re doing what you’re doing, and seeking a different path to the reward.)

Page 73: Unsurprisingly, a lot of relapses occur under  stress.  Importantly, though:

“They picked up a bottle because that’s how they automatically dealt with anxiety.

However, once they learned alternate routines for dealing with stress, the drinking stopped for good.

[…] once they incorporated those new routines for coping with stress and anxiety into their lives, the successes were dramatic.”

Read-across to Dr. Judith Beck’s Cognitive Behavior Therapy ( CBT review + notes) here – the whole idea of CBT is basically making a habit of  adaptive rather than maladaptive thoughts, coping mechanisms, etc.

Pages 74 – 75: nice example here of why “grit” is bullshit – a habitual nail-biter tries willpower and, of course, fails.

More effective is  mindfulness and the CBT type stuff I discussed above – figure out the cue, substitute a different routine.

Pages 76 – 77: Duhigg notes that the process for reforming habits isn’t complicated – but it’s not easy either.

Pages 82 – 83: very nice story illustrating the stress-caused relapse phenomenon addressed above.

Pages 84 – 85: ahahahahaha Researchers hated that explanation.  God and spirituality are not testable hypotheses.”

Belief is discussed here as a self-fulfilling prophecy, although – oddly – the path to it involves giving up  agency.  Weird.

Duhigg here cites  social proof indirectly – i.e. the power of the group.

Page 91: if you want to watch the video of this play, it’s here.

I do think there’s a little too much  storytelling here regarding football, but it’s okay.

Page 100: Alcoa CEO Paul O’Neill:

You can’t order people to change.  That’s not how the brain works.”

So he focused on changing “keystone habits” – ones that matter more than others.

Pages 102 – 103: Not clear if these are Duhigg or O’Neill’s words, but he previously worked at the Office of Management and Budget, where bizarre institutional processes […] in many ways, operated like habits.”  See  culture / status quo bias.  

See also, for example, Jonathan Waldman discussing (via Dan Dunmire) the DoD’s stuck-in-the-mud view toward rust in “ Rust: The Longest War” (RUST review + notes).

Here, from Duhigg, O’Neill:

“We were basically ceding decision making to a process that occurred without actually thinking.”

See Sunstein/Thaler in “ Nudge” ( NDGE review + notes) citing some research on the persistence of group behavior.

Pages 105 – 106: Safety was a goal everyone could agree on and it provided cover to change institutional habits.  The exploration here is pretty interesting.

Page 109: I don’t make my bed, ever.  In fact, I make a  habit of not doing things with zero  utilitybecause of  opportunity costs.  I totally get the “small win” approach, but I’d rather my “small wins” be something with utility… like, watering a plant, or saying something nice to a friend, or so on.

Pages 112 – 115: The idea of small wins is explored here… relatively self-evident.  Basically, it’s compounding.

Page 119: what Duhigg calls “keystone habits” – like lowering the infant death rate via teaching nutrition – is really more a function (in my opinion) of  disaggregation n-order impacts, etc.  It’s not immediately clear (at least as he presents it here) how you can ex-ante determine what will be a keystone habit.  In some sense, a lot of this feels to me like ex post analysis.

Page 120: the idea of food journaling as a keystone habit makes sense… but Duhigg doesn’t really explain the underlying mechanisms here.   salience and  feedback.

Just as Megan McArdle discusses in The Up Side of Down (UpD review + notes) how counting out cash is more salient than swiping a credit card, counting out food (in a journal) is salient feedbackthat brings to mind mindless eating.

Page 121: to the point above, it’s difficult for me to imagine that O’Neill planned for worker safety to lead to Alcoa taking advantage of the Internet.

Page 123: Nice bit about corporate  culture here, reminds me of the Munger bit about firing people for one offense because of the  n-order impacts of not doing so…

Page 124: Duhigg cites Duckworth’s “ Grit” here.  Frequent readers are aware of my antipathy towards this stupid concept that’s less than worthless (it’s not just wrong, it’s wrong and getting wronger: actively heading in the wrong direction).

See the  Grit review and the  agency  mental model, specifically the  dose-dependency section, as well as David Denby’s fantastic The Limits of Grit essay in The New Yorker.

Page 131: Duhigg cites researching finding that  willpower drives more of academic performance than IQ.  We’ll keep going on this…

Page 133: Marshmallow experiment sighting!  Samir’s FIrst Law of Pop Psychology Books, stipulating that any psychology book must reference one or more of Milgram, gorilla, or marshmallow, is still intact…

Page 135 – 140: to his credit, Duhigg overviews some of the work on willpower depletion here.

Pages 142 – 144: Duhigg here cites examples of how writing down specific, detailed plans and goals can help people accomplish stuff.

I think he’s a bit of a  man with a hammer here – you could also frame this via  activation energy.  See Sunstein/Thaler in “Nudge” (NDGE review + notes) on Yale students, tetanus vaccines, and marked maps – or Shawn Achor’s The Happiness Advantage (THA review + notes) on behavioral modification via the 20-second rule.

This occurs over periods way too short for habit to kick in.

Pages 145 – 147: good example here of using habit to reduce the need for willpower via  structural problem solving and  cognition vs. intuition and, of course,  habitconditioning.  The Starbucks employees really aren’t having to use willpower at all… or at least, much less so.

I would also point to Cal Newport in Deep Work (DpWk review + notes) explaining why willpower isn’t the answer:

“Your will […] is not a manifestation of your character that you can deploy without limit; it’s instead like a muscle that tires.  

This is why the [studied subjects] had such a hard time fighting desires […] the same will happen to you, regardless of your intentions, unless, that is, you’re smart about your habits.”

Also, Duhigg here references The Container Store.  See Kip Tindell’s Uncontainable (UCT review + notes), which y’all know I adore.

Given the focus on Starbucks, see also Howard Schultz’s “ Pour Your Heart Into It (PYH review + notes) and Onward” (O review + notes).

Page 151: on the relationship between  agencywillpower, and engagement: Duhigg cites Mark Muraven, the professor doing the willpower studies:

“When people are asked to do something that takes self-control, if they think they are doing it for personal reasons – if they feel like it’s a choice […] it’s much less taxing.  If they feel like they have no autonomy, if they’re just following orders, their willpower muscles get tired much faster.”

The Container Store, referenced earlier, does a great job of this sort of empowerment – see Tindell’s “ Uncontainable for a lot more on this.

Page 153: this comment is made in passing, but I’ve always thought (every time I’ve read this book) that “acknowledge her authority, and then ask politely for one small exception” is a super useful tidbit.

Page 156: Part of the problem at Rhode Island Hospital was related to a  culture where nobody was allowed to question doctors’ orders.  See David Oshinsky’s Bellevue (BV review + notes) for an exploration of how this started, and Atul Gawande’s The Checklist Manifesto (TCM review + notes) for a  structural problem solving look at how the checklist dealt with this culture.

Page 161: Duhigg cites the paper “An Evolutionary Theory of Economic Change” – the soundbite is:

“Much of firm behavior […] [reflects] general habits and strategic orientations coming from the firm’s past.”

Again, see  culture and  status quo bias.

Page 162: Duhigg rejects the economic fantasy of rational companies, noting they’re more like:

“fiefdoms where executives compete for power and credit”

Ahahahaha.  See  local vs. global optimization, and also Richard Thaler’s “ Misbehaving ( M review + notes) on a different take on principal-agent theory.

Pages 168 – 169: local vs. global optimization as a cause of the King’s Cross fire.  this whole bit is a great case study.  I also would note  trait adaptivity as a model here – these habits are adaptive until circumstances change and they aren’t…

Page 172: note that this “flashover point” is an example of a  critical threshold, a form of nonlinearity

Pages 178 – 180:  salience (a big crisis) as a motivator for change

Pages 191 – 192: the famous Target story here… from a habit perspective, Duhigg notes that big life changes coincide with habit changes, which isn’t surprising when you think about it.

Pages 197 – 204, 206 – 209: the bit about familiarity / sandwiching with Hey Ya! is interesting.  association bias.

Pages 209 – 210: on  humans vs. econsfairness, and  salience: pregnant women (and pregnant teenagers’ dads) don’t appreciate being targeted by advertisements.  So Target intersperses them with a bunch of random stuff like lawnmowers to make it more subtle.

Page 211: on social connection keeping people going to the gym.  see also The Container Store; Tindell’s book notes it’s not uncommon for people to go in just to talk to TCS employees.

Page 229: nothing specific I want to note, but here Duhigg goes deeper into the idea referenced earlier (via AA) about habit being especially powerful in groups:  social proof x  habit.

Pages 235 – 236: the bit about Saddleback Church is great.  On how Rick Warren built it into one of the largest iminitries in the world:

“When [Rick] Warren first arrived in Saddleback valley, he spent twelve weeks going door-to-door […] asking strangers why they didn’t go to church.  Many of the answers were practical: it was boring […] the music was bad […] they needed child care, they hated dressing up, the pews were uncomfortable.

Warren’s church would address each of those complaints.  He told people to wear shorts and Hawaiian shirts […] Warren’s sermons focused on practical topics […] his lessons were easy to understand, focused on real, daily problems, and could be applied as soon as parishioners left church.”

Inversion, or, more specifically, nixing the “veto vote” – i.e. the Cheesecake Factory business model.  (and then of course habits, social proof, etc.)

Page 263: on gambling – this section is powerful – examples of  reciprocity bias (they did nice things for her),  self-justification (see “ Mistakes were Made (but not by me) – MwM review + notes), and  loss aversion, specifically the gambler’s fallacy.  Bachmann:

“This desperation starts once you realize how much you’ve lost, and then you feel like you can’t stop because you’ve got to win it back.”

Of course, as Munger might put it, the first rule of holes is “stop digging” and you don’t have to win it back where you lost it…

Page 264: Duhigg on “near misses” – an example of  salience.  near misses are motivating. and contrast bias

Page 270: Duhigg cites Aristotle’s “Nicomachean Ethics” (the founding document of positive psychology.)  Sounding almost Stephen Covey like (“ The 7 Habits of Highly Effective People” – 7H review + notes), Duhigg notes:

“Habits – even once they are rooted in our minds – aren’t destiny.  We can choose our habits, once we know how. […]

Once you understand that habits can change, you have the freedom – and the responsibility – to remake them.”


Page 285: habit cues usually fit into one of five cues:

  • Location
  • Time
  • Emotional state
  • Other people
  • Immediately preceding action

First Read: 2015

Last Read: 2018

Number of Times Read: 3

Planning to Read Again?: maybe


Review Date: 2018

Notes Date: 2018