The Power of Habit

by Charles Duhigg

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Publisher: Random House
Copyright: 2012, 2014
Printing: 2014
ISBN: 0-679-60385-9
Format: Kindle
Pages: 366

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One problem with reading pop psychology is that one runs into a lot of books like this one: summaries of valid psychological research that still leave one with the impression that the author was more interested in being dramatic and memorable than accurate. But without reproducing the author's research, it's hard to tell whether that fear is well-grounded or unfair, so one comes away feeling vaguely dissatisfied and grumpy.

Or at least I do. I might be weird.

As readers of my book reviews may have noticed, and which will become more apparent shortly, I'm going through another round of reading "self-help" books. This time, I'm focusing on work habits, concentration, and how to more reliably reach a flow state. The Power of Habit isn't on that topic but it's adjacent to it, so I picked it up when a co-worker recommended it.

Duhigg's project here is to explain habits, both good ones and bad ones, at a scientific level. He starts with a memorable and useful model of the habit loop: a cue triggers a routine, which results in a reward. The reward reinforcement strengthens the loop, and the brain starts internalizing the routine, allowing it to spend less cognitive energy and essentially codifying the routine like a computer program. With fully-formed habits (one's daily bathing routine, for example), the routine is run by a small, tuned part of your brain and requires very little effort, which is why we can have profound shower thoughts about something else entirely. That example immediately shows why habits are valuable and why our brain is so good at creating them: they reduce the mental energy required for routine actions so that we can spend that energy elsewhere.

The problem, of course, is that this mechanism doesn't first consult our conscious intent. It works just as well for things that we do repeatedly but may not want to automatically do, like smoking a pack of cigarettes a day. It's also exploitable; you are not the only person involved in creating your habits. Essentially every consumer product company is trying to get you to form habits around their products, often quite successfully. Duhigg covers marketing-generated habits as well as social and societal habits, the science behind how habits can be changed, and the evidence that often a large collection of apparently unrelated habits are based in a "keystone habit" that, if changed, makes changing all of the other habits far easier.

Perhaps the most useful part of this book is Duhigg's discussion of how to break the habit loop through substitution. When trying to break habits, our natural tendency is to consciously resist the link between cue and routine. This is possible, but it's very hard. It requires making an unconscious process conscious, and we have a limited amount of conscious decision-making energy available to us in a day. More effective than fighting the cues is to build a replacement habit with the same cue, but this requires careful attention to the reward stage so that the substituted habit will complete the loop and have a chance of developing enough strength to displace the original habit.

So far, so good. All of this seems consistent with other psychological research I've read (particularly the reasons why trying to break habits by willpower alone is rarely successful). But there are three things that troubled me about this book and left me reluctant to recommend it or rely on it.

The first is that a useful proxy for checking the research of a book is to look at what the author says about a topic that one already knows something about. Here, I'm being a bit unfair by picking on a footnote, but Duhigg has one anecdote about a woman with a gambling problem that has following definitive-sounding note attached:

It may seem irrational for anyone to believe they can beat the house in a casino. However, as regular gamblers know, it is possible to consistently win, particularly at games such as blackjack. Don Johnson of Bensalem, Pennsylvania, for instance, won a reported $15.1 million at blackjack over a six-month span starting in 2010. The house always wins in the aggregate because so many gamblers bet in a manner that doesn't maximize their odds, and most people do not have enough money to see themselves through losses. A gambler can consistently win over time, though, if he or she has memorized the complicated formulas and odds that guide how each hand should be played. Most players, however, don't have the discipline or mathematical skills to beat the house.

This is just barely this side of being outright false, and is dangerously deceptive to the point of being casino propaganda. And the argument from anecdote is both intellectually bogus (a lot of people gamble, which means that not only is it possible that someone will go on that sort of winning streak through pure chance, it is almost guaranteed) and disturbingly similar to how most points are argued in this book.

If one assumes an effectively infinite deck (in other words, assume each card dealt is an independent event), there is no complicated rule you can memorize to beat the house at blackjack. The best that you can do is to reduce the house edge to 1-2% depending on the exact local rules. Wikipedia has a comprehensive discussion if you want the details. Therefore, what Duhigg has to be talking about is counting cards (modifying your play based on what cards have already been dealt and therefore what cards are remaining in the deck).

However, and Duhigg should know this if he's going to make definitive statements about blackjack, US casinos except in Atlantic City (every other example in this book is from the US) can and do simply eject players who count cards. (There's a legal decision affecting Atlantic City that makes the story more complicated there.) They also use other techniques (large numbers of decks, frequent reshuffling) to make counting cards far less effective. Even if you are very good at counting cards, this is not a way to win "consistently over time" because you will be told to stop playing. Counting cards is therefore not a matter of memorizing complicated formulas and odds. It's a cat-and-mouse game against human adversaries to disguise your technique enough to not be ejected while still maintaining an edge over the house. This is rather far from Duhigg's description.

Duhigg makes another, if less egregious, error by uncritically accepting the popular interpretation of the Stanford marshmallow experiment. I'll spare you my usual rant about this because The Atlantic has now written it for me. Surprise surprise, new research shows that the original experiment was deeply flawed in its choice of subjects and that the effect drastically decreases once one controls for social and economic background.

So that's one problem: when writing on topics about which I already have some background, he makes some significant errors. The second problem is related: Duhigg's own sources in this book seem unconvinced by the conclusions he's drawing from their research.

Here, I have to give credit to Duhigg for publishing his own criticism, although you won't find it if you read only the main text of the book. Duhigg has extensive end notes (distinct from the much smaller number of footnotes that elaborate on some point) in which he provides excerpts from fact-checking replies he got from the researchers and interview subjects in this book. I read them all after finishing the rest of the book, and I thought a clear pattern emerged. After reading early drafts of portions of the book, many of Duhigg's sources replied with various forms of "well, but." They would say that the research is accurately portrayed, but Duhigg's conclusion isn't justified by the research. Or that Duhigg described part of the research but left out other parts that complicated the picture. Or that Duhigg has simplified dangerously. Or that Duhigg latched on to an ancillary part of their research or their story and ignored the elements that they thought were more central. Note after note reads as a plea to add more nuance, more complication, less certainty, and fewer sweeping conclusions.

Science is messy. Psychological research is particularly messy because humans are very good at doing what they're "supposed" to do, or changing behavior based on subtle cues from the researcher. And most psychological research of the type Duhigg is summarizing is based on very small sample sizes (20-60 people is common) drawn from very unrepresentative populations (often college students who are conveniently near the researchers and cheap to bribe to do weird things while being recorded). When those experiments are redone with larger sample sizes or more representative populations, often they can't be replicated. This is called the replication crisis.

Duhigg is not a scientist. He's a reporter. His job is to take complicated and messy stories and simplify them into entertaining, memorable, and understandable narratives for a mass audience. This is great for making difficult psychological research more approachable, but it also inherently involves amplifying tentative research into rules of human behavior and compelling statements about how humans work. Sometimes this is justified by the current state of the research. Sometimes it isn't. Are Duhigg's core points in this book justified? I don't know and, based on the notes, neither does Duhigg, but none of that uncertainty is on the pages of the main text.

The third problem is less foundational, but seriously hurt my enjoyment of The Power of Habit as a reader: Duhigg's examples are horrific. The first chapter opens with the story of a man whose brain was seriously injured by a viral infection and could no longer form new memories. Later chapters feature a surgeon operating on the wrong side of a stroke victim's brain, a woman who destroyed her life and family through gambling, and a man who murdered his wife in his sleep believing she was an intruder. I grant that these examples are memorable, and some are part of a long psychological tradition of learning about the brain from very extreme examples, but these were not the images that I wanted in my head while reading a book about the science of habits. I'm not sure this topic should require the reader brace themselves against nightmares.

The habit loop, habit substitution, and keystone habits are useful concepts. Capitalist manipulation of your habits is something everyone should be aware of. There are parts of this book that seem worth knowing. But there's also a lot of uncritical glorification of particular companies and scientific sloppiness and dubious assertions in areas I know something about. I didn't feel like I could trust this book, or Duhigg. The pop psychology I like the best is either written by practicing scientists who (hopefully) have a feel for which conclusions are justified by research and which aren't, or admits more questioning and doubt, usually by personalizing the research and talking about what worked for the author. This is neither, and I therefore can't bring myself to recommend it.

Rating: 6 out of 10

Reviewed: 2018-07-20

Last modified and spun 2018-07-21