Review: The Power of Habit, by Charles Duhigg

[Russ Allbery]

The Power of Habit
by Charles Duhigg

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

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

-- 
Russ Allbery (eagle at eyrie.org)              <http://www.eyrie.org/~eagle/>