“Why We Sleep” update: some thoughts while we wait for Matthew Walker to respond to Alexey Guzey’s criticisms

So. It’s been a week since Alexey Guzey posted his wonderfully-titled article, “Matthew Walker’s ‘Why We Sleep’ Is Riddled with Scientific and Factual Errors.”

I few days ago I reviewed Guzey’s post, and I summarized:

I’ve not read Walker’s book and I don’t know anything about sleep research, so I won’t try to judge Guzey’s claims. I read through and I found Guzey’s arguments to be persuasive, but, hey, I’m easily persuaded.

I’d be happy to read a followup article by Michael Walker, “Alexey Guzey’s ‘Matthew Walker’s “Why We Sleep” Is Riddled with Scientific and Factual Errors’ Is Riddled with Scientific and Factual Errors.” That (hypothetical) post could completely turn me around! Then, of course, I’d be waiting for Guzey’s reply, “Michael Walker’s ‘Alexey Guzey’s “Matthew Walker’s ‘Why We Sleep’ Is Riddled with Scientific and Factual Errors” Is Riddled with Scientific and Factual Errors’ Is Riddled with Scientific and Factual Errors.” At that point, I’d probably have heard enough to have formed a firm opinion. Right now, the ball is totally in Walker’s court.

As of this writing, the ball remains in Walker’s court.

I googled *”matthew walker” “alexey guzey”* and *”matthew walker” sleep* and a few other things, but nowhere did I find any response from Walker to Guzey’s criticisms.

It’s hard for me to imagine that Walker hasn’t heard about Guzey’s article by now, but I guess it’s possible that he (Walker) is on vacation or that he’s preparing a response but has not finished yet.

The closest to a response to Guzey that I’ve seen is this by Kinkajoe from reddit forum. But I didn’t find that response to be very persuasive, and indeed Guzey replied in detail here.

The fact that Guzey successfully responded to an anonymous internet commenter does not, of course, rule out the possibility that Walker could have something useful to say here. But it does suggest to me that Guzey did not make any clear or obvious mistakes; if he did, I suspect that someone—if not Walker, someone who cares about Walker’s work—would’ve replied by now.

Again, we’ll see what happens.

While we’re waiting for Walker to respond, I had a few more thoughts:

1. A few years ago, if someone were to claim that a celebrated professor of neuroscience and psychology at a major university had published a book on his own field of expertise, and the book was full of scientific and factual errors, that would’ve been a major scandal, no? But now, we’re like, yeah, sure, that’s just more same old same old. As the saying goes, the big scandal is how little a scandal this has been.

2. What would be really cool would be if NPR and Joe Rogan ran interviews with Alexey Guzey about this story. NPR probably won’t bite. But Joe Rogan . . . he might go for this, right? I bet Joe Rogan, or someone on his team, reads social media. And Rogan likes combat. He’s had Walker on his show, now time to have Guzey come in with the critique. That said, I don’t know that a podcast is the best format for such a debate. I think blogging is a better way to go, as then there’s enough space to lay out all the evidence.

3. Assuming Guzey’s criticisms hold up, I’m still trying to figure out what happened with that book. How could Walker introduce so many errors on his own area of expertise (or, I guess I should say, supposed expertise)? Was he just really really confused? Did he delegate the research and writing to lazy research assistants? Did he feel that his underlying story was important so the details didn’t matter? Did he conduct his research by putting all his notes onto index cards, then mistype material off the cards? I just don’t have a good way of thinking about these things.

4. Guzey’s article is careful and in many ways bulletproof: he backs up each of his statements, he doesn’t exaggerate (even for humorous purposes), and nobody seems to have found any mistakes in what he wrote. In addition, Guzey has gone on the web and responded to comments: where people claim he got things wrong, he has responded in detail.

This is excellent behavior on Guzey’s part but I just want to say that it should not be required. Suppose, just for the sake of argument, that Guzey was gratuitously rude, that he made some claims without making his the evidence clear, even that he made some mistakes. Suppose that he spent 13 hours or even 1.3 hours rather than 130 hours writing this post, so that he only got to the highlights and didn’t carefully check everything he wrote? That would be unfortunate, but it wouldn’t make his critique less valid.

What I’m saying is: by preparing a critique that’s clean, clear, well sourced, well written—actually enjoyable to read—, a critique that doesn’t make any questionable claims, by being so careful, Guzey has done us a favor. He’s made it easier to follow what he’s written, and he’s making it more difficult for someone to dismiss his arguments on superficial grounds. He’s raising the game, and that’s wonderful.

But if Guzey hadn’t gone to that trouble, he could still be making a useful contribution. It would just be the duty of Walker to extract that contribution.

Just by analogy, a few years ago someone on the internet somewhat rudely criticized some of my work. Indeed, some of the criticism was not only impolite but also incorrect! However, some of the criticism was correct. I took the useful aspects of the criticism and spent a few months fixing my work. That was my duty. I’m an expert on statistical models for voting, I present myself as an expert in this area, and I have the duty to do my best and to fix my errors. Sure, I could’ve ignored the criticism, or focused on the critic’s rudeness, or on his mistakes—but what would be the point of that?

Guzey has made it easier for Walker by not leaving any clear vulnerabilities: it seems that, for Walker, the simplest response will be the most direct, to accept the criticism and release a corrected version of his book. And that’s how it should be. But, again, let’s not let the care and excellence of Guzey’s work take away from the general value of all sorts of criticism. Let’s not hold criticism to a higher standard than we hold any other academic discourse.

And, of course, I remain open to be convinced by whatever Walker offers in response.

Finally, and most importantly:

5. Remember all that gum I chewed in junior high? I think it permanently dislocated my jaw or something, cos every now and then when I chew, my jaw gets out of alignment and I have to kind of put it back in place. So don’t try this at home, kids!

25 thoughts on ““Why We Sleep” update: some thoughts while we wait for Matthew Walker to respond to Alexey Guzey’s criticisms

  1. “Let’s not hold criticism to a higher standard than we hold any other discourse”. I feel like this must be in your dictionary of definitions post somewhere…! A thought-provoking phrase though, thanks.

  2. I did my PhD in a circadian rhythms/sleep lab, and I find a number of Guzey’s criticisms to be tendentious at best. I haven’t read Walker’s book, and it does sound like he makes a lot of lazy or poorly sourced claims (e.g. sleep deprivation doubles cancer risk), but:

    1. The data on human sleep duration and longevity is obviously hopelessly confounded. People who regularly sleep more than 7-8 hours a day are often depressed or sick in other ways that affect lifespan. Fortunately, controlled experiments can be done in animals, primarily rodents and insects. Here, there is substantial evidence that sleep deprivation reduces lifespan, in some cases significantly. Mice and fruit flies are not humans of course, but the (still preliminary) work on the effects of sleep deprivation in animal models finds the same kind of metabolic disruptions that are common in sleep-deprived humans (i.e. shift workers), and suggests that similar mechanisms are at work.

    2. Guzey points out that fatal familial insomnia is not a good example to show that total sleep deprivation is lethal. This is true. However, it is well known from the experiences of humans in POW camps and other such nasty places, as well as from controlled experiments in rodents, that total sleep deprivation invariably leads to death, and relatively quickly. I find it hard to believe that Guzey doesn’t know this, or that Walker doesn’t mention it in his book. Interestingly, it’s not clear whether or how total sleep deprivation kills fruit flies, but that’s neither here nor there.

    3. I also haven’t read “The Encyclopedia of Sleep” and have no intention of tracking one down, but I am not aware of any examples of animals that don’t sleep. There are animals that don’t have circadian rhythms (Arctic circle mammals and troglodytes), but they still sleep. There are animals where sleep is highly physiologically divergent from mammalian sleep (nematodes) such that it is controversial whether to call the behavior “sleep.” There are animals that suppress sleep for long periods (migratory birds), and animals that sleep with only half of their brain at a time (dolphins). All of these odd phenomena are specific to the physiology of particular animals, and shouldn’t be used to suggest that sleep deprivation isn’t bad for humans, because it almost certainly is. If the claim is that Walker shouldn’t have cited some crappy encyclopedia, then I agree.

    Walker’s book sounds like junky pop science, and I think it’s unfortunate for serious academics to put out work of this sort. But, the broad claim that not sleeping enough is bad for you is supported by mountains of evidence. Exactly how and why it’s bad for you, and how much sleep any given person really needs, remain open questions.

    • Excellent post Phil.

      This is a good example of why you have to let both sides speak.

      Guzey lines up a series of negative points that sound (and many probably are) devastating in some narrow way. And when you line up only negative points, it makes it sound like the Walker book is 100% bogus. But when the other side gets to talk, the overall story can sound very different.

      Suppressing the other side’s points is probably the most important aspect of propaganda.

      FWIW, I suspect the Guzey point that the WHO never declared a sleep loss epidemic is much less than it appears. I would be astonished if the WHO or the CDC or another such organization has not said something like that.

    • Hi Phil,

      1. You write:

      “People who regularly sleep more than 7-8 hours a day are often depressed or sick in other ways that affect lifespan.”

      This argument about the U-curve works both ways and thus I don’t believe it proves anything: many illnesses that affect lifespan cause insomnia https://en.wikipedia.org/wiki/Insomnia#Causes

      2. You write:

      “controlled experiments can be done in animals, primarily rodents and insects. Here, there is substantial evidence that sleep deprivation reduces lifespan, in some cases significantly. Mice and fruit flies are not humans of course, but the (still preliminary) work on the effects of sleep deprivation in animal models finds the same kind of metabolic disruptions that are common in sleep-deprived humans (i.e. shift workers), and suggests that similar mechanisms are at work.”

      It seems that you write that sleep deprivation in rodents and fruit flies in particular reduces lifespan. Later you write:

      “Interestingly, it’s not clear whether or how total sleep deprivation kills fruit flies, but that’s neither here nor there.”

      I don’t believe that fruit flies are a good model to investigate the effects of sleep on humans and I wouldn’t use them in an argument about effects of sleep deprivation on humans. However, since you bring fruit flies up, here’s a recent paper from that seems to use the best methods so far trying to answer the questions you cover: https://advances.sciencemag.org/content/5/2/eaau9253. 6% of flies sleep less than 72 minutes a day, with a minimum of 4 minutes a day:

      “we analyzed sleep for four consecutive days in 881 female (Fig. 1A) and 485 male (Fig. 1B) CantonS flies, a commonly used laboratory “wild-type” strain. As expected, in both males and females, sleep amounts were widely distributed, with male flies sleeping for 618.5 (CI95%, 606.7 to 630.3) min a day and female flies sleeping for 299.2 (CI95%, 288.8 to 309.6) min a day [mean (95% bootstrap confidence interval)]. The distribution of sleep amount in females uncovered a previously undescribed fraction of extreme short sleepers: 50% of female flies slept less than 20% of their time and 6% slept for less than 5% of their time (72 min a day). At the very end of the curve laid three flies that spontaneously slept an average of 15, 14, and 4 min a day, respectively (Fig. 1A and fig. S1).”

      Extreme sleep deprivation did not lead to reduced life expectancy:

      “In our setup, flies were housed in individual tubes and each tube experienced a 1-s rotation at the approximate speed of 300 rpm whenever the animal housed inside had shown 20 s of continuous immobility (24). The treatment led to a highly efficient sleep deprivation, with flies losing, on average, 95.6% (CI95%, 93.5 to 98.2) of their sleep (Fig. 4A), and yet, surprisingly, we could not detect any major effect on survival (Fig. 4, B and C). In particular, sleep-deprived male flies lived as long as the control group [with a median of 41.5 (CI95%, 38.0 to 44.0) days against 46.0 (CI95%, 41.0 to 48.5) days for the controls], and a statistically relevant effect was only evident in female flies, with a reduction of median life span of 3.5 days [37.5 (CI95%, 33.0 to 38.5) and 41.0 (CI95%, 38.5 to 44.0)]. In flies, forced sleep restriction has little or no consequences on life span when performed in a controlled, specific manner. Given the variability of sleep within our wild-type population (Fig. 1, A and B), we also wondered whether sleep amount in an individual fly could predict its life span. We performed a linear regression (see Materials and Methods) and found no overall effect, neither in males [+1.05 days of life per hour of sleep a day (CI95%, −0.08 to 1.91); Fig. 4D, cyan] nor in females [+0.41 days of life per hour of sleep a day (CI95%, −0.51 to 1.55); Fig. 4D, pink] (overall R2 = 0.12). That is, as previously suggested (34), we confirm here that spontaneous short sleepers do not die faster and, conversely, high sleepers do not tend to live longer.”

      Am curious what you think about the paper’s methodology.

      3. You write:

      “it is well known from the experiences of humans in POW camps and other such nasty places, as well as from controlled experiments in rodents, that total sleep deprivation invariably leads to death, and relatively quickly.”

      I’m glad that these effects in humans are well known, since it will be easy for you to point me to specific examples of people dying from total sleep deprivation. In the process of my research, I was not able to find any such examples. I will absolutely add the examples you have to the essay.

      I don’t believe rodent evidence can be used in such arguments as any other than weakly suggestive.

      4. You write:

      “I also haven’t read “The Encyclopedia of Sleep” and have no intention of tracking one down, but I am not aware of any examples of animals that don’t sleep. … If the claim is that Walker shouldn’t have cited some crappy encyclopedia, then I agree.”

      I will copy the entire claim I make about this directly from my essay:

      “On page 6, Walker writes:

      [E]very species studied to date sleeps

      This is false, at least, according to Walker’s own source.”

      5. You write:

      “Walker’s book sounds like junky pop science, and I think it’s unfortunate for serious academics to put out work of this sort.”

      I devote an entire section to this: https://guzey.com/books/why-we-sleep/#appendix-is-why-we-sleep-pop-science-or-is-it-an-academic-book-also-miscitations-impossible-numbers-and-walker-copy-pasting-papers

      I will quote parts of it:

      “Why We Sleep is not just a popular science book. As I note in the introduction, Walker specifically writes that the book is intended to be scientifically accurate: … Walker and other researchers are actively citing the book in academic papers, propagating the information contained in it into the academic literature. … Google Scholar indicates that (a), in the 2 years since the book’s publication, it has been cited more than 100 times. … Since Why We Sleep was published, Walker published two academic papers that cited it. Many of the claims in both papers originate from Why We Sleep. The first one was published in The Lancet in 2018. The second one was published in Neuron in 2019. It’s 4 pages long and it references Why We Sleep 7 times.”

      6. You write:

      “the broad claim that not sleeping enough is bad for you is supported by mountains of evidence.”

      I agree that sleeping not enough in the short term makes you sleepy and somewhat stressed. I would grateful if you pointed me to any causal evidence that would show that not sleeping enough long-term is bad for you. I will add it to the essay.

      As a general note — if any of the points I make in this comment turn out to be wrong, I will correct them. I already corrected the essay (although not significantly), and indicated where the corrections were made with the word “Correction”.

      • Using POW camps as evidence of the effects of sleep deprivation is frankly an asinine thing to do. Do you think maybe there were other factors that might affect the life expectancy of someone in a POW camp?

        • “Using POW camps as evidence of the effects of sleep deprivation is frankly an asinine thing to do.”

          Sleep deprivation has been used as a form of torture. While there are obviously other factors that impacting lifespan in a POW camp, you can’t go around intentionally putting humans into a life-threatening state and it’s possible that substantive records are available in some cases, so IMO you have to make the best of what info you have with appropriate caveats.

        • Right, “caveats”, like starvation, being worked to death and physical and mental torment. But sure, untangle that while making your “caveats”.

          That information can’t tell you anything about sleep deprivation, why are social scientists afraid of admitting their data is sometimes useless for the purposes they use it? Stop pretending you have data when you don’t.

      • Hi Alexey!

        I agree with a lot of this. You’re certainly correct that the unreliability of human lifespan data cuts both ways, and there just isn’t any direct, conclusive evidence about the effect of sleep on lifespan in humans. The more convincing evidence comes from studies of other health problems in sleep-deprived people, of which there are many. People working in jobs that require chronic sleep deprivation have increased rates of diabetes, higher BMI, increased rates of depression, and a variety of other issues. Of course, this is purely epidemiological! Unfortunately, there’s just no good way for systematically proving the causal effects of sleep deprivation on human health.

        Our main point of disagreement is on the relevance of animal sleep research for human physiology. This is of course an open, and controversial, question, even among people who do sleep research on animal models. It’s hard to say if the physiological role of sleep is the same in rats and humans when we don’t really know what the physiological role of sleep is! But, we can consider a couple theories:

        1. Sleep is important for learning and memory consolidation. Many experiments have shown defects in learning tasks in animals deprived of sleep. Synaptic remodeling (likely important for memory formation) is also known to occur during sleep in flies and mice. It is very likely that the physiological mechanisms of learning and memory are similar in humans and mice, and even flies. We share the same neurotransmitters, the same synaptic release mechanisms, and the same structural proteins associated with axon guidance and synapse formation. If sleep matters for learning in mice, it almost certainly does in humans as well.

        2. Sleep is important for maintenance and toxin clearance. Experiments in mice have shown metabolite clearance in the brain during sleep: https://science.sciencemag.org/content/342/6156/373. Recent work has shown modulation of blood-brain barrier permeability in Drosophila during sleep, liekly for related reasons: https://elifesciences.org/articles/43326. If sleep is important for toxin clearance in mice and flies, it probably is in humans as well. Our neurons are virtually identical in their metabolic mechanisms, and almost certainly produce the same toxins and byproducts.

        The evidence for effects of sleep on lifespan in Drosophila and rodents is extensive. There are many genetic mutations affecting sleep duration in Drosophila, in many different pathways, and virtually all of them have large negative effects on lifespan (see this review https://www.embopress.org/doi/10.15252/embr.201846807). The classical experiment showing that total sleep deprivation leads to death in rats is here: https://science.sciencemag.org/content/221/4606/182. The fact that animals in such widely separated clades show negative effects of sleep deprivation makes it seem pretty plausible that humans do too!

        Of course there are caveats. Not all humans (or animals) need the same amount of sleep. There is also at least one study showing that short sleep can be selected for in Drosophila, and that this does not lead to decreased lifespan. The Science Advances paper you mention is a good example as well, though I might mildly object to the claim that a 3.5 day reduction in lifespan is insignificant in an animal that only lives 40-50 days. That’s a comparable effect to moderate lifetime smoking in humans. In any case, I would claim that, each human (or animal) needs some amount of sleep for good health, and getting less sleep than that can have severe health consequences beyond just sleepiness and stress.

        • “The more convincing evidence comes from studies of other health problems in sleep-deprived people, of which there are many. People working in jobs that require chronic sleep deprivation have increased rates of diabetes, higher BMI, increased rates of depression, and a variety of other issues. Of course, this is purely epidemiological! Unfortunately, there’s just no good way for systematically proving the causal effects of sleep deprivation on human health.”

          To quote a random reddit commenter:

          “Ioannidis and Trepanowski say that without RCTs, nutrition science can never credibly answer important questions about nutrition. That Harvard department’s response is that RCTs are essentially impossible because you cannot get people to meaningfully change their diets over long periods of time.
          It seems clear to me that both sides are correct.”

          I agree re: learning and lack of sleep. I got a bit carried away with arguing about negative effects (or absence of them) of not getting enough sleep. I don’t claim that there are no effects in the essay because I don’t believe I can actually defend that position.

      • “I don’t believe rodent evidence can be used in such arguments as any other than weakly suggestive.”

        The claim that rodent evidence about sleep is “weekly suggestive” regarding sleep in humans isn’t supportable.

        Sleep is a major physiologic activity common to all mammals. Rats and mice are the number one animal models for humans. There are already mountains of evidence that sleep deprivation has a strong negative impacts human behavior and is a common indirect cause of fatality. If mice die from sleep deprivation, there’s a every reason to believe that most other animals, humans included, would as well.

        It may not be appropriate to claim that there is direct evidence that sleep deprivation kills humans. But while there may be no direct testing of that claim for obvious reasons, all other lines of evidence suggest that it does.

  3. Hi Andrew,

    “3. Assuming Guzey’s criticisms hold up, I’m still trying to figure out what happened with that book. How could Walker introduce so many errors on his own area of expertise (or, I guess I should say, supposed expertise)? Was he just really really confused? Did he delegate the research and writing to lazy research assistants? Did he feel that his underlying story was important so the details didn’t matter? Did he conduct his research by putting all his notes onto index cards, then mistype material off the cards? I just don’t have a good way of thinking about these things.”

    I have a section that partly covers this – section 14: https://guzey.com/books/why-we-sleep/#appendix-is-why-we-sleep-pop-science-or-is-it-an-academic-book-also-miscitations-impossible-numbers-and-walker-copy-pasting-papers

    In 14.2 and 14.3 I show that Walker is also careless in his academic work. For example parts of the papers he published in 2018 in *The Lancet* and in 2019 in *Neuron* are virtually identical to each other as well to Why We Sleep, down to such details as impossible mathematics. e.g. from one of these near-identical paragraphs:

    Why We Sleep: “residents made 400 to 600 percent fewer diagnostic errors to begin with.”
    The Lancet: “residents make 400–600% fewer diagnostic errors to begin with.”
    Neuron: “residents make 400%–600% fewer diagnostic errors to begin with (Walker, 2017).”

    • Alexey:

      This is relevant evidence in that it makes it more believable that Walker could’ve acted with poor scientific ethics in writing the book (writing things that he either knew were false, or not doing the due diligence to check that he was not publishing false statements). I still wonder exactly how it went. Did he add errors in purpose, thinking that they would make his story better and no one would check? (After all, he had gone pretty far without anyone checking.) Did he just not really understand what he was writing? Was it just massive sloppiness? Reliance on sloppy or unethical research assistants? (That could explain what went on with the academic papers.) There are lots of possibilities here.

      To put it another way, there are three questions (again, assuming your criticisms hold up, which it seems they do):

      1. Does Walker have the lack of scruple necessary to introduce multiple errors into a published book, either knowingly putting in errors or not putting in the effort to check his claims?

      2. Why would he do so? (The default would be to not introduce errors: I’d assume that as a scientist he’d want to get the facts in order.)

      3. How did he do it?

      The answers:

      1. The problems you note in his academic work supply evidence in support of the claim that, yes, Walker has the necessary lack of scruple.

      2. I have no idea, but there are lots of possibilities. On the low end, motivations include laziness, desire to get credit for writing a book, desire for fame and fortune, an assumption that nobody would check the references so he could get away with it, etc. On the high end, motivations include a belief that inaccuracy in the details can allow him to tell better stories which serve the larger truth, just being too busy to check details because he has other important commitments in his life, and a deep enough understanding of the subject that he can be sloppy in lots of places while knowing that his underlying message is still valid.

      3. “How did he do it?” is what I’m curious about here. Did he realize the book had errors? Did he care? Etc.

        • Alexey

          Interesting. It seems that Walker gets an instrumental benefit from making clear public claims that are not supported by the data. By making these dramatic claims, he gets a better, more compelling Ted talk. So I guess one possibility is that he goes through the literature and figures out how he can exaggerate the findings in order to get things to say that sound more impressive. This is a step beyond what many researchers do (but shouldn’t do), which is to report results selectively in order to make a stronger case. At that point, Walker could convince himself that his unsupported claims were true in some larger sense.

          If that’s what’s going on, we could draw an analogy between Walker and disgraced primatologist Marc Hauser, who went one step beyond the usual practice of selectively reporting the literature and instead misreported his own data.

          Indeed, had Walker merely selectively misreported the literature, I guess we wouldn’t be having this conversation at all, because your article (had there been one) would’ve been less compelling. On the other hand, had Walker merely selectively misreported the literature and not actually made things up (or whatever he did), maybe the Ted talk would never have happened and he wouldn’t be such a superstar.

          This all possibly supplies some insight into the whole CDC/WHO thing you discussed here. One possible explanation for what happened is that he saw this CDC report, liked the phrase “public health epidemic,” but decided that the World Health Organization just sounded better than the CDC. Again, he could then justify this to himself by saying that lack of sleep is a big problem, he’s doing a service to the world by dramatizing this problem, and who cares about the details.

          The difficulty is that, even if that’s the real story, he can’t very well admit it! It’s kind of like when David Brooks got caught out on that Red Lobster thing. All he could do was accuse his critic “too pedantic,” of “taking all of this too literally,” of “taking a joke and distorting it.” He couldn’t literally say that he made things up in order to make his story more compelling. And it worked! Brooks got to have his cake and eat it too, and he remains a well-paid pundit.

  4. >3. Assuming Guzey’s criticisms hold up, I’m still trying to figure out what happened with that book. How could Walker introduce so many errors on his own area of expertise (or, I guess I should say, supposed expertise)?

    IMO this happened because Walker is allergic to citations & referencing for some reason.

    Over 16 chapters the average number of citations per chapter is ~6.5. Considering his many claims it’s quite low.

  5. I apologize for this comment. But reading Andrew’s post just kept making me think of the past 2 weeks of impeachment inquiry hearings. Contrast the diplomatic professionals careful statements with the political sloppiness – you don’t need to take sides in the debate, the contrast works on both sides of the aisle.

  6. Not directly relevant to Walker’s book but perhaps will find the following at least entertaining. Frequently cited “fact” that drove me crazy for months… today I finally found its source. I am talking sleep positions here. This link may or may not be the original mention of it but it is one of the earliest I could find and it seems that it was picked by numerous outlets and made it’s way to mattress marketing campaigns and every mattress salesman’s pitch.
    http://news.bbc.co.uk/2/hi/health/3112170.stm#sleep
    From what I gathered, Professor Chris Idzikowski, claimed to have studied sleep positions and came up with some correlations between sleep positions and personalities. Obviously he isn’t the first one and I am sure i saw at least a couple of papers published back in 1920ies. The original research of Idzikowski could not be found (I am not the only one who tried). I suspect he writes about it in one of his books on sleep (I think he wrote at least three and I have no plans to waste my time on those). What also transpires is that he derived his conclusions from patient’s surveys.
    Why am I outraged?
    1) Idzikowski’s claims rely on patient’s self assessment of sleeping position. It became pretty clear in the 80ies that humans do not know what position they assume while asleep and cannot control said position. Good research is done with analysis of video recording or, more recently, using accelerometers.
    2) Idzikowski’s claims intend to say that a person sleeps in one position (or at least, mostly in one position). Which is not true. At least three independent groups (let me know if you find more) clearly demonstrated that sleep is not static (we rollover 30 min on average).
    https://www.sciencedirect.com/science/article/abs/pii/S1389945709000549?via%3Dihub
    https://academic.oup.com/sleep/article/15/2/143/2742862
    https://www.dovepress.com/sleep-positions-and-nocturnal-body-movements-based-on-free-living-acce-peer-reviewed-article-NSS

    Professor Idzikowski is a former President of Sleep Medicine Section of Royal Society of Medicine. Did he not know about the publications or chose to ignore them?

  7. Once I read Alexey’s point #5, that Walker doesn’t know how arithmetic works, I realized the whole book was junk and I had been had. How did those ‘200%’ etc. decreases even get passed the editor? It is very hard for me to take anything in the book seriously after that.

  8. Do we really want to hold pop science books to the same standard of rigor that we do peer reviewed articles?
    Of course not.

    In a peer reviewed articles the editors are scientists.
    In a pop science book the editors are trying to make money.

    And in the end. Is it dangerous to get people to value sleep?

    • Edward:

      It’s very simple. Walker could simply write in his book something like, “Much of this book is speculation. When I refer to the scientific literature, I’m often misrepresenting it. But this is for the greater good of getting people to value sleep.” Similarly with the Ted talk. But he didn’t do that. Instead he misrepresented his speculations and occasional falsehoods as representing the scientific literature. In doing this he was leveraging his academic reputation, basically using his peer-reviewed publications as collateral for his speculations. I think this is bad for readers in that he’s presenting speculations as scientific findings.

      And, the editors are trying to make money. Walker (and I) are also paid money to teach and do research. So what? I don’t think “trying to make money” is a justification for lying.

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