The Nurture Assumption review

On this Mother's Day, I'd like to direct everyone's attention to The Nurture Assumption, a book by science writer Judith Rich Harris about the mistaken notion that parents have much influence on their children's outcomes in life, at least in the field of personality development.

I got the idea to review this book on this day by going to church with my mother.  Predictably, the homily/sermon focused on "what your spiritual legacy will be," with special emphasis and examples from the legacy of mothers.  Mothers were doing this and ruining their children but then improved themselves and everything was okay.  Or mothers did that and saved their children from a future of emotional and financial destitution.

It's tempting to believe these anecdotes.  Everyone seems to be able to see evidence of them with their own eyes.  As Harris states in the very title of the book, our culture's default assumption is that nurture is somehow responsible for children's outcomes.  But as Harris takes pains to point out, a lot of science is about examining our assumptions and observations in the light of testing and evidence.  And her message is that, when the evidence is examined critically, there isn't much support for the notion that mothers, or fathers, have much influence on their children's personality development.

Readers of this blog who are Paleo dieters will no doubt be familiar with Dr. Kurt Harris (no relation to the author) and his emphasis on ranking different sciences' validity in constructing dietary advice.  Epidemiology is a relatively weak way to find things out about the human body compared with studies in physiology and biochemistry.  When you, essentially, take surveys instead of doing interventional studies, you open yourself to all sorts of confounding problems creeping into your results.  Science journalist Gary Taubes points out much the same thing in Good Calories, Bad Calories.

The point of The Nurture Assumption is much the same.  Harris was an author of textbooks in developmental psychology, but after years of writing textbooks, she had started noticing problems with the research she was citing in her books.  The upshot is that, if you throw out all but the gold-standard studies in developmental psychology, it appears that most of the influence on children's development is genetic.  And the rest is not attributable to parenting styles.  She suggests, then, the non-genetic remainder is attributable to another influence--peer groups.

Her theory rests on several contentions about the brain and the course of development.  For example, she says that, contrary to the assumption that children's brains are trying to figure out how to be successful adults, they are in fact trying to figure out how to be successful children.  She also contends that it is an important part of development for the brain to be able to identify the group to which it belongs and its status within that group.  Both these characteristics make it much more likely that children identify with and look to their peer groups for their ultimate personality development rather than to their parents, who are adults and not part of their group.

Harris examines what's wrong with studies that suggest nurturing is important, reviews the evidence from more robust studies (like those of twins raised apart) but also shows how her ideas are consistent with what we know of our paleo ancestors and other hunter-gatherer groups today.

The biggest obstacle to people assessing her theories fairly is the very strong and persistent tendency people have to confuse, mix-up, or ignore correlation and causation.  The recent hullabaloo over the Mother's Day TIME magazine cover article provides a perfect example:

I was riding in the car the other day when there was a talk radio show on about attachment parenting.  The interviewer asked who attachment parenting appealed to, and the interviewee answered that many of those doing attachment parenting were people who were very concerned that their children grow up into empathetic adults.

So, let's say that these empathy-valuing parents choose attachment parenting and raise some empathetic children.  What does that prove about attachment parenting?  Absolutely nothing.  It is just as likely--actually, I suspect more likely--that empathy-valuing parents pass on empathy-valuing genes to their children.  Mixing up the effects of genetics and parenting styles would be textbook human observational error, and so in the context of the research and analysis Harris presents, I am strongly inclined to favor her theory of genes + peer influence.

good read for HCPs

I wouldn't say this book blew my mind, but I did have one of those "everything makes a lot more sense now" moments.  This is definitely a book that health care professionals should read.  In addition to specific errors the health care system has made in the past, like blaming mothers for autism, the health care system has a general stance of advice-giving to the population at large that is probably largely irrelevant when it comes to the field of pediatrics.  I'm not talking about physical disease here, but child-rearing advice.  Even if you, as an HCP, are unconvinced by The Nurture Assumption's case, it worth knowing about Harris' theory and talking a more skeptical attitude to whatever child-rearing theories you do hold.

Addiction for Nurses review

Addiction for Nurses seems to me a very good overview of the current (published 2010) trends in thinking about addiction in the health care field. The author is from the UK, so some of the comments he makes about professional opportunities for nurses in the field of addiction don't apply, but his foreign status also gives his writing a wider perspective.

Specifically, he addresses the theory of "harm reduction," which apparently tends to get short shrift in the US. If you work in public health, you may be familiar with this interventional modality, but as a student who went from school right into critical care, I don't ever remember hearing the term before this book. Harm reduction is a recognition that quitting addictive substances is extremely hard, and that it may be more productive to get users to change behavior related to their addictions rather than stop. In alcoholics, this might entail designated driver campaigns, while in IV drug users, it might entail needle exchanges. Simple ideas that have been tried in teh US before, but the presentation of a paradigmatic interventional strategy puts these programs in a different light and suggests others.

The book is not only about harm reduction, however. It also has chapters that can be used like a workbook to challenge the reader's assumptions about addiction and addicts. And it presents information on professional matters as well as outlining current interventional strategies for a variety of substances and summarizing the research on the effectiveness of these strategies. I had never heard of Motivational Interviewing or Brief Interventions before, either, but both are shown to work with equal or greater effectiveness compared to 12-step programs.

This is a great book for nurses to read, I think. Much of it is available as a preview at GoogleBooks.

Drunken Comportment review

In this book originally published in, I believe, the 1970s and re-issued in 2003, the authors take issue with what was then and still seems to be the widely held assumption that the behavioral effects of alcohol are due to disinhibiting of alcohol on the brain. In place of that model, they propose that behavior when drunk is learned and socially conditioned. Much of the book contains examples from around the world of cultures in which the behavior of people when drunk does not conform to our expectations of drunkenness. The book concludes with an examination of Native American alcohol abuse tries to put that in a cultural-historical context as against the widely held notion that "Indians can't hold their liquor."

While there is definitely some truth in the book, it is not a thorough success. Their cultural examinations are both interesting and informative. To give an example that does not appear in the book, the Japanese now or in the recent past had a habit of going drinking with their boss after work. During these drinking bouts, people were allowed to say things to one another that would not be acceptable in a state of sobriety. This is what the authors call a "time-out," and is the purpose they say alcohol serves in most cultures. This part of the book is very believable. There is no doubt that alcohol can serve as a "time-out."

However, the authors are also transparently at the task of blaming the conditions of Native American alcohol use on Europeans and European culture. If NA are universally violent while drunk, it is because they learned that this is how drunk people act from being around fur traders, frontier soldiers, etc. This is a thin argument. As the authors themselves point out, the violence perpetrated by drunk NA was simply perpetrated by sober NA before the introduction of alcohol by Europeans. So, what Europeans introduced was social restraint with "time-out"s for violence, a net improvement I think most people would say over constant violence.

Another problem the authors don't really address is the fact that most the alcohol "time-out"s they site from South American, Asia, and Africa are connected with cultural rituals, whereas NA would simply drink and get violent when alcohol was available. This poses two problems for the authors. First, if alcohol and rituals are connected in "time-out," is there is a reason to believe that "time-out" occurs when not connected to ritual. The experience of modern bar-goers will demonstrate that people all act very differently when drunk, and also differently when drinking alone as opposed to in groups. Is it possible that some people simply are disinhibited? Second, if there is no ritual reason for drinking, and drinking results in murders and other violence, the question arises why people would seek out alcohol.

Also, the book essentially addresses only the problem of binge or group drinking. The loner dependant who buys up his family's food and education money in booze does not fit into this model.

However, the general point that there are at least some cultural learning effects on drunken behavior is no doubt true. And that point has definite suggestions as far as public health and policy are concerned. I don't know what happened to this theory of alcohol abuse in the decades since 1980 or the years since 2003, but I think it is a good book for nurses to read. Especially those who live ethnically diverse communities where they may be dealing with alcoholics from very different cultures.

Health and the Rise of Civilization: a good intro to ancestral health

Healthcare is a top-down industry where news and changes move slow. In order to institute 'evidence-based medicine' or 'evidence-based nursing', information has to be spread widely and discussed. To that end, I recommend Health and the Rise of Civilization (HRC) by Professor Mark Cohen as an excellent introduction to the concept of "ancestral health" for health care professionals.
Author Mark Cohen (who was previously profiled on this blog and spoke at the recent Ancestral Health Symposium) is a professor of anthropology who pioneered the forensic study of ancient skeletons as a tool to learn about the health of ancient hunter-gatherers and farmers. HRC is his summary of our pre-historic ancestors' health and the effects on our own health of living in complex, modern societies. Spoiler: compared to us, cavemen were a lot better off than you'd guess.

HRC is a good introduction to ancestral health because, unlike The Paleo Diet or The Paleo Solution, it is not a fad diet book. There is no eating plan in this book and no controversial recommendations that contradict the American Heart Assoication or the government's 'food pyramid'. As a health care professional, you shouldn't be able to dismiss this book automatically.

HRC is a good introduction because it is real scholarship. Any MD or PA, or any BSN, should understand the importance of, and be interested in, real scholarship related to health.

HRC is a good introduction because it was written to be a good introduction. Cohen wrote this book back in the 1980s, before low-carb, CrossFit, Paleo diet, or any of the rest. But it is a highly accessible essay that works well as an introduction to any approach to health that criticizes our modern way of eating and obtaining food. Although the book has almost 100 pages of footnotes and 50 pages of references, these are all at the end of the book. The main text--the part you really need to read--is only about half the book's total pages. And it reads easily and quickly.

HRC introduces concepts from anthropology that health care professionals would need to know in order to make sense of the interdisciplinary approach to "ancestral health."

One chapter is devoted to explaining the evolution of societies from small groups of hunter-gatherers to complex, modern civilization. An anthropological understanding of this evolution is necessary in order to get over our modern idea of continuous progress in medicine and nutrition.

Another chapter documents changes in the human diet since pre-historic times. Although we've all grown up with images of cavemen hunting mastodons, many people also seem to have the contradictory belief that a more "natural" diet is a vegetarian one. The story is a lot more complicated than that.

Yet another chapter demonstrates that infectious disease is not simply a matter of our immune system fighting germs with the help of antibiotics. Changes in our pattern of living since ancient times have undermined some of nature's built-in defenses.

Health and the Rise of Civilization should be a common starting point for everyone interested in ancestral health. The "Paleo community" tends to be dominated by personality, thriving older men like Art Devany or thriving younger men like Robb Wolf. But this model is not appropriate for health care professionals or researchers. HRC provides a firm ground in scholarship from which modern nutritional and health advice can and should be examined.

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Body by Science review

I was prompted to get Body by Science after following author Doug McGuff's comments on the Theory to Practice blog. Body by Science strives to prescribe a work-out routine that takes proper advantage of physiological knowledge to promote fitness, defined as the ability to take part in non-sedentary activities. The book does derive a work-out routine from a presentation of physiology. The recommendations include one short strength-training work-out per week with no traditional cardiovascular work (e.g., jogging) and a "hunter-gatherer"-type diet.

The physiology presented in this book is more extensive than what I've seen in traditional weight-lifting or diet-exercise books aimed at the public. Compared to two text-books for university courses in nutrition and exercise science, the physiology here is about as broad, presented in a slightly more truncated and easy to read format.

The thing that really distuingishes Body by Science, however, is that the physiology is presented in a manner that deconstructs traditional concepts of exercise. To sum up, the book contends (1) that cardiovascular fitness is something that occurs primarily in a diffuse manner throughout the body at the level of the musculature, not primarily as adaptations in the heart and lungs, and (2) that the musculature does not know if it is getting stressed by resistance training or traditional cardio work. The logical conclusion from these two premises is that the best overall fitness training is pure resistance strength training done in a manner that stresses the muscles without stressing joints, ligaments, etc.

I must confess that although I was aware that cardiovascular adaptations occurred at the muscular level, I was also under the impression that there are adaptations in the heart that occur specific to traditional styles of aerobic work such as jogging. However, I am at a loss to say what those are. I have a vague notion that sustained moderately elevated heart rate is important to the heart, but I couldn't tell you what exactly it achieves.

Of course, my failure to refute the physiological and exercise science presented here does not make it correct. That is the biggest draw-back with this or any exercise book--you are always at the mercy of those with more expertise. The only recourse you have as a reader is to educate yourself with some basic knowledge about research and publishing standards and try to evaluate how honest and accurate a book appears to be.

From this perspective, Body by Science holds up well, but not as well as its hype. Subtitled "A Research-Based Program...," you expect a book swamped by citations like an academic paper. The book does have more citations than a typical exercise book, but it is not near what I expected. For example, it says, "Virtually every study undertaken to assess the cardiovascular effects of proper strength training has concluded that they at least equal the effects of more conventional approaches such as running or other steady-state activities." However, the citations given to support this statement are two studies from 1985 and 1988. This is really not acceptable, even if the statement is accurate. Either many more (recent) studies need to be cited (or at least a review paper that examines this issue in depth). This is one example, but I think it fairly characterizes the whole book.





The book's biggest drawback is its failure to present evidence that its specific program has been demonstrated to work. The authors repeatedly mention the years of experience they and other trainers have in using their techniques, but they present no study they've conducted and only one photo of someone they've trained. The use of photos showing muscled young men is dismissed at the beginning of the book by referring to genetic variability in response to weight training. This is true, but in the absence of studies, anecdote shows something. Maybe doing the Bill Phillips Body-for-Life workout won't make you look like those contest winners (see above), but at least we know it can possibly do anything at all. Maybe eveybody's training will stagnate with Body by Science. Who knows?

In addition to its central message, the book touches briefly on a variety of peripheral issues. Some, such as the connection between an attempt to moderate training and a regression in training, confirm my personal experience. Others are silly, like the suggestion to drink cold water all day in order to burn off about 125 Kcal through thermodynamic effects. Any lifestyle cost-benefit analysis of this proposal could not hold up, especially for people living north of Florida.

Despite the criticisms, I think this is a useful book for fitness hobbyists to read. I really want its core recommendations to be correct (and I'm probably going to experimenting with them a little), and even if it is not the best program for otherwise fit and healthy individuals, I can see that it might still have applicability for the elderly, those needing rehab, or those with cardiac or respiratory disorders. It is worth investigation by health professionals as well.

If I were going to improve this book a great deal, I would demonstrate much more thoroughly and specifically that the program lives up to its claim "research-based." If McGuff, an ER doctor, recommended to me that I receive the medication tPA and I found out his recommendation was based on knowledge of two small studies conducted in the 1980s and that he couldn't show me any of his other patients who had success with this medication, I would be flipping mad. If you're going to claim exercise should be approached like a medication, you need to treat it with similar rigour.