Archive for the ‘Book Reviews’ Category

Paleofantasy

Friday, April 26th, 2013

Book review: Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live, by Marlene Zuk

This book refutes some myths about what would happen if we adopted the lifestyle of some imaginary hunter-gather ancestor who some imagine was perfectly adapted to his environment.

I’m a bit disappointed that it isn’t as provocative as the hype around it suggested. It mostly just points out that there’s no single environment that we’re adapted to, plus uncertainty about what our ancestors’ lifestyle was.

She spends a good deal of the book demonstrating what ought to be the well-known fact that we’re still evolving and have partly adapted to an agricultural lifestyle. A more surprising point is that we still have problems stemming from not yet having fully evolved to be land animals rather than fish (e.g. hiccups).

She provides a reference to a study disputing the widely held belief that the transition from hunter-gatherer to farmer made people less healthy.

She cites evidence that humans haven’t evolved much adaptation to specific diets, and do about equally well on a wide variety of diets involving wild foods, so that looking at plant to animal ratios in hunter-gather diets isn’t useful.

Her practical lifestyle advice is mostly consistent with an informed guess about how we can imitate our ancestors’ lifestyle (e.g. eat less processed food), and mainly serves to counteract some of the overconfident claims of the less thoughtful paleo lifestyle promoters.

Why Nations Fail

Saturday, March 16th, 2013

Book review: Why Nations Fail: The Origins of Power, Prosperity, and Poverty, by Daron Acemoglu and James Robinson.

This book claims that “extractive institutions” prevent nations from becoming wealthy, and “inclusive institutions” favor wealth creation. It is full of anecdotes that occasionally have some relevance to their thesis. (The footnotes hint that they’ve written something more rigorous elsewhere).

The stereotypical extractive institutions certainly do harm that the stereotypical inclusive institutions don’t. But they describe those concepts in ways that do a mediocre job of generalizing to non-stereotypical governments.

They define “extractive institutions” broadly to include regions that don’t have “sufficiently centralized and pluralistic” political institutions. That enables them to classify regions such as Somalia as extractive without having to identify anything that would fit the normal meaning of extractive.

Their description of Somalia as having an “almost constant state of warfare” is strange. Their only attempt to quantify this warfare is a reference to a 1955 incident where 74 people were killed (if that’s a memorable incident, it would suggest war kills few people there; do they ignore the early 90’s because it was an aberration?). Wikipedia lists Somalia’s most recently reported homicide rate as 1.5 per 100,000 (compare to 14.5 for their favorite African nation Botswana, and 4.2 for the U.S.).

They don’t discuss the success of Dubai and Hong Kong because those governments don’t come very close to fitting their stereotype of a pluralistic and centralized nation.

They describe Mao’s China as “highly extractive”, but it looks to me more like ignorant destruction than an attempt at extracting anything. They say China’s current growth is unsustainable, somewhat like the Soviet Union (but they hedge and say it might succeed by becoming inclusive as South Korea did). Whereas I predict that China’s relatively decentralized planning will be enough to sustain modest growth, but it will be held back somewhat by the limits to the rule of law.

They do a good (but hardly novel) job of explaining why elites often fear that increased prosperity would threaten their position.

They correctly criticize some weak alternative explanations of poverty such as laziness. But they say little about explanations that partly overlap with theirs, such as Fukuyama’s Trust (a bit odd given that the book contains a blurb from Fukuyama). Fukuyama doesn’t seem to discuss Africa much, but the effects of slave trade seem to have large long-lasting consequences on social capital.

For a good introduction to some more thoughtful explanations of national growth such as the rule of law and the scientific method, see William Bernstein’s The Birth of Plenty.

Why Nations Fail may be useful for correcting myths among people who are averse to math, but for people who are already familiar with this subject, it will just add a few anecdotes without adding much insight.

Error Statistics

Friday, February 8th, 2013

Book review: Error and the Growth of Experimental Knowledge by Deborah Mayo.

This book provides a fairly thoughtful theory of how scientists work, drawing on
Popper and Kuhn while improving on them. It also tries to describe a quasi-frequentist philosophy (called Error Statistics, abbreviated as ES) which poses a more serious challenge to the Bayesian Way than I’d seen before.

Mayo’s attacks on Bayesians are focused more on subjective Bayesians than objective Bayesians, and they show some real problems with the subjectivists willingness to treat arbitrary priors as valid. The criticisms that apply to objective Bayesians (such as E.T. Jaynes) helped me understand why frequentism is taken seriously, but didn’t convince me to change my view that the Bayesian interpretation is more rigorous than the alternatives.

Mayo shows that much of the disagreement stems from differing goals. ES is designed for scientists whose main job is generating better evidence via new experiments. ES uses statistics for generating severe tests of hypotheses. Bayesians take evidence as a given and don’t think experiments deserve special status within probability theory.

The most important difference between these two philosophies is how they treat experiments with “stopping rules” (e.g. tossing a coin until it produces a pre-specified pattern instead of doing a pre-specified number of tosses). Each philosophy tells us to analyze the results in ways that seem bizarre to people who only understand the other philosophy. This subject is sufficiently confusing that I’ll write a separate post about it after reading other discussions of it.

She constructs a superficially serious disagreement where Bayesians say that evidence increases the probability of a hypothesis while ES says the evidence provides no support for the (Gellerized) hypothesis. Objective Bayesians seem to handle this via priors which reflect the use of old evidence. Marcus Hutter has a description of a general solution in his paper On Universal Prediction and Bayesian Confirmation, but I’m concerned that Bayesians may be more prone to mistakes in implementing such an approach than people who use ES.

Mayo occasionally dismisses the Bayesian Way as wrong due to what look to me like differing uses of concepts such as evidence. The Bayesian notion of very weak evidence seems wrong given her assumption that concept scientific evidence is the “right” concept. This kind of confusion makes me wish Bayesians had invented a different word for the non-prior information that gets fed into Bayes Theorem.

One interesting and apparently valid criticism Mayo makes is that Bayesians treat the evidence that they feed into Bayes Theorem as if it had a probability of one, contrary to the usual Bayesian mantra that all data have a probability and the use of zero or one as a probability is suspect. This is clearly just an approximation for ease of use. Does it cause problems in practice? I haven’t seen a good answer to this.

Mayo claims that ES can apportion blame for an anomalous test result (does it disprove the hypothesis? or did an instrument malfunction?) without dealing with prior probabilities. For example, in the classic 1919 eclipse test of relativity, supporters of Newton’s theory agreed with supporters of relativity about which data to accept and which to reject, whereas Bayesians would have disagreed about the probabilities to assign to the evidence. If I understand her correctly, this also means that if the data had shown light being deflected at a 90 degree angle to what both theories predict, ES scientists wouldn’t look any harder for instrument malfunctions.

Mayo complains that when different experimenters reach different conclusions (due to differing experimental results) “Lindley says all the information resides in an agent’s posterior probability”. This may be true in the unrealistic case where each one perfectly incorporates all relevant evidence into their priors. But a much better Bayesian way to handle differing experimental results is to find all the information created by experiments in the likelihood ratios that they produce.

Many of the disagreements could be resolved by observing which approach to statistics produced better results. The best Mayo can do seems to be when she mentions an obscure claim by Pierce that Bayesian methods had a consistently poor track record in (19th century?) archaeology. I’m disappointed that I haven’t seen a good comparison of more recent uses of the competing approaches.

How to Measure Anything

Friday, December 28th, 2012

Book review: How to Measure Anything, by Douglas Hubbard.

I procrastinated about reading this book because it appeared to be only relevant to a narrow type of business problem. But it is much more ambitious, and aims to convince us that anything that matters can be measured. It should be a good antidote to people who give up on measuring important values on grounds such as it’s too hard or too subjective (i.e. it teaches people to do Fermi estimates).

A key part of this is to use a sensible definition of the word measurement:

A quantitatively expressed reduction of uncertainty based on one or more observations

.

He urges us to focus on figuring out what observations are most valuable, because there are large variations in the value of different pieces of information. If we focus on valuable observations, the first few observations are much more valuable than subsequent ones.

He emphasizes the importance of calibration training which, in addition to combating overconfidence, makes it hard for people to claim they don’t know how to assign numbers to possible observations.

He succeeds in convincing me that anything that matters to a business can be measured. There are a few goals for which his approach doesn’t seem useful (e.g. going to heaven), but they’re rarer than our intuition tells us. Even vague-sounding concepts such as customer satisfaction can either be observed (possible with large errors) via customer behavior or surveys, or they don’t matter.

It will help me avoid the temptation of making Quantified-Self types measurements to show off how good I am at quantifying things, and focus instead on being proud to get valuable information out of a minimal number of observations.

Food and Western Disease

Tuesday, December 4th, 2012

Book review: Food and Western Disease: Health and nutrition from an evolutionary perspective, by Staffan Lindeberg.

This book provides evidence that many causes of death in developed nations are due to a lifestyle that is different from hunter-gatherer lifestyles.

His studies of existing hunter-gatherer societies show moderately good evidence that cardiovascular disease is rare, that aging doesn’t cause significant dementia, and shows weaker evidence of less cancer.

He has some vaguely plausible reasons for focusing on diet as the main lifestyle difference. I’m disappointed that he doesn’t mention intermittent fasting as a factor worth investigating (is it obvious from his experience that some hunter-gatherer societies don’t do this?).

He uses this evidence to advocate a mostly paleo diet, although with less fat than is often associated with that label.

Much of the book is devoted to surveying the evidence about other proposed dietary improvements, mostly concluding they don’t do much (or in the case of calorie restriction, might work by causing a more paleo-like diet).

I don’t have a lot of confidence in his ability to interpret the evidence.

He gives the impression that Omega-3 consumption has little effect on health, citing papers such as this review, whose abstract includes:

showed no strong evidence of reduced risk of total mortality (relative risk 0.87, 95% confidence interval 0.73 to 1.03)

I’d call that evidence for a moderately important benefit of Omega-3, and I consider it strong evidence in comparison to typical dietary studies, although it’s weak compared to the evidence that other scientific fields aim for.

One response from nutrition experts says:

The null conclusion of the Cochrane report rests entirely upon inclusion of one trial, DART 2.

A quick glance at recent publications from another author he cites (Mozaffarian) got me this:

Considerable research supports cardiovascular benefits of consuming omega-3 PUFA, also known as (n-3) PUFA, from fish or fish oil.

Excessive skepticism is probably better than hype, but it will discourage many people from reading it. Plus the style is somewhere in between a reference book and a book that I’d read from start to end.

Willpower

Sunday, November 11th, 2012

Book review: The Willpower Instinct: How Self-Control Works, Why It Matters, and What You Can Do To Get More of It, by Kelly McGonigal.

This book starts out seeming to belabor ideas that seem obvious to me, but before too long it offers counterintuitive approaches that I ought to try.

The approach that I find hardest to reconcile with my intuition is that self-forgiveness over giving into temptations helps increase willpower, while feeling guilt or shame about having failed reduces willpower, so what seems like an incentive to avoid temptation is likely to reduce our ability to resist the temptation.

Another important but counterintuitive claim is that trying to suppress thoughts about a temptation (e.g. candy) makes it harder to resist the temptation. Whereas accepting that part of my mind wants candy (while remembering that I ought to follow a rule of eating less candy) makes it easier for me to resist the candy.

A careless author could have failed to convince me this is plausible. But McGonigal points out the similarities to trying to follow an instruction to not think of white bears – how could I suppress thoughts of white bears of some part of my mind didn’t activate a concept of white bears to monitor my compliance with the instruction? Can I think of candy without attracting the attention of the candy-liking parts of my mind?

As a result of reading the book, I have started paying attention to whether the pleasure I feel when playing computer games lives up to the anticipation I feel when I’m tempted to start one. I haven’t been surprised to observe that I sometimes feel no pleasure after starting the game. But it now seems easier to remember those times of pleasureless playing, and I expect that is weakening my anticipation or rewards.

The Signal and the Noise

Monday, October 29th, 2012

Book review: The Signal and the Noise: Why So Many Predictions Fail-but Some Don’t by Nate Silver.

This is a well-written book about the challenges associated with making predictions. But nearly all the ideas in it were ones I was already familiar with.

I agree with nearly everything the book says. But I’ll mention two small disagreements.

He claims that 0 and 100 percent are probabilities. Many Bayesians dispute that. He has a logically consistent interpretation and doesn’t claim it’s ever sane to believe something with probability 0 or 100 percent, so I’m not sure the difference matters, but rejecting the idea that those can represent probabilities seems at least like a simpler way of avoiding mistakes.

When pointing out the weak correlation between calorie consumption and obesity, he says he doesn’t know of an “obesity skeptics” community that would be comparable to the global warming skeptics. In fact there are people (e.g. Dave Asprey) who deny that excess calories cause obesity (with better tests than the global warming skeptics).

It would make sense to read this book instead of alternatives such as Moneyball and Tetlock’s Expert Political Judgment, but if you’ve been reading books in this area already this one won’t seem important.

The Righteous Mind

Friday, July 27th, 2012

Book review: The Righteous Mind: Why Good People Are Divided by Politics and Religion, by Jonathan Haidt.

This book carefully describes the evolutionary origins of human moralizing, explains why tribal attitudes toward morality have both good and bad effects, and how people who want to avoid moral hostility can do so.

Parts of the book are arranged to describe the author’s transition from having standard delusions about morality being the result of the narratives we use to justify them and about why other people had alien-sounding ideologies. His description about how his study of psychology led him to overcome his delusions makes it hard for those who agree with him to feel very superior to those who disagree.

He hints at personal benefits from abandoning partisanship (”It felt good to be released from partisan anger.”), so he doesn’t rely on altruistic motives for people to accept his political advice.

One part of the book that surprised me was the comparison between human morality and human taste buds. Some ideologies are influenced a good deal by all 6 types of human moral intuitions. But the ideology that pervades most of academia only respect 3 types (care, liberty, and fairness). That creates a difficult communication gap between them and cultures that employ others such as sanctity in their moral system, much like people who only experience sweet and salty foods would have trouble imagining a desire for sourness in some foods.

He sometimes gives the impression of being more of a moral relativist than I’d like, but a careful reading of the book shows that there are a fair number of contexts in which he believes some moral tastes produce better results than others.

His advice could be interpreted as encouraging us to to replace our existing notions of “the enemy” with Manichaeans. Would his advice polarize societies into Manichaeans and non-Manichaeans? Maybe, but at least the non-Manichaeans would have a decent understanding of why Manichaeans disagreed with them.

The book also includes arguments that group selection played an important role in human evolution, and that an increase in cooperation (group-mindedness, somewhat like the cooperation among bees) had to evolve before language could become valuable enough to evolve. This is an interesting but speculative alternative to the common belief that language was the key development that differentiated humans from other apes.

The Intelligence Paradox

Tuesday, July 3rd, 2012

Book review: The Intelligence Paradox: Why the Intelligent Choice Isn’t Always the Smart One, by Satoshi Kanazawa.

This book is entertaining and occasionally thought-provoking, but not very well thought out.

The main idea is that intelligence (what IQ tests measure) is an adaptation for evolutionarily novel situations, and shouldn’t be positively correlated with cognitive abilities that are specialized for evolutionarily familiar problems. He defines “smart” so that it’s very different from intelligence. His notion of smart includes a good deal of common sense that is unconnected with IQ.

He only provides one example of an evolutionarily familiar skill which I assumed would be correlated with IQ but which isn’t: finding your way in situations such as woods where there’s some risk of getting lost.

He does make and test many odd predictions about high IQ people being more likely to engage in evolutionarily novel behavior, such as high IQ people going to bed later than low IQ people. But I’m a bit concerned at the large number of factors he controls for before showing associations (e.g. 19 factors for alcohol use). How hard would it be to try many combinations and only report results when he got conclusions that fit his prediction? On the other hand, he can’t be trying too hard to reject all evidence that conflicts with his predictions, since he occasionally reports evidence that conflicts with his predictions (e.g. tobacco use).

He reports that fertility is heritable, and finds that puzzling. He gives a kin selection based argument saying that someone with many siblings ought to put more effort into the siblings reproductive success and less into personally reproducing. But I see no puzzle – I expect people to have varying intuitions about whether the current abundance of food will last, and pursue different strategies, some of which will be better if food remains abundant, and others better if overpopulation produces a famine.

He’s eager to sound controversial, and his chapter titles will certainly offend some people. Sometimes those are backed up by genuinely unpopular claims, sometimes the substance is less interesting. E.g. the chapter title “Why Homosexuals Are More Intelligent than Heterosexuals” says there’s probably no connection between intelligence and homosexual desires, but there’s a connection between intelligence and how willing people are to act on those desires (yawn).

Here is some evidence against his main hypothesis.

The Beginning of Infinity

Friday, April 20th, 2012

Book review: The Beginning of Infinity by David Deutsch.

This is an ambitious book centered around the nature of explanation, why it has been an important part of science (misunderstood by many who think of science as merely prediction), and why it is important for the future of the universe.

He provides good insights on jump during the Enlightenment to thinking in universals (e.g. laws of nature that apply to a potentially infinite scope). But he overstates some of its implications. He seems confident that greater-than-human intelligences will view his concept of “universal explainers” as the category that identifies which beings have the rights of people. I find this about as convincing as attempts to find a specific time when a fetus acquires the rights of personhood. I can imagine AIs deciding that humans fail often enough at universalizing their thought to be less than a person, or that they will decide that monkeys are on a trajectory toward the same kind of universality.

He neglects to mention some interesting evidence of the spread of universal thinking – James Flynn’s explanation of the Flynn Effect documents that low IQ cultures don’t use the abstract thought that we sometimes take for granted, and describes IQ increases as an escape from concrete thinking.

Deutsch has a number of interesting complaints about people who attempt science but are confused about the philosophy of science, such as people who imagine that measuring heritability of a trait tells us something important without further inquiry – he notes that being enslaved was heritable in 1860, but that was useless for telling us how to change slavery.

He has interesting explanations for why anthropic arguments, the simulation argument, and the doomsday argument are weaker in a spatially infinite universe. But I was disappointed that he didn’t provide good references for his claim that the universe is infinite – a claim which I gather is controversial and hasn’t gotten as much attention as it deserves.

He sometimes gets carried away with his ambition and seems to forget his rule that explanations should be hard to vary in order to make it hard to fool ourselves.

He focuses on the beauty of flowers in an attempt to convince us that beauty is partially objective. But he doesn’t describe this objective beauty in a way that would make it hard to alter to fit whatever evidence he wants it to fit. I see an obvious alternative explanation for humans finding flowers beautiful – they indicate where fruit will be.

He argues that creativity evolved to help people find better ways of faithfully transmitting knowledge (understanding someone can require creative interpretation of the knowledge that they are imperfectly expressing). That might be true, but I can easily create other explanations that fit the evidence he’s trying to explain, such as that creativity enabled people to make better choices about when to seek a new home.

He imagines that he has a simple way to demonstrate that hunter-gatherer societies could not have lived in a golden age (the lack of growth of their knowledge):

Since static societies cannot exist without effectively extinguishing the growth of knowledge, they cannot allow their members much opportunity to pursue happiness.

But that requires implausible assumptions such as that happiness depends more on the pursuit of knowledge than availability of sex. And it’s not clear that hunter-gatherer societies were stable – they may have been just a few mistakes away from extinction, and accumulating knowledge faster than any previous species had. (I think Deutsch lives in a better society than hunter-gatherers, but it would take a complex argument to show that the average person today does).

But I generally enjoyed his arguments even when I thought they were wrong.

See also the review in the New York Times.