Book Reviews

Islands of Genius

Posted by Peter on December 28, 2011
Posted in: Book Reviews, The Human Mind. Tagged: .

Book review: Islands of Genius: The Bountiful Mind of the Autistic, Acquired, and Sudden Savant, by Darold A. Treffert.

This book contains a fair amount of interesting information, but the writing style leaves much to be desired, and many parts disappointed me.

It describes savant syndrome (formerly known as “idiot savant”), where unusually good numeric or artistic skills coexist with some sort of mental disability (and usually prodigious memory).

Some people appear to have been born with savant skills, a few developed the skills in what appears to be a sudden insight. But the cases that seem to tell us the most about what is special about savants are the ones where the skills emerge after a brain injury. Savant skill seem to be often caused by a left brain dysfunction removing some inhibitions that prevented the right side of the brain from developing or displaying unusual skills.

This suggests that there may be some sense in which we all can potentially develop savant skills.

He doesn’t provide a good explanation of why the syndrome is defined so that savants with no disability fail to qualify. There seems to be some tendency for savant skills to coexist with some drawbacks (such as the drawbacks associated with autism), but the author denies that there’s any trade-off requiring that savant skill cause deficiencies in other areas.

Some of the weaker parts of the book claim some savants know things they couldn’t have learned, and attribute skills to genetic memory. I find it much more plausible that the savants learned their skills in ways that would look like an extreme form of normal learning, and that we just don’t know how to observe when and where they accomplished the learning.

The Better Angels of Our Nature

Posted by Peter on November 23, 2011
Posted in: Book Reviews, Politics. Tagged: .

Book review: The Better Angels of Our Nature: Why Violence Has Declined, by Steven Pinker.

Pinker provides a cautiously optimistic view of the dramatic reduction in violence over the past few centuries. He has tied together a wide variety of violent behavior (from genocide to cruelty to animals) into one broad pattern of people becoming more civilized.

He mostly covers the west, and I wished for more about the trends in the mideast and the more peaceful parts of asia. And why does he avoid commenting on the reported homicide rate for Somalia that’s less than the US – does he have reject the data as inaccurate, or does he want to ignore evidence that’s inconsistent with his claim that the rise of leviathan reduced crime?

The substance of the book is less reassuring than a casual glance would suggest. In particular, the section on the power law distribution of war deaths shows that the model he uses says the expected number of war deaths is infinite, apparently due to small probabilities of really destructive wars. It’s easy to overlook this disturbing implication if you aren’t reading carefully. I’m disappointed that Pinker didn’t talk about this more – how is it altered if we try to incorporate the finiteness of the available population? Should we focus a lot of our attention on avoiding unlikely megawars?

He cautiously speculates about possible causes (increased global communications, trade, democracy, self-control, reason, feminization, education, and intelligence via the Flynn effect).

If you’re an ideologue looking for an excuse to be offended, you’re fairly sure to find one in this book.

Pinker exaggerates the evidence for violence among hunter-gatherers (see the book Sex at Dawn for the other side of this debate). And the evidence Pinker does present is quite consistent with the hypothesis that violence increased when people switched from hunter-gatherers to stationary farmers.

The book is very long, and that’s not due to a simple desire to be thorough. Much of the evidence seems selected more for vividness and memorability (e.g. his evidence from fairy tales – not completely frivolous, but insignificant enough evidence that he wouldn’t have put it in a peer-reviewed article).

I didn’t learn enough from it to justify the time spent, but the ideas in it deserve to be known more widely.

The Taylor Rule

Posted by Peter on November 7, 2011
Posted in: Book Reviews, Economics. Tagged: .

Book review: Getting Off Track: How Government Actions and Interventions Caused, Prolonged, and Worsened the Financial Crisis, by John B. Taylor.

This book contains a few good ideas, expressed simply and clearly. It explains some of what caused the 2008 financial crisis. But he exaggerates a good deal when he claims he has “provided empirical proof that monetary policy was a key cause of the boom”.

He provides clear evidence that counterparty risk was a more important problem than lack of liquidity, and has some hints about how counterparty risk could have been handled better. But that doesn’t say much about whether policies to deal with liquidity problems were mistaken – I doubt that many of the people pushing those liquidity related policies were denying that counterparty risk was a problem.

I’ve been convinced since before the crisis that having the Fed follow the Taylor Rule would have been better than the monetary policy that we actually had. But the details of the rule seem somewhat arbitrary, and I’m disappointed that the book doesn’t provide much explanation of why the Taylor Rule is better than alternative rules.

I’ve found a link on Taylor’s blog to an article (The Taylor Rule and QE2 By David Papell) which compares it to some alternatives which seem motivated primarily by a desire to rationalize more monetary or fiscal stimulus. But what I want to know is whether it’s possible to create a rule that is more countercyclical without being more inflationary.

I have an intuition that it’s not too hard to improve on the inflation component of the rule. The CPI seems to have many drawbacks, such as being slow to reflect changes. I suspect Taylor’s inflation coefficient of 1.5 is larger than what an ideal rule would use in order to make up for the delays associated with using the CPI. When I’m estimating inflation for my investment decisions, I pay more attention to the ISM price index, the money supply (MZM), commodity prices, and stock prices. And the ISM Purchasing Managers Index should provide more up to date evidence of the “output gap” than GDP figures. A version of the Taylor Rule which emphasized those should react more quickly to changes in the economy.

Expected Returns

Posted by Peter on August 23, 2011
Posted in: Book Reviews, Investing. Tagged: , .

Book review: Expected Returns: An Investor’s Guide to Harvesting Market Rewards, by Antti Ilmanen.
This book is causing me to change my approach to investing much more than any other book has. It is essential reading for any professional investor.

The foreword starts by describing Ilmanen as insane, and that sounds like a good description of how much effort was needed to write it.

Amateur investors will have trouble understanding it – if you’re not familiar with Sharpe ratios, you should expect to spend a lot of time looking elsewhere for descriptions of many concepts that the book uses. I had a few problems understanding the book – he uses the term information ratio on page 188, but doesn’t explain it until page 491 (and it’s not indexed). I was also somewhat suspicious about how he handled data mining (overfitting) concerns in momentum strategies until I found a decent answer in a non-obvious place (page 404).

The most important benefit of this book is that he has put a lot of thought into identifying which questions investors should be trying to answer. Questions such as whether past performance is a good indicator of future returns, and what would cause a pattern of superior returns to persist or vanish.

Some other interesting topics:

  • why it’s important to distinguish between different types of undiversifiable risk, and how to diversify your strategies so that the timing of losses aren’t highly correlated across those strategies.
  • why earnings per share growth has been and probably will continue to be below GDP growth, contrary to what most forecasts suggest.
  • how to estimate the premium associated with illiquidity
  • why it’s useful to look at changes in correlations between equities

It’s really strange that I ordered this a few weeks after what Amazon lists as the publication date, but it took them nearly 7 weeks to find a copy of it.

Some quotes:

overfitting bias is so insidious that we cannot eliminate it (we cannot “become virgins again” and forget our knowledge)

the leverage of banks will soon be more tightly restricted by new regulations. The practical impact will be more pronounced risk premia for low-volatility assets, more sustained mispricings, and greater opportunities for those who can still apply leverage

The Ego Tunnel

Posted by Peter on July 25, 2011
Posted in: Book Reviews, The Human Mind. Tagged: , , , .

Book review: The Ego Tunnel: The Science of the Mind and the Myth of the Self, by Thomas Metzinger.

This book describes aspects of consciousness in ways that are often, but not consistently, clear and informative. His ideas are not revolutionary, but will clarify our understanding.

I didn’t find his tunnel metaphor very helpful.

I like his claim that “conscious information is exactly that information that must be made available for every single one of your cognitive capacities at the same time”. That may be an exaggeration, but it describes an important function of consciousness.

He makes surprisingly clear and convincing arguments that there are degrees of consciousness, so that some other species probably have some but not all of what we think of as human consciousness. He gives interesting examples of ways that humans can be partially conscious, e.g. people with Cotard’s Syndrome can deny their own existence.

His discussion of ethical implications of neuroscience points out some important issues to consider, but I’m unimpressed with his conclusion that we shouldn’t create conscious machines. He relies on something resembling the Precautionary Principle that says we should never risk causing suffering in an artificial entity. As far as I can tell, the same reasoning would imply that having children is unethical because they might suffer.

The Rational Optimist

Posted by Peter on June 18, 2011
Posted in: Book Reviews, Politics, Science and Technology.

Book review: The Rational Optimist: How Prosperity Evolves by Matt Ridley.

Ridley is more eloquent than Julian Simon, but like Simon he seems like a lawyer focusing all the reader’s attention on the evidence most favorable to his conclusions rather than an objective scientist.

A lot of what he says is right, but I’m bothered by the frequency with which he exaggerates. E.g. he says “justice has improved” [since the 1950s] because 234 innocent Americans were freed due to DNA evidence. That seems like such a tiny fraction of the total injustices that’s it’s nearly useless – it’s easy to imagine that declining jury quality has overwhelmed the improvements.

The book has a bit more history than I wanted, much of it devoted to the idea that free trade is an important cause of progress. He has an interesting claim that trade an important factor in pre-agricultural human success – it reportedly was virtually nonexistent in other species (even Neanderthals), and it may have started around the time that human population began to grow significantly. But the industrial revolution has been discussed often enough elsewhere that I got little out of his summary of the causes.

I’m disappointed that he presented trends of slowing population growth as reasons for optimism. There are many ways those trends could change, such as evolution or cheaper ways reproducing. And there are good arguments that more population growth would be desirable at least for this century.

Beyond Boundaries

Posted by Peter on June 5, 2011
Posted in: Book Reviews, The Human Mind. Tagged: , .

Book review: Beyond Boundaries: The New Neuroscience of Connecting Brains with Machines and How It Will Change Our Lives, by Miguel Nicolelis.

This book presents some ambitious visions of how our lives will be changed by brain-machine and brain to brain (“mind meld”) interfaces, along with some good reasons to hope that we will adapt well to them and think of machines and other people as if they are parts of our body. Many people will have trouble accepting his broad notion of personal identity, but I doubt they will find good arguments against it.

But I wish I’d skipped most of the first half, which focuses on the history of neuroscience research, with too much attention to debates over the extent to which brain functions are decentralized.

He’s disappointingly vague about the obstacles that researchers face. He hints at problems with how safe and durable an interface can be, but doesn’t tell us how serious they are, whether progress is being made on them, etc. I also wanted more specific data about how much information could be communicated each way, how precisely robotic positioning can be controlled, and how much of a trend there is toward improving those.

Too Loud, Too Bright, Too Fast, Too Tight

Posted by Peter on May 25, 2011
Posted in: Book Reviews, The Human Mind. Tagged: .

Book review: Too Loud, Too Bright, Too Fast, Too Tight: What to Do If You Are Sensory Defensive in an Overstimulating World by Sharon Heller.

This book has lots of information about sensory overload and sensory integration problems, but left me confused about the extent to which I have the problems that the book describes and whether there are good solutions.

The book mostly focuses on problems of being overwhelmed by sensory input, but also says sensory numbness can be associated with the same kind of problems. Some of the symptoms discussed describe me rather well, but a majority do not. The book seems to suggest that almost any nonstandard reaction to stimuli might mean a person is sensory defensive, which makes me wonder whether many unrelated conditions have been lumped into one category.

Many reviewers seem pleased that the book tells them they’re not alone in the problems that they’re facing. But I kept having conflicting impressions about whether the people described in the book are like me.

The book lists many possible solutions to sensory problems, which are described as making up a “sensory diet” – more suggestions than the author could plausibly understand well enough to know whether they work. Many are supported by anecdotal evidence, some by evidence that appears to be moderately good science, and for some the evidence seems inconclusive. I believe that they are better than random guesses, but I don’t expect to get much out of them without a good deal of trial and error.

Auditory integration training sounds like the kind of help I’m looking for, and the book makes that and some similar programs sound promising. But the Wikipedia entry on AIT is rather discouraging, and the Wikipedia entry on Sensory integration therapy isn’t very encouraging.

The book reports some interesting claims about the benefits of natural full-spectrum light, such as a large decrease in cavities (see “The effects of lights of different spectra on caries incidence in the golden hamster” by I. M. Sharon, R. P. Feller, S. W. Burney). But how much of this becomes unimportant when we take vitamin D supplements?

I just tried a full-spectrum light (OttLite 15ED12R 15w) recommended by the book. It provides more illumination with 15 watts than the 20 watt fluorescent bulb I normally use, and it was immediately obvious that the book I was reading looked better because it was whiter. But it has a distracting hum. Shouldn’t a book like this be able to warn me of this drawback?

There isn’t a lot out there on the subject of sensory integration, and educated guesses are better than nothing.

The Honor Code

Posted by Peter on May 1, 2011
Posted in: Book Reviews, Politics. Tagged: .

Book review: The Honor Code: How Moral Revolutions Happen by Kwame Anthony Appiah.

This book argues that moral changes such as the abolition of dueling, slavery, and foot-binding are not the result of new understanding of why they are undesirable. They result from changes in how they affect the honor (or status) of the groups that have the power to create the change.

Dueling was mostly associated with a hereditary class of gentlemen, and feeling a responsibility to duel was a symbol of that status. When the nature of the upper class changed to include a much less well defined class that included successful businessmen, and society became more egalitarian, the distinction associated with demonstrating that one was a member of the hereditary elite lost enough value that the costs of dueling outweighed the prestige.

Slave-owners increasingly portrayed the labor that slaves preformed in a way that also implied the work of British manual laborers deserved low status, and rising resentment and political power of that labor class created a movement to abolish slavery.

The inability of Chinese elites to ignore the opinions of elites in other nations whose military and technological might made it hard for China to dismiss them as inferior altered the class of people whom the Chinese elites wanted respect from.

These are plausible stories, backed by a modest amount of evidence. I don’t know of any strong explanations that compete with this. But I don’t get the impression that the author tried as hard as I would like to find evidence for competing explanations. For instance, he presents some partial evidence to the effect that Britain abolished slavery at a time when slavery was increasingly profitable. But I didn’t see any consideration of the costs of keeping slaves from running away, which I expect were increasing due to improved long-distance transportation such as railroads. He lists references which might constitute authoritative support for his position, but it looks like it would be time-consuming to verify that.

Whether this book can help spark new moral revolutions is unclear, but it should make our efforts to do so more cost-effective, if only by reducing the effort put into ineffective approaches.

War and Peace and War

Posted by Peter on April 15, 2011
Posted in: Book Reviews, Politics. Tagged: , .

Book review: War and Peace and War: The Rise and Fall of Empires, by Peter Turchin

This book describes a plausible model of how conflict between hostile cultures such as Islam versus Christianity can create the kind of large-scale cooperation (asabiya) needed to create empires, and that the absence of a nearby border with such a conflict results in the decay of that empire.

It is very hard to evaluate how accurately he analyzes the evidence for his theory without a really complete knowledge of the history of several empires.

Asabiya resembles what Fukuyama calls trust, but is stronger, and includes some willingness to risk ones life for other members of ones society. Turchin implies that this is a desirable quality (although I can’t recall anything explicitly saying that). I wonder whether the wars it contributes to outweigh the benefits. The answer might depend on the extend to which it is possible to have trust without much asabiya (Turchin’s analysis suggests a pessimistic answer).

Much of the book contains standard style histories, mostly of times and places that haven’t received much attention. I often found these parts annoying because I couldn’t figure out which parts contained evidence for Turchin’s model, and most of them didn’t seem important enough for me to remember.

He suggests that inequality within an empire reduces its stability. Most of this isn’t very original nor backed up by much evidence. One idea that I hadn’t heard before involves the upper class intentionally reducing the asabiya of lower classes, especially with extreme forms of inequality such as slavery. It seems quite likely that the upper classes sometimes attempt this. But the other parts of the book suggest that this may backfire – conflict normally increases asabiya. Turchin writes as if geographic separation between the conflicting cultures is needed for this effect, but it isn’t obvious to me why.

The book is in some ways gloomy, suggesting that it would take an alien attack to create a big increase in worldwide cooperation. But he does leave some hope that recent technological changes may have made his model obsolete.