The Secret of our Success, by Joseph Henrich

Joseph Henrich's The Secret of Our Success has a fair amount of overlap with Herculano-Houzel's The Human Advantage, which I reviewed in July. Both spend most of their attention on explaining why humans, of all the products of evolution, turned out to be the smartest and hence dominant species on the planet. The Human Advantage focused on what makes the human brain unique, and found some surprising neuronal traits that sets mammals apart from other other animals, and that make primates unique among mammals in their neuronal architecture. Henrich, on the other hand, takes pains to point out that individual humans (even very smart ones) aren't very good at figuring out how to survive in new environments. He uses that evidence to argue that communication and culture make the difference. As individuals, he claims, we aren't much smarter than other primates.

They both agree that cooking was a huge step forward for us, but Henrich takes pains to point out that this only an advantage when we're raised in a cultural group. Unlike practically all other animals, we don't instintively know how to unlock the nutrition in common foodstuffs—without training, it would take a long time (during which you have to be subsisting on something else) to figure out how to prepare most of what we eat.

The book starts out with several stories about lost european explorers becoming stranded, and if they didn't get help from locals, they would starve in the midst of what the locals would consider plenty. In Australia, the Arctic, and Florida, well-funded and trained explorers slowly starved because they couldn't figure out how to find, harvest, or prepare the foods the locals subsisted on, and they either didn't think to ask for help, or they drove away those who tried to help them. In contrast, there are a couple of stories of individual aborigines who are separated from their kin, and do just fine for years, since they grew up gathering and preparing the local bounty. His point is that our strength, as a species, is learning from one another, and picking up on every small increment in survivability.

I've been saying for years (since reading Jared Diamond's Guns, Germs, and Steel) that the thing to realize about the spread of humans and their ability to make use of local flora and fauna is that there were enough people, and people are curious enough that we tried to exploit everything, and we tried to make use of everything available in all conceivable ways. How else to explain the fact that people ate acorns, seal livers, and nardoo. In preparing nardoo, the Australian aborigines grind seeds, leech them with water, mix them with ash during heating, and use mussell shells to serve them. If you miss any step, then like the explorers, you'll die of poisoning or stavation with a full belly.

Along the way, this book has lots of interesting proposals about how culture affects prestige and dominance in ways that make it possible for us to live in larger groups and take advantage of the skills and abilities of more people; how competition for living space between groups leads to cultural differences, and how our ability and drive to share culture and learn from each other leads to increasing communication abilties and common grammar strength across the species. There are interesting tidbits spread throughout.

In talking about how living in larger groups with a larger repertoire of tools and techniques make us more capable without requiring more individual smarts or inventiveness, Henrich gave a list of simple tools that is more interesting than the standard list of 6 simple machines known since antiquity:

wheels, pulleys, springs, screws, projectiles, elastically stored energy (e.g. bows, spring traps), levers, poisons, compressed air (blow guns), rafts, leisters [a barbed spear], and heating (fire and coooking).

Instead of focusing on mechanical advantage as we do with the simple machines, this focuses on shared, reusable knowledge, and shows that there were ideas around to be re-used even in societies that were very primitive by modern standards.

Henrich has a longer more detailed time-line than Herculan-Houzel, and his focuses on evidence about tool use showing accumulation of culture rather than archeological evidence relating to brain size, cooking, and gut size. I enjoyed this book as much as Human Advantage, and it added an interesting, non-conflicting story about the roots of our intelligence. It didn't feel as if it has as much relevance to the question about our place in the universe—once we set out on the path toward communication and shared culture, Henrich didn't mention further roadblocks toward increasing advantage as we exploited the new niche better.

0.3productChris Hibbert

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Chris Hibbert

Suzana Herculano-Houzel's The Human Advantage is a good book with some important insights hidden behind a fairly dry and dense presentation on "how I made these important discoveries." Herculano-Houzel (by her own account) pioneered a technique for determining the number of neurons in brain tissue, and managed (through a fair number of mildly interesting adventures) to bring together samples of many different primate, rodent, and other mammalian brains in order to work out the scaling laws that govern how brains and neuron counts grow with body mass in different tissues across different lineages. She shows a lot of graphs and charts to demonstrate that (with two exceptions) for most mammals, neuron counts scale up with an exponent of .5 with body mass, but in primates, the scaling factor is .8. If neurons have to be added in order to increase intelligence, this means that primates have a huge advantage. In order to get smarter, brains and neuron count have to increase. Larger bodies are necessary in order to sustain a larger brain, and if neuron count or neuron density is the limiting factor in intelligence, then you want to be able to pack more neurons into a denser brain in order not to require an enormous body.

Once Herculano-Houzel has established the basic scaling laws, she delves into the economics of maintaining a sufficiently neuron rich brain. The comparative scaling laws mean that as you look at bigger and bigger species of mammals, the neuron counts increase with the square root of the body mass. As primate species get larger, their neuron count increases much more quickly, which means that for a given body size, a primate is capable of supporting a larger brain than would a mammal. The cross-over point where the two lineages have comparable neuron sizes are with body sizes in the 10 gram range. At any larger size, if you compare a primate with another similar sized mammal, the primate is probably smarter.

There is a separate literature showing the energy requirements for many particular species. Herculano-Houzel used her new numbers on neurons for rodent and primate species to show that there is a direct correlation between the number of neurons and the amount of glucose consumed per minute by the brain. For humans (and others in the Homo lineage, being able to take advantage of the primate scaling laws gives a big boost, but you still have to find a way to ingest sufficient calories to afford the bigger brain.

Humans have two main advantages on this score compared to other primates. Walking on two legs is much more energy efficient than knuckle-walking like other (primarily arboreal) primates or on four legs. This increases the range over which foragers could range, and also freed up hands for gathering and carrying. It's not clear what originally drove bipedalism in the homo line, but it occurs at the same branch point that leads to the massive growth in cranial capacity.

The other big human advantage is cooking. I've seen discussions before that cooking increases the efficiency of digestion, and led to our shorter digestive tract, which allowed us to switch energy resources from digestion to our brains, but Herculano-Houzel points out that even before control of fire, other kinds of preparation (chopping and mashing for example) reduce the energy required for digestion. The anthropological evidence for food preparation goes back much further than the evidence of cooking, and significantly after bipedalism. The earliest evidence of eating meat is swiftly followed by anatomic adaptations to a more efficient diet, which is quickly followed by better tools, and the then bigger brains. Part of the evolutionary adaptation for bigger brains included smaller jaws.

Evidence of tool use and manufacture date back to 3.3 MYA (Million Years Ago). This date was recently pushed back from 2.6 MYA. These tools were simple flint knives. Archaeologists wouldn't count rocks that were used for pounding, since they are impossible to distinguish from unworked rocks. The flint knives would have been useful for cutting up meat, which would make it more digestible, and is necessary in order to survive with smaller jaws. Presumably, eating primitively processed foods had to become habitual before later evolutionary steps that relied on it would have survived in the population. The archaeological evidence gives the following timeline:

1. 4.4 MYA: bipedalism appears
2. 3.3 MYA: earliest tool use
3. 2.5 MYA: eating meat
4. 2.4 MYA: beginning of the reduction in size of the jaw
5. 1.9 MYA: smaller gut is clearly present
6. 1.7 MYA to 300 KYA: The Acheulean hand axe
7. 1.5 MYA-100 KYA: start of the increase in cranial capacity
8. 1 MYA: Clear indications of cooking

Another tantalizing clue is that the taste for cooked food may pre-date adoption of the habit. Herculano-Houzel refers to two studies that show that chimpanzees have a very strong preference for the taste of cooked food over raw. I don't know whether this has been investigated in other lineages, but if so, (even if it's just the body innately being able to detect foods that are provide big efficiency gains) it provides a boost for any lineage that can figure out how to reliably prepare foods--once you start, it would be an easy habit to keep, providing that the right food sources and tools are accessible.

Earlier, I mentioned that there are two exceptions to the laws regulating the number of neurons in primates and in all other mammals. The first is gorillas, which have brains and neuron counts much closer to those of other mammals rather than those expected of a primate. This fact about gorillas has been throwing off the results of previous researchers, who could only measure brain capacity. They concluded that the rules for primates would be the same as for other mammals, and argued that it was humans that were outliers. Once you plot the detailed data from small and medium primates and compare to mammals, it's easy to see a different trend line applies, and that humans fit on the primate line and gorillas do not. The other exception is elephants. (Herculano-Houzel has an entertaining section about her adventures getting elephant brains to analyze.) Elephants have brains whose size follows the standard scaling rule for mammals. They're huge, and they have huge brains. But their neurons are distributed very differently from all other species. 98% of the neurons are in the cerebellum, while the normal number doesn't get much above 80%. So elephants have big brains and a lot of neurons, but this explains why they're not even smarter than us, presuming neurons in the cerebral cortex are the thing that matters most.

Anyway, the later clues about cooking and bipedalism only added to my reaction that this work may provide an improved answer to the Fermi paradox. Herculano-Houzel doesn't appear to have data about the brains of animals beyond mammals, but if all the mammals outside of primates share a common scaling factor, then that's an indication that it's hard to evolve intelligence given the standard energy budget. It takes a special trick (which didn't have an immediate obviously benefit in the small primates in which it evolved) which was only discovered in one previously obscure branch of the mammal family tree to enable the efficient scaling that allows bodies to grow large enough to support brains supporting enough neurons to enable tool use. This enables (with other accidents like bipedalism and prepared food appearing in the same lineage) the feedback cycle that led to our massive growth in intelligence.

I've never been very worried by the argument that says the Fermi paradox indicates that there's a Great Filter, and if we can't figure out what the hard step was in our past, we should expect to encounter a hurdle in our future that has stopped other species from getting to space. The Human Advantage makes me even more sanguine. It's hard to evolve an intelligent species. There are a lot of happy accidents in our past, and the likely number of extra-terrestrial species in our light cone may be smaller than we thought. It would be nice to see more data showing the scaling laws that apply outside the primates (and in the cetaceans, which she didn't give much data about). I'll be surprised if any of them show divergent scaling progression compared to baseline mammals.

Vernor Vinge: The Children of the Sky

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Chris Hibbert

Vernor Vinge's The Children of the Sky is a sequel to his wonderful A Fire Upon the Deep. In this novel, we visit the home world of the Tines, a dog-like species who only achieve sentience when melded into packs of 3 to about 6. The main human characters are the children of a group of scientists who found a way to engender a widespread Slow Zone, where higher technology and FTL isn't possible, in order to slow the advance of the Blight, a malignant entity bent on a civilization-wide attack. The humans have been revived from cold sleep by various tine factions, and are trying to understand the galactic context that left them abandoned and possibly vulnerable in the Slow Zone. A few of them remember what life was like on a research station, and there is much recrimination and internecine battling among the maturing adolescents. At the same time, the Tines have their own politics and factions, some of whom are ruthless. They also only have second hand knowledge of the higher technology that was lost, and are jealous to be the first to invent useful tools and weapons.

Vinge is a master a depicting truly alien characters, and keeping them true to the characteristics he assigns them. The Tines are individually quite incapable, and don't function well when in close proximity to Tines other than their their own small pack. In this story, we also get to see that the Tropical Choir, which is a super-pack of millions of Tines, somehow manages to operate somewhat cohesively, to the surprise of the northern Tines. Individual packs of Tines have distinct personalities, and can plan and make and keep agreements. When they lose members, it's a lot like aphasic people, with distinct skills and knowledge getting lost. Some Tines and humans explore various approaches to sidestep these problems, but the alternatives have drawbacks that are often worse.

Children of the Sky is a nominee for this year's Prometheus award, and it may be the best written of this year's novels, but the libertarian elements are hard to spot. The Tines don't have an organized government, and no one seems to collect taxes. It's hard to say that they have a well-functioning spontaneous order, since there's little commerce to be seen, even though Tycoon is portrayed as a successful and innovative businessman. (Also, he/they seems to operate sweatshop-style factories, and imprisons and tortures rivals.)

Since the story takes place entirely on one backwoods planet in the slow zone in Vinge's enormous universe, the scope is necessarily narrow, so the implications for galactic civilization that we're used to in Vinge's stories in this universe are missing. The story is still one of adventure, intrigue, invention, progress and loyalty. The way that Tine packs can change attitude, knowledge, and alliance when they gain or lose members gives Vinge unusual opportunities for plot twists. It's definitely a fun read. Whether you like Vinge, or haven't yet seen how he can bring an alien civilization to life, you'll enjoy this.

What Intelligence Tests Miss, Keith Stanovich

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Chris Hibbert

Keith Stanovich's What Intelligence Tests Miss does a reasonable job of arguing that we have a couple of different things in mind when we talk about how "smart" a person is, and that some of the important aspects are very different from what IQ tests measure. His goal seems to be to convince us that the other parts are important and we would do better if we either found good ways to measure them (though there are caveats there) or reduce the societal importance of IQ tests and their ilk.

Most of the areas that Stanovich is interested in could loosely be called rationality skills. He starts out the book with the example of George Bush, whose apparent IQ (estimated from various of his tests results that are on the record) is about 120, but who is agreed to not have conventional smarts, or be a thorough, consistent, or deep thinker. The main point here is talking about how people are surprised, but shouldn't be, that IQ is separate from what we call smart. The book is mainly a riff on Kahneman and Tversky's work on human decision making, and all the kinds of rationality traps that we fall for.

Apparently, Stanovich's own research is in how the various layers of processing—the Autonomous mind, the Algorithmic mine, and the Reflective mind— interact and override one another in order to determine the kinds of processing we do. We spend most of our time in autonomous mode, with occasional incidents propelling us into slower Algorithmic thinking, and only rarely do we have a reason to actually think about what we're doing reflectively. Stanovich has a detailed model showing the interactions, and pointing to the Reflective mind as the director that gives the signal for when to invoke the Algorithmic level. His argument seems to be that people who don't "act smart" fail to engage their Reflective layer, and so end up on auto-pilot most of the time.

The rest of the book is mainly a rehash of the literature on rationality errors, and a plea for approaches like Thaler and Sunstein's Libertarian Paternalism, which are intended to provide support for people so they can get smarter results without having to reason more clearly.

In the end, I guess I'd say that there are some interesting ideas here, but not enough to make the book worthwhile.

Malclm Gladwell: Outliers

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Chris Hibbert

Malcolm Gladwell's Outliers was an engaging read, but a disappointing argument. Gladwell presents a series of separate incidents, each painted in a fair amount of detail. He doesn't focus on the common threads, and sometimes it's hard to see how the stories are pulling in the same direction, since he fills in the theme with a really light hand.

Gladwell presents a number of success stories and a few stories of failure in order to show that luck and circumstances contribute substantially to both. The preface shows us a small Pennsylvania town whose residents mostly came from a single small Italian town. Both towns show unusual longevity, and Gladwell points to a low-pressure lifestyle with lots of community contact as the reason. The first chapter shows that the top Canadian hockey players (and around the world) all have birthdays that are clustered just after January 1(toward the beginning of the year (January 1 is the cutoff date for entry into the youngest organized leagues). This means that each year, this cohort includes the biggest kids, who get the most attention and training, and the investment compounds over the years.

Lewis Terman's gifted kids are presented to show that intelligence isn't a sure precursor for success. There were very few successes out of the class of extremely bright kids that Terman followed for decades.

Gladwell then presents details about various successes who happened to already have the right preparation when their skills came to be valued by the marketplace (Bill Gates and Bill Joy, as well as Jewish lawyers who'd been handling corporate proxy fights when they'd been out of favor by the white shoe firms in New York). Gladwell argues that 10,000 hours of focused practice is necessary to turn someone into the kind of expert how can take advantage of situations like this. He seems to want us to believe that luck determines which of the available experts will ultimately succeed, but he fails to establish that 10,000 hours is an important benchmark. It's certainly plausible that in order to be considered a pioneer, you have to have picked up the expertise before it was obvious that there was a field available to excel in.

Gladwell tries to put the Beatles in the category of people who picked up the 10,000 hours of experience, and then won because the time was right. The evidence he shows makes it look like they worked very hard in Germany for a few summers before they achieved their success, but it doesn't look like 10,000 hours. And it's not obvious what wave of change they rode to gain their success, comparable to the opportunities available to Gates, Joy, and the New York lawyers who were ready for the wave of corporate lawsuits in the 1970's.

Along the way, we also get a few stories of surprising failures, uniformly due to socialization. Some cultures are poorly suited to producing successes in particular fields. He focuses on a particular bad period for Korean Air Lines, which the long term investigations eventually laid at the feet of the extreme deference due to pilots (and high status individuals in general) in Korean society. Gladwell dissects several crashes to show that even when the co-pilot could tell the plane was in trouble, Korean social mores prevented him from saying anything directly to the pilot. Eventually, the international community convinced Korean aviation to change their training to ensure that cockpits were much more egalitarian, so communication didn't have this fatal flaw. There are a couple of other stories of individuals from dysfunctional societies, or of dysfunctional societies themselves.

The book closes with the story of KIPP, a free open-enrollment school that has shown that pretty much all kids can be successful and prepared for college if the social environment is appropriate. It takes a culture that embraces hard work (which Gladwell also emphasized in the previous chapter on Asian farmers), but doesn't require selective admissions.

Gladwell tells a good story, but he didn't spend much time stitching it together. I had to review the whole array of pieces in order to see how they fit together. Before going to that extra effort, I had a different impression of the intended moral. The high-profile success stories (the Beatles, Bill Joy, Bill Gates, and Joe Flom the Jewish lawyer) were the most vivid, so I remembered it as a story of how hard work makes you eligible for success, but requires the addition of fortuitous timing in order to win the brass ring. Once I brought in the pro athletes, Terman's gifted kids, and KIPP, I could see that the point must have had something to do with those who just missed greatness, too. The commonality that Gladwell wants us to find is that success is mostly a matter of luck and circumstance. And he we wants us to know that luck and circumstance can also work against us. (That's how the Korean pilots fit in and southern culture's deleterious effects on socialization.)

So he wants us to believe that community and context matter more than ability. Hard work apparently gives you a chance at success, but the chance is out of your control. All you can do is pick something you care about and work hard at it. If you're lucky things might turn out well for you, but they probably won't.

This is a pretty discouraging story if you stop there. While it may be a reasonable story about which people get to be the big winners, it's misleading as a guide to living a successful life. Success at the level of the characters he describes probably is mostly a matter of luck, but ordinary success and modest achievement is much more attainable, as the KIPP example shows. There aren't many fields like pro hockey or pro baseball in which the winners are picked early, and there's no reasonable chance to catch up if you miss the initial cut-off. But Gladwell doesn't provide any hints about that and he makes this story harder to follow than it needs to be.

Gregory Cochran and Henry Harpending: The 10,000 Year Explosion

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Chris Hibbert

Gregory Cochran and Henry Harpending's The 10,000 Year Explosion talks about how humans have evolved over the period since we've been relatively civilized. They explicitly want to challenge the (sometimes vociferously propounded, but seldom cogently defended) notions that humanity hasn't evolved significantly since homo sapiens emerged, and that there's no significant genetic difference among populations in different places. They open Chapter 1 with quotes from Stephen Jay Gould and Ernst Mayr to demonstrate that they aren't fighting a straw man.

Mostly, this notion seems to be held in order to defend a liberal notion of equality, as if we could only defend equal treatment if we all have equal abilities, endowments, and if none of our observable differences are innate. If this notion isn't supportable, we'll have to be clearer that equal treatment is right for other reasons, and perhaps we'll have to be articulate about what those other reasons are. But that's an argument that Cochran and Harpending leave for someone else.

Cochran and Harpending's argument here is that there are quite a few differences between different modern populations, and that many are clearly genetic in origin. They first go to some pains to show that genetic changes can easily arise in this kind of time period. Particular examples are dogs, which have evolved all their modern variety since separating from wolves only about 15000 years ago, and domesticated plants which have changed enormously since the end of the last ice age 11,500 years ago. There are particular changes in humans that are also clearly of recent origin including skin color, eye color, lactose tolerance, and resistance to various diseases, all of which can be shown to be related to geography and to react to evolutionary pressures on much shorter time scales.

With that as background they make a couple of (they expect) radical arguments, and explain a few things that seemed puzzling before. Their first radical argument is that modern humans probably interbred with Neanderthals in Europe, and that therefore, the populations that left Africa probably got a significant contribution from them. I thought they did a reasonable job of demonstrating opportunity, plausibility, and some indications from recent genetic studies that some variations were introduced in the right time frame to have come from Neanderthals. This argument was presented as if the authors expected people to be "outraged at the charge", but it seemed sensible and plausible to me.

The radical argument that I expected to have trouble with is the claim that there's something genetically different about the Ashkenazi Jews. One of the members of the reading group I attend has been making this point for years, and I've been passively resisting it for just as long. Well, Cochran and Harpending put an end to that, easily and without much fight. They showed that the time-frame isn't extreme, that there were sufficient environmental pressures to push for particular changes, and that there's a reasonable case that the Ashkenazi were genetically isolated for long enough for the hypothesized changes in intelligence and susceptibility to diseases to have arisen. They add in some evidence that the diseases specific to the Ashkenazi are tied to genetic changes in neuron development to hammer home the point that the changes in brain function and disease susceptibility are probably tied together. The fact that we already knew (even if we didn't admit it in discussions of evolution) that Tay-Sachs is specific to Ashkenazi and is of genetic origin helps cement the case that evolution has continued into the modern era.

If there had been any remaining doubt that there are genetic predispositions to varying intelligence by race, this pretty clearly puts them to bed. I still agree with the sentiments Les Earnest expressed in his 1989 article Can Computers Cope with Human Races? It's not clear that there's anything useful to be done with this fact, and it's pretty clear that many people mis-apply the fact, but it's a fact none-the-less.

Explosion makes a fairly strong case that evolutionary stasis doesn't happen without a static environment. Humanity hasn't been static over the last 100,000 years--there have been many changes in our way of life over that period, and the changes keep accruing faster than evolution has been able to catch up. Our bodies are still adapting to changes in diet since the agricultural revolution and continuing changes in the sources of our food. Our susceptibility to disease has varied dramatically across populations, and the differences haven't settled down yet. There are still vast differences in hygiene between first world and developing nations and many places in the world where populations are sparser and provide fertile ground for new diseases to arise or transfer to human hosts. There is less of a case for sufficient continuing genetic isolation to drive differing evolutionary pressures for intelligence, but there is certainly pressure for differing intellectual capabilities than were selected for 200 or 500 years ago, much less 1000 years ago.

We haven't finished adapting to the civilization that surrounds us, and the form of our civilization continues to change. We shouldn't expect continuing evolution to be visible on a human time scale, but we shouldn't be surprised that many of the differences among people can be explained as the effect of different evolutionary pressures on our ancestors. In some cases, like disease susceptibility, we can take advantage of it if we stop treating it as tainted information. In others, as race, we should in most cases pay more attention to the abilities of individuals, rather than to the predispositions predicted by apparent racial categories.

Nick Humphrey: Seeing Red

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Chris Hibbert

Nick Humphrey's Seeing Red is another attempt to explain consciousness, but from a slightly different angle. Humphrey clearly understands what it would mean to produce an explanation, and makes some progress on the task. Humphrey starts not with what it means to think about something or to be aware of something, but with the more fundamental fact of perception of something outside of ourselves. The focal perception is of a red sensation. There's something in your environment that produces the perception of redness. What just happened to you? What does it mean that it makes you sense the presence of red? Why can you share this experience with others who also perceive the redness or with people who aren't present but still understand what you mean?

Humphrey first concentrates his attention on the internal details: first you perceive, then you become aware that you are perceiving. You may put words to the sensation or you might not, but Humphrey takes pains to point out that the perceiving and awareness are two separate facts. If you then talk to someone else about the perception (which you can do because you're aware of it), then of necessity each of you has some kind of "theory of mind"; a mental model that represents the fact that whatever it means to perceive, you are something that can do it, and other people are capable of the same thing.

Having set these aspects of reality out, Humphrey goes to some trouble to demonstrate that they are separate facets of reality, and all need to be present in an actual explanation. He talks about things like 'blindsight' and optical illusions in order to convince people who aren't keeping up that all these things are distinct facets of reality and need to be distinct in any explanation.

In the second half of this small book, Humphrey explains that consciousness arises out of the neurons in the brain, and that their role is to reflect and represent what's really going on in the world. He wants to present an evolutionary explanation of why they arose, but he only really justifies the fact that they are useful. The mechanism and history that allowed a feedback process between sensing and acting to arise and be passed down as a competitive advantage eludes him. And he doesn't have much to say about how the neural substrate might represent facts about reality in such a way that it could actually be useful to an aware, active agent interacting with the world.

My bottom line is that this book lays out the issues fairly clearly in a way that ought to be interesting and convincing to someone who is just starting to think about how consciousness might work, but the explanations fall short of answering the deeper questions. On the other hand, Humphrey's stated goal in the book is to show that consciousness matters and that it can be productive to think carefully about it. That much he succeeded at.

James Flynn: What is Intelligence?

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Chris Hibbert

In his new book, What is Intelligence?, James Flynn tries to explain a few things. First he wants to explain what intelligence is and what its components are, second he wants to explain his new understanding of the Flynn effect, and what it implies about genes and intelligence, and thirdly, he wants to convince us that what The Bell Curve said about intelligence and race isn't supported by these new understandings. He succeeds admirably at the latter two; his success in explaining the nature of intelligence is limited.

For anyone who isn't familiar with the Flynn Effect, I'll repeat the findings briefly. More than two decades ago, Flynn noticed that IQs have been going up over time. About 3-5 points per decade, independent of culture, location, sex and race. The people who write intelligence tests have known for quite a while; they reissue their tests every decade or so, and "re-norm" the results. Since the definition of IQ is that 100 is the average score across the population (which population? That's a separate question; read the book if you want the details) they have to measure the results for a standardized group, and set the scoring so the current test will give the right results.

One of the consequences that matters to Flynn is the implication for death penalty cases, which he has been brought into recently. The implication is that if you give someone a test that is 10 to 15 years out of date, their score will be artificially inflated, since they are being measured by the norms of an earlier period. The obvious argument among defenders of capital cases is that death row inmates should be tested by up-to-date standards so as not to inflate their scores and accidentally rate them as competent to stand trial when they are in fact borderline or below it. Flynn points out that it's common for schools in disadvantaged areas and for prisons to not replace their existing stock of test booklets when a revision is issued, so they can be significantly out-of-date, which artificially inflates the scores and negates one escape route.

Like all good scientific revolutions, Flynn starts with four paradoxes arising from the combined data about rising scores.

• Different sub-tests (e.g. vocabulary, spatial reasoning, abstract analogies, pattern matching) have shown different increases. What's different about the areas in which intelligence is growing the fastest?
• Given the size of the increase, why doesn't it seem clear in everyday interactions that each generation is significantly smarter? 20 years is almost 10 IQ points, so two generations is nearly 20.
• How did our ancestors get by if only 100 years ago, everyone was mentally retarded by current standards?
• The changes are so rapid that they can't be genetic, so they must be due to environmental changes, yet studies comparing twins raised together and apart show that environment makes little difference to adult intelligence. Why does the environment make so much difference in some cases and so little in others?

Flynn's resolution is that the environmental differences that matter are large-scale and societal. He also argues that the societal differences compound, so even though small changes are scattered throughout our schooling, entertainment, child-rearing practices, employment expectations, and hobbies, the effects can be pervasive. The area of change that Flynn pinpoints is reliance on abstraction. This turns out to be a common thread among the sub-tests with the highest increases. Our ancestors dealt with the world much more concretely, and modern child rearing, education and entertainment all exercise our growing competence at abstraction. The results from twin studies are dominated by society-wide practices, and show that which family one is raised in, or which schools one goes to don't matter nearly as much as which era, and which society. An agrarian society that doesn't expect its children to grow up and leave the farm raises them to focus on the here and now. Expectations change when horizons open up, and we should expect every society to undergo a Flynn effect as people expect the next generation to live in cities, work in information-intensive jobs, and socialize with people who aren't all doing the same work their ancestors have done since time immemorial.

Ultimately, Flynn's book provides a satisfying resolution to the problems raised by IQ differences. The implications of Murray and Herrnstein's The Bell Curve for racial differences have been neutralized. Not by ethical arguments or posturing, but by a careful analysis of the data. Murray and Herrnstein were led astray by the surface implications of the data when analyzed within generations. If they hadn't written up their analysis carefully and thoroughly, Flynn wouldn't have been impelled to revisit the data and produce a sounder conclusion. Murray and Herrnstein's conclusions weren't original with them; their contribution was their willingness to explain an unpopular idea carefully enough that its limitations would become visible when the right context became apparent.

Murray and Herrnstein's other conclusions still stand: modern societies do an extremely good job of separating out the (relatively small, we now know) within-generation differences in intelligence, and directing people to different pursuits and occupations. The consequences is a shortage of general problem solvers in areas where intelligence is less valuable, while our institutions evolved in circumstances where general problem solvers were widely distributed.

J. Phillipe Rushton: Race, Evolution, and Behavior

0.2 Chris Hibbert Race, Evolution, and Behavior

J. Phillipe Rushton's Race, Evolution, and Behavior covers a sensitive topic, racial differences, in a lot of detail, and with a heavy hand. Most of the book is overflowing with statistics and citations to an enormous number of references in quite a few fields by quite a few researchers. If the idea was to overwhelm the reader, I'll admit it was successful in my case. I eventually learned that I could skim the statistics, and look for prose summaries of the significance. Rushton didn't pay much attention to what it all means until near the end.

Rushton's main point is that there are several attributes on which there is systematic variation among the races, and his claim is that the consistency hints at a possible cause. He's mostly interested in convincing us of his pet theory of the cause of the differences. He's weighing us down with evidence to show us how consistent the inter-racial differences are. He mentions exceptions to the trends, but doesn't give them much emphasis, or provide plausible explanations within his framework.

The traits that Rushton focuses on include brain size, intelligence (as measured by IQ tests and other tests that correlate with g), maturation rate, personality, social organization, and reproductive effort. Other than intelligence (and brain size which is strongly correlated with it), and arguably social organization, these are not scales with a good end and a bad end, they're just differences. The consistency that Rushton focuses on is that whichever of these attributes you measure, you end up with whites in the middle, and orientals and blacks to either side. The story that Rushton wants to build out of that data is that the differences line up the way you'd expect if you tried to predict the direction from r/K evolutionary theory. (Basically, differential evolution in environments of scarcity and plenty; in this case, evolution in the tropics versus the northern latitudes in the Ice age.) He makes a fairly good case for the consistency; there appears to be something going on that puts orientals and blacks at two extremes and whites somewhere between them. But his favorite explanation doesn't seem to be strongly supported. It's roughly consistent with the data, but I'd need more explanation for the exceptions before I'll accept the case as demonstrated.

My biggest complaint about the book is about an important point, orthogonal to Rushton's argument, that he doesn't address at all. Rushton clearly knows that discussion of racial differences is a hot-button issue, and the reason that people care is not because of the difference the data will make to our beliefs about the evolutionary causes of the difference. It's a hot-button issue because accepting the data seems to tell us something significant about innate differences or tendencies to differ among people on aspects of behavior that matter to social policy. When Murray and Herrenstein addressed these issues in The Bell Curve, they were careful to give us the important caveat: the differences between the mean IQs are significant, but the overlap among the curves is large. That means that you can predict the average IQ of a group if you know the racial make-up, but you don't really know much about an individual from that detail. (Wikipedia has a nice graphic showing how much overlap there is among the curves. With the other attributes Rushton discusses (aggressiveness, impulsivity, law abidingness, life span), it's much harder to figure out what interventions might be called for if we knew the differences were significant and pervasive, but not knowing how much overlap there is between races on these measurements makes it hard for me to even tell whether they matter other than in discussions about evolutionary causes.

Another factor, relating to intelligence, that was brought up at the reading group, is fascinating and was completely unaddressed. Rushton says that American Blacks have an average IQ of 85, while in central Africa, the number is closer to 70. In the US, we have the feeling that we could immediately recognize someone with an IQ of 70 as subnormal, but if that's the average in sub-saharan Africa, then something else is going on, because you have to assume that 90% of the population is functional. So the IQ of 70 must mean something different than what we'd assume here, where it normally implies other deficits than just cognitive. It's not clear what an average IQ of 70 in a functioning population would mean. This casts some doubt in my mind on the usefulness of IQ for cross-cultural or cross-racial comparisons. The Wikipedia article makes similar observations.

As to Rushton's thesis, I remain unconvinced that r/K theory is the best explanation for the differences. r/K theory is well-established from studies of other animals, but Rushton isn't careful in marshalling his arguments to convince me that r/K with appropriate caveats for some unexpected cases provides a good enough match to the data. Wikipedia mentions several attacks on Rushton's thesis and methods, but no alternative explanations of note. That's fine; sometimes the facts you need for the right theory aren't at hand when you want them.

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