Book Reviews

enforces a one-child policy, introduced systems better explain the differences in postulate that, as Darwin said, all organ- in 1979. The government boasts that the level and quality of democracy’ (p. isms do their darndest to reproduce. 400 million births have been avoided, 248). Leaving North Korea aside, there The result is unsustainable population but abortions are indispensable and is not a great difference between the growth and the struggle for existence in the population is skewed toward governments of Singapore, Taiwan, which only the fittest survive. Oddly 60/40% male ratio in the younger South Korea, and Japan. And China, enough, this principle was no sooner generation. The only ostensibly demo- which Vanhanen styles ‘an extremely launched than European reproductive cratic east-Asian governments are deviating country’ (p. 248), is not so rates commenced a long term decline Taiwan, South Korea, and Japan. The much an outlier as the main Asian that continues today. Indeed, many first two have oscillated between stream because its population exceeds European nations, notably Russia, are in auhoritarian and democratic govern- that of all other east Asian nations by dramatic population decline. How can ments, while Japan has been governed about 1 billion people. It exceeds the this be reconciled with , by the Liberal Democratic Party since combined populations of the EU and and what are its implications for the 1955. Do these facts not refute the the . From these data I continuing advance of democracy? hypothesis that high IQ nations tend don’t detect a trend toward democracy toward democracy? Do ‘Asian values’ at the highest IQ level, but a split down 1 and published a detailed study of recent evo- perhaps better explain the discrepancy? the middle between authoritarianism lution, in terms of single nucleotide Vanhanen rejects this proposal because and democracy. polymorphisms, in their book The 10,000 it ‘cannot explain the extreme differ- The author does not include repro- Year Explosion: How Civilization Accelerated ences in the level of democratization ductive rates among his variables, yet . : Basic Books, within the group of east Asian countries they are significant for projecting 2008. Website: http://the10000year ... clear differences in socioeconomic national futures and for the evolutionary explosion.com/

The 10,000 Year Explosion: How Civilization Accelerated Human Evolution

Gregory Cochran and Henry Harpending. (2009). New York: Basic Books, 304 pp, US$27.00, ISBN: 0465002218. Reviewed by Rosalind Arden, King’s College London

The 10,000 Year Explosion, by physi- Graaf generator. It was exactly like in behavioral differences. Moreover the cist Gregory Cochran and population watching a physicist lecture at CERN: sky doesn’t seem to have fallen. What a geneticist Henry Harpending, should the excited gestures, the scribbled relief, we can acknowledge what must be required reading for students of scrappy slides with formulae, instead of be true — human groups vary in genetics, evolution, archaeology, the usual nancy-pants greater-crested noticeable ways for genetic reasons and and palaeontology. It is powerpoints with their horrid, vacuous that’s just fine. Perhaps our morality is stuffed with suggestions about recent bullet-points on pelagic backgrounds. sturdier than we surmise; very few human evolution; many of which are It was thrilling; the mile-a-minute talk readers, perhaps none, will become testable, some of which may even be (which over-ran) was electric; the ideas cannibals, bigots or sadists by reading right. But it is not the proportion of hummed with originality and credibil- this book. So what are its big ideas? right versus wrong hypotheses that ity. I’m sure many left the room, as I The central narrative is that evolu- makes it a must read; it’s because the did, thinking ‘every department should tion has not stopped; in fact it has book is an implicit primer on how to have one of those’ — if only there are likely sped up. The reason is forehead- think expansively, speculatively and enough to go around. slappingly simple: mutations hit larger imaginatively about the big questions Two key features make these scien- mating populations more often than in our cultural history. tists (Greg and Henry) special. First, smaller ones (random arrows hit larger I first fell under Greg Cochran’s they are not afraid to be wrong. targets more often than small targets). spell when he gave a talk at the Second, they are most impolite; in Even if most mutations are neutral or a few years rebutting ‘received wisdom’ they make harmful, some are beneficial. These ago. He was arresting. How could our clinging to it seem silly. In this arose more often in the big, settled dressing be such a mystery? Shirt respect they are almost Swiftian. communities generated by farming, buttons were all hooked into the Where we like to avow that there are than the smaller, more nomadic or wrong button-hole, the sagging ‘50 no genetically based population differ- hunter-gatherer communities. A muta- cent’ trousers, huge spectacles last ences, they present strong evidence for tion that promotes lactose tolerance cleaned in the Miocene, hair by Van de such differences: not just in looks, but into adulthood confers a huge benefit

Twin Research and Human Genetics August 2009 409 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.139, on 28 Sep 2021 at 21:33:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1375/twin.12.4.409 Book Reviews

to farmers, but not to hunter-gather- basis for making assertions about nation: the occupational possibilities ers, so even if such a mutation did within and between group differences. for the Ashkenazim in Christian arise among them, it would not Group differences don’t frighten Europe were limited to those which spread. The same is true for mutations Cochran and Harpending. Nor does required abstract reasoning. Those affecting personality and intelligence: mating across species. who were good at jobs of high com- the advantage of any particular change When it got going, agriculture plexity, especially financial work depends a lot on the ecology includ- triggered many changes. One of them including money-lending, became ing the social dimension. A puzzle was a dramatic increase in population wealthy and supported large families remains, why did farming get going in size. Size brought its own hazards. who survived. Those who couldn’t do the first place? Whereas warfare had been a major, if these intelligence-saturated jobs left no During the previous interglacial, not leading, cause of death in adults, heirs. Persecution, then further occu- the Eemian ~131,000 years ago, infectious disease became the Grim pational restriction, led to even more farming never developed. Yet in the Reapers’ new best friend. Immuno- intense selection on high intelligence. Holocene, which began around 12,000 competence, in the form of HLA Selection was rapid, it acted so fast years ago, it was invented every second diversity, hurried along behind infec- that genomic trouble brewed along Tuesday (at least seven times indepen- tious disease, huffing and puffing to with intelligence. Several diseases dently). Why? The wild and curly keep up. But in the New World, where occur at a much higher rate among proposal from our intrepid authors is the population density was lower, Jewish people of Ashkenazim descent, that Homo sapiens mated occasionally HLA did not evolve much diversity. these include Gaucher’s and Niemann- with Neanderthals. Some of those No wonder the death rate from small- Pick disease. Perhaps in the race to matings produced offspring with a pox in the New World was up to 90% enhance intelligence, evolution did fitness advantage derived from while the European invaders’ death not have time to purge the harmful, Neanderthal alleles. How silly is that? rate was only 30%. Cochran and pleiotropic side-effects. Again the Not so much it turns out. We humans Harpending’s genetic history contin- idea can be tested — is there any rela- do have sex with other species; cross- ues beyond disease, by discussing the tionship, in Jewish people, between species fertile hybrids do exist and causes and implications of normal intelligence and genes associated with there is some sketchy skeletal evidence variation of human mental traits these diseases? Are these disease side- supporting the thesis. Perhaps benefits within and between populations. effects of higher intelligence? from the Neanderthal ‘introgression’ Farmers store wealth; wealth is I’ve sketched cartoons of their triggered farming. Perhaps it didn’t; at always unequally distributed where ideas, but the authors have fleshed out least Neanderthal introgression is an there is phenotypic variation in the their hypotheses and set out their evi- empirically testable idea. We think of ability to acquire it, and social mobil- dential stalls very neatly. The journal evolution as taking place on very long ity. Variance in reproductive success papers on which the chapters are based time-scales. Could mental or physical increased in settled societies. But the are well referenced in a useful set of changes really have emerged since pathways to that reproductive success chapter notes. The book is funny, farming? The authors say that although vary between populations: different learned and engaging. It neglects sexual new complex adaptations may not traits are desirable in different places. selection (why oh why?) but it’s not have had time to evolve since the It follows that there is selection on hopeless since other books ably intro- advent of farming ~12,000 years ago, diverse personalities and cognitive duce Darwin’s other brilliant idea. there has been plenty of time for genet- abilities among various populations. The 10,000 Year Explosion is ically shallow, but phenotypically deep, For example, in East Asia the 7R allele replete with facts and ideas; we need changes. One only has to look at dogs. of the DRD4 gene (an allele associated more books like it. Cracking stories In just ~15,000 years of selection with ADHD) is almost absent, but are bumper to bumper; the historical we’ve turned wolves into Chihuahuas. importantly, alleles derived from the and cultural reach of the authors is It’s not all bad — we have created 7R allele are common. That suggests impressive. It’s a cultural genetics pot- Border collies too. The morphological that the 7R allele did not play well in boiler with a serious academic punch. changes are startling, but the behav- East Asia although it may have been If it sparks no real intellectual curiosity ioral ones even more so. Try asking a quite a benefit in other populations. in your students, worry about it. If wolf to watch the pram. Although Intelligence has also been under differ- nobody on the faculty is interested, 70% of dog genetic variance is within ential selection around the globe. you’re probably in a department where breed, and 30% between breed, who In the last two decades, Jewish there were, sadly, not enough Gregs to wants to argue that the average differ- people numbered around 3% of the go around. ence within Great Danes is larger than US population, yet they won almost the average difference between a Great 30% of the Nobel prizes. It’s not skul- Disclaimer (potential bias hazard Dane and a Chihuahua. The problem duggery on the Swedish selection warning): reviewer commented on is that until we know how allelic vari- committee, it’s because they are three chapters of the book prior to its ants relate to phenotypes we have no brighter. This book suggests an expla- publication.

410 Twin Research and Human Genetics August 2009 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.139, on 28 Sep 2021 at 21:33:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1375/twin.12.4.409