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May 26, 2003

Ridley's Riddles

Matt Ridley's new book Nature via Nurture has an interesting title-but the central thesis is rather prosaic, that the "nature vs. nurture" controversy is simply much ado about nothing, the line between the two is fuzzier than one might suppose because of gene/environment interaction. A more accurate title might be "Genome: 2003." Ridley's 1999 book, GENOME, was a meatier work, a bit longer and less fluffed up by the pretentious premise that he was attempting to transcend the nature vs. nurture debate. Steven Pinker in The Blank Slate covers much of the same material, at greater length, though again, he is weighed down by his fixation on the peripheral issues of the "ghost in the machine" (mind-material dualism) and the "noble savage."

Perhaps part of the problem is that books like these are aimed at a very general audience, all the way from science neophytes to those who regularly read books on evolutionary psychology and practicing scientists. The general audience must always be told that though the books might focus on biology-that is not the sum of who we are, but the building block from which we start. For instance, just because this blog focuses on genes, that does not mean that is "all we care about," rather, we wish to spotlight that aspect of our nature that is more difficult to speculate about in coffee shops because Psychologly 101 is much more likely to be in the educational arsenal of the typical person than Genetics 101 [1]. That complex emergent structures like family, clan, society, etc. have an influence in shaping who we are seems so obvious that I find it peculiar when people accuse those of us who speak of biology in the context of human nature as being "determinists," for of course we acknowledge that there are other aspects of humanity. It seems so clear & assumed that I simply don't want to start every discussion of biology with caveat on non-biology, just as every discussion on social/public policy doesn't begin with caveats on economics or other fields of possible interest or concern that serve as limiting parameters on the core discussion.

Ridley puts in his ten cents in one of the first chapters on the issue of human nature, that we are an animal like any other (sort of), titled The Paragon of Animals. He makes clear that man is a beast, a brute, though an exceedingly clever one [2]. Even the religious who believe that we are made in the image of god(s) must acknowledge the face of an animal looking back at themselves when they gaze at their reflections in a mirror-whatever the "soul" animates, the body is flesh and bone. Like his previous books, the aforementioned GENOME, but especially THE RED QUEEN and THE ORIGINS OF VIRTUE, the author uses animals to illustrate how behaviors we view as human in fact are rooted in our bestial inheritance. Ridley himself is a zoologist by training so he is on strong ground here, though I would wish he would divulge his own political biases, for he has worked for The Economist as a journalist for many years rather than a practicing scientist, and tends to mirror its neoliberal/libertarian orientation [3].

After the preliminaries, Ridley starts venturing into more controversial waters. One of the chapters has a rough sketch on Francis Galton, the thinker who triggered the eugenics movement, and he addresses IQ testing and Bouchard's twin studies. Yes, Ridley does go into the heritability of IQ. If you read GENOME this isn't a surprise, he touches upon this a bit, and even hints that there might be average differences between populations, though he does not come down on either side. He goes further in this book (perhaps this makes sense since he's had 4 years to go over the literature). Ridley admits that The Pioneer Fund backed Bouchard's study, but echoes the researcher's claim that it was because only they offered him the grant without strings that pushed for any conclusion after the data was collected. Ridley also mentions two things that make me think that he read a bit of Rushton-he trots out the correlation between head size (a proxy for brain size) and IQ (40%) and the fact that blacks have higher twinning rates than whites who have higher twinning rates than Asians (this last piece of data was what really opened me up to discussions on human biodiversity because it seems more than cosmetic in import). Though Rushton has been villified, milder versions of what he has asserted, that different groups of modern humans might have followed divergent adaptive strategies, seems to be percolating through the works of others now (Calvin and Wells for instance), though all without attribution and stripped away of the most explicit and socially offensive implications.

Much of the middle section of the book is a wide collection of recent studies that relate to biology, environment, and their intersection (developmental biology and epigenetic factors on the molecular level, etc.). Going back to twins, Ridley points out some of the traits that don't seem to have a strong genetic component, humor, food preference, social & political attitudes and religion. None of this is surprising, but one thing that might surprise some people, religious fervor does have a strong heritable component. What does this exactly mean? Well, if one identical twin is raised Evangelical Lutheran and another United Methodist, as adults, they might gravitate toward the fundamentalist sects that split off from their traditions, the Missouri Synod Lutherans and Free Methodists. "Religious fervor" is simply a subset of personality, which often has a strong heritable component [4]. I wouldn't be surprised if radical Leftists and Rightists who were atheists had twins who were Christian fundamentalists-"religious fervor" is probably an indicator for overall "zeal."

Then the author touches upon a topic that interests many people for different reasons: schizophrenia. Ridley explores the various theories and hypothesis that have been offered as causal agents. Scientists have long known of a strong correlation between twins, but since it is not perfect, there must be other factors than genes. Disease, time of year of conception, various prenatal factors, etc. probably all come into play. Ridley points out that many "brilliant" people have a history of schizophrenia, either themselves or in their families, a caution against those who wish to "purge" undesirables from the gene pool. Ridley also touches upon the prevelance of Asperger's Syndrome among geeks, and notes with some sadness that those who have the flip-side of it, lack of technical fluency but greater interpersonal skills, tend not be osctracized by society to the same extent [5]. Many "mental diseases" are probably multifactorial, and combine genetic predisposition with environmental triggers, so that nature & nurture act as a lock & key that open the pandora's box when there is a meeting of both variables. Additionally, Ridley emphasizes prenatal development, something all geneticists have to take into account in biological development as genetic changes dynamically in the womb can alter the mendelian substrate considerably. As the book progresses Ridley throws in issues like the mother's immune response to prior male pregnancies and the idea of "imprinting" in the context of language & incest aversion. Though both language and incest aversion have root genetic causal factors-they must be triggered by a particular social context, in this case, peer groups and close family members during formative years. To say that it is "nature vs. nurture" is obviously a bit much in this case-but rather nature + nuture => human. I find this to be a mundane and obvious point, but perhaps this is revolutionary to many people out there, because that is basically all that separates this book in emphasis from his previous work, especially GENOME.

Along the way there are stop overs at old favorites-Franz Boas, Emile Durkheim, Freud, Skinner & Watson, and so forth. The behaviorists are torn to shreds, the Freudians are laughed at and the neural connectionists are dismissed. Ridley tries to assert that some of these "nurturists" made a proper contribution to the sum of human knowledge-but I always get the feeling that much of what they contributed was either common sense or methodology applied later in a more fruitfull context or paradigm. Just like the old hereditarians were tiresome and simplistic, the old nurturists were also captivated by their one-size-fits-all paradigm, and while the determinists gave birth to fascism, many of the nurturists have assocations with the communists. In the end the sciences of man in the service of the state or ideology can be a dangerous thing-one generation's "scientific wisdom" is refuted in the next. In the context of chemistry or engineering this might be problematic, resulting in chemicals that might cause cancer or machines that malfunction, but when applied to societies the outcome is positively disasterous if it takes a wrong turn.

There are other nuggets of wisdom and tales of studies scattered from front to back. An obligatory chapter on the speculation about the origin of modern humans sits awkardly next to the prior chapters on evolutionary psychology today where they at least have flesh & blood subjects-and a dismisal of racial differences is tacked on in a short and sweet page after discussion on possible genetic differences between modern & archaic Homo sapiens that might have contribued to The Great Leap Forward (Spencer Wells talked about this sort of thing in Journey of Man as well, I suspect that all of these writers have a small cabal of book agents that have a mandatory TODO list). This is not a reference book-the studies will be vindicated or overturned in the next few years, and the prose is a bit less enchanting than that of GENOME (a book that I think doesn't take itself as seriously). Additionally, the "Nature via Nurture" angle isn't very exciting at all. On getting this book I thought Ridely was going to speak of the changes that culture has on biology (genetics) in more detail. He hints at this in GENOME, but doesn't seem willing to go much further. In fact his most explicit reference is a negative in the shape of Konrad Lorenz, prominent geneticist and enthusiastic Nazi, who wondered if humans were becoming "domesticated" and therefore as sickly and infantile as many domestic animals are in comparison to their wild relatives. Well, what of it? Ridley adds a sentence here and there about the possible changes that the Neolithic Revolution and the coalescence of large human population centers might have had on the human personality, or selection for various types of personality, but he does not keep the ball rolling. Is it any surprise that myopia rates are highest among Jews and Chinese, lowest among blacks? To certain people perhaps. To most, no. What are the implications of that fact that different populations practiced different forms of agriculture and engaged in different lifestyles for thousands of years?

Ridley is not craven in that he does not attack those who have attracted to themselves negative press over the years because of their boldness or lack of Oxbridge tact-he echoes The Bell Curve in suggesting that a perfect meritocracy based on abilities would be anything but "fair," as genes (alleles) are distributed unequally in individuals through the population. He points out the peculiarity that nurture, in the form of prenatal and early childhood experience & development, can be fixed so that its effects are unchangeable in later life, refuting the idea that nurture by definition is "malleable" while nature is set-in-stone. This book is an extension of his work over the years, a compilation of studies that have been ongoing and progressed since GENOME, tied together by an interesting premise that's really not that revolutionary.

Let me add also that the typeface is large and at 285 pages it's a quick read-especially if you've read in this area much. The last few chapters are pretty boring-he tries to be a political philosopher & wise man, but he should stick to reporting other people's research, that's what he's good at. The ideas presented in the meat of the book aren't difficult, and an intelligent lay person doesn't need Ridley to organize and systematize their thinking for them.

On a final note, the jacket picture indicates that he's lost a lot of hair since GENOME came out. Probably he finally got a new picture taken. Why does it matter? As James Watson responded when asked why Rosalind Franklin's appearence mattered so much, "because it does."

[1] We are clever, but language, math, and much that "sets us apart" are emergent properties of our neural hardwiring, in other words, rooted in our animal nature. We are a beast as any other, and just as the baby chick is born able to scurry after its mother if she's there to tug at them with her maternal apron-strings, we are born babblers who have a propensity to talk when placed in the correct environmental context because we have the genetic building blocks and instincts.

[2] Human nature is what it is-though we might err on occasion in the science, it almost certainly exists. It is not relevant what our politics are, though it might be relevant to policy prescriptions that follow from our norms, so whether we be Left or Right, religious or not, an understanding of the animal substrate from which our emergent properties issue is important.

[3] I share this position in the ideological typology myself-but in the interests of full disclosure, one should put that on the table. Ridley's attacks on Marxists for instance almost certainly have a bit more bite because he disagrees with the dastardly Leftists on normative grounds as well as their addiction to bad science (from Lysenko to Steve Rose). And of course the Right has also a sweet-tooth for rotten-science at times....

[4] From a human biodiversity perspective I would be curious to see if there are differences in "religious fervor" between the races. Neuroscientists have found evidence of a "God Module" in the brain, so there are multiple avenues of exploration out there if people choose to follow them.

[5] But those that have tasted the sweetness of mathematical elegance, and I have only have a small dose of this ambrosia, might accept social ostracism as the price one pays for this particular nirvana.

Posted by razib at 01:59 AM