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Data d'iscrizione : 04.02.09
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|Oggetto: Race: No Such Thing … or is There? Mer 17 Nov 2010 - 11:08|| |
FONTE: http://www.skeptic.com/eskeptic/05-02-18/ Race:
No Such Thing … or is There?a review by Paul R. GrossWhat response would you get were you to ask almost any college student ormember of the current, self-identified American intelligentsia, “What is thissociety’s most serious problem?” Almost certainly, a large proportion of youreligible interviewees would give this answer without hesitation: “Race!” Buthere is an oddity: The same interviewees who answer your question with “Race!”will assure you, also without hesitation, that there is no such thing. Theywill maintain that for humans the concept of “race” is meaningless: that thereare no biologically significant human group differences, hence no human races.This is a public catechism: it is recited regularly, with conviction andfeeling, in the media and in the social sciences. The au courant, includingwell-known scientists and a good many official voices of science, insist thatrace is—speaking of biology or genetics—a recent illusion, fostered by Europeanimperialism and triumphalism. If pushed, most respondents will try to invokesome authority on this, although of course the vast majority has not understoodor even heard of the relevant science. The reference is usually to “modernbiology.” Or, if the respondents have actually read some popular writing on thesubject (or watched Race: The Power of an Illusion, the much admired 2003 PBS documentary), they will appeal to some suchvisible scientific name as Gould or Lewontin, or to one of the leaders of theHuman Genome Project, or to a science journalist at, say, The New York Times.Why then do governments set so bad an example? Why do they appear to insistthat race does exist—as evidenced by the requirement that we specify, interalia, our race (choose one of three? of nine? of seventeen?) in respondingto the census-taker, or when completing an application for admission, biddingfor a contract, or being tested for a job? The answer you get, if you get oneat all, will take this form:“Well, there is no such thing as race. We’re all the same, and the littledifferences in various competences noted among us are due to upbringing,lifestyle, unequal social services, and the like. The differences we see are nomore than skin deep; any difference we can measure is socially constructed.But: bad people argue that we are not all the same. Therefore we must assembleand keep data and records on this false category—“race”—so as to defeat theracists and to undo the social evils they propagate.”Did you follow that? If not, don’t worry. That explanation is incoherent.There has long been the need for a scientifically reliable, accessible tradebook on the biology and anthropology of human differences, on what the researchactually says about them so far: about group variations in human genetics,morphology, and physiological function—and how those variations, such as theyare, must have arisen in the course of our species history. An epitome thereofis what Vincent Sarich, a biochemist and anthropologist, and Frank Miele,Senior Editor at Skeptic, set out to produce in their compact volume Race.About the relevant qualifications of this pair there is no doubt. As aneditor of Skeptic, Miele is no stranger to controversial issues in the socialsciences; in fact, he co-organized and co-hosted a symposium at Caltech on raceand I.Q. when The Bell Curve was published, and another symposium onrace and sports when the book Taboo was published. Sarich, a professor of anthropologyat Berkeley, was one of those young turks associated with the distinguishedBerkeley biochemist Allan Wilson, who, forty years ago, first applied the thennew molecular-level understanding of genetic change over time—the “molecularclock”—to the problems of primate classification and evolutionary history. Theyattacked the problem of genetic relationships and the timing of speciationamong the apes (including us). Sarich contributed to the eventual recognitionof the close relationship between gorillas, chimpanzees, and humans, and, moreimportantly, of the genetic difference—the genetic “distance”—separating thesespecies.Such a distance translates directly to a time of evolutionary separation.This work, expanded and refined in succeeding decades by the explosion of newmethods in molecular genetics, especially the shift from studies of proteinpolymorphisms to direct study of the genes, established the chimps as ourclosest relatives and the age of our own lineage at not more than five millionyears.“Race” is a word used widely and traditionally in biology to identifysubpopulations within a species, that is, varieties, extended families, fuzzysubsets of individuals of common descent, sets more or less differentiable onefrom the other by appearance and/or behavior. It is no surprise that races orrecognizable varieties in other species turn out to be distinguishable—althoughnot necessarily easily—at the level of genetics. To put this another way:obvious external differences among the races of a plant or animal species turnout to result from genetic differences, although those can sometimes be subtle.But of course this must be so! For a race or variety to persist in time, itsobvious distinguishing traits must be to some significant extent heritable. Andif heritable, the traits must reside ultimately in genes (or more likely) incombinations of genes. “Traits” are the products of gene sets—genomes—acting inparticular environments over particular life histories.The book’s title announces that Sarich and Miele recognize human groupdifferences, and that however fuzzy these sets may be, they are stillsufficiently stable as biological subpopulations, varieties, extended families,and “races” to be identified as such. Which word one uses doesn’t matter: thephysical reality does. They argue that the recognition of group differences, ofraces, among humans is very ancient, a cognitive capability (i.e., not aninvention of capitalism or colonialism, as is claimed by many politicallycorrect commentators), of a piece with other category-making competences weshare. The burden of the book’s central scientific sections is that thosedifferences have a highly plausible evolutionary (and therefore genetic,biological) basis. Far from minimizing the significance of group differences,the relatively short history of our species implies that they must have beenvery strongly selected for in the several different environments in which ourancestors first flourished. None of which, as the authors insist (perhaps invain) is any excuse for racism or racial discrimination.It is not hard to predict the response to this book; not just the generalresponse, but the scientific, technical one. For here, as in no other domain ofcontemporary science except, perhaps, in global climate research, politicalcorrectness reigns. There will be denunciations of Sarich and Miele; it hasalready begun. The general-professional weekly magazine Nature, based inLondon, is one of the two world-class journals of its kind (the other is Science,based in Washington). Nature commissioned a review from the leftishhistorian Robert N. Proctor, who relates the argument of this book, atgratuitous length, to questions of racial injustice. He connects, and therebydismisses, its claim for the reality of race to the works of such often-abused“raciologists” as Arthur R. Jensen and J. Philippe Rushton (with whose work infact this book has very little to do). He describes the case made by Sarich andMiele as “an exercise in bombast and overstatement”; and, remarkably for thisdistinguished science magazine, he offers no analysis of the scientificarguments that are the core of the book. But in Race, those arguments dolead with hard, new, molecular-genetic data to a general conclusion. Here is arecent, independent statement of it:[W]hen the taxonomic term [race] is used consistently across species, it’sdifficult to see any justification for the common assertion that human racesare merely “social constructs.” The motivation behind the assertion is apositive one, but denying biological realities at the outset is unlikely tolead to productive social dialogue on coping with human differences.
— J. Goodrum. www.goodrumj.com/RFaqHTML.htmlThere is no bombast in Race. It is an effort to define for thegeneral reader, in broadest terms, those features of human genetics andanthropology testifying to a surprisingly recent origin of our lineage, butalso to a long interval (before the present) of sufficient geographicseparation of human subpopulations to have given rise to the currentlyrecognizable races. The message is the opposite of typology: among the races ofman, now that we can move freely over the planet and because we are a singlespecies, able to interbreed, differences will become steadily less marked, thesets fuzzier. Eventually, in a distant future, they will disappear. Barringworld-wide catastrophe, the prospects for re-segregation and new raciation arenil. But the differences acquired in our evolutionary history haven’tdisappeared yet. I know of no other popular work that makes this scientificcase so simply and places it so clearly in social context as Race.Would that it had been better edited! The publisher seems not to have investedmuch effort in bringing the separate contributions of the co-authors into tonalconsonance. And the courageous decision on the part of the authors to publishsuch a book would have justified filling out and documenting more fully thecore scientific argument. It is perfectly sound so far as it goes, butnevertheless sketchier than it needed to be given the commitment to book-lengthexposition. Still, the primary literature is available for those who care andknow how to examine it. The best summary of its conclusions is like the onequoted above: Human subpopulations are “races”; they exist. They are familialsubdivisions of the one species, Homo sapiens, to which we all belong.General readers who wish to be informed on the biology of race, in preparationfor the next official hyperventilation on the subject, will do well to startwith this book.Paul R. Gross is University Professor of Life Sciences, emeritus, at theUniversity of Virginia. His latest book, co-authored with Barbara Forrest, is Creationism’sTrojan Horse: The Wedge of Intelligent Design (Oxford University Press). Heis also the co-author (with Norman Levitt) of Higher Superstition: TheAcademic Left and Its Quarrels with Science (Johns Hopkins UniversityPress). TheAdaptionist Yardstick:
Rethinking the Social Implications of Sarich’s and Miele’s Fast-TrackMicro-Evolutiona review By Alondra OubréIn Race: The Reality of Human Differences, Vincent Sarich and FrankMiele attempt to prove the existence of human biological races in a discoursethat challenges the claims made in the PBS documentary, Race: the Power of an Illusion. Drawing on research in paleoanthropology, molecular anthropology,genetics, and to some extent, history, Sarich and Miele endeavor to trace theorigin of race as a biological construct. They claim that “human racialdifferences are both real and significant,” not only in regard to physicaltraits, but also (and perhaps more importantly), to cognitive and behavioraltraits. Sarich and Miele assert that human social behaviors, which they contenddiffer along racial lines, are functional adaptations that emerged fairlyquickly in each “race” as a result of natural selection.While much of their presentation is based on well-known scientific studies,their work is distinguished by their seminal claim that contemporary biologicalraces of modern humans, Homo sapiens, evolved rapidly within a time spanof only 50,000 years. The notion that modern human races are not more than50,000 years old, and perhaps only 15,000 years old, represents a radicaldeparture from the conventional wisdom that until quite recently has dominatedthe field of human bioevolution. Sarich and Miele offer noteworthy findings tosupport a revised, indeed a considerably shorter, timeline for the making ofmodern human “races” (or, more accurately, geographical mega-populations).However, it is their interpretation of what a revamped timeline of thissort signals for “racial adaptations”—alleged race-based functionaldifferences—that potentially places Race: The Reality of Human Differencesin the controversial realm of racialist writings—the genre of modern scientificracism. Race meets the main criterion that defines a pro-race work. Itincisively embraces the perspective that human races are valid biologicalcategories, despite the fact that they remain fuzzy sets, at best, withoutclearly defined borders.Yet it may be unfair to label Race as intrinsically racialist simplybecause the authors maintain that human races are a biological reality. To theircredit, Sarich and Miele base their conclusion not on a whimsical ideologicalstance of fear-based “race realism” (as some folk in the pro-race camp labelthemselves), but instead on a broad (though arbitrarily selected) cross-sectionof published research in biological sciences. Nonetheless, the relevance ofsome of their supporting evidence is open to debate. Codifying selectiveresearch findings that appear to lend credibility to one’s hypothesis is onething. Formulating a compelling theory that successfully explainscontradictions to one’s own hypothesis (in other words, that can account foranomalies in various sets of data) is quite another.In a casual journalistic style designed to entice the average lay reader,Sarich and Miele cover a wide array of topics which, though pertinent, are notwell integrated into a cohesive thesis. Although the book is one of the latestadditions to scientifically-informed books on race-realism, it lacks the focus,cogency, and conviction, if you will, of writings in the “new racial science,”perhaps best embodied in Richard Herrnstein’s and Charles Murray’s 1994 TheBell Curve.As staunch proponents of the race concept, both Sarich and Miele claim thathuman races are biological phenomena and not, as those in the anti-race campproclaim, only social constructs. Sarich and Miele hold impressive trackrecords in their respective fields of academia and journalism that should makethem, individually and combined, qualified to write this book. Sarich, afterall, attained widespread acclaim in the scientific community after he and histhen senior co-worker, Alan Wilson, of the University of California atBerkeley, recalculated the evolutionary timeline of the ape-hominid divergenceusing immunological data (in this case, proteins) rather than fossil evidence. 1 Sarich (whohas graduate level training in chemistry) was one of the first physicalanthropologists to apply quantitative laboratory techniques used in biologicalsciences, particularly molecular biology, to paleoanthropology—the study offossil remains of human ancestors. Sarich has earned a legitimate place in thehalls of biological anthropology as that rare icon who (at least during theearly part of his career) helped catalyze the cross-fertilization of severalfields, namely biochemistry, genetics, and osteology.Although Sarich’s critics may point out, and correctly so, that hisempirical research experience is limited, he is nonetheless well-respected byhis peers across the political spectrum for his intellectual contributions totheoretical and conceptual developments in molecular anthropology. On more thanone occasion, Sarich has been right in his predictions—his “scientifichunches”—even after his colleagues thought him wrong. For example, during the1990s Sarich insisted that the mitochondrial DNA (mtDNA) timeline estimated forthe divergence of human races (or more accurately, human populations) waslonger than that projected at that time by Alan Wilson, Mark Stoneking, andRebecca Cann. Sarich appeared initially to be way off the mark, but the dataeventually proved his position to be correct. In an analogous situation, overthe past decade Sarich has publicly stated that the timeline for themicro-evolution, or differentiation, of modern human races is much shorter thanscientists ever thought possible. 2 As theresearch summaries presented in Race reveal, once again Sarich’smaverick position on a temporal event in human bioevolution may have somevalidation, even in the face of initial opposition.In like manner, Frank Miele is not just another science writer. Miele’scurriculum vitae is several cuts above the vast majority of sciencejournalists, particularly those who focus on race and human evolution, forseveral reasons. As Senior Editor of Skeptic magazine, Miele hasinterviewed a coterie of highly public (if not controversial) scientists,including E.O. Wilson, Charles Murray, Richard Dawkins, and Arthur Jensen.Miele’s knowledge of evolutionary biology, including its contentious spin-offfield of evolutionary psychology (and its sister field, sociobiology) is notentirely self-taught, however. Earlier in his career, Miele pursued graduatestudies in psychology, including subfields of behavioral genetics andpsychometrics, at the University of Georgia. During his tenure as anundergraduate student majoring in psychology, he was published in journals suchas Mankind Quarterly (which, incidentally, is one of the premier voicesof academic racial science). More recently, Miele has collaborated on scholarlyprojects with Richard Lynn, a British racial scientist and eugenicist.Regardless of any controversy that may surround Sarich and Miele, thepivotal issue at stake here is not whether or not human races per seexist, regardless of what biological criteria are used to define a race.Rather, the crux of their book, I submit, is the assertion that over the past15,000 to 30,000 years, modern human races evolved different sets of behavioraltraits because each race was subjected to differing ecological selectionpressures. Many experts agree that natural selection was the predominantDarwinian force that determined which traits were adaptive for a givenpopulation, or local geographical race, in a given environment. According toSarich and Miele, however, natural selection not only shaped the physicaltraits that distinguish different populations, but it also drove the emergenceof certain social behavioral patterns that (allegedly) vary from one “race” toanother.The implications of Sarich and Miele’s contention are staggering. If true,they suggest that what appear to be ethnic behavioral styles are linked more toinborn racial genetic tendencies than to nongenetic causes—that is,environmental and developmental causes. In the tradition of the post-Jenseniancontemporary racial scholars, Sarich and Meile imply, rather meekly, thatethnic disparities in educational, economic, vocational, and social achievementare the result of race-based differences in physical and behavioraltraits. Furthermore, they maintain that because these traits evolved throughnatural selection acting on the level of the population (which for them istantamount to race), social behaviors are generally fixed and unchangeable inany population. The authors make this assertion while ignoring a wide array ofenvironmental constraints as well as the impact of environmental influencesknown to affect human developmental biology, including the soft-wiring of thebrain.If Sarich and Miele’s goal is to garner praise from their own choir—“hard”and “softer” race-realists alike—for an eclipsed (and thus potentially distorted)canon of the origin of modern human races, they may have succeeded. If,however, their intent is to advance a substantive, data-driven argument for theevolutionary-genetic origins of race-based behavioral traits—traits which theyseem to think are “fixed” by natural selection—then they have short-changedtheir readers (on “both sides” of this fierce debate). The predictive power andscientific valence of their assertions must ultimately be gauged by thestrength of the replicable empirical evidence used to buttress their arguments.In the final analysis, Sarich and Miele may have failed to persuade asignificant portion of their readers not because they have taken a (presumably)politically incorrect position. Rather, their treatise falls short because theyhave opted to pander a “mainstream public” that is (understandably) irritatedby growing ethnic gaps in social performance rather than uphold the rigor ofthe scientific process. Although portions of their presentation may beentertaining (especially to dog lovers), Sarich and Miele ignore a wealth ofpertinent research findings that must be considered in any discourse on groupdifferences, particularly differences in such highly valued human traits asintelligence and social behaviors.Regardless of one’s position on the race-genes-and-ability debate, omittingsalient counter-findings that go against the grain of one’s own a prioristance can severely compromise the scientific method. It can impede inductivereasoning, a quality critical to hypothesis testing. And it can renderineffective parsimonious interpretations of the available evidence as a wholeneeded to construct valid scientific models.There are several lines of counter-evidence that cast doubt on, if notpatently refute, the validity of Sarich and Miele’s hypothesis that human“races” are genetically predisposed to varying levels of cognitive ability andpro-social (or anti-social) behaviors. This review focuses on the validity andparsimony of the authors’ hypothesis that human races vary in their innatepredispositions toward certain social behaviors. It addresses their idea thatalleged behavioral tendencies in ethnic groups are rooted in racially-linkedadaptations to varying ecological environments.More importantly, this critique challenges Sarich and Miele’s assertionthat presumed race-based behavioral adaptations that occurred during the courseof human micro-evolution are necessarily a direct outcome of natural selectionand, therefore, are generally fixed in most members of a racial group. Itshould be noted, however, that Sarich and Miele do allow for individualexceptions to what they call race-based behavioral proclivities. For thisreason, they endorse a meritocracy in the United States that rewardsindividuals on the basis of individual achievement, regardless of theindividual’s “racial” heritage.TheSarich-Miele Proposition:
Fast-Track Human Evolution As Evidence of Race-Based Behavioral AdaptationsIn order to evaluate the validity of the Sarich-Miele hypothesis, we mustconsider not only the supporting evidence presented by the authors, but alsosalient counter-findings that the authors have ignored. This critique considersfour crucial issues within bio-evolution that bear directly on the validity, orlack thereof, of Sarich and Miele’s hypothesis about inborn, race-basedbehavioral traits.1. Population-based (orrace-based) differentials in the selection-driven functionality of physical,behavioral, and cognitive traitsSarich and Miele propose that natural selection explains the origins ofalleged behavioral differences along racial lines, yet, they never answer thequestion (in fact, they never even raise it): How do we know for certainwhether a trait evolved through natural selection or instead, through a neutralevolutionary mechanism of genetic drift? This question (as well as any answerswe may offer) is fundamental to understanding the adaptive significance, ifany, of population-based (or race-based) differences in functional traits.Many experts maintain that although natural selection plays a critical rolein the evolutionary origin of many traits, it is not the driving force behindall biological phenomena. In fact, according to some evolutionary biologistswho conduct empirical field research, genetic drift is typically assumed bydefault to account for most traits. Proving that natural selection is involvedin the origin of a particular trait is a complicated process. Given thecomplexity of natural selection, it is not surprising that biologists cannotascertain if there are long term differences in traits that have evolvedthrough natural selection versus those that emerged through neutral selection. 3There are other enigmas that must be sorted out as well if we are toidentify the features that distinguish natural selection from neutralselection. For instance, genetic drift tends to be more influential in smallpopulations while natural selection is more powerful in large populations. Themicroevolution of human races that occurred over the past 15,000 to 30,000years affected smaller human populations. At the same time, however, naturalselection had a momentous impact on the evolution of certain anatomical andphysiological traits in larger geographical populations. Both genetic drift andselection could have operated in tandem to initiate the emergence of differenttraits in the same populations, or in clusters of geographical populations.Positive natural selection increases fitness, which is measured in terms ofsurvival and reproduction. However, natural selection may act on differentlevels of biological organization, even simultaneously at times. Classicbioevolutionary studies emphasize the influence of natural selection on individualorganisms, populations, and even species. Yet, selection can also act at thelevel of the genome, chromosomes, and genes (DNA sequences). 4Sarich and Miele’s treatise may have been more scientifically credible ifthey had clarified, even briefly, the limitation of our current scientificunderstanding of natural selection as the ultimate determinant of racialadaptations. To call for this clarification is neither to deny or espouse theexistence of human races. Rather, it is a plea for scientific accountability:presentation of balanced pro and con evidence on the presumed functionality ofrace-based traits, particularly behavioral traits which the authors speculatediffer along racial lines.2. Population-based (orrace-based) differentials in life history traitsSarich and Miele do not examine the multifactorial causes—and the delicateinterplay between biology and environment—that best explain populationdifferentials in life history traits, such as rate of sexual maturation,fertility and birth rate, average number of births, and longevity. On the otherhand, had they thoroughly examined the literature, they would have uncoverednumerous inconsistencies in studies which show one of two things: eithernatural selection is not pivotally involved in the evolution of alllife-history traits in human races; or life-history traits vary within thegeographical mega-groups that Sarich and Meile insist on calling human races.Consider, for instance, the rate of sexual maturation in African Americangirls, which is considerably faster than in girls in raised in various Africanpopulations living in Africa. 5 The mixed-race ancestry of African Americans does not account for thisphenomenon. Instead, the differences in these rates appear to be linked todevelopmental biology.In a similar vein, Sarich and Miele cite published studies on “race andbrain size” without ever mentioning the well-known limitations of thesestudies. According to Michael Peters of the University of Guelph in Canada, andhis colleagues, researchers who indiscriminately use only one formula formeasuring human skulls of different shapes are more likely to make systematicerrors in measuring brain size. 6 Forexample, the German Formula gives a smaller average brain size for male Blackswho have dolichocephalic, or long-headed, skulls. There is a wide amount ofvariation in skull shapes among people of African descent—even within a singleAfrican ethnic group, or local population. Peters and his co-investigators notethat the solution for producing accurate calculations for cranial size in Blacks,in particular, is to use multiple cranial size formulas. For instance, the Ainuformula places more weight on the length rather than the breadth of the skull.In one study, the cranial size of Black skulls was 1359 cm3 when using theGerman formula. By contrast, the same skulls of Blacks averaged 1418 cm3 whenthe researchers used the Ainu formula (which gives more weight to the length ofthe skull) . As Leonard Lieberman points out, human populations that evolved incold climates have a more spherical brain case to prevent loss of body heatduring cold weather. 7In addition, Sarich and Miele do not consider the nature of gene expressionin the genes that guide the development of neural patterning. Nor do theyaddress the complex phenomenon of gene-environment interactions, which canresult in varying manifestations of genetic proclivities. They supportSpearman’s hypothesis: the claim that Blacks typically score lower on the moredifficult “g-loaded” IQ test questions that are reportedly associatedwith abstract reasoning. However, they ignore the fact that there is noconsensus among experts on precisely what g signals. In fact, leading scholarscannot even agree on which IQ test questions are more “g-loaded.” 83. The role of developmentalbiology versus population genetics in determining human cognitive andbehavioral traitsIn their discussion of purported inborn, race-based behavioral patterns,Sarich and Miele omit findings from several relevant fields of study thatreveal the powerful role of developmental genetics in shaping human cognitionand behavior. These authors fail to clarify both the evolutionary constraintsand environmental influences (including psychosocial and biotic factors) thatare known to affect developmental biology. Experts have shown that long termdevelopmental biology can mimic genetic transmission in producing some traitsin certain populations. Slight population differences in life-history traitssuch as growth and maturation, fertility, and reproductive rate in somepopulations may appear to be a result of population genetics—“racialgenetics”—when in fact, in certain situations the ethnic differences mainlyreflect varying environmental exposures.In the United States the age of menarche in African American girls isearlier than that of European American girls. 9 However, asnoted previously, a similar “precocious” onset of menstruation (“precocious”only if a White female standard is used) has not been reported in various BlackAfrican girls born and reared in West and Central African societies 10 or in East African nations. 11 Yet, some racial scientists are erroneously convinced that the earlier averageage of sexual maturation seen in African American girls reflects a geneticpredisposition. 12 The evidence does not support their view. Cross-cultural surveys clearlyshow that the age of onset of menarche varies rather widely across geographicalpopulations and ethnic groups.Ethnic differences in developmental patterns appear to be associated withenvironmental influences. Candidate environmental factors include a wide rangeof nutritional deficiencies; exposure to lead, fluosilicic acid and sodiumsilicofluoride used tofluoridate water; and possibly estrogenic compounds foundin both soy-based infant formula and placenta-containing hair cosmeticproducts. 13 Preliminary findings from various studies suggest that African Americaninfants, toddlers, and girls may be over-exposed to estrogen-like compounds,including PCB’s, from environmental toxins found in certain ethnic,placenta-containing hair products and in phytoestrogens (natural plantestrogens) found in soy-based infant formula. Compared to non-Black newborns inthe United States, a higher proportion of African American babies are fedsoy-based infant formula. (It should be noted, however, that even though theseparticular environmental factors are correlated with aberrant neurological andbehavioral conditions, unequivocal cause-and-effect relationships have not beenestablished.)While findings linking environmental toxins such as lead, silicoflourides,manganese and estrogen-like compounds to psychosexual development areinconclusive, certain environmental factors have been shown to influencetestosterone and serotonin levels. Research strongly suggests that “racial”differences—especially Black/White/Asian differences in testosterone levels inmen—is associated with diet and social factors such as dominance and socialstatus. Several studies contradict the claim that variations in this male sexhormone are tied to racial genetics. 14 Similarly, population differences in the levels of keyneurotransmitters—brain chemicals such as serotonin and dopamine—may be linkedto environmental influences rather than race-based genetics. 15Sarich and Miele suggest that brain size and certain other neurologicaltraits are associated with intelligence, or cognitive performance. They draw ondata that seemingly supports their claim that Black African populations andtheir Diasporas have smaller cranial volumes. For these authors, “race-based”differences in brain size are the result of different adaptations to differentgeographical climates. Nonetheless, emerging evidence increasingly counters thelong-held scientific claim, if not folk belief, that Blacks are geneticallywired for a smaller cranial capacity.According to several neuroscientists, the differences reported in the brainsize of populations, especially in comparative studies on White, NortheastAsian, and Black African populations, reflect developmental differences ratherthan inborn race-based differences. The developmental biology of the humanbrain is influenced by myriad environmental and epigenetic factors—complexinteractions between genes and environment. These factors include not only agamut of nutritional factors, but also environmental toxins. As notedpreviously, the problems of objectively measuring brain size have distorted atleast some of the reported population (“race-based”) differences in brainvolume.Sarich and Miele also fail to explain critical anomalies regarding g—the“thing” that IQ tests supposedly measure—in relation to Black/White differencesin IQ tests scores. First, as noted, is the fact that there is a lack ofconsensus among experts on which IQ test questions are more abstract—that is,allegedly more difficult to answer. 16 Second, even pro-nature researchers, including some behavioralgeneticists, cannot agree among themselves on either the neurophysiological orgenetic substrates of g. And third, the relatively lower heritabilitiesfor IQ in black twins suggests that environmental forces may play a relativelygreater role in influencing the average IQ scores in African Americans comparedto Whites. 17In fact, a host of counter findings strongly suggests that the wide rangeof IQ scores reported in African populations depends on prior academiclearning, including experience with taking tests. While racialists continuallypoint to the “African IQ of 70,” the evidence clearly indicates that Africanpopulations as a whole do not have single average IQ. There is considerablevariation in average IQ scores among Black Africans, even within the samepopulation. Ugandans living in Uganda, for example, earned an average score of80 on the Terman Vocabulary and Kohs Blocks Test, and a score of 88 points onRaven’s Progressive Matrices. In another study, Tanzanians in Tanzania alsoaveraged 88 points on Raven’s Progressive Matrices. 18 Note that these latter scores, while low, are slightly higher then thetypically reported IQ norm for African Americans. 19If Sarich and Miele’s hypothesis carries any weight, then it must be allowresearchers to differentiate traits shaped by developmental biology from traitsthat are primarily under genetic control. This concern immediately raisesseveral questions. How strong of an influence do multiple environmental forceshave on the genes and haplotypes that guide developmental biology? Do geneslinked to developmental biology have a higher heritability? In other words, arethey less subject to natural selection and therefore more easily influenced byenvironmental fluctuations—both internal and external environmental forces? Canenvironmental change affect the gene expression of functional traits thatevolved through natural selection?Detailed answers to these questions are beyond the scope of this review. Ingeneral, however, it appears that environment can change gene expressionbecause developmental biology is itself subject to ongoing environmentalinfluences that act through continuous—at times competing and at timescooperating—environmental forces. Supporting evidence for this claim mayexplain some of the inconsistencies in research on “race-based” genes linked totestosterone and serotonin.To ignore, let alone discount, the impact of the environment on anylife-history trait in humans is not simply incomplete science, but also disingenuousscience. The mere act of dismissing crucial evidence in regard to scientifictopics such as ethnicity and IQ—topics that have far-reaching socialramifications—borders on questionable science at best and, at its worse,fraudulent science.4. The Role of neutralselection versus natural selection in population-based (or race-based)molecular traits associated with behaviorIn the late 1960s, Motoo Kimura, a Japanese biologist, challenged thecanons of evolutionary science when he stated that natural selection,particularly on the molecular level, was not necessarily a potent force inevolution. Extending the theory of genetic drift first proposed in the 1930s,Kimura argued that molecular variation was selectively neutral. Kimura focusedon the randomness, or selective neutrality, of variation in proteins and DNA.The gist of his neutral theory of molecular evolution, usually called “neutraldrift,” is that the vast amount of evolutionary change observed on themolecular level—the level of DNA and proteins—is driven by genetic drift ratherthan natural selection. This position contrasts with the Neo-Darwinianevolutionary perspective in which molecular evolution is thought to be theresult of natural selection. 20Although Kimura’s anti-selectionist position challenged the neo-Darwiniansynthetic theory of evolution, his arguments were so compelling that hisneutral theory was eventually incorporated into the modern synthesis of evolutionarybiology. In other words, although Kimura is considered an anti-Darwinist, histheory is compatible with the tenets of neo-Darwinism. During the 1970s,leading neo-Darwinists such as Ernst Mayr critiqued the limitations of theneutral theory which, in Mayr’s initial view, did not address traits that havebecome fixed in a species or population. Nonetheless, Mayr’s perspective couldnot explain a possible relationship between random molecular variation andfitness, including cumulative DNA changes that could ultimately lead tofitness.By the 1980s, Mayr shifted his own position, noting that an increasingnumber of sites in the largest molecules were found to have specific functions.For Mayr, it was only a matter of time before the function of “functionlesssites” of large molecules (conceivably both nucleotide sequences and aminoacids) would be discovered. As Mayr pointed out, “neutral” base-pairreplacements are widespread. More importantly, however, he acknowledged thatnumerous alleles once thought to be neutral had “selective significance.” In sodoing, Mayr gave Kimura’s neutral theory a boost of credibility within thescientific community.At the same time, Kimura admitted that the neutral theory is inadequate inexplaining Darwinian evolutionary change at the phenotypic level—the level onwhich a trait manifests. Instead, Kimura argued, the value of the neutraltheory lies in its prediction that the most variation occurs in thefunctionally less critical parts of a gene. 21 According to the neutral selection theory, the functionally significantcomponents of a molecule will change more slowly than the functionallyinsignificant components. This view contrasts with the Darwinian position,which predicts that evolution will be most rapid in the functionally importantparts of molecules—the area where selection is strongest.In the neutral theory, genetic drift plays a comparatively larger role thannatural selection in evolutionary processes. Evolutionary change is assumed toresult from genetic drift acting on neutral alleles. In neutral selection, genevariants that become more prevalent in a population may decline or evendisappear through random events. On rare occasion, a neutral substitution toone of these gene variants may become “fixed” and give rise to a widespreadtrait. If enough new substitutions accumulate on the gene variant, the genomewill evolve. However, the evolution that occurs in such a rare case results fromthe additive effects of neutral substitutions to the gene variant. It does notemerge through natural selection.Ironically, Sarich and Meile never mention the neutral selection theory inrelation to the micro-evolution of human behavioral phenotypes. There are atleast two reasons why they could have mentioned this theory in relation totheir hypothesis about race-based differences in behavior. First, the earlytechniques used to determine the molecular clock—techniques that Sarich helpedto develop—are based on the neutral theory. And second, if as Sarich and Mieleclaim, purported “race-base” behavioral differences reflect each “race’s”unique genetic-evolutionary history, then the molecular source—the genetics—ofthose differences should have been closely examined.Consider new findings in molecular psychiatry—the study of the role ofgenetics in behavioral traits, or what scientists call behavioral phenotypes.Human geneticists working at the interface between molecular biology and thebehavioral sciences have identified a small number of population-based (theterm preferred by most mainstream researchers) polymorphisms, or differences inthe genes that regulate brain chemicals involved in mood and certain socialbehaviors. For example, some populations differ slightly in their frequency ofdopamine and serotonin gene variants linked to behavioral traits such asalcoholism, drug addiction, novelty seeking, and anxiety. 22This line of research is highly controversial because of its potential use,or misuse, to support the existence of inborn race-based hierarchies inlaw-abiding behaviors, emotional stability, and even the capacity for (Western)cultural achievement. On a cautionary note, experts have yet to draw anydefinitive conclusions about cause-and-effect relationships between most of theneurochemical gene variants studied so far and social behaviors across a widegamut of populations. Only a few associations have been established forindividuals, and even fewer for populations. The research conducted to datetypically has focused on smaller regional populations instead of huge,ill-defined social groupings that correspond to popular notions of human races.Yet, this is one of the most important arenas in which pro-race advocates suchas Sarich and Miele should search if they are seeking irrefutablecause-and-effect evidence linking racial genetics and perceived ethnicbehavioral patterns.What happens when we examine the evidence produced thus far in this field?Alas, in a few cases we discover gene variants that do differ along populationlines. In most cases, however, even race-based gene variants that reportedlypredict certain behaviors in individuals are not consistently predictive at thegroup level. Whether or not an individual who carries one or more gene variantslinked with socially deviant and unproductive behaviors actually manifestsaberrant behaviors depends on myriad other influences, including an array ofenvironmental factors. Moreover, there is no evidence for robust associationsbetween specific gene variants and behaviors at the mega-population (racial)level.For the sake of argument, let us assume that Sarich and Miele are correctin their thesis about relatively rapid evolution resulting in modern humanraces (as some findings suggest may be the case). If so, then certain genevariants that are linked to social behaviors and that may also differ slightlyalong population lines become likely biological (in this case, molecular andgenetic) substrates for race-based behavioral differences. If Sarich and Meileare right, this variation is the product of natural selection. Yet, thedifferences seen in variant genes regulating serotonin, dopamine, andtestosterone, as well as other genes involved in brain chemical and hormonalproduction, may reflect molecular variation. From the vantage of Kimura’sneutral theory, the molecular differences in these gene variants are a primeexample of neutral evolutionary change. Granted, preliminary findings from arecent study suggest that selection may operate at the molecular level. 23 (see Yaris, 2002.) However, in many (though certainly not all) cases,evolutionary changes appear to have resulted from molecular genetic driftrather than selection, whether natural selection or sexual selection. 24ConclusionAlthough an in-depth analysis of the “neutralist-selectionist” debate isoutside the purview of this critique, this debate is relevant to the assertionsmade in Sarich and Miele’s Race: The Reality of Human Differences. Thecentral question is not whether or not natural selection accounts for certaintraits in human populations since it clearly does. Instead, the paramountconcern is over the relative proportion of neutral and selected, ornon-neutral, alleles that determine traits. If a trait emerged throughselection, the trait can be assumed to have fitness and functionality. However,if it arose through genetic drift, then it is neutral in terms of fitness. Bydefinition it could not have evolved as an adaptation. Moreover, becauseneutral traits are not normally fixed, they can decrease in frequency or evenvanish in a given population over time.Are neutral genetic traits linked to mood and behavior more influenced bythe environment than selected traits? This would appear to be the case—afterall selected traits are fixed. This idea is consistent with the neutral theory,which states that evolution at the molecular level is non-adaptive. In fact,research in molecular psychiatry suggests that this may well be the case. Thisalso may explain numerous inconsistencies in the relationship between, on theone hand, serotonin- and dopamine-related genes and, on the other hand, certainmood and behavioral states across ethnic populations. 25This does not mean that population differences found at the molecularlevel, including gene variants implicated in human psychosocial behaviors, areirrelevant. They are. However, population variance at the molecular level ismore likely the outcome of random evolutionary processes. The point here isthat within the context of molecular micro-evolution, human populationdifferences—“racial differences”—in gene variants linked with mood and behaviormay not be unchangeable or fixed as in the case of a physical traits shaped bynatural selection. A growing body of research suggests that a wide array ofenvironmental factors can significantly affect the manner in which a particulargene, or gene variant, is expressed.An introductory level treatise such as Race: The Reality of HumanDifferences cannot be expected to be comprehensive, but surely it is notprudent to overlook salient data, including important counter-data. To ignorethe profound implications of developmental biology when talking aboutrace-based differences in behavior is to offer bold, if not ludicrous, claimsthat often have no basis in reality. This misguided process renders scientificinquiry a frivolous pursuit of “perilous notions.”By relying on assertions more than arguments throughout much of their text,Sarich and Miele unwittingly do scientific inquiry an injustice. While some oftheir material may be new to some readers, the misleading information, if notunfounded contentions, that plagues much of their text is disappointing.Despite their best intentions to present an objective, scientifically informeddiscussion of human race, Race: The Reality of Human Differencesironically may only further the “scientific dumbing down of America.”References & Notes
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- Sarich, Vincent. 1995. “Race.” Paper presented at the Eighth Annual Meeting of the Human Behavior and Evolution Society (HBES). Northwestern University. Evanston, IL.
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- Ceci, 1996, op cit.
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- Herrnstein and Murray, 1994, op cit.
- Kimura, Motoo. 1983. Neutral Theory of Molecular Evolution. Cambridge University Press; Kimura, Motoo. 1994. Population Genetics, Molecular Evolution, and the Neutral Theory: Selected Papers.
- Kimura, 1994, op cit.
- Hamer, D.H. and Copeland P. 1998. Living With Our Genes. New York: Doubleday.
- Yarris, Lynn. 2002. “Survival of the Fittest Molecules.” Berkeley Lab Currents. March 8. www.lbl.gov/Publications/Currents/Archive/Mar-08-2002.html
- Wayne and Simonsen, 1998, op cit.
- Gelernter, et al, 1998; Gelernter, et al, 1997, op cit.