Haplogroups as evolutionary markers of cognitive ability
Heiner Rindermann, Michael A. Woodley, James Stratford (2012)
Studies investigating evolutionary theories on the origins of national differences in intelligence have been criticized on the basis that both national cognitive ability measures and supposedly evolutionarily informative proxies (such as latitude and climate) are confounded with general developmental status. In this study 14 Y chromosomal haplogroups (N=47 countries) are employed as evolutionary markers. These are (most probably) not intelligence coding genes, but proxies of evolutionary development with potential relevance to cognitive ability. Correlations and regression analyses with a general developmental indicator (HDI) revealed that seven haplogroups were empirically important predictors of national cognitive ability (I, R1a, R1b, N, J1, E, T[+L]). Based on their evolutionary meaning and correlation with cognitive ability these haplogroups were grouped into two sets. Combined, they accounted in a regression and path analyses for 32–51% of the variance in national intelligence relative to the developmental indicator (35–58%). This pattern was replicated internationally with further controls (e.g. latitude, spatial autocorrelation etc.) and at the regional level in two independent samples (within Italy and Spain). These findings, using a conservative estimate of evolutionary influences, provide support for a mixed influence on national cognitive ability stemming from both current environmental and past environmental (evolutionary) factors.
(J’ai désactivé les commentaires dans la mesure où l’article présent est très loin d’être achevé, et probablement causera des lags de chargements si la page devient trop allongé. Mais comme la cadence du blog ralentit, je le poste quand même. Certaines parties sont en anglais, dû à un manque de temps pour les traductions, qui sera fait dans un avenir proche. D’autres parties sont peut-être aussi redondantes voire inutiles, et seront probablement effacées dans la version finale de l’article. Tant que ce message en gras ne disparaît pas, l’article n’est pas achevé, les liens et images manquants, et je ne crois pas sage, donc, que ce brouillon non structuré mérite d’être cité. En attendant, il y a de quoi lire.)
1. Persistence of The Black-White IQ Gap
2. Africans : Poverty, Geography, and Infectious Disease
3. Interpretation of the Regression to the Mean
4. Within-Group Heritability (WGH) vs Between-Group Heritability (BGH)
5. Transracial Adoption and the IQ of Mixed-Race
6. Africans : Parenting, Culture, and Discrimination
7. Socio-Economic Status : A Moderate of Genetic Influences on IQ
8. Improving IQ Through Interventions : A Broken Dream
9. The Flynn Effect : A Mere Artifact
10. No Bias : Reliability and Validity of IQ Tests
11. National IQs : Explaining Differences in Achievement
12. Evolutionary Theory and the Case for Race Realism
Under the Skin: On the Impartial Treatment of Genetic and Environmental Hypotheses of Racial Differences
David C. Rowe 2005
University of Arizona
Environmental and genetic explanations have been given for Black–White racial differences in intelligence and other traits. In science, viable, alternative hypotheses are ideally given equal Bayesian prior weights; but this has not been true in the study of racial differences. This article advocates testing environmental and genetic hypotheses of racial differences as competing hypotheses. Two methods are described: (a) fitting means within structural equation models and (b) predicting means of interracial children. These methods have limitations that call for improved research designs of racial differences. One improvement capitalizes on biotechnology. Genetic admixture estimates — the percentage of genes of European origin that a Black individual possesses (independent of genes related to skin coloration) — can represent genetic influences. The study of interracial children can be improved by increasing sample size and by choosing family members who are most informative for a research question. Eventually, individual-admixture estimates will be replaced by molecular genetic tests of alleles of those genes that influence traits.
Race: a social destruction of a biological concept
It is nowadays a dominant opinion in a number of disciplines (anthropology, genetics, psychology, philosophy of science) that the taxonomy of human races does not make much biological sense. My aim is to challenge the arguments that are usually thought to invalidate the biological concept of race. I will try to show that the way ‘‘race’’ was defined by biologists several decades ago (by Dobzhansky and others) is in no way discredited by conceptual criticisms that are now fashionable and widely regarded as cogent. These criticisms often arbitrarily burden the biological category of race with some implausible connotations, which then opens the path for a quick eliminative move. However, when properly understood, the biological notion of race proves remarkably resistant to these deconstructive attempts. Moreover, by analyzing statements of some leading contemporary scholars who support social constructivism about race, I hope to demonstrate that their eliminativist views are actually in conflict with what the best contemporary science tells us about human genetic variation.
Those who subscribe to the opinion that there are no human races are obviously ignorant of modern biology.
Ernst Mayr, 2002
Understanding Human History, Michael H. Hart. 2007.
Racial Differences in Intelligence
Section 3 – IQ data: Blacks and whites in the United States
Although the studies differ, virtually all show a large difference between the average scores of American blacks and whites, with the differences clustering around one standard deviation. A few of those studies, including several of the largest ones, are listed in Table 15-1. [footnote 4] It is worth remarking, though, that those studies (like most others) probably underestimate the true value of δ (where δ is defined as the difference between the mean IQ of American whites of European descent and the mean IQ of American blacks). At least two factors contribute to this:
1) Many such studies include only students who are attending school, and omit high school dropouts. This factor causes us to overestimate average IQs. As proportionally more blacks than whites drop out of high school, the effect is to reduce the measured value of δ. [footnote 5]
2) Almost all such studies omit the prison population. Since prisoners, on average, have much lower IQs than the public at large, omitting them has the effect of overestimating the average IQ of every racial group in the United States. Since about 3% of American blacks are prisoners (but less than . of 1% of whites), omitting this factor leads to underestimating δ.
Racism, Guilt, Self-Hatred & Self-Deceit, par Gedaliah Braun.
Prelude To a Continuing Discussion: Can A Fact Be Racist? (p. 10)
Question: can such a true belief – a fact – be racist? The very idea seems absurd. A fact is merely something that is the case, and such a thing cannot, in and of itself, be racist. To call something racist is to say it is morally bad and it would seem absurd to call a fact morally bad.
But if a fact cannot be racist, neither can a proposition, for a proposition is simply what is made true (or false) by facts. A proposition, therefore, is like a ‘picture’ of a fact: to every fact there corresponds the proposition which would assert that fact, while, conversely, to every proposition there corresponds either a fact (which makes it true) or the absence of that fact (whose absence makes it false). So propositions and facts are intimately related, and if facts cannot be racist neither can propositions.