Jesse

I just found a list of some Rushton critiques in academic journals:

http://www.anatomy.usyd.edu.au/danny...1994/0233.html

I couldn't find any of these articles online, but in the course of searching I found some other Rushton-related stuff online:

Race and IQ

A critical look at intelligence research (scroll down to the section 'Reliance on Poor Research: the Examples of Rushton and Lynn')

Environmental Variability Selects for Large Families only in Special Circumstances: Another Objection to Differential K Theory

Here's a list of other articles on intelligence and race by the author of the above article:

http://www.lrainc.com/swtaboo/stalkers/miller.html

God Fearing Atheist

This one is pretty interesting.

Do you know of any detailed replies Rushton has made to critics of his application of r-K?

-GFA

Jesse

Hi GFA, I looked for responses by Rushton to Miller, and I found this article which contains the following reference:

Race, Genetics, and Human Reproductive Strategies

Rushton, J.P., & Ankney, C. D. (1993). The evolutionary selection of human races: A response to Miller. Personality and Individual Differences, 15, 677-680

The "Environmental Variability" article was written in 1995 though, so I don't know if he's responded to that article. But the "challenges and rejoinders" section of the above article may include answers to other criticisms.

And here's a bunch of online Rushton articles, some of which answer critiques by others:

http://www.mugu.com/cgi-bin/Upstream/Rushton

ps418

Franz Boas data on 'race' and skull morphology, discussed in the article above, was for a long time considered the scientific proof that race is "just" a social construct. Considering out fascination with ourselves and reconstructing our past, its remarkable that it took so long for someone else to examine his data and point out that it was fraudulent (same thing with Margaret Mead's ethnographic data). This really only happened because some researchers were still citing Boas' work, arguing for instance that Kennewick Man cannot be assigned to any regional group because skull morphology is so dependent upon environment (so the reasoning went).

But now Boas' conclusions on this particular matter are known to be false. Skulls can be assigned to geographic groups with high accuracy, and you see the same set of clusters with skull morphological features as you do with DNA polymorphisms. This is documented clearly in a forthcoming article in the American Journal of Physical Anthropology, for instance. Contrary to Boas' fears, I don't see such findings as supporting racism in any way.



Hanihara, T, Ishida, H, Dodo, Y, 2003. Characterization of biological diversity through analysis of discrete cranial traits. AJPA Published Online: 13 Mar 2003

Patrick

God Fearing Atheist

Rushton, like most advocates of genetic intelligence, believes about 30% of the BW difference can be explained using standard SES variables.

The problem, as Jensen points out, is making sense of that other 70% using environmental factors; finding that environmental "Factor X".

ps418

Well, attained SES is partly a function of cognitive ability to begin with, so is not always clear what the nature of the SES influence on IQ is. Importantly, in adoption studies and reared-apart twin studies, adoptive parent SES does not predict adult IQ, yet remarkably the IQ of the biological parents, in adoption studies, or cotwins, in reared-apart twin studies, does predict the IQ of the reared-apart children/twins. More importantly, the SES of the biological parents still signficantly predicts the offspring IQ, even when adopted away in infancy. These findings strongly suggest that the SES - IQ correlations observed in normal biological families are substantially mediated by shared genetic factors. It is not clear the extent to which SES has an effect independent of parental IQ.


That's true. It occurs to me though that it should be possible to determine the extent to which the between-group differences in cognitive ability are mediated by genetic factors using admixture mapping, supposing someone was interested in funding and conducting the study (perhaps doubtful on both counts - personally I can't think of any good reasons to spend money on such research). Admixture mapping can help determine the extent to which between-population differences are mediated by genetic factors. To quote from Schriver et al (2003):

For examples of how AM is being used to determine the genetic basis of various human phenotypes, particularly disease phenotypes, see the references below. Theoretically you could do the same thing for between-group differences (African, Asian, European) in cognitive ability. Of course, even if the study were done, and seemed to indicate that the gaps were largely mediated by genetic factors, there would still be the possibility of unidentified X Factor confounds.

To get an idea of what such a study would look like, let's look at a study of the relationship between risk of type 2 diabetes and European admixture in a population of Pima Indians (Williams et al, 2000). Williams et al's abstract states:

The graph below illustrates the relationshop between european admixture and risk of type 2 diabetes in the population of Pimans:



A case like this provides strong evidence that the differential susceptibility to type 2 diabetes between european and Piman populations is largely due to genetic differences.

Studies along these lines of cognitive ability have in fact been conducted in the past, but they used fairly crude measures of admixture such as blood groups, and individuals imprecisely defined as "white" or "black" (none involved 'asian' admixture, as far as I know). Today the same type of studies could be done in a much more precise way using genetic marker measures of admixture (Parra et al, 1998; Destro-Bisol et al, 1998).

Nevertheless, the studies which do exist, flawed though they might be, do not provide much support a substantial genetic component to between group differences. Some suggested a signficant genetic component, while others suggested little or no genetic component. For a review of this type of study, see Richard Nisbett's chapter on "Race, Genetics, and IQ" in the book "The Bell Curve Wars" (1995). There have also been adoption studies looking at the relationship between ancestry and IQ, and again the results are mixed. Some do in fact seem to show a signficant genetic component, while others do not.

Patrick


Refs

Collins-Schramm et al, 2002. Ethnic-Difference Markers for Use in Mapping by Admixture Linkage Disequilibrium. American Journal Human Genetics 70, pp. 737-750.

Destro-Bisol et al, 1998. Estimating European admixture in African Americans by using microsatellites and a microsatellite haplotype (CD4/Alu). Human Genetics 104(2), pp. 149-157.

Molokhia et al, 2003. Relation of risk of systemic lupus erythematosus to west African admixture in a Caribbean population. Human Genetics 112(3), pp 310-318.

Parra et al, 1998. Estimating African American Admixture Proportions by Use of Population-Specific Alleles. American Journal Human Genetics 63:1839-1851.

Shriver et al, 2003. Skin pigmentation, biogeographical ancestry and admixture mapping. Human Genetics 112(4), pp 387-399.

Smith et al, 2001. Markers for Mapping by Admixture Linkage Disequilibrium in African American and Hispanic Populations. American Journal Human Genetics 69:1080-1094.

Williams et al, 2000. Individual Estimates of European Genetic Admixture Associated with Lower Body-Mass Index, Plasma Glucose, and Prevalence of Type 2 Diabetes in Pima Indians. American Journal Human Genetics 66, pp. 527-538.

God Fearing Atheist

Hey Patrick,

Do you have any thoughts on African Negroid (that is, Negroids who are not of mixed ancestry like most African-Americans) IQ in particular? Ive been reading that they average out at about 70, which seems extremely low (could the average African really be, quite literally, retarded?).

On the other hand, Rushton did they study where black college students in Africa fell about 15 points above that 70 racial average, which is typical for college students of all races in all countries...