RE: The Negroid, And the truth of races
than that for Mexican-American and non-Hispanic white children, indicating that differences in risk for exposure still persist."[75]
Environmental factors including childhood lead exposure,[74] low rates of breast feeding,[76] and poor nutrition[77][78] can significantly affect cognitive development and functioning. For example, childhood exposure to lead, associated with homes in poorer areas[79] causes an average IQ drop of 7 points,[80] and iodine deficiency causes a fall, on average, of 12 IQ points.[81][82] Such impairments may sometimes be permanent, sometimes be partially or wholly compensated for by later growth. The first two years of life is the critical time for malnutrition, the consequences of which are often irreversible and include poor cognitive development, educability, and future economic productivity.[83] The African American population of the United States is statistically more likely to be exposed to many detrimental environmental factors such as poorer neighborhoods, schools, nutrition, and prenatal and postnatal health care.[84][85] Mackintosh points out that for American blacks infant mortality is about twice as high as for whites, and low birthweight is twice as prevalent. At the same time white mothers are twice as likely to breastfeed their infants, and breastfeeding is highly correlated with IQ for low birthweight infants. In this way a wide number of health related factors that influence IQ are unequally distributed between the two groups.[86]
The Copenhagen consensus in 2004 stated that lack of both iodine and iron has been implicated in impaired brain development, and this can affect enormous numbers of people: it is estimated that one-third of the total global population are affected by iodine deficiency. In developing countries, it is estimated that 40% of children aged four and under suffer from anaemia because of insufficient iron in their diets.[87]
Other scholars have found that simply the standard of nutrition has a significant effect on population intelligence, and that the Flynn effect may be caused by increasing nutrition standards across the world.[88] James Flynn has himself argued against this view.[89]
Some recent research has argued that the retardation caused in brain development by infectious diseases, many of which are more prevalent in non-white populations, may be an important factor in explaining the differences in IQ between different regions of the world.[90] The findings of this research, showing the correlation between IQ, race and infectious diseases was also shown to apply to the IQ gap in the US, suggesting that this may be an important environmental factor.[91]
Earl Hunt states that brain size is found to have a correlation of about .35 with intelligence among whites and cites studies showing that genes may account for as much as 90% of individual variation in brain size. According to Hunt, race differences in average brain size could potentially be an important argument for a possible genetic contribution to racial IQ gaps. Nonetheless, Hunt notes that Rushton's head size data would account for a difference of .09 standard deviations between black and white average test scores, less than a tenth of the 1.0 standard deviation gap in average scores that is observed.[154][189] Wicherts, Borsboom, & Dolan (2010) argue that black-white differences in brain size are insufficient to explain 91% to 95% of the black-white IQ gap.[190]
Archaeological data
Archaeological evidence does not support claims by Rushton and others that blacks' cognitive ability was inferior to whites' during prehistoric times as a result of evolution.[191]
And the argument that hanging around people with low-IQ will reduce quality of life is.. Dumb, because a) that would mean that the black person hanging around you would also have a high IQ, b) hanging around “dumb” people shouldn’t make you dumber, and c) is high IQ associated with high quality of life, or is high quality of life associated with high IQ? It’s been proven that socio-economic status affects IQ, not the other way around.
There’s a famous result in intelligence studies called the Flynn Effect. What it tells us is that average IQs rose about 3 points per decade throughout the 20th century. That’s roughly 20 points of IQ throughout the entire period, and it’s obvious that this couldn’t have been caused by genes.³ It’s 100 percent environmental. This is clear evidence that environmental factors are quite powerful and can easily account for very large IQ differences over a very short period of time.
The difference in average IQ recorded in different European countries is large: on the order of 10 points or more. The genetic background of all these countries is nearly identical, which means, again, that something related to culture, environment, and education is having a large effect.
It is very common for marginalized groups to have low IQs. In the early years of the 20th century, for example, the recorded IQs of Italian-Americans, Irish-Americans, Polish-Americans and so forth were very low. This was the case even for IQ scores recorded from the children of immigrants, all of whom were born and educated in the US and were fluent English speakers. These IQ scores weren’t low because of test discrimination (at least not primarily because of that), they were low because marginalized groups often internalize the idea that they aren’t intelligent. However, over the decades, as these groups became accepted as “white,” their IQ scores rose to the average for white Americans.
The same thing has happened elsewhere. In the middle part of the 20th century, the Irish famously had average IQ scores that were similar to those of American blacks—despite the fact that they’re genetically barely distinguishable from the British. However, as Ireland became richer and the Irish themselves became less marginalized, their IQ scores rose. Today their scores are pretty average.
In 1959, Klaus Eyferth performed a study of children in Germany whose fathers had been part of the occupation forces. Some had white fathers and some had black fathers. The IQ scores of the white children and the racially mixed children was virtually identical.
Over the past few decades, the black-white IQ gap has narrowed. Roughly speaking, it was about 15 points in 1970 and it’s about 10 points now. This obviously has nothing to do with genes.
Currently, the 1.1 standard deviation difference in average IQ between Blacks and Whites in the United States is not in itself a matter of empirical dispute. A meta-analytic review by Roth, Bevier, Bobko, Switzer, and Tyler (2001) showed it also holds for college and university application tests such as the Scholastic Aptitude Test (SAT; N 2.4 million) and the Graduate Record Examination (GRE; N 2.3 million), as well as for tests for job applicants in corporate settings (N 0.5 million) and in the military (N 0.4 million). Because test scores are the best predictor of economic success in Western society (Schmidt & Hunter, 1998), these group differences have important societal outcomes (R. A. Gordon, 1997; Gottfredson, 1997). The question that still remains is whether the cause of group differences in average IQ is purely social, economic, and cultural or whether genetic factors are also involved. Following publication of The Bell Curve, the American Psychological Association (APA) established an 11-person Task Force (Neisser et al., 1996) to evaluate the book’s conclusions. Based on their review of twin and other kinship studies, the Task Force for the most part agreed with Jensen’s (1969) Harvard Educational Review article and The Bell Curve, that within the White population the heritability of IQ is “around .75” (p. 85). As to the cause of the mean Black–White group difference, however, the Task Force concluded: “There is certainly no support for a genetic interpretation” (p. 97)
Among scientists, it has been common knowledge that both black and white IQs have been rising over the decades, with black IQs converging upwards towards whites. This fits nicely with America's rising standard of living, which has been rising somewhat faster for blacks, thanks to the Civil Rights movement and other anti-poverty measures.
The authors of The Bell Curve, then, face an uphill battle in trying to prove that black and white IQs are not converging, but diverging. They attribute this divergence to "dysgenesis," which supposedly results when dull people interbreed. In fact, they assert this downward trend in spite of the famous "Flynn Effect," which has been raising IQs for all people and all classes world-wide, about 3 points per decade.
In a second departure from scientific consensus, the authors also maintain that the IQ gap between blacks and whites is 15 points, an usually high figure. But this is not what four major IQ tests for children have found:
Black/white IQ gap in major IQ tests (1991) (1)
Ravens Standard Progressive Matrices 7 points
Kaufman Assessment Battery for Children 7
Stanford-Binet IV (two separate studies) 10
The authors of The Bell Curve note these numbers, but dismiss them. The Kaufman-ABC results, they claim, suffer from statistical problems. (2) Even granting them their objection, however, still leaves three major studies showing a 7 to 10-point gap, not a 15-point one.
Why do the authors discount both the Flynn Effect and these test results in their assessment of black IQ? Because of a single study: their analysis of the National Longitudinal Survey of Youth (NLSY). The NLSY has tracked the lives of 12,000 young people since 1979, at one point giving them an Armed Forces Qualification Test (AFQT). But The Bell Curve's analysis of the NLSY data is deeply flawed. First of all, the AFQT isn't even an IQ test. "This is an achievement test," said Halford Fairchild of the American Psychological Association said, in its authoritative review of The Bell Curve. "It shows the extent to which you've benefited from school. To assert it's a proxy for IQ is a big lie." (3)
Even if we accept the AFQT as an IQ test, however, the authors still commit serious errors analyzing it. One of the best-known critics of their methodology is psychologist Richard Nisbett, whose arguments follow here. (4) Herrnstein and Murray's comparison of black and white IQs did not follow the changing IQs of children over a period of time (the most reliable method), but differences of IQ between mothers and children at a fixed point in time (which introduces all sorts of statistical complications). Herrnstein and Murray found that the black/white IQ gap among mothers was 13.2 points, but among their children was 17.5 points. (5) This four-point increase forms the basis of their claim that the black/white IQ gap is growing.
However, the study itself is unrepresentative of the nation at large; the average IQ of the children was 92, significantly below the national average of 100. The reason is because the women in this long-term survey had not finished their childbearing years, so all the children in the study had been born to young mothers. Unfortunately, young motherhood is correlated to low IQ, which is why their children scored so far below the national average.
Herrnstein and Murray note this problem, and claim that sampling weights added to the NLSY make the survey sample "nationally representative." (6) But this leads to trouble when they attempt to analyze a growing IQ gap in children. Young motherhood is not unusual for black women, but for white mothers it suggests low socioeconomic status, which in turn suggests low IQ. Therefore, the IQs of the young white and black mothers were similar… although the IQs of their children were bound to diverge. Why? Because black mothers, having average black IQs, would have children with the same. But white mothers, with below-average white IQs, would have children with IQs that would tend to rebound back towards the higher white average. That's because trait variation is natural in children, and if white parents are already near the bottom, then their children, if they vary, have nowhere else to go but up. This is technically known as "regression towards the mean," and it is a common statistical deception. You can get the opposite "result" by comparing average black mothers with the smartest white mothers; the white children would tend to drop back down to the white average, having nowhere else to go but down. In this case, Herrnstein and Murray could have reported that IQ gap is shrinking, not growing!
Thanks to this statistical anomaly, Herrnstein and Murray found a four-point increase in the black/white IQ gap in their particular sample. On this basis, they then argued that the gap is growing everywhere. But this is certainly not the case, and the mainstream studies remain the best indicator of the shrinking black/white IQ gap.