Thirty years of research on race differences in cognitive ability.

In the citing paper

“This estimate of between-group heritability is consistent with Rushton and Jensen's [9] hereditarian model, according to which 50%-80% of the African-/European-American cognitive difference is due to genetic differences.”

In the citing paper

“However, the above-average mean IQ of even severely malnourished East Asian infants adopted into White European homes is more consistent with those infants having a genetic than a cultural advantage over their White European peers.”

In the citing paper

“Rushton and Jensen's (2005) hereditarian hypothesis is that Black-White differences in general intelligence (IQ, or the general mental ability factor, g ) are 'substantially' genetic in origin, which they quantify as 50% genetic and 50% environmental.”

In the citing paper

“By undermining culture-only explanations of racial inequality, the 'provisional truth' of Rushton and Jensen's (2005) hereditarian hypothesis thereby undermines the moral legitimacy of all rationales for racial equalization that posit White misbehavior as its cause.”

In the citing paper

“The following major facts from Rushton and Jensen's (2005) Sections 3-6 and 10-12 have been replicated many times, and all with independent sources of data. All are consistent with hereditarian theory but contradict culture-only theory:”

In the citing paper

“So far, the three-way race pattern for IQ/ g differences has been replicated with reaction/inspection time and brain size, both of which are highly heritable and correlated with g , as well as with a large collection of purely physical attributes (e.g., twinning).”

In the citing paper

“Evidence contradicting the culture-only theory's prediction that group differences in cognitive ability should, in essence, track group differences in identifiable cultural practices and socioeconomic advantage (Section 12).”

In the citing paper

“The most g -loaded tests predict school and job performance best, and they predict performance equally well for Blacks and Whites in both the United States and South Africa.”

In the citing paper

“Natural variation in environments likewise fails to alter the common developmental processes by which abilities are assembled in different races.”

In the citing paper

“Rushton and Jensen (2005) make no recommendations for specific policies and correctly argue that the hereditarian hypothesis implies none in particular.”

In the citing paper

“Worldwide Black-White-East Asian differences in IQ (Section 3), reaction time (Section 4), and brain size, with Whites having the intermediate scores (Section 6);”

In the citing paper

“As the studies of malnourished East Asian adoptees illustrate, extreme deprivation of the sort that humans have always had to contend with (e.g., starvation, infectious disease) seldom permanently impairs cognitive ability to any substantial degree once conditions are rectified.”

In the citing paper

“The most direct individual tests of genetic versus environmental effects on mental ability-transracial adoption (Section 7), racial admixture (Section 8), and behavior genetic modeling of mean group differences (Section 5)-have either been uncommon or fraught with ambiguity.”

In the citing paper

“Small (.2) and moderate (.4) correlations of IQ, respectively, with skull size and in vivo brain volume (Section 6);”

In the citing paper

“In summary, Rushton and Jensen (2005) have presented a compelling case that their 50%-50% hereditarian hypothesis is more plausible than the cultureonly hypothesis.”

In the citing paper

“Worldwide Black-White-East Asian mean differences in a large suite of biological variables (e.g., twinning, gestation time, sex ratio at birth) and social variables (e.g., law abidingness, marital stability), with the three races always in the same rank order (Section 10);”

In the citing paper

“As Rushton and Jensen (2005) suggest, g theory can predict fairly accurately how large the racial disparities in achievement will be in different settings, depending on their demands for g and the IQ distributions of the groups involved.”

In the citing paper

“This commonality in cognitive architecture is indicated, for instance, by cross-race identity of g factors and input-output achievement covariance matrices (Section 5). This commonality also contradicts predictions that different cultures create different intelligences.”

In the citing paper

“A genetic divergence (quantitative, not qualitative) of world population (i.e., racial) groups during evolution (Section 11); and”

In the citing paper

“The g factor is highly heritable within races and also has replicated metabolic, electrical, and structural correlates in the brain, most of them also known to be heritable (these studies are mostly with Whites).”

In the citing paper

“The rising heritability of IQ with age (within races) and the virtual disappearance by adolescence of any shared environmental effects on IQ (e.g., parental income, education, child-rearing practices; Section 5);”

In the citing paper

“A moderately high correlation (usually .6-.7) of different IQ subtests' g loadings, not only with the magnitude of Black-White-East Asian mean differences on those subtests (Section 6) but also with measures of those subtests' rootedness in biological and genetic processes (e.g., heritability; Section 4);”

In the citing paper

“Our findings are also inconsistent with the hypothesis discussed in some prior work (e.g., Rushton and Jensen 2005) that racial disparities may be due to differences in cognitive ability, as there is no biological reason that racial differences in cognitive ability would vary by gender.”

In the citing paper

“First, the prior literature suggests no ex ante biological reason that racial differences in cognitive ability would vary by gender (Rushton and Jensen 2005).”