Special Issue "Beyond Thirty Years of Research on Race Differences in Cognitive Ability"

A special issue of Psych (ISSN 2624-8611).

Deadline for manuscript submissions: closed (15 July 2019).

Special Issue Information

This Special Issue is closed and no longer accepting submissions.

Fully 13 years have passed since Rushton and Jensen (2005) published their review of race differences in cognitive ability. The article now has over 500 citations. Rushton and Jensen’s (2005) work was impactful, partly because it carefully pitted culture-only versus hereditation models of the cause of race differences in intelligence. The authors were also thorough (the article is 60 pages long) in that they reviewed literature across ten “categories of evidence” regarding which model was possibly true. Ultimately, Rushton and Jensen (2005) concluded that “some genetic component [exists] in Black–White differences in mean IQ.”

Were they correct? What newer research has or will come to bear on this question? The special issue seeks high-quality scientific contributions regarding either Rushton and Jensen’s (2005) overall conclusion, or any of the ten categories of evidence they reviewed. Multiple perspectives are welcome. So too are reviews, new empirical evidence on the question(s), and articles that expand the scope beyond just Black / White comparisons. The contributions may focus on individuals as the unit of analysis, or feature aggregate-level (e.g., nations, regions, states) data.

The question is critically important because IQ is arguably the most powerful variable in social science. As such, group differences on IQ correlate with group differences on a host of variables (e.g., education, income, health, crime) that together seem to comprise human well-being. Without understanding the source of group-mean differences, we cannot make progress toward maximizing human well-being for everyone.

The ten categories of evidence include:

  • The worldwide distribution of test scores,
  • The g factor of mental ability,
  • Heritability,
  • Brain size and cognitive ability,
  • Transracial adoption
  • Racial admixture
  • regression
  • related life-history traits
  • human origins research
  • hypothesized environmental variables

 

Keywords

  • Intelligence
  • Group differences
  • Race
  • Ethnicity
  • Nature / Nurture
  • Well-being

Published Papers (16 papers)

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Editorial

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Open AccessEditorial
A Conversation with Gerhard Meisenberg
Psych 2019, 1(1), 364-374; https://doi.org/10.3390/psych1010026 - 20 Jun 2019
Abstract
Gerhard Meisenberg is a retired professor of biochemistry who lives in the Caribbean island nation of Dominica [...] Full article
Open AccessEditorial
A Conversation with Michael A. Woodley of Menie, Yr.
Psych 2019, 1(1), 207-219; https://doi.org/10.3390/psych1010015 - 09 May 2019
Abstract
Michael Anthony Woodley of Menie, Yr (Younger), is a British ecologist and evolutionary psychologist, whose research on secular trends in dierent aspects of human intelligence has earned him considerable notability.[...] Full article

Research

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Open AccessArticle
Rushton and Jensen’s Work has Parallels with Some Concepts of Race Awareness in Ancient Greece
Psych 2019, 1(1), 391-402; https://doi.org/10.3390/psych1010028 - 20 Jun 2019
Abstract
Rushton and Jensen’s “Thirty Years of Research on Race Differences in Cognitive Ability” documents IQ differences in populations on the basis of race. The authors explain these data by arguing that cold winter conditions in Europe had greater pressure for the selection of [...] Read more.
Rushton and Jensen’s “Thirty Years of Research on Race Differences in Cognitive Ability” documents IQ differences in populations on the basis of race. The authors explain these data by arguing that cold winter conditions in Europe had greater pressure for the selection of higher intelligence. Critics of Rushton and Jensen, and of the very category of race, claim that race is a social construct that only came up in the 16th century, as a result of overseas voyages and the Atlantic slave trade. The goal of this article is to refute that particular claim, by documenting how, long before the 16th century, in classical antiquity race was already a meaningful concept, and how some Greek authors even developed ideas that bear some resemblance to Rushton and Jensen’s theory. The article documents how ancient Egyptians already had keen awareness of race differences amongst various populations. Likewise, the article documents passages from the Hippocratic and Aristotelian corpus, which attests that already in antiquity, there was a conception that climatic differences had an influence on intelligence, and that these differences eventually become enshrined in fixed biological traits. Full article
Open AccessArticle
Should Cognitive Differences Research Be Forbidden?
Psych 2019, 1(1), 306-319; https://doi.org/10.3390/psych1010021 - 01 Jun 2019
Cited by 1
Abstract
Some authors have proposed that research on cognitive differences, including differences between ethnic and racial groups, needs to be prevented because it produces true knowledge that is dangerous and socially undesirable. From a consequentialist perspective, this contribution investigates the usually unstated assumptions about [...] Read more.
Some authors have proposed that research on cognitive differences, including differences between ethnic and racial groups, needs to be prevented because it produces true knowledge that is dangerous and socially undesirable. From a consequentialist perspective, this contribution investigates the usually unstated assumptions about harms and benefits behind these proposals. The conclusion is that intelligence differences provide powerful explanations of many important real-world phenomena, and that denying their causal role requires the promotion of alternative false beliefs. Acting on these false beliefs almost invariably prevents the effective management of societal problems while creating new ones. The proper questions to ask are not about the nature of the research and the results it is expected to produce, but about whether prevailing value systems can turn truthful knowledge about cognitive differences into benign outcomes, whatever the truth may be. These value systems are the proper focus of action. Therefore, the proposal to suppress knowledge about cognitive ability differences must be based on the argument that people in modern societies will apply such knowledge in malicious rather than beneficial ways, either because of universal limitations of human nature or because of specific features of modern societies. Full article
Open AccessArticle
Filling in the Gaps: The Association between Intelligence and Both Color and Parent-Reported Ancestry in the National Longitudinal Survey of Youth 1997
Psych 2019, 1(1), 240-261; https://doi.org/10.3390/psych1010017 - 22 May 2019
Cited by 1
Abstract
Little research has dealt with intragroup ancestry-related differences in intelligence in Black and White Americans. To help fill this gap, we examined the association between intelligence and both color and parent-reported ancestry using the NLSY97. We used a nationally-representative sample, a multidimensional measure [...] Read more.
Little research has dealt with intragroup ancestry-related differences in intelligence in Black and White Americans. To help fill this gap, we examined the association between intelligence and both color and parent-reported ancestry using the NLSY97. We used a nationally-representative sample, a multidimensional measure of cognitive ability, and a sibling design. We found that African ancestry was negatively correlated with general mental ability scores among Whites (r = −0.038, N = 3603; corrected for attenuation, rc = −0.245). In contrast, the correlation between ability and parent-reported European ancestry was positive among Blacks (r = 0.137, N = 1788; rc = 0.344). Among Blacks, the correlation with darker skin color, an index of African ancestry, was negative (r = −0.112, N = 1455). These results remained with conspicuous controls. Among Blacks, both color and parent-reported European ancestry had independent effects on general cognitive ability (color: β = −0.104; ancestry: β = 0.118; N = 1445). These associations were more pronounced on g-loaded subtests, indicating a Jensen Effect for both color and ancestry (rs = 0.679 to 0.850). When we decomposed the color results for the African ancestry sample between and within families, we found an association between families, between singletons (β = −0.153; N = 814), and between full sibling pairs (β = −0.176; N = 225). However, we found no association between full siblings (β = 0.027; N = 225). Differential regression to the mean results indicated that the factors causing the mean group difference acted across the cognitive spectrum, with high-scoring African Americans no less affected than low-scoring ones. We tested for measurement invariance and found that strict factorial invariance was tenable. We then found that the weak version of Spearman’s hypothesis was tenable while the strong and contra versions were not. The results imply that the observed cognitive differences are primarily due to differences in g and that the Black-White mean difference is attributable to the same factors that cause differences within both groups. Further examination revealed comparable intraclass correlations and absolute differences for Black and White full siblings. This implied that the non-shared environmental variance components were similar in magnitude for both Blacks and Whites. Full article
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Open AccessArticle
Race as Social Construct
Psych 2019, 1(1), 139-165; https://doi.org/10.3390/psych1010011 - 29 Apr 2019
Abstract
It is often claimed that race is a social construct and that scientists studying race differences are disruptive racists. The recent April 2018 “Race Issue” of the widely distributed National Geographic Magazine (NG) provided its millions of readers with a particularly illustrative example [...] Read more.
It is often claimed that race is a social construct and that scientists studying race differences are disruptive racists. The recent April 2018 “Race Issue” of the widely distributed National Geographic Magazine (NG) provided its millions of readers with a particularly illustrative example of this position. As discussions of race issues often recur, in both scientific and lay literature, stir considerable polemics, and have political, societal and human implications, we found it of both scientific and general interest to identify and dissect the following partly overlapping key contentions of the NG race issue magazine: (1) Samuel Morton’s studies of brain size is reprehensible racism (2) Race does not relate to geographic location, (3) Races do not exist as we are all equals and Africans, (4) Admixture and displacement erase race differences as soon as they appear, and (5) Race is only skin color deep. Also examined is the claim that Race does not matter. When analyzed within syllogistic formalism, each of the claims is found theoretically and empirically unsustainable, as Morton’s continuously evolving race position is misrepresented, race relates significantly to geography, we are far from equals, races have definitely not been erased, and race, whether self-reported or defined by ancestry, lineage, ecotype, species, or genes, is much more than skin color deep. Race matters vitally for people and societies. We conclude that important research on existing population differences is hurt when widely respected institutions such as NG mobilize their full authority in a massively circulated attempt to betray its scientific and public readership by systematically misrepresenting historical sources and scientific positions, shaming past scientists, and by selectively suppressing unwanted or unacceptable results–acts included as examples of academic fraud by the National Academy of Sciences (US, 1986). Any unqualified a priori denial of the formative evolutionary aspects of individual and population differences threatens to impede the recent promising research on effects of genome wide allelic associations, which would lames us in the vital quest to develop rational solutions to associated globally pressing societal problems. Full article
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Open AccessArticle
The Intelligence of Biracial Children of U.S. Servicemen in Northeast Asia: Results from Japan
Psych 2019, 1(1), 132-138; https://doi.org/10.3390/psych1010010 - 24 Apr 2019
Abstract
The IQ averages of biracial children have long been of interest to intelligence researchers for clarifying the causes of group differences in intelligence. We carried out a search for IQ test results of biracial children fathered by U.S. servicemen after World War 2 [...] Read more.
The IQ averages of biracial children have long been of interest to intelligence researchers for clarifying the causes of group differences in intelligence. We carried out a search for IQ test results of biracial children fathered by U.S. servicemen after World War 2 and indigenous Asian women in northeast Asian countries (Japan, Korea, China). We were able to locate a report from Japan from a foster home (n = 28–48 biracial children across tests). Results showed that there was only a minuscule IQ gap (<1 IQ) between children of Black–Japanese and White–Japanese parents. However, interpretation of the results is difficult owing to the very small sample size, the non-representative sample, and unknown patterns of assortative mating. We suggest possible avenues for future research. Full article
Open AccessArticle
Evidence for Recent Polygenic Selection on Educational Attainment and Intelligence Inferred from Gwas Hits: A Replication of Previous Findings Using Recent Data
Psych 2019, 1(1), 55-75; https://doi.org/10.3390/psych1010005 - 28 Mar 2019
Cited by 5
Abstract
Genetic variants identified by three large genome-wide association studies (GWAS) of educational attainment (EA) were used to test a polygenic selection model. Weighted and unweighted polygenic scores (PGS) were calculated and compared across populations using data from the 1000 Genomes (n = 26), [...] Read more.
Genetic variants identified by three large genome-wide association studies (GWAS) of educational attainment (EA) were used to test a polygenic selection model. Weighted and unweighted polygenic scores (PGS) were calculated and compared across populations using data from the 1000 Genomes (n = 26), HGDP-CEPH (n = 52) and gnomAD (n = 8) datasets. The PGS from the largest EA GWAS was highly correlated to two previously published PGSs (r = 0.96–0.97, N = 26). These factors are both highly predictive of average population IQ (r = 0.9, N = 23) and Learning index (r = 0.8, N = 22) and are robust to tests of spatial autocorrelation. Monte Carlo simulations yielded highly significant p values. In the gnomAD samples, the correlation between PGS and IQ was almost perfect (r = 0.98, N = 8), and ANOVA showed significant population differences in allele frequencies with positive effect. Socioeconomic variables slightly improved the prediction accuracy of the model (from 78–80% to 85–89%), but the PGS explained twice as much of the variance in IQ compared to socioeconomic variables. In both 1000 Genomes and gnomAD, there was a weak trend for lower GWAS significance SNPs to be less predictive of population IQ. Additionally, a subset of SNPs were found in the HGDP-CEPH sample (N = 127). The analysis of this sample yielded a positive correlation with latitude and a low negative correlation with distance from East Africa. This study provides robust results after accounting for spatial autocorrelation with Fst distances and random noise via an empirical Monte Carlo simulation using null SNPs. Full article
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Open AccessArticle
The Effect of Biracial Status and Color on Crystallized Intelligence in the U.S.-Born African–European American Population
Psych 2019, 1(1), 44-54; https://doi.org/10.3390/psych1010004 - 07 Mar 2019
Cited by 2
Abstract
The relationship between biracial status, color, and crystallized intelligence was examined in a nationally representative sample of adult Black and White Americans. First, it was found that self-identifying biracial individuals, who were found to be intermediate in color and in self-reported ancestry, had [...] Read more.
The relationship between biracial status, color, and crystallized intelligence was examined in a nationally representative sample of adult Black and White Americans. First, it was found that self-identifying biracial individuals, who were found to be intermediate in color and in self-reported ancestry, had intermediate levels of crystallized intelligence relative to self-identifying White (mostly European ancestry) and Black (mostly sub-Saharan African ancestry) Americans. The results were transformed to an IQ scale: White (M = 100.00, N = 7569), primarily White–biracial (M = 96.07, N = 43, primarily Black–biracial (M = 94.14 N = 50), and Black (M = 89.81, N = 1381). Next, among self-identifying African Americans, a statistically significant negative correlation of r = −0.102 (N = 637) was found between interviewer-rated darker facial color and vocabulary scores. After correction for the reliability of the measures, this correlation increased to r = −0.21. Corrections for the validity of color as an index of African ancestry would raise this correlation to around r = −0.48. This association among self-identifying African Americans was not accounted for by confounding factors, such as region of residence and interviewer race, or by parental socioeconomic status and individual educational attainment. In the multivariate models, the standardized betas for color and crystallized intelligence among African Americans ranged from β = −0.112 to β = −0.142. Based on the coefficients from the multivariate analysis, it was further found that cognitive ability was a significant mediator in the context of color and education, while education was not in the context of color and cognitive ability. It is concluded that these results further substantiate the statistical relation between intelligence and biogeographic ancestry in African and European American populations. Full article
Open AccessArticle
Spearman’s Hypothesis Tested Comparing 47 Regions of Japan Using a Sample of 18 Million Children
Psych 2019, 1(1), 26-34; https://doi.org/10.3390/psych1010002 - 11 Feb 2019
Cited by 1
Abstract
Many groups differ in their mean intelligence score. Spearman’s hypothesis states that the differences are a function of cognitive complexity. There tend to be large differences on subtests of high cognitive complexity and small differences on subtests of low cognitive complexity. Spearman’s hypothesis [...] Read more.
Many groups differ in their mean intelligence score. Spearman’s hypothesis states that the differences are a function of cognitive complexity. There tend to be large differences on subtests of high cognitive complexity and small differences on subtests of low cognitive complexity. Spearman’s hypothesis has been supported by a large number of studies. Can Spearman’s hypothesis be generalized to regions of a country, where these regions differ in mean intelligence? We utilized data from 86 different cognitive tests from all 47 Japanese prefectures and correlated the g loadings of 86 subtests with standardized differences on the same subtests. Spearman’s hypothesis was clearly supported: the biggest differences between the regions were on the tests that were of the greatest complexity, meaning that Spearman’s hypothesis may be generalizable from groups to regions. In Japan, g loadings offer a better explanation of group differences in intelligence than cultural differences. Future research should explore whether Spearman’s hypothesis is also supported for differences between regions of other countries. Full article
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Open AccessArticle
Biogeographic Ancestry, Cognitive Ability and Socioeconomic Outcomes
Psych 2019, 1(1), 1-25; https://doi.org/10.3390/psych1010001 - 10 Jan 2019
Cited by 6
Abstract
The cause(s) of ubiquitous cognitive differences between American self-identified racial/ethnic groups (SIREs) is uncertain. Evolutionary-genetic models posit that ancestral genetic selection pressures are the ultimate source of these differences. Conversely, sociological models posit that these differences result from racial discrimination. To examine predictions [...] Read more.
The cause(s) of ubiquitous cognitive differences between American self-identified racial/ethnic groups (SIREs) is uncertain. Evolutionary-genetic models posit that ancestral genetic selection pressures are the ultimate source of these differences. Conversely, sociological models posit that these differences result from racial discrimination. To examine predictions based on these models, we conducted a global admixture analysis using data from the Pediatric Imaging, Neurocognition, and Genetics Study (PING; N = 1,369 American children). Specifically, we employed a standard methodology of genetic epidemiology to determine whether genetic ancestry significantly predicts cognitive ability, independent of SIRE. In regression models using four different codings for SIRE as a covariate, we found incremental relationships between genetic ancestry and both general cognitive ability and parental socioeconomic status (SES). The relationships between global ancestry and cognitive ability were partially attenuated when parental SES was added as a predictor and when cognitive ability was the outcome. Moreover, these associations generally held when subgroups were analyzed separately. Our results are congruent with evolutionary-genetic models of group differences and with certain environmental models that mimic the predictions of evolutionary-genetic ones. Implications for research on race/ethnic differences in the Americas are discussed, as are methods for further exploring the matter. Full article
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Review

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Open AccessReview
A Meta-Analysis of Spearman’s Hypothesis Tested on Latin-American Hispanics, Including a New Way to Correct for Imperfectly Measuring the Construct of g
Psych 2019, 1(1), 101-122; https://doi.org/10.3390/psych1010008 - 18 Apr 2019
Cited by 1
Abstract
Spearman’s hypothesis states that the difference in intelligence between groups is a function of the g loadings of the subtests, where larger differences are found on tests with higher g loadings. This finding has consistently been supported on various groups. In this study [...] Read more.
Spearman’s hypothesis states that the difference in intelligence between groups is a function of the g loadings of the subtests, where larger differences are found on tests with higher g loadings. This finding has consistently been supported on various groups. In this study we look at samples of Latin-American Hispanics in comparison to Whites. We carried out a meta-analysis based on 14 data points and a total of 16,813 Latin-American Hispanics, including a new way to correct for imperfectly measuring the construct of g. Spearman’s hypothesis was strongly supported with a mean r of 0.63. After correction for various statistical artifacts this value became rho = 0.91. Therefore, we conclude that Spearman’s hypothesis also holds true for White/Latin-American Hispanic differences. Full article
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Other

Open AccessEssay
The Fallacy of Equating the Hereditarian Hypothesis with Racism
Psych 2019, 1(1), 262-278; https://doi.org/10.3390/psych1010018 - 24 May 2019
Cited by 1
Abstract
There is a large amount of evidence that groups differ in average cognitive ability. The hereditarian hypothesis states that these differences are partly or substantially explained by genetics. Despite being a positive claim about the world, this hypothesis is frequently equated with racism, [...] Read more.
There is a large amount of evidence that groups differ in average cognitive ability. The hereditarian hypothesis states that these differences are partly or substantially explained by genetics. Despite being a positive claim about the world, this hypothesis is frequently equated with racism, and scholars who defend it are frequently denounced as racists. Yet equating the hereditarian hypothesis with racism is a logical fallacy. The present article identifies ten common arguments for why the hereditarian hypothesis is racist and demonstrates that each one is fallacious. The article concludes that society will be better served if the hereditarian hypothesis is treated the same way as any other scientific claim—critically, but dispassionately. Full article
Open AccessEssay
The Original Industrial Revolution. Did Cold Winters Select for Cognitive Ability?
Psych 2019, 1(1), 166-181; https://doi.org/10.3390/psych1010012 - 02 May 2019
Cited by 1
Abstract
Rushton and Jensen argued that cognitive ability differs between human populations. But why are such differences expectable? Their answer: as modern humans spread out of Africa and into northern Eurasia, they entered colder and more seasonal climates that selected for the ability to [...] Read more.
Rushton and Jensen argued that cognitive ability differs between human populations. But why are such differences expectable? Their answer: as modern humans spread out of Africa and into northern Eurasia, they entered colder and more seasonal climates that selected for the ability to plan ahead, in order to store food, make clothes, and build shelters for winter. This cold winter theory is supported by research on Paleolithic humans and recent hunter-gatherers. Tools become more diverse and complex as effective temperature decreases, apparently because food has to be obtained during limited periods and over large areas. There is also more storage of food and fuel and greater use of untended traps and snares. Finally, shelters have to be sturdier, and clothing more cold-resistant. The resulting cognitive demands are met primarily by women because the lack of opportunities for food gathering pushes them into more cognitively demanding tasks, like garment making, needlework, weaving, leatherworking, pottery, and kiln operation. The northern tier of Paleolithic Eurasia thus produced the “Original Industrial Revolution”—an explosion of creativity that preadapted its inhabitants for later developments, i.e., farming, more complex technology and social organization, and an increasingly future-oriented culture. Over time, these humans would spread south, replacing earlier populations that could less easily exploit the possibilities of the new cultural environment. As this environment developed further, it selected for further increases in cognitive ability. Indeed, mean intelligence seems to have risen during recorded history at temperate latitudes in Europe and East Asia. There is thus no unified theory for the evolution of human intelligence. A key stage was adaptation to cold winters during the Paleolithic, but much happened later. Full article
Open AccessOpinion
Reflections on Sixty-Eight Years of Research on Race and Intelligence
Psych 2019, 1(1), 123-131; https://doi.org/10.3390/psych1010009 - 24 Apr 2019
Cited by 2
Abstract
I first encountered the question of race and intelligence sixty-eight years ago [...] Full article
Open AccessCommentary
Reservations about Rushton
Psych 2019, 1(1), 35-43; https://doi.org/10.3390/psych1010003 - 11 Feb 2019
Cited by 3
Abstract
Rushton believed not only that East Asians, whites, and blacks could be ranked in that order for desirable traits but also that the black/white IQ gap is predominantly genetic in origin. Concerning the first, he relied on the “ice ages hypothesis”to show that [...] Read more.
Rushton believed not only that East Asians, whites, and blacks could be ranked in that order for desirable traits but also that the black/white IQ gap is predominantly genetic in origin. Concerning the first, he relied on the “ice ages hypothesis”to show that the evolutionary history of the three races had varied as East Asians were subjected to the most demanding environment (north of the Himalayas), whites to the next most demanding (north of the Alps), and blacks to the least demanding (Africa). As to the second, he appealed to arguments based on the method of correlated vectors (Jensen effects) and regression to the mean. To assess his contribution I argue: (1) That the racial ranking for desirable traits is not as tidy as it seems; (2) That the ice ages hypothesis has been falsified; (3) That the black/white Q gap is more likely to be environmental, with black American subculture as the culprit; and (4) That appeals to correlated vectors and regression cannot disentangle genetic and environmental causes. Full article
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