Race and intelligence: Difference between revisions
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==Research into the possible genetic influences on test score differences== |
==Research into the possible genetic influences on test score differences== |
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{{see also|Heritability of IQ}} |
{{see also|Heritability of IQ}} |
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According to [[James A. Banks]], the argument that group differences are based on genetics is |
According to [[James A. Banks]], the argument that group differences are based on genetics is "untenable".<ref name=SAGE /> There is no scientific evidence that the test score gap has a genetic component,{{sfn|Mackintosh|2011|p=358}}{{sfn|Nisbett|Aronson|Blair|Dickens|2012a}}{{sfn|Kaplan|2015}} and growing evidence indicates that environmental factors, not genetic ones, explain the racial IQ gap.{{sfn|Nevid|2014|page=271}} |
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===Genetics of race and intelligence=== |
===Genetics of race and intelligence=== |
Revision as of 13:24, 2 May 2020
![]() | This article's factual accuracy is disputed. (February 2020) |
Discussions of race and intelligence, as well as claims of genetic differences in intelligence along racial lines, have appeared in both popular science and academic research since the inception of IQ testing in the early 20th century. Concepts such as "race" and "intelligence" are social constructs that defy objective definition; and the validity of IQ tests as a metric for general intelligence is itself disputed. In particular, there is no scientific evidence that the average IQ scores of different population groups can be attributed to any claimed genetic differences between those groups.
The first tests showing differences in IQ scores between different population groups in the United States were the tests of United States Army recruits in World War I. In the 1920s, groups of eugenics lobbyists argued that this demonstrated that African-Americans and certain immigrant groups were of inferior intellect to Anglo-Saxon white people, due to innate biological differences, using this as an argument for policies of racial segregation. However, soon other studies appeared, contesting these conclusions and arguing instead that the Army tests had not adequately controlled for environmental factors, such as socio-economic and educational inequality between black people and white people. Later observations of phenomena such as the Flynn effect have also highlighted the ways that environmental factors affect group IQ differences.
History of the controversy
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Alfred_Binet.jpg/160px-Alfred_Binet.jpg)
Claims of differences in intelligence between races have been used to justify colonialism, slavery, racism, social Darwinism, and racial eugenics. Racial thinkers such as Arthur de Gobineau relied crucially on the assumption that black people were innately inferior to white people in developing their ideologies of white supremacy. Even enlightenment thinkers such as Thomas Jefferson, a slave owner, believed black people to be innately inferior to white people in physique and intellect.[1]
Early IQ testing
The first practical intelligence test was developed between 1905 and 1908 by Alfred Binet in France for school placement of children. Binet warned that results from his test should not be assumed to measure innate intelligence or used to label individuals permanently.[2] Binet's test was translated into English and revised in 1916 by Lewis Terman (who introduced IQ scoring for the test results) and published under the name Stanford–Binet Intelligence Scales. When Terman's test was published, there was great concern in the United States about the abilities and skills of recent immigrants. Some of the nationalities of the more recent immigrants, such as Slavs, were sometimes thought to belong to different races from native-born Americans.[citation needed]
The US Army used a different set of tests developed by Robert Yerkes to evaluate draftees for World War I. Researchers[clarification needed] found that people from southern and eastern Europe scored lower than native-born Americans, that Americans from northern states had higher scores than Americans from southern states, and that black Americans scored lower than white Americans.[3] The results were widely publicized by a lobby of anti-immigration activists, including the conservationist and theorist of scientific racism Madison Grant, who considered the so-called Nordic race to be superior, but under threat because of immigration by inferior breeds. In his influential work, A Study of American Intelligence, psychologist Carl Brigham used the results of the Army tests to argue for a stricter immigration policy, limiting immigration to countries considered to belong to the "Nordic race".[4]
In the 1920s, some US states enacted eugenic laws, such as Virginia's 1924 Racial Integrity Act, which established the one-drop rule (of 'racial purity') as law. Many scientists reacted negatively to eugenicist claims linking abilities and moral character to racial or genetic ancestry. They pointed to the contribution of environment (such as speaking English as a second language) to test results.[5] By the mid-1930s, many psychologists in the US had adopted the view that environmental and cultural factors played a dominant role in IQ test results. The psychologist Carl Brigham repudiated his own earlier arguments, explaining that he had come to realize that the tests were not a measure of innate intelligence.
Discussions of the issue in the United States, especially in the writings of Madison Grant, influenced German Nazi claims that the "Nordics" were a "master race."[6] As American public sentiment shifted against the Germans, claims of racial differences in intelligence increasingly came to be regarded as problematic.[7] Anthropologists such as Franz Boas, Ruth Benedict, and Gene Weltfish did much to demonstrate that claims about racial hierarchies of intelligence were unscientific.[8] Nonetheless, a powerful eugenics and segregation lobby funded largely by textile-magnate Wickliffe Draper continued to use intelligence studies as an argument for eugenics, segregation, and anti-immigration legislation.[9]
The Pioneer Fund and The Bell Curve
As the desegregation of the American South gained traction in the 1950s, debate about black intelligence resurfaced. Audrey Shuey, funded by Draper's Pioneer Fund, published a new analysis of Yerkes' tests, concluding that black people really were of inferior intellect to white people. This study was used by segregationists to argue that it was to the advantage of black children to be educated separately from the superior white children.[10] In the 1960s, the debate was revived when William Shockley publicly defended the view that black children were innately unable to learn as well as white children.[11] Arthur Jensen expressed similar opinions in his Harvard Educational Review article, "How Much Can We Boost IQ and Scholastic Achievement?," which questioned the value of compensatory education for African-American children. He suggested that poor educational performance in such cases reflected an underlying genetic cause rather than lack of stimulation at home or other environmental factors.[12][13]
Another revival of public debate followed the appearance of The Bell Curve (1994), a book by Richard Herrnstein and Charles Murray that supported the general viewpoint of Jensen.[14] A statement in support of Herrnstein and Murray titled "Mainstream Science on Intelligence," was published in The Wall Street Journal with 52 signatures. The Bell Curve also led to critical responses in a statement titled "Intelligence: Knowns and Unknowns" of the American Psychological Association and in several books, including The Bell Curve Debate (1995), Inequality by Design (1996) and a second edition of The Mismeasure of Man (1996) by Stephen Jay Gould.[15][16][15]
Some of the authors proposing genetic explanations for group differences have received funding from the Pioneer Fund, which was headed by J. Philippe Rushton until his death in 2012.[9][15][17][18][19] Arthur Jensen, who jointly with Rushton published a 2005 review article arguing that the difference in mean IQs between blacks and whites is partly due to genetics,[20] received $1.1 million from the Pioneer Fund.[21][22] According to Ashley Montagu, "The University of California's Arthur Jensen, cited twenty-three times in The Bell Curve's bibliography, is the book's principal authority on the intellectual inferiority of blacks."[23]
The Southern Poverty Law Center lists the Pioneer Fund as a hate group, citing the fund's history, its funding of race and intelligence research, and its connections with racist individuals.[24] Other researchers have criticized the Pioneer Fund for promoting scientific racism, eugenics and white supremacy.[9][25][26][27]
Criticisms of race and intelligence as biologically defined concepts
Intelligence, IQ, g and IQ tests
The concept of intelligence and the degree to which intelligence is measurable are matters of debate. There is no consensus about how to define intelligence; nor is it universally accepted that it is something that can be meaningfully measured by a single figure.[28] A recurring criticism is that different societies value and promote different kinds of skills and that the concept of intelligence is therefore culturally variable and cannot be measured by the same criteria in different societies.[28] Consequently, some critics argue that it makes no sense to propose relationships between intelligence and other variables.[29]
In relation to racial differences in IQ test scores, it is crucial to ask exactly what it is that IQ tests measure. Arthur Jensen was a proponent of the view that there is a correlation between scores on all the known types of IQ tests, and that this correlation points to an underlying g factor corresponding to general intelligence. Jensen considered the g factor to be mostly fixed in a given individual and unresponsive to training or other environmental influences. In his view, test score differences, especially in tasks considered to be particularly "g-loaded," reflect the test taker's innate capability.
Other psychometricians have argued that, whether or not there is such a thing as a general intelligence factor, performance on tests relies crucially on knowledge acquired through prior exposure to the types of tasks that such tests contain. This means that comparisons of test scores between persons with widely different life experiences and cognitive habits do not reveal their relative innate potentials.[30]
Race
The majority of anthropologists today consider race to be a sociopolitical phenomenon rather than a biological one,[31] a view supported by considerable genetics research.[32][33] The current mainstream view in the social sciences and biology is that race is a social construction based on folk ideologies that construct groups based on social disparities and superficial physical characteristics.[34] Sternberg, Grigorenko & Kidd (2005) state, "Race is a socially constructed concept, not a biological one. It derives from people's desire to classify."[29] The concept of human "races" as natural and separate divisions within the human species has also been rejected by the American Anthropological Association. The official position of the AAA, adopted in 1998, is that advances in scientific knowledge have made it "clear that human populations are not unambiguous, clearly demarcated, biologically distinct groups" and that "any attempt to establish lines of division among biological populations [is] both arbitrary and subjective."[35]
In studies of human intelligence, race is almost always determined using self-reports rather than analyses of genetic characteristics. According to psychologist David Rowe, self-report is the preferred method for racial classification in studies of racial differences because classification based on genetic markers alone ignore the "cultural, behavioral, sociological, psychological, and epidemiological variables" that distinguish racial groups.[36] Hunt and Carlson write that "Nevertheless, self-identification is a surprisingly reliable guide to genetic composition. Tang et al. (2005) applied mathematical clustering techniques to sort genomic markers for over 3,600 people in the United States and Taiwan into four groups. There was almost perfect agreement between cluster assignment and individuals' self-reports of racial/ethnic identification as white, black, East Asian, or Latino."[37] Sternberg and Grigorenko disagree with Hunt and Carlson's interpretation of Tang, "Tang et al.'s point was that ancient geographic ancestry rather than current residence is associated with self-identification and not that such self-identification provides evidence for the existence of biological race."[38]
Anthropologist C. Loring Brace[39] and geneticist Joseph Graves disagree with the idea that cluster analysis and the correlation between self-reported race and genetic ancestry support the notion of biological races.[40] They argue that while it is possible to find biological and genetic variation corresponding roughly to the groupings normally defined as races, this is true for almost all geographically distinct populations. The cluster structure of the genetic data is dependent on the initial hypotheses of the researcher and the populations sampled. When one samples continental groups, the clusters become continental; if one had chosen other sampling patterns, the clusters would be different. Kaplan 2011 concludes that, while differences in particular allele frequencies can be used to identify populations that loosely correspond to the racial categories common in Western social discourse, the differences are of no more biological significance than the differences found between any human populations (e.g., the Spanish and Portuguese).
Group differences
The study of human intelligence is one of the most controversial topics in psychology, in part because of difficulty reaching agreement about the meaning of intelligence and objections to the assumption that intelligence can be meaningfully measured by IQ tests. Claims that there are innate differences in intelligence between racial and ethnic groups – which go back at least to the 19th century – have been criticized both for relying on specious assumptions and research methods and for serving as an ideological framework for discrimination and racism. The scientific consensus is that group differences in IQ scores are caused not by genetic differences between races or ethnicities, but rather by "other correlated demographic variables such as socioeconomic status, education level, and motivation."[41]
Test scores
In the US, generally individuals identifying themselves as Asian tend to score higher on IQ tests than do Caucasians, who score higher than Hispanics, who score higher than African Americans. Nevertheless, greater variation in IQ scores exists within each ethnic group than between them.[42] Roth et al. (2001), in a review of the results of a total of 6,246,729 participants in other tests of cognitive ability or aptitude, found a difference in mean scores between black people and white people of 1.1 SD. Consistent results were found for college and university application tests such as the Scholastic Aptitude Test (N = 2.4 million) and Graduate Record Examination (N = 2.3 million), as well as for tests of job applicants in corporate settings (N = 0.5 million) and in the military (N = 0.4 million).[43]
In response to the controversial 1994 book The Bell Curve, the American Psychological Association (APA) formed a task-force of eleven experts, which issued a report "Intelligence: Knowns and Unknowns" in 1995. Regarding group differences, the report reaffirmed the consensus that differences within groups are much wider than differences between groups, and that claims of ethnic differences in intelligence should be scrutinized carefully, as such claims had been used to justify racial discrimination. The report also acknowledged problems with the racial categories used, as these categories are neither consistently applied, nor homogeneous (see also race and ethnicity in the United States).[44]
Flynn effect and the closing gap
During the 20th century raw scores on IQ tests were rising; this score increase is known as the "Flynn effect," named after James R. Flynn. In the United States, the increase was continuous and approximately linear from the earliest years of testing to about 1998 when the gains stopped and some tests even showed decreasing test scores. For example, the average scores of black people on some IQ tests in 1995 were the same as the scores of white people in 1945.[45] As one pair of academics phrased it, "the typical African American today probably has a slightly higher IQ than the grandparents of today's average white American."[46]
Flynn has argued that, given that these changes took place between one generation and the next, it is highly unlikely that genetic factors could have accounted for the increasing scores, which must then have been caused by environmental factors. The importance of the Flynn effect in the debate over the causes of the black/white IQ gap lies in demonstrating that environmental factors may cause changes in test scores on the scale of 1 SD. This had previously been doubted.
A separate phenomenon from the Flynn effect has been the discovery that the IQ gap was gradually closing over the last decades of the 20th century, as black test-takers increased their average scores relative to white test-takers. For instance, Vincent reported in 1991 that the black-white IQ gap was decreasing among children, but that it was remaining constant among adults.[47] Similarly, a 2006 study by Dickens and Flynn estimated that the difference between mean scores of black people and white people closed by about 5 or 6 IQ points between 1972 and 2002,[48] a reduction of about one-third. In the same period, the educational achievement disparity also diminished.[49] Reviews by Flynn and Dickens,[50] Mackintosh,[51] and Nisbett et al[52] accept the gradual closing of the gap as a fact.
Environmental influences on group differences in IQ
Health and nutrition
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Lead_levels_children.png/220px-Lead_levels_children.png)
Environmental factors including childhood lead exposure,[53] low rates of breast feeding,[55] and poor nutrition[56][57] can significantly affect cognitive development and functioning. For example, childhood exposure to lead, associated with homes in poorer areas[58] causes an average IQ drop of 7 points,[59] and iodine deficiency causes a fall, on average, of 12 IQ points.[60][61] 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.[62] 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.[63][64] Mackintosh points out that for American black people infant mortality is about twice as high as for white people, 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.[65]
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.[66]
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.[67] James Flynn has himself argued against this view.[68]
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.[69] 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.[70]
A 2013 meta-analysis by the World Health Organization found that, after controlling for maternal IQ, breastfeeding was associated with IQ gains of 2.19 points. The authors suggest that this relationship is causal but state that the practical significance of this gain is debatable; however, they highlight one study suggesting an association between breastfeeding and academic performance in Brazil, where "breastfeeding duration does not present marked variability by socioeconomic position."[71] Colen and Ramey (2014) similarly find that controlling for sibling comparisons within families, rather than between families, reduces the correlation between breastfeeding status and WISC IQ scores by nearly a third, but further find the relationship between breastfeeding duration and WISC IQ scores to be insignificant. They suggest that "much of the beneficial long-term effects typically attributed to breastfeeding, per se, may primarily be due to selection pressures into infant feeding practices along key demographic characteristics such as race and socioeconomic status."[72] Reichman estimates that no more than 3 to 4% of the black-white IQ gap can be explained by black-white disparities in low birth weight.[73]
Education
Several studies have proposed that a large part of the gap can be attributed to differences in quality of education.[74] Racial discrimination in education has been proposed as one possible cause of differences in educational quality between races.[75] According to a paper by Hala Elhoweris, Kagendo Mutua, Negmeldin Alsheikh and Pauline Holloway, teachers' referral decisions for students to participate in gifted and talented educational programs were influenced in part by the students' ethnicity.[76]
The Abecedarian Early Intervention Project, an intensive early childhood education project, was also able to bring about an average IQ gain of 4.4 points at age 21 in the black children who participated in it compared to controls.[55] Arthur Jensen agreed that the Abecedarian project demonstrated that education can have a significant effect on IQ, but also declared his view that no educational program thus far had been able to reduce the black-white IQ gap by more than a third, and that differences in education are thus unlikely to be its only cause.[77]
A series of studies by Joseph Fagan and Cynthia Holland measured the effect of prior exposure to the kind of cognitive tasks posed in IQ tests on test performance. Assuming that the IQ gap was the result of lower exposure to tasks using the cognitive functions usually found in IQ tests among African American test takes, they prepared a group of African Americans in this type of tasks before taking an IQ test. The researchers found that there was no subsequent difference in performance between the African-Americans and white test takers.[78][79] Daley and Onwuegbuzie conclude that Fagan and Holland demonstrate that "differences in knowledge between black people and white people for intelligence test items can be erased when equal opportunity is provided for exposure to the information to be tested".[80] A similar argument is made by David Marks who argues that IQ differences correlate well with differences in literacy suggesting that developing literacy skills through education causes an increase in IQ test performance.[81][82]
A 2003 study found that two variables — stereotype threat and the degree of educational attainment of children's fathers — partially explained the black-white gap in cognitive ability test scores, undermining the hereditarian view that they stemmed from immutable genetic factors.[83]
Socioeconomic environment
Different aspects of the socioeconomic environment in which children are raised have been shown to correlate with part of the IQ gap, but they do not account for the entire gap.[84] According to a 2006 review, these factors account for slightly less than half of one standard deviation.[85]
Other research has focused on different causes of variation within low socioeconomic status (SES) and high SES groups.[86][87][88] In the US, among low SES groups, genetic differences account for a smaller proportion of the variance in IQ than among high SES populations.[89] Such effects are predicted by the bioecological hypothesis – that genotypes are transformed into phenotypes through nonadditive synergistic effects of the environment.[90] Nisbett et al. (2012a) harvp error: multiple targets (2×): CITEREFNisbettAronsonBlairDickens2012a (help) suggest that high SES individuals are more likely to be able to develop their full biological potential, whereas low SES individuals are likely to be hindered in their development by adverse environmental conditions. The same review also points out that adoption studies generally are biased towards including only high and high middle SES adoptive families, meaning that they will tend to overestimate average genetic effects. They also note that studies of adoption from lower-class homes to middle-class homes have shown that such children experience a 12 to 18 point gain in IQ relative to children who remain in low SES homes.[91] A 2015 study found that environmental factors (namely, family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors, child birth order, and child birth weight) accounted for the black-white gap in cognitive ability test scores.[92] Hart and Risley argue that there is a huge disparity in the amount of language children hear in welfare, working-class, and professional families (between 13 million and 45 million words) in the age range of zero to three years, and that by age nine these differences lead to large differences in child outcomes.[93]
Test bias
A number of studies have reached the conclusion that IQ tests may be biased against certain groups.[94][95][96][97] The validity and reliability of IQ scores obtained from outside the United States and Europe have been questioned, in part because of the inherent difficulty of comparing IQ scores between cultures.[98][99] Several researchers have argued that cultural differences limit the appropriateness of standard IQ tests in non-industrialized communities.[100][101]
A 1996 report by the American Psychological Association states that intelligence can be difficult to compare across cultures, and notes that differing familiarity with test materials can produce substantial differences in test results; it also says that tests are accurate predictors of future achievement for black and white Americans, and are in that sense unbiased.[44] The view that tests accurately predict future educational attainment is reinforced by Nicholas Mackintosh in his 1998 book IQ and Human Intelligence,[102] and by a 1999 literature review by Brown, Reynolds & Whitaker (1999).
James R. Flynn, surveying studies on the topic, notes that the weight and presence of many test questions depends on what sorts of information and modes of thinking are culturally valued.[103]
Stereotype threat and minority status
Stereotype threat is the fear that one's behavior will confirm an existing stereotype of a group with which one identifies or by which one is defined; this fear may in turn lead to an impairment of performance.[104] Testing situations that highlight the fact that intelligence is being measured tend to lower the scores of individuals from racial-ethnic groups who already score lower on average or are expected to score lower. Stereotype threat conditions cause larger than expected IQ differences among groups.[105] Psychometrician Nicholas Mackintosh considers that there is little doubt that the effects of stereotype threat contribute to the IQ gap between black people and white people.[106]
A large number of studies have shown that systemically disadvantaged minorities, such as the African American minority of the United States, generally perform worse in the educational system and in intelligence tests than the majority groups or less disadvantaged minorities such as immigrant or "voluntary" minorities.[44] The explanation of these findings may be that children of caste-like minorities, due to the systemic limitations of their prospects of social advancement, do not have "effort optimism", i.e. they do not have the confidence that acquiring the skills valued by majority society, such as those skills measured by IQ tests, is worthwhile. They may even deliberately reject certain behaviors that are seen as "acting white."[44][107][108]
Research published in 1997 indicates that part of the black-white gap in cognitive ability test scores is due to racial differences in test motivation.[109]
However, attempts to replicate studies evincing significant effects of stereotype threat have not yielded the same results. In 2004 Sackett et al. found that eliminating stereotype threat does not eliminate the racial test performance gap, and in 2005 Tyson et al. found that African Americans have motivation similar to or even better than that of white Americans.[110][111] Self-affirmation exercises promoted by research scientists such as Geoffrey L. Cohen have not been shown to be effective in attempts to replicate his studies.[112]
Research into the possible genetic influences on test score differences
According to James A. Banks, the argument that group differences are based on genetics is "untenable".[42] There is no scientific evidence that the test score gap has a genetic component,[113][91][114] and growing evidence indicates that environmental factors, not genetic ones, explain the racial IQ gap.[115]
Genetics of race and intelligence
Geneticist Alan R. Templeton argues that the question about the possible genetic effects on the test score gap is muddled by the general focus on "race" rather than on populations defined by gene frequency or by geographical proximity, and by the general insistence on phrasing the question in terms of heritability.[116] Templeton points out that racial groups neither represent sub-species nor distinct evolutionary lineages, and that therefore there is no basis for making claims about the general intelligence of races.[116] From this point of view the search for possible genetic influences on the black-white test score gap is a priori flawed, because there is no genetic material shared by all Africans or by all Europeans. Mackintosh (2011) harvp error: multiple targets (2×): CITEREFMackintosh2011 (help), however, argues that by using genetic cluster analysis to correlate gene frequencies with continental populations it might be possible to show that African populations have a higher frequency of certain genetic variants that contribute to an average lower intelligence. Such a hypothetical situation could hold without all Africans carrying the same genes or belonging to a single evolutionary lineage. According to Mackintosh, a biological basis for the gap thus cannot be ruled out on a priori grounds.
Intelligence is a polygenic trait. This means that intelligence is under the influence of several genes, possibly several thousand. The effect of most individual genetic variants on intelligence is thought to be very small, well below 1% of the variance in g. Current studies using quantitative trait loci have yielded little success in the search for genes influencing intelligence. Robert Plomin is confident that QTLs responsible for the variation in IQ scores exist, but due to their small effect sizes, more powerful tools of analysis will be required to detect them.[117] Others assert that no useful answers can be reasonably expected from such research before an understanding of the relation between DNA and human phenotypes emerges.[64] Several candidate genes have been proposed to have a relationship with intelligence.[118][119] However, a review of candidate genes for intelligence published in Deary, Johnson & Houlihan (2009) failed to find evidence of an association between these genes and general intelligence, stating "there is still almost no replicated evidence concerning the individual genes, which have variants that contribute to intelligence differences".[120] In 2001, a review in the Journal of Black Psychology refuted eight major premises on which the hereditarian view regarding race and intelligence is based.[121]
A 2005 literature review article by Sternberg, Grigorenko and Kidd stated that no gene has been shown to be linked to intelligence, "so attempts to provide a compelling genetic link of race to intelligence are not feasible at this time".[122] Hunt (2010, p. 447) and Mackintosh (2011, p. 344) harvtxt error: multiple targets (2×): CITEREFMackintosh2011 (help) concurred, both scholars noting that while several environmental factors have been shown to influence the IQ gap, the evidence for a genetic influence has been circumstantial, and according to Mackintosh negligible. Mackintosh however suggests that it may never become possible to account satisfyingly for the relative contributions of genetic and environmental factors. The 2012 review by Nisbett et al. (2012a) harvp error: multiple targets (2×): CITEREFNisbettAronsonBlairDickens2012a (help) concluded that "Almost no genetic polymorphisms have been discovered that are consistently associated with variation in IQ in the normal range". Hunt and several other researchers however maintain that genetic causes cannot be ruled out, and that new evidence may yet show a genetic contribution to the gap. Hunt concurs with Rushton and Jensen who considered the 100% environmental hypothesis to be impossible. Nonetheless, Nisbett and colleagues (2012) consider the entire IQ gap to be explained by the environmental factors that have thus far been demonstrated to influence it, and Mackintosh does not find this view to be unreasonable.[91]
Heritability within and between groups
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Heritability_plants.jpeg/220px-Heritability_plants.jpeg)
Twin studies of intelligence have reported high heritability values. However, these studies are based on questionable assumptions.[123] When used in the context of human behavior genetics, the term "heritability" is highly misleading, as it does not convey any information about the relative importance of genetic or environmental factors on the development of a given trait, nor does it convey the extent to which that trait is genetically determined.[124] Arguments in support of a genetic explanation of racial differences in IQ are sometimes fallacious. For instance, hereditarians have sometimes cited the failure of known environmental factors to account for such differences, or the high heritability of intelligence within races, as evidence that racial differences in IQ are genetic.[125]
Psychometricians have found that intelligence is substantially heritable within populations, with 30–50% of variance in IQ scores in early childhood being attributable to genetic factors in analyzed US populations, increasing to 75–80% by late adolescence.[44][120] In biology heritability is defined as the ratio of variation attributable to genetic differences in an observable trait to the trait's total observable variation. The heritability of a trait describes the proportion of variation in the trait that is attributable to genetic factors within a particular population. A heritability of 1 indicates that variation correlates fully with genetic variation and a heritability of 0 indicates that there is no correlation between the trait and genes at all. In psychological testing, heritability tends to be understood as the degree of correlation between the results of a test taker and those of their biological parents. However, since high heritability is simply a correlation between traits and genes, it does not describe the causes of heritability which in humans can be either genetic or environmental.
Therefore, a high heritability measure does not imply that a trait is genetic or unchangeable, however, as environmental factors that affect all group members equally will not be measured by heritability and the heritability of a trait may also change over time in response to changes in the distribution of genes and environmental factors.[44] High heritability also doesn't imply that all of the heritability is genetically determined, but can also be due to environmental differences that affect only a certain genetically defined group (indirect heritability).[126] The figure to the left demonstrates how heritability works. In both gardens the difference between tall and short cornstalks is 100% heritable as cornstalks that are genetically disposed for growing tall will become taller than those without this disposition, but the difference in height between the cornstalks to the left and those on the right is 100% environmental as it is due to different nutrients being supplied to the two gardens. Hence the causes of differences within a group and between groups may not be the same, even when looking at traits that are highly heritable.[126] In his criticism of the Bell Curve, Noam Chomsky further illustrated this with the example of women wearing earrings:
To borrow an example from Ned Block, "some years ago when only women wore earrings, the heritability of having an earring was high because differences in whether a person had an earring was due to a chromosomal difference, XX vs. XY." No one has yet suggested that wearing earrings, or ties, is "in our genes," an inescapable fate that environment cannot influence, "dooming the liberal notion."[127]
In regards to the IQ gap the question becomes whether racial groups can be shown to be influenced by different environmental factors that may account for the observed differences between them. Jensen originally argued that given the high heritability of IQ the only way that the IQ gap could be explained as caused by the environment would be if it could be shown that all black people were subject to a single "x-factor" which affected no white populations while affecting all black populations equally.[128] Jensen considered the existence of such an x-factor to be extremely improbable, but Flynn's discovery of the Flynn effect showed that in spite of high heritability environmental factors could cause considerable disparities in IQ between generations of the same population, showing that the existence of such an x-factor was not only possible but real.[129]
Jensen has also argued that heritability of traits rises with age as the genetic potential of individuals becomes expressed. He sees this as related to the fact that the IQ gap between white and black test takers has been shown to appear gradually, with the gap widening as cohorts reach adulthood. This he sees as a further argument in favor of Spearman's hypothesis (see section below).[citation needed]
In contrast, Dickens and Flynn argued that the conventional interpretation ignores the role of feedback between factors, such as those with a small initial IQ advantage, genetic or environmental, seeking out more stimulating environments which will gradually greatly increase their advantage, which, as one consequence in their alternative model, would mean that the "heritability" figure is only in part due to direct effects of genotype on IQ.[130][131][132]
Today researchers such as Hunt (2010), Nisbett et al. (2012a) harvp error: multiple targets (2×): CITEREFNisbettAronsonBlairDickens2012a (help) and Mackintosh (2011) harvp error: multiple targets (2×): CITEREFMackintosh2011 (help) consider that rather than a single factor accounting for the entire gap, probably many different environmental factors differ systematically between the environments of white and black people converge to create part of the gap and perhaps all of it. They argue that it does not make sense to talk about a single universal heritability figure for IQ, rather, they state, heritability of IQ varies between and within groups. They point specifically to studies showing a higher heritability of test scores in white and medium-high SES families, but considerably lower heritability for black and low-SES families. This they interpret to mean that children who grow up with limited resources do not get to develop their full genetic potential.[91]
Multiple studies have been conducted over the past several decades to survey scientific estimates on the heritability of the IQ gap. A review by Snydermann and Rothman in 1988 found that 45% of the scientists they questioned believed the gap to be "a product of genetic and environmental variation," 15% and 1% respectively "entirely to environmental" and "genetic variation," while the remaining 38% either declined to answer or stated that the evidence was inconclusive.[133] The heritability of intelligence was estimated on average to be 59.6% for white Americans and 57.0% for black Americans among those who answered that the evidence was sufficiently conclusive.[134][broken footnote] The Wall Street Journal published an editorial by Linda Gottfredson in 1994, signed by 52 professors specializing in intelligence and allied fields, that estimated the heritability of individual variation to range between 40–80%, but also stating that "there is no definitive answer" to explain the racial gap.[135] Social psychologist Donald T. Campbell criticized the report, arguing that it overstated the plausibility of genetic explanations and underestimated the extent of environmental differences between races.[136] A 1995 report by the APA stated that there is more plausible evidence for an environmental than for a genetic explanation, but that there was "no adequate explanation" for the black-white IQ gap.[44] In a 2013 followup on Snyderman & Rothman, Rindermann et al. found the average and median estimates of the black-white IQ gap to be heritable by 47% and 50% respectively among surveyed scientists who believed that the available evidence allowed for a reasonable estimate. This survey however yielded a response rate of 18% (228 participants) compared to Snyderman & Rothman's 65% (661 participants).[137]
Spearman's hypothesis
Spearman's hypothesis states that the magnitude of the black-white difference in tests of cognitive ability is entirely or mainly a function of the extent to which a test measures general mental ability, or g. The hypothesis was first formalized by Arthur Jensen who devised the statistical Method of Correlated Vectors to test it. Jensen holds that if Spearman's hypothesis holds true then some cognitive tasks have a higher g-load than others, and that these tasks are exactly the tasks in which the gap between black and white test takers are greatest. Jensen, and other psychometricians such as Rushton and Lynn, take this to show that the cause of g and the cause of the gap are the same—in their view genetic differences.[20]
Mackintosh (2011, pp. 338–39) harvtxt error: multiple targets (2×): CITEREFMackintosh2011 (help) acknowledges that Jensen and Rushton have shown a modest correlation between g-loading, heritability, and the test score gap, but did not accept that this demonstrates a genetic origin of the gap. Mackintosh points out that it is the results of exactly those tests that Rushton and Jensen consider to have the highest g-loading and heritability, such as the Wechsler test, that have seen the highest increases due to the Flynn effect. This likely suggests that they are also the most sensitive to environmental changes, which undermines Jensen's argument that the black-white gap is most likely caused by genetic factors. Mackintosh also argues that Spearman's hypothesis, which he considers to be likely to be correct, simply shows that the test score gap is based on whatever cognitive faculty is central to intelligence, but not what this factor is. Nisbett et al. (2012a, p. 146) harvtxt error: multiple targets (2×): CITEREFNisbettAronsonBlairDickens2012a (help) make the same point, noting also that the increase in the IQ scores of black test takers is necessarily also an increase in g. However a 2013 meta-analysis concluded that the Flynn effect did not occur on g.[138]
James Flynn (2012, pp. 140–1) argues that there is an inherent flaw in Jensen's argument that the correlation between g-loadings, test scores and heritability support a genetic cause of the gap. He points out that as the difficulty of a task increases a low performing group will naturally fall further behind, and heritability will therefore also naturally increase. The same holds for increases in performance which will first affect the least difficult tasks, but only gradually affect the most difficult ones. Flynn thus sees the correlation between in g-loading and the test score gap to offer no clue to the cause of the gap.[139]
Hunt (2010, p. 415) states that many of conclusions of Jensen, and his colleagues rest on the validity of Spearman's hypothesis, and the method of correlated vectors used to test it. Hunt points out that other researchers have found this method of calculation to produce false positive results, and that other statistical methods should be used instead. According to Hunt, Jensen and Rushton's frequent claim that Spearman's hypothesis should be regarded as empirical fact does not hold, and that new studies based on better statistical methods would be required to confirm or reject the hypothesis that the correlation between g-loading, heritability and the IQ gap is due to IQ gaps consisting mostly of g.[citation needed]
Adoption studies
A number of studies have been done on the effect of similar rearing conditions on children from different races. The hypothesis is that by investigating whether black children adopted into white families demonstrated gains in IQ test scores relative to black children reared in black families. Depending on whether their test scores are more similar to their biological or adoptive families, that could be interpreted as either supporting a genetic or an environmental hypothesis. The main point of critique in studies like these however is whether the environment of black children—even when raised in white families—is truly comparable to the environment of white children. Several reviews of the adoption study literature has pointed out that it is perhaps impossible to avoid confounding of biological and environmental factors in this type of studies.[140] Given the differing heritability estimates in medium-high SES and low-SES families, Nisbett et al. (2012a, pp. 134) harvtxt error: multiple targets (2×): CITEREFNisbettAronsonBlairDickens2012a (help) argue that adoption studies on the whole tend to overstate the role of genetics because they represent a restricted set of environments, mostly in the medium-high SES range.
The Minnesota Transracial Adoption Study (1976) examined the IQ test scores of 122 adopted children and 143 nonadopted children reared by advantaged white families. The children were restudied ten years later.[141][142][143] The study found higher IQ for white people compared to black people, both at age 7 and age 17.[141] Acknowledging the existence of confounding factors, Scarr and Weinberg, the authors of the original study, did not themselves consider that it provided support for either the hereditarian or environmentalist view.[144]
Three other adoption studies found contrary evidence to the Minnesota study, lending support to a mostly environmental hypothesis:
- Eyferth (1961) studied the out-of-wedlock children of black and white soldiers stationed in Germany after World War 2 and then raised by white German mothers in what has become known as the Eyferth study. He found no significant differences in average IQ between groups.
- Tizard et al. (1972) studied black (West Indian), white, and mixed-race children raised in British long-stay residential nurseries. Two out of three tests found no significant differences. One test found higher scores for non-white people.
- Moore (1986) compared black and mixed-race children adopted by either black or white middle-class families in the United States. Moore observed that 23 black and interracial children raised by white parents had a significantly higher mean score than 23 age-matched children raised by black parents (117 vs 104), and argued that differences in early socialization explained these differences.
Frydman and Lynn (1989) showed a mean IQ of 119 for Korean infants adopted by Belgian families. After correcting for the Flynn effect, the IQ of the adopted Korean children was still 10 points higher than the indigenous Belgian children.[145][20][146]
Reviewing the evidence from adoption studies, Mackintosh considers the studies by Tizard and Eyferth to be inconclusive, and the Minnesota study to be consistent only with a partial genetic hypothesis. On the whole, he finds that environmental and genetic variables remain confounded and considers evidence from adoption studies inconclusive, and fully compatible with a 100% environmental explanation.[140] Similarly, Drew Thomas argues that race differences in IQ that appear in adoption studies are in fact an artifact of methodology and that East Asian IQ advantages and Black IQ disadvantages disappear when this is controlled for.[147]
Racial admixture studies
Most people have an ancestry from different geographic regions, particularly African Americans typically have ancestors from both Africa and Europe, with, on average, 20% of their genome inherited from European ancestors.[148] If racial IQ gaps have a partially genetic basis, one might expect black people with a higher degree of European ancestry to score higher on IQ tests than black people with less European ancestry, because the genes inherited from European ancestors would likely include some genes with a positive effect on IQ.[149] Geneticist Alan Templeton has argued that an experiment based on the Mendelian "common garden" design where specimens with different hybrid compositions are subjected to the same environmental influences, would be the only way to definitively show a causal relation between genes and IQ. Summarizing the findings of admixture studies, he concludes that it has shown no significant correlation between any cognitive and the degree of African or European ancestry.[150]
Studies have employed different ways of measuring or approximating relative degrees of ancestry from Africa and Europe. One set of studies have used skin color as a measure, and other studies have used blood groups. Loehlin (2000) surveys the literature and argues that the blood groups studies may be seen as providing some support to the genetic hypothesis, even though the correlation between ancestry and IQ was quite low. He finds that studies by Eyferth (1961), Willerman, Naylor & Myrianthopoulos (1970) did not find a correlation between degree of African/European ancestry and IQ. The latter study did find a difference based on the race of the mother, with children of white mothers with black fathers scoring higher than children of black mothers and white fathers. Loehlin considers that such a finding is compatible with either a genetic or an environmental cause. All in all Loehlin finds admixture studies inconclusive and recommends more research.
Reviewing the evidence from admixture studies Hunt (2010) considers it to be inconclusive because of too many uncontrolled variables. Mackintosh (2011, p. 338) harvtxt error: multiple targets (2×): CITEREFMackintosh2011 (help) quotes a statement by Nisbett (2009) to the effect that admixture studies have not provided a shred of evidence in favor of a genetic basis for the gap.
Mental chronometry
Mental chronometry measures the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response by the participant. This reaction time (RT) is considered a measure of the speed and efficiency with which the brain processes information.[151] Scores on most types of RT tasks tend to correlate with scores on standard IQ tests as well as with g, and no relationship has been found between RT and any other psychometric factors independent of g.[151] The strength of the correlation with IQ varies from one RT test to another, but Hans Eysenck gives 0.40 as a typical correlation under favorable conditions.[152] According to Jensen individual differences in RT have a substantial genetic component, and heritability is higher for performance on tests that correlate more strongly with IQ.[153] Nisbett argues that some studies have found correlations closer to 0.2, and that the correlation is not always found.[154]
Several studies have found differences between races in average reaction times. These studies have generally found that reaction times among black, Asian and white children follow the same pattern as IQ scores.[155][156][157] Black-white differences in reaction time, however, tend to be small (average effect size .18).[158] Rushton & Jensen (2005) have argued that reaction time is independent of culture and that the existence of race differences in average reaction time is evidence that the cause of racial IQ gaps is partially genetic instead of entirely cultural. Responding to this argument in Intelligence and How to Get It, Nisbett has pointed to the Jensen & Whang (1993) study in which a group of Chinese Americans had longer reaction times than a group of European Americans, despite having higher IQs. Nisbett also mentions findings in Flynn (1991) and Deary (2001) suggesting that movement time (the measure of how long it takes a person to move a finger after making the decision to do so) correlates with IQ just as strongly as reaction time, and that average movement time is faster for black people than for white people.[159] Mackintosh (2011, p. 339) harvtxt error: multiple targets (2×): CITEREFMackintosh2011 (help) considers reaction time evidence unconvincing and points out that other cognitive tests that also correlate well with IQ show no disparity at all, for example the habituation/dishabituation test. And he points out that studies show that rhesus monkeys have shorter reaction times than American college students, suggesting that different reaction times may not tell us anything useful about intelligence.
Brain size
A number of studies have reported a moderate statistical correlation between differences in IQ and brain size between individuals in the same group.[160][161] Some scholars have reported differences in average brain sizes between racial groups,[162] although this is unlikely to be a good measure of IQ as brain size also differs between men and women, but without significant differences in IQ. At the same time newborn black children have the same average brain size as white children, suggesting that the difference in average size could be accounted for by differences in environment. Several factors that reduce brain size have been demonstrated to disproportionately affect black children.[91]
Archaeological data
Archaeological evidence does not support claims by Rushton and others that black people' cognitive ability was inferior to white people' during prehistoric times as a result of evolution.[163]
Policy relevance and ethics
The 1996 report of the APA commented on the ethics of research on race and intelligence.[37] Gray & Thompson (2004) as well as Hunt & Carlson (2007) have also discussed different possible ethical guidelines.[37][164][non-primary source needed] Nature in 2009 featured two editorials on the ethics of research in race and intelligence by Steven Rose (against) and Stephen J. Ceci and Wendy M. Williams (for).[165][166]
Steven Rose maintains that the history of eugenics makes this field of research difficult to reconcile with current ethical standards for science.[166]
Linda Gottfredson argues that suggestion of higher ethical standards for research into group differences in intelligence is a double standard applied in order to undermine disliked results.[167] James R. Flynn has argued that had there been a ban on research on possibly poorly conceived ideas, much valuable research on intelligence testing (including his own discovery of the Flynn effect) would not have occurred.[168]
Jensen and Rushton argued that the existence of biological group differences does not rule out, but raises questions about the worthiness of policies such as affirmative action or placing a premium on diversity. They also argued for the importance of teaching people not to overgeneralize or stereotype individuals based on average group differences, because of the significant overlap of people with varying intelligence between different races.[169][non-primary source needed]
Some who hold the environmentalist viewpoint argue for increased interventions in order to close the gaps.[170] Nisbett argues that schools can be greatly improved and that many interventions at every age level are possible.[171] Flynn, arguing for the importance of the black subculture, writes that "America will have to address all the aspects of black experience that are disadvantageous, beginning with the regeneration of inner city neighbourhoods and their schools. A resident police office and teacher in every apartment block would be a good start."[172] Researchers from both sides agree that interventions should be better researched.[154][173][broken footnote]
Especially in developing nations, society has been urged to take on the prevention of cognitive impairment in children as of the highest priority. Possible preventable causes include malnutrition, infectious diseases such as meningitis, parasites, cerebral malaria, in utero drug and alcohol exposure, newborn asphyxia, low birth weight, head injuries, lead poisoning and endocrine disorders.[174]
See also
- Behavioral epigenetics
- Model minority
- Outline of human intelligence
- Race and crime in the United States
References
Notes
- ^ Jackson & Weidman 2004, p. 23.
- ^ Plotnik & Kouyoumdjian 2011.
- ^ Jackson & Weidman 2004, p. 116.
- ^ Jackson & Weidman 2004, p. 116, 309.
- ^ Pickren & Rutherford 2010, p. 163.
- ^ Spiro 2009.
- ^ Ludy 2006
- ^ Jackson & Weidman 2004, pp. 130–32.
- ^ a b c Tucker 2002.
- ^ Jackson 2005.
- ^ Shurkin 2006.
- ^ Panofsky, Aaron (2014). Misbehaving Science. Controversy and the Development of Behavior Genetics. Chicago: University of Chicago Press. ISBN 978-0-226-05831-3.
- ^ Alland 2002, pp. 79–80.
- ^ Herrnstein & Murray 1994.
- ^ a b c Maltby, Day & Macaskill 2007
- ^ Mackintosh 1998
- ^ Graves 2002a.
- ^ Graves 2002b.
- ^ Grossman & Kaufman 2001
- ^ a b c Rushton & Jensen 2005.
- ^ Adam, Miller (1994). "The Pioneer Fund: Bankrolling the Professors of Hate". The Journal of Blacks in Higher Education (6): 58–61.
- ^ Blakemore, Bill; Jennings, Peter; Nissen, Beth (November 22, 1994). "The Bell Curve and the Pioneer Fund". ABC World News Tonight. ABC News. Vanderbilt Television News Archive : ABC Evening News for Tuesday, Nov 22, 1994. Headline: American Agenda (Intelligence)
- ^ Montagu, Ashley (2002). Race and IQ (2 ed.). New York: Oxford University Press. ISBN 9780195102215.
- ^ Berlet 2003.
- ^ Pioneer Fund Board Archived 2011-05-25 at the Wayback Machine
- ^ Falk 2008, p. 18
- ^ Wroe 2008, p. 81
- ^ a b Schacter, Gilbert & Wegner 2007, pp. 350–1
- ^ a b Sternberg, Grigorenko & Kidd 2005
- ^ Mackintosh 2011, p. 359. sfn error: multiple targets (2×): CITEREFMackintosh2011 (help)
- ^ Daley & Onwuegbuzie 2011, p. 294.
- ^ Smay & Armelagos 2000.
- ^ Rotimi, Charles N. (2004). "Are medical and nonmedical uses of large-scale genomic markers conflating genetics and 'race'?". Nature Genetics. 36 (11 Suppl): 43–47. doi:10.1038/ng1439. PMID 15508002.
Two facts are relevant: (i) as a result of different evolutionary forces, including natural selection, there are geographical patterns of genetic variations that correspond, for the most part, to continental origin; and (ii) observed patterns of geographical differences in genetic information do not correspond to our notion of social identities, including 'race' and 'ethnicity
- ^ Schaefer 2008
- ^ AAA 1998
- ^ Rowe 2005
- ^ a b c Hunt & Carlson 2007
- ^ Sternberg & Grigorenko 2007
- ^ Brace 2005
- ^ Graves 2001
- ^ Hampshire et al. 2012.
- ^ a b Encyclopedia of Diversity in Education. SAGE. 2012. p. 1209. ISBN 9781412981521.
- ^ Roth et al. 2001
- ^ a b c d e f g Neisser et al. 1996.
- ^ Mackintosh 1998, p. 162
- ^ Swain, Carol (2003). Contemporary voices of white nationalism in America. Cambridge, UK New York: Cambridge University Press. p. 70. ISBN 978-0521016933. Note: this quote is from the authors' introductory essay, not from the interviews.
- ^ Vincent 1991.
- ^ Dickens & Flynn 2006. sfn error: multiple targets (2×): CITEREFDickensFlynn2006 (help)
- ^ Neisser, Ulric (Ed). 1998. The rising curve: Long-term gains in IQ and related measures. Washington, DC, US: American Psychological Association
- ^ Dickens, William T; Flynn, James R (2006). "Black Americans Reduce the Racial IQ Gap: Evidence from Standardization Samples" (PDF). Psychological Science. 17 (10): 913–20. CiteSeerX 10.1.1.186.2540. doi:10.1111/j.1467-9280.2006.01802.x. PMID 17100793. Archived from the original (PDF) on 2009-10-09.
{{cite journal}}
: Invalid|ref=harv
(help) - ^ Mackintosh, N. J. (2011). IQ and Human Intelligence (second ed.). Oxford: Oxford University Press. ISBN 978-0-19-958559-5.
{{cite book}}
: Invalid|ref=harv
(help); Unknown parameter|lay-date=
ignored (help); Unknown parameter|lay-url=
ignored (help) - ^ Nisbett, Richard E.; Aronson, Joshua; Blair, Clancy; Dickens, William; Flynn, James; Halpern, Diane F.; Turkheimer, Eric (2012a). "Intelligence: new findings and theoretical developments" (PDF). American Psychologist. 67 (2): 130–159. doi:10.1037/a0026699. ISSN 0003-066X. PMID 22233090. Retrieved 22 July 2013.
{{cite journal}}
: Invalid|ref=harv
(help); Unknown parameter|lay-date=
ignored (help); Unknown parameter|lay-url=
ignored (help) - ^ a b Bellinger, Stiles & Needleman 1992
- ^ MMWR 2005
- ^ a b Campbell et al. 2002
- ^ Ivanovic et al. 2004
- ^ Saloojee & Pettifor 2001
- ^ Agency For Toxic Substances And Disease Registry Case Studies In Environmental Medicine (CSEM) (2012-02-15). "Principles of Pediatric Environmental Health, The Child as Susceptible Host: A Developmental Approach to Pediatric Environmental Medicine" (PDF). U.S. Department for Health and Human Services. Retrieved 2019-01-30.
- ^ Lanphear, Bruce P.; Hornung, Richard; Khoury, Jane; Yolton, Kimberly; Baghurst, Peter; Bellinger, David C.; Canfield, Richard L.; Dietrich, Kim N.; Bornschein, Robert; Greene, Tom; Rothenberg, Stephen J.; Needleman, Herbert L.; Schnaas, Lourdes; Wasserman, Gail; Graziano, Joseph; Roberts, Russell (2005-03-18). "Low-Level Environmental Lead Exposure and Children's Intellectual Function: An International Pooled Analysis". Environmental Health Perspectives. 113 (7): 894–899. doi:10.1289/ehp.7688. ISSN 0091-6765. PMC 1257652. PMID 16002379.
- ^ Qian et al. 2005
- ^ Feyrer, James; Politi, Dimitra; Weil, David N. (2017). "The Cognitive Effects of Micronutrient Deficiency: Evidence from Salt Iodization in the United States" (PDF). Journal of the European Economic Association. 15 (2): 355–387. doi:10.1093/jeea/jvw002. PMC 6919660. PMID 31853231.
- ^ The Lancet Series on Maternal and Child Undernutrition, 2008.
- ^ Nisbett 2009, p. 101
- ^ a b Cooper 2005
- ^ Mackintosh 2011, pp. 343–44. sfn error: multiple targets (2×): CITEREFMackintosh2011 (help)
- ^ Behrman, Alderman & Hoddinott 2004
- ^ Colom, R.; Lluis-Font, J. M.; Andrés-Pueyo, A. (2005). "The generational intelligence gains are caused by decreasing variance in the lower half of the distribution: supporting evidence for the nutrition hypothesis". Intelligence. 33: 83–91. doi:10.1016/j.intell.2004.07.010.
- ^ Flynn, J. R. (2009). "Requiem for nutrition as the cause of IQ gains: Raven's gains in Britain 1938 to 2008". Economics and Human Biology. 7 (1): 18–27. doi:10.1016/j.ehb.2009.01.009. PMID 19251490.
- ^ Eppig, Fincher & Thornhill 2010
- ^ Eppig 2011
- ^ "Long-term effects of breastfeeding – a systemic review" (PDF). World Health Organization. 2013. Retrieved 18 June 2018.
{{cite web}}
: Unknown parameter|authors=
ignored (help) - ^ Cynthia G. Colen and David M. Ramey (2014). "Is Breast Truly Best? Estimating the Effect of Breastfeeding on Long-term Child Wellbeing in the United States Using Sibling Comparisons". Social Science & Medicine. 109 (1): 55–65. doi:10.1016/j.socscimed.2014.01.027. PMC 4077166. PMID 24698713.
- ^ Reichman 2005
- ^ Manly et al. 2002 and Manly et al. 2004
- ^ Mickelson 2003
- ^ Elhoweris et al. 2005
- ^ Miele 2002, p. 133
- ^ Fagan, Joseph F; Holland, Cynthia R (2002). "Equal opportunity and racial differences in IQ". Intelligence. 30 (4): 361–387. doi:10.1016/S0160-2896(02)00080-6.
- ^ Fagan, J.F.; Holland, C.R. (2007). "Racial equality in intelligence: Predictions from a theory of intelligence as processing". Intelligence. 35 (4): 319–334. doi:10.1016/j.intell.2006.08.009.
- ^ Daley & Onwuegbuzie 2011.
- ^ Marks, D.F. (2010). "IQ variations across time, race, and nationality: An artifact of differences in literacy skills". Psychological Reports. 106 (3): 643–664. doi:10.2466/pr0.106.3.643-664. PMID 20712152.
- ^ Barry, Scott (2010-08-23). "The Flynn Effect and IQ Disparities Among Races, Ethnicities, and Nations: Are There Common Links?". Psychology Today. Retrieved 2014-08-22.
- ^ McKay, Patrick F.; Doverspike, Dennis; Bowen‐Hilton, Doreen; McKay, Quintonia D. (2003). "The Effects of Demographic Variables and Stereotype Threat on Black/White Differences in Cognitive Ability Test Performance". Journal of Business and Psychology. 18 (1): 1–14. doi:10.1023/A:1025062703113.
- ^ Hunt 2010, p. 428.
- ^ Magnuson, Katherine A.; Duncan, Greg J. (December 2006). "The role of family socioeconomic resources in the black–white test score gap among young children". Developmental Review. 26 (4): 365–399. doi:10.1016/j.dr.2006.06.004.
- ^ Scarr-Salapatek, S. (1971). "Race, social class, and IQ". Science. 174 (4016): 1285–95. Bibcode:1971Sci...174.1285S. doi:10.1126/science.174.4016.1285. PMID 5167501.
- ^ Scarr-Salapatek, S. (1974). "Some myths about heritability and IQ". Nature. 251 (5475): 463–464. Bibcode:1974Natur.251..463S. doi:10.1038/251463b0.
- ^ D. C. Rowe. (1994). The Limits of Family Influence: Genes, Experience and Behaviour. Guilford Press. London
- ^ Kirkpatrick, R. M.; McGue, M.; Iacono, W. G. (2015). "Replication of a gene-environment interaction Via Multimodel inference: additive-genetic variance in adolescents' general cognitive ability increases with family-of-origin socioeconomic status". Behav Genet. 45 (2): 200–14. doi:10.1007/s10519-014-9698-y. PMC 4374354. PMID 25539975.
- ^ Bronfenbrenner, Urie; Ceci, Stephen J. (October 1994). "Nature-nuture reconceptualized in developmental perspective: A bioecological model". Psychological Review. 101 (4): 568–586. doi:10.1037/0033-295x.101.4.568. PMID 7984707.
- ^ a b c d e Nisbett et al. 2012a. sfn error: multiple targets (2×): CITEREFNisbettAronsonBlairDickens2012a (help)
- ^ Cottrell, Newman & Roisman 2015.
- ^ Hart, Betty; Risley, Todd (1995). Meaningful Differences in the Everyday Experience of Young American Children. Brookes Publishing, Baltimore, Maryland, USA.
- ^ Cronshaw et al. 2006, p. 278
- ^ Verney et al. 2005
- ^ Borsboom 2006
- ^ Shuttleworth-Edwards et al. 2004
- ^ Richardson 2004
- ^ Hunt & Wittmann 2008
- ^ Irvine 1983
- ^ Irvine & Berry 1988 a collection of articles by several authors discussing the limits of assessment by intelligence tests in different communities in the world. In particular, Reuning (1988) describes the difficulties in devising and administering tests for Kalahari bushmen.
- ^ Mackintosh 1998, p. 174: "Despite widespread belief to the contrary, however, there is ample evidence, both in Britain and the USA, that IQ tests predict educational attainment just about as well in ethnic minorities as in the white majority."
- ^ "Reflections about intelligence over 40 years" (PDF). Intelligence (70): 73–83. 2018.
- ^ Aronson, Wilson & Akert 2005
- ^ Steele, Claude M. (1997). "A threat in the air: How stereotypes shape intellectual identity and performance". American Psychologist. 52 (6): 613–629. CiteSeerX 10.1.1.319.8283. doi:10.1037/0003-066X.52.6.613. ISSN 0003-066X. PMID 9174398.
- ^ Mackintosh 2011, p. 348. sfn error: multiple targets (2×): CITEREFMackintosh2011 (help)
- ^ Ogbu 1978.
- ^ Ogbu 1994.
- ^ Chan, D.; Schmitt, N.; DeShon, R. P.; Clause, C. S.; Delbridge, K. (April 1997). "Reactions to cognitive ability tests: the relationships between race, test performance, face validity perceptions, and test-taking motivation". The Journal of Applied Psychology. 82 (2): 300–310. doi:10.1037/0021-9010.82.2.300. ISSN 0021-9010. PMID 9109288.
- ^ "It's Not "a Black Thing": Understanding the Burden of Acting White and Other Dilemmas of High Achievement". American Sociological Review. 70 (4): 582–605. 1 August 2005. doi:10.1177/000312240507000403.
{{cite journal}}
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ignored (help) - ^ "On Interpreting Stereotype Threat as Accounting for African American-White Differences on Cognitive Tests". American Psychologist. 59 (1): 7–13. January 2004. doi:10.1037/0003-066X.59.1.7. PMID 14736315.
{{cite journal}}
: Unknown parameter|authors=
ignored (help) - ^ Yong, Ed (9 September 2016). "A Worrying Trend for Psychology's 'Simple Little Tricks'". The Atlantic. Retrieved 11 September 2016.
- See also:
- Borman, Geoffrey D.; Grigg, Jeffrey; Hanselman, Paul (March 2016). "An effort to close achievement gaps at scale through self-affirmation". Educational Evaluation and Policy Analysis. 38 (1): 21–42. doi:10.3102/0162373715581709.
{{cite journal}}
: Invalid|ref=harv
(help) - Hanselman, Paul; Rozek, Christopher S.; Grigg, Jeffrey; Borman, Geoffrey D. (April 2017). "New evidence on self-affirmation effects and theorized sources of heterogeneity from large-scale replications". Journal of Educational Psychology. 109 (3): 405–424. doi:10.1037/edu0000141. PMC 5403146. PMID 28450753.
{{cite journal}}
: Invalid|ref=harv
(help) Pdf.
- Borman, Geoffrey D.; Grigg, Jeffrey; Hanselman, Paul (March 2016). "An effort to close achievement gaps at scale through self-affirmation". Educational Evaluation and Policy Analysis. 38 (1): 21–42. doi:10.3102/0162373715581709.
- ^ Mackintosh 2011, p. 358. sfn error: multiple targets (2×): CITEREFMackintosh2011 (help)
- ^ Kaplan 2015.
- ^ Nevid 2014, p. 271.
- ^ a b Templeton 2001
- ^ Plomin, Kennedy & Craig 2005, p. 513
- ^ Zinkstok et al. 2007
- ^ Dick et al. 2007
- ^ a b Deary, Johnson & Houlihan 2009
- ^ Onwuegbuzie & Daley 2001
- ^ Sternberg, Grigorenko & Kidd 2005, p. 46.
- ^ Carson & Beckwith 2001.
- ^ Moore & Shenk 2016.
- ^ Mackenzie 1984
- ^ a b Block 2002
- ^ Rollback, Part II Noam Chomsky, 1995
- ^ Jensen, A.R. (1998). The g factor: The science of mental ability. Westport, CT: Praeger. pp. 456–8. ISBN 978-0-275-96103-9.
{{cite book}}
: Invalid|ref=harv
(help) - ^ Flynn 2012, pp. 134–141.
- ^ Hunt & Carlson 2007.
- ^ Nisbett 2009, p. 212.
- ^ Dickens & Flynn 2001.
- ^ Snyderman & Rothman (1987:255), cited in Eysenck (1994:66).
- ^ Silverman 1991, p. 250
- ^ Gottfredson, Linda (1997). "Mainstream Science on Intelligence: An Editorial With 52 Signatories, History, and Bibliography" (PDF). Intelligence. 24 (1): 13–23. doi:10.1016/S0160-2896(97)90011-8.
- ^ Campbell, Donald T. (1996), "Unresolved Issues in Measurement Validity : An Autobiographical Overview", Psychological Assessment, 8 (4): 363–368, doi:10.1037/1040-3590.8.4.363
- ^ "2013 survey of expert opinion on intelligence". International Society for Intelligence Research, 2013. Retrieved 12 January 2018.
{{cite web}}
: Unknown parameter|authors=
ignored (help) - ^ te Nijenhuis, Jan; van der Flier, Henk (1 November 2013). "Is the Flynn effect on g?: A meta-analysis". Intelligence. 41 (6): 802–807. doi:10.1016/j.intell.2013.03.001.
- ^ Flynn 2010.
- ^ a b Mackintosh 2011, p. 337. sfn error: multiple targets (2×): CITEREFMackintosh2011 (help)
- ^ a b Weinberg, Scarr & Waldman 1992
- ^ Scarr & Weinberg 1976.
- ^ Loehlin 2000, p. 185.
- ^ Scarr & Weinberg 1990.
- ^ Loehlin 2000, p. 187.
- ^ Frydman and Lynn (1989). "The intelligence of Korean children adopted in Belgium". Personality and Individual Differences. 10 (12): 1323–1325. doi:10.1016/0191-8869(89)90246-8.
{{cite journal}}
: Invalid|ref=harv
(help) - ^ Thomas, Drew (2017). "Racial IQ Differences among Transracial Adoptees: Fact or Artifact?". Journal of Intelligence. 5 (1): 1. doi:10.3390/jintelligence5010001. PMC 6526420. PMID 31162392.
- ^ Bryc et al. 2009
- ^ Loehlin 2000.
- ^ Templeton 2001.
- ^ a b Jensen 2006
- ^ Eysenck 1987
- ^ Jensen 1998 harvnb error: multiple targets (2×): CITEREFJensen1998 (help)
- ^ a b Nisbett 2009
- ^ Lynn & Vanhanen 2002.
- ^ Jensen & Whang 1993.
- ^ Pesta & Poznanski 2008.
- ^ Sheppard & Vernon 2008.
- ^ Nisbett 2009, pp. 221–2.
- ^ Deary, Penke & Johnson 2010.
- ^ McDaniel 2005.
- ^ Ho et al. 1980.
- ^ MacEachern 2006.
- ^ Gray & Thompson 2004
- ^ Ceci & Williams 2009
- ^ a b Rose 2009, pp. 786–88
- ^ Gottfredson 2007
- ^ Flynn 2009 harvnb error: multiple targets (2×): CITEREFFlynn2009 (help)
- ^ Rushton & Jensen 2005
- ^ Jencks, Christopher; Phillips, Meredith. "The Black-White Test Score Gap". New York Times. Brookings Institution Press. Retrieved 2 October 2016.
- ^ Nisbett 2009
- ^ Flynn 2008
- ^ Rushton & Jensen 2010
- ^ Olness 2003
Bibliography
- Alland, Alexander, Jr (2002). Race in Mind. Palgrave Macmillan. pp. 79–80.
{{cite book}}
: Invalid|ref=harv
(help)CS1 maint: multiple names: authors list (link) - "American Anthropological Association Statement on 'Race' and Intelligence". American Anthropological Association. December 1994.
- "American Anthropological Association Statement on 'Race'". American Anthropological Association. 17 May 1998.
- "AAPA Statement on Biological Aspects of Race". American Journal of Physical Anthropology. 101 (4): 569–570. 1996. doi:10.1002/ajpa.1331010408. Archived from the original on 2011-09-28. Retrieved 2011-05-24.
- Aronson, E; Wilson, TD; Akert, AM (2005). Social Psychology (5th ed.). Upper Saddle River, NJ: Prentice Hall. ISBN 978-0-13-178686-8.
{{cite book}}
: Invalid|ref=harv
(help) - Behrman, JR; Alderman, H; Hoddinott, J (2004). "Hunger and Malnutrition" (PDF). Copenhagen Consensus. Archived from the original (PDF) on 2006-10-25.
{{cite journal}}
: Invalid|ref=harv
(help) - Bellinger, David C; Stiles, Karen M; Needleman, Herbert L (December 1992). "Low-Level Lead Exposure, Intelligence and Academic Achievement: A Long-term Follow-up Study". Pediatrics. 90 (6): 855–61. PMID 1437425.
{{cite journal}}
: Invalid|ref=harv
(help) - Berlet, Chip (Summer 2003). "Into the Mainstream". Intelligence Report (110). Archived from the original on 2 February 2010. Retrieved 21 February 2012.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Block, Ned (2002). "How heritability misleads about race". In Fish, Jefferson (ed.). Race and Intelligence: Separating Science from Myth. Lawrence Erlbaum and Associates.
{{cite book}}
: Invalid|ref=harv
(help) - Borsboom, Denny (September 2006). "The attack of the psychometricians". Psychometrika. 71 (3): 425–40. doi:10.1007/s11336-006-1447-6. PMC 2779444. PMID 19946599.
{{cite journal}}
: Invalid|ref=harv
(help) - Brace, C Loring (1999). "An Anthropological Perspective on 'Race' and Intelligence: The non-clinal nature of human cognitive capabilities". Journal of Anthropological Research. 55 (2): 245–64. doi:10.1086/jar.55.2.3631210. JSTOR 3631210.
{{cite journal}}
: Invalid|ref=harv
(help) - Brace, C. Loring (2005). Race is a four letter word. Oxford University Press. p. 326. ISBN 978-0-19-517351-2.
{{cite book}}
: Invalid|ref=harv
(help) - "race". Encyclopædia Britannica (Online ed.). Encyclopædia Britannica Inc. 2012.
- Brown, Robert T; Reynolds, Cecil R; Whitaker, Jean S (1999). "Bias in Mental Testing since "Bias in Mental Testing"". School Psychology Quarterly. 14 (3): 208–38. doi:10.1037/h0089007.
{{cite journal}}
: Invalid|ref=harv
(help) - Bryc, Katarzyna; Auton, Adam; Nelson, Matthew R.; Oksenberg, Jorge R.; Hauser, Stephen L.; Williams, Scott; Froment, Alain; Bodo, Jean-Marie; Wambebe, Charles; Tishkoff, Sarah A.; Bustamante, Carlos D. (2009). "Genome-wide patterns of population structure and admixture in West Africans and African Americans". Proceedings of the National Academy of Sciences of the United States of America. 107 (2): 786–91. Bibcode:2010PNAS..107..786B. doi:10.1073/pnas.0909559107. PMC 2818934. PMID 20080753.
- Campbell, FA; Ramey, CT (1994). "Effects of early intervention on intellectual and academic achievement: A follow-up study of children from low-income families". Child Development. 65 (2): 684–698. doi:10.1111/j.1467-8624.1994.tb00777.x.
{{cite journal}}
: Invalid|ref=harv
(help) - Campbell, Frances A; Ramey, Craig T; Pungello, Elizabeth; Sparling, Joseph; Miller-Johnson, Shari (2002). "Early Childhood Education: Young Adult Outcomes From the Abecedarian Project". Applied Developmental Science. 6: 42–57. doi:10.1207/s1532480xads0601_05.
- Carson, Michael; Beckwith, Jon (2001). 'Race', IQ and Genes. John Wiley & Sons, Ltd. pp. 1–5. doi:10.1002/9780470015902.a0005689.pub3. ISBN 9780470015902.
{{cite book}}
: CS1 maint: ref duplicates default (link) - Ceci, SJ; Williams, WM (2009). "Darwin 200: Should scientists study race and IQ? Yes: the scientific truth must be pursued". Nature. 457 (7231): 788–9. Bibcode:2009Natur.457..788C. doi:10.1038/457788a. PMID 19212385.
{{cite journal}}
: Invalid|ref=harv
(help) - Cooper, R. S. (2005). "Race and IQ: Molecular Genetics as Deus ex Machina". American Psychologist. 60 (1): 71–76. CiteSeerX 10.1.1.624.5059. doi:10.1037/0003-066X.60.1.71. PMID 15641923.
{{cite journal}}
: Invalid|ref=harv
(help) - Cottrell, Jonathan M.; Newman, Daniel A.; Roisman, Glenn I. (November 2015). "Explaining the black-white gap in cognitive test scores: Toward a theory of adverse impact". The Journal of Applied Psychology. 100 (6): 1713–1736. doi:10.1037/apl0000020. ISSN 1939-1854. PMID 25867168.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Cronshaw, Steven F; Hamilton, Leah K; Onyura, Betty R; Winston, Andrew S (September 2006). "Case for Non-Biased Intelligence Testing Against Black Africans Has Not Been Made: A Comment on Rushton, Skuy, and Bons". International Journal of Selection and Assessment. 14 (3): 278–287. doi:10.1111/j.1468-2389.2006.00346.x.
- Daley, C. E.; Onwuegbuzie, A. J. (2011). "Race and Intelligence". In Sternberg, R.; Kaufman, S. B. (eds.). The Cambridge Handbook of Intelligence. Cambridge New York: Cambridge University Press. pp. 293–306. ISBN 9780521518062.
{{cite book}}
: Invalid|ref=harv
(help) - Deary, Ian J (2001). Intelligence: A Very Short Introduction. Oxford University Press. ISBN 978-0-19-289321-5.
{{cite book}}
: Invalid|ref=harv
(help) - Deary, I. J.; Penke, L.; Johnson, W. (2010). "The neuroscience of human intelligence differences" (PDF). Nature Reviews Neuroscience. 11 (3): 201–211. doi:10.1038/nrn2793. PMID 20145623.
{{cite journal}}
: Invalid|ref=harv
(help) - Deary, IJ; Johnson, W; Houlihan, LM (2009). "Genetic foundations of human intelligence" (PDF). Human Genetics. 126 (1): 215–32. doi:10.1007/s00439-009-0655-4. hdl:20.500.11820/c3e0a75b-dad6-4860-91c6-b242221af681. PMID 19294424.
{{cite journal}}
: Invalid|ref=harv
(help) - Danielle M., Dick; Fazil, Aliev; John, Kramer; Jen C., Wang; Anthony, Hinrichs; Sarah, Bertelsen; Sam, Kuperman; Marc, Schuckit; John, Jr, Nurnberger; Howard J., Edenberg; Bernice, Porjesz; Henri, Begleiter; Victor, Hesselbrock; Alison, Goate; Laura, Bierut (2007). "Association of CHRM2 with IQ: converging evidence for a gene influencing intelligence". Behavioral Genetics. 37 (2): 265–72. doi:10.1007/s10519-006-9131-2. PMID 17160701.
- Dickens, William T; Flynn, James R (2001). "Heritability estimates versus large environmental effects: The IQ paradox resolved". Psychological Review. 108 (2): 346–69. CiteSeerX 10.1.1.139.2436. doi:10.1037/0033-295X.108.2.346. PMID 11381833.
{{cite journal}}
: Invalid|ref=harv
(help) - Dickens, William T; Flynn, James R (2006). "Black Americans Reduce the Racial IQ Gap: Evidence from Standardization Samples" (PDF). Psychological Science. 17 (10): 913–20. CiteSeerX 10.1.1.186.2540. doi:10.1111/j.1467-9280.2006.01802.x. PMID 17100793. Archived from the original (PDF) on 2009-10-09.
{{cite journal}}
: Invalid|ref=harv
(help) - Elhoweris, Hala; Mutua, Kagendo; Alsheikh, Negmeldin; Holloway, Pauline (2005). "Effect of Children's Ethnicity on Teachers' Referral and Recommendation Decisions in Gifted and Talented Programs". Remedial and Special Education. 26: 25–31. doi:10.1177/07419325050260010401.
- Eppig, Christopher; Fincher, Corey L; Thornhill, Randy (2010). "Parasite prevalence and the worldwide distribution of cognitive ability". Proceedings of the Royal Society B. 277 (1701): 3801–8. doi:10.1098/rspb.2010.0973. PMC 2992705. PMID 20591860.
{{cite journal}}
: Invalid|ref=harv
(help) - Eppig, Christopher (2011). "Why Is Average IQ Higher in Some Places?". Scientific American.
{{cite journal}}
: Invalid|ref=harv
(help) - Eyferth, K (1961). "Leistungern verscheidener Gruppen von Besatzungskindern Hamburg-Wechsler Intelligenztest für Kinder (HAWIK)". Archiv für die Gesamte Psychologie (in German). 113: 222–41.
{{cite journal}}
: Invalid|ref=harv
(help) - Eysenck, Hans J (1987). "Intelligence and Reaction Time: The Contribution of Arthur Jensen". In Modgil, S; Modgil, C (eds.). Arthur Jensen: Consensus and controversy. New York, NY: Falmer.
{{cite book}}
: Invalid|ref=harv
(help) - Falk, Avner (2008). Anti-semitism: a history and psychoanalysis of contemporary hatred. Praeger. p. 312. ISBN 978-0-313-35385-7.
{{cite book}}
: Invalid|ref=harv
(help) - Flynn, James R (1991). "Reaction times show that both Chinese and British children are more intelligent than one another". Perceptual and Motor Skills. 72 (2): 544–6. doi:10.2466/pms.1991.72.2.544.
{{cite journal}}
: Invalid|ref=harv
(help) - Flynn, James R (3 September 2008). "Perspectives: Still a question of black vs white?". New Scientist. 199 (2672) (magazine issue ed.): 48–50. doi:10.1016/S0262-4079(08)62253-8.
{{cite journal}}
: Invalid|ref=harv
(help) - Flynn, James R (2009). "Would you wish the research undone?". Nature. 458 (7235): 146. Bibcode:2009Natur.458..146F. doi:10.1038/458146a. PMID 19279612.
{{cite journal}}
: Invalid|ref=harv
(help) - Flynn, James R (2010). "The spectacles through which I see the race and IQ debate" (PDF). Intelligence. 38 (4): 363–6. doi:10.1016/j.intell.2010.05.001.
{{cite journal}}
: Invalid|ref=harv
(help) - Flynn, James R. (2012). Are We Getting Smarter? Rising IQ in the Twenty-First Century. Cambridge: Cambridge University Press. ISBN 978-1-107-60917-4.
{{cite book}}
: Invalid|ref=harv
(help); Unknown parameter|lay-date=
ignored (help); Unknown parameter|lay-url=
ignored (help) - Gottfredson, Linda S (1997). "Mainstream Science on Intelligence (editorial)" (PDF). Intelligence. 24: 13–23. doi:10.1016/S0160-2896(97)90011-8.
{{cite journal}}
: Invalid|ref=harv
(help) - Gottfredson, Linda S (2007). "Applying Double Standards to 'Divisive' Ideas: Commentary on Hunt and Carlson". Perspectives on Psychological Science. 2 (2): 216–220. doi:10.1111/j.1745-6916.2007.00039.x. PMID 26151962.
{{cite journal}}
: Invalid|ref=harv
(help) - Gould, Stephen Jay (1981). The Mismeasure of Man. New York, London: Norton. ISBN 978-0-393-30056-7.
{{cite book}}
: Invalid|ref=harv
(help) - Graves, Joseph L. (2001). The Emperor's New Clothes: Biological Theories of Race at the Millennium (Kindle ed.). Rutgers University Press. ASIN B000SARS70.
{{cite book}}
: Invalid|ref=harv
(help) - Graves, Joseph L (2002a). "The Misuse of Life History Theory: JP Rushton and the Pseudoscience of Racial Hierarchy". In Fish, Jefferson M (ed.). Race and Intelligence: Separating Myth from Reality. Laurence Erlbaum Associates. pp. 57–94. ISBN 978-0-8058-3757-5.
{{cite book}}
: Invalid|ref=harv
(help) - Graves, Joseph L, Jr (2002b). "What a tangled web he weaves: Race, reproductive strategies and Rushton's life history theory". Anthropological Theory. 2 (2): 131–54. doi:10.1177/1469962002002002627.
{{cite journal}}
: Invalid|ref=harv
(help)CS1 maint: multiple names: authors list (link) - Gray, Jeremy R; Thompson, Paul M (2004). "Neurobiology of intelligence: science and ethics" (PDF). Nature Reviews Neuroscience. 5 (6): 471–82. doi:10.1038/nrn1405. PMID 15152197.
{{cite journal}}
: Invalid|ref=harv
(help) - Grossman, James B; Kaufman (2001). "Evolutionary Psychology: Promise and Perils". In Sternberg, Robert J; Kaufman, James C (eds.). The evolution of intelligence. Routledge. ISBN 978-0-8058-3267-9.
{{cite book}}
: Invalid|ref=harv
(help) - Hampshire, A.; Highfield, R. R.; Parkin, B. L.; Owen, A. M. (2012). "Fractionating human intelligence". Neuron. 76 (6): 1225–1237. doi:10.1016/j.neuron.2012.06.022. PMID 23259956.
{{cite journal}}
: Invalid|ref=harv
(help) - Herrnstein, Richard J; Murray, Charles (1994). The Bell Curve: Intelligence and Class Structure in American Life. New York: Free Press. ISBN 978-0-02-914673-6.
{{cite book}}
: Invalid|ref=harv
(help) - Ho, KC; Roessmann, U; Straumfjord, JV; Monroe, G (December 1980). "Analysis of brain weight. I. Adult brain weight in relation to sex, race, and age". Archives of Pathology & Laboratory Medicine. 104 (12): 635–9. PMID 6893659.
- Hunt, Earl (2010). Human Intelligence. Cambridge University Press. ISBN 978-0-521-70781-7.
{{cite book}}
: Invalid|ref=harv
(help) - Hunt, Earl; Carlson, Jerry (2007). "Considerations relating to the study of group differences in intelligence". Perspectives on Psychological Science. 2 (2): 194–213. doi:10.1111/j.1745-6916.2007.00037.x. PMID 26151960.
{{cite journal}}
: Invalid|ref=harv
(help) - Hunt, Earl; Wittmann, Werner (January–February 2008). "National intelligence and national prosperity". Intelligence. 36 (1): 1–9. doi:10.1016/j.intell.2006.11.002.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Irvine, SH (1983). "Where intelligence tests fail". Nature. 302 (5907): 371. Bibcode:1983Natur.302..371I. doi:10.1038/302371b0.
{{cite journal}}
: Invalid|ref=harv
(help) - Irvine, SH; Berry, JW, eds. (1988). Human Abilities in Cultural Context. Cambridge University Press. ISBN 978-0-521-34482-1.
{{cite book}}
: CS1 maint: ref duplicates default (link) - Ivanovic, Daniza M.; Leiva, Boris P.; Pérez, Hernán T.; Olivares, Manuel G.; Dı́az, Nora S.; Urruti, Marı́a Soledad C.; Almagià, Atilio F.; Toro, Triana D.; Miller, Patricio T.; Bosch, Enrique O.; Larraı́n, Cristián G. (2004). "Head size and intelligence, learning, nutritional status and brain development. Head, IQ, learning, nutrition and brain". Neuropsychologia. 42 (8): 1118–31. doi:10.1016/j.neuropsychologia.2003.11.022. PMID 15093150.
- Jackson, John P.; Weidman, Nadine M. (2004). Race, Racism, and Science: Social Impact and Interaction. ABC-CLIO. p. 23.
{{cite book}}
: Invalid|ref=harv
(help) - Jackson, John P. (2005). Science for Segregation: Race, Law, and the Case against Brown v. Board of Education. NYU Press. ISBN 978-0-8147-4271-6.
{{cite book}}
: Invalid|ref=harv
(help); Unknown parameter|lay-date=
ignored (help); Unknown parameter|lay-url=
ignored (help) - Jensen, Arthur R (1969). "How Much Can We Boost IQ and Scholastic Achievement?". Harvard Educational Review. 39: 1–123. doi:10.17763/haer.39.1.l3u15956627424k7.
{{cite journal}}
: Invalid|ref=harv
(help) - Jensen, Arthur R (1973). Educability and Group Differences. London: Methuen. ISBN 978-0-06-012194-5.
{{cite book}}
: Invalid|ref=harv
(help) - Jensen, Arthur R; Whang, PA (1993). "Reaction times and intelligence: a comparison of Chinese-American and Anglo-American children". Journal of Biosocial Science. 25 (3): 397–410. doi:10.1017/s0021932000020721. PMID 8360233.
{{cite journal}}
: Invalid|ref=harv
(help) - Jensen, Arthur R (1998). The g factor: The science of mental ability. Westport, CT: Praeger. ISBN 978-0-275-96103-9.
{{cite book}}
: Invalid|ref=harv
(help) - Jensen, AR (2006). Clocking the mind: Mental chronometry and individual differences. Amsterdam: Elsevier. ISBN 978-0-08-044939-5.
{{cite book}}
: Invalid|ref=harv
(help) - Jensen, Arthur R; Johnson, Fred W (May–June 1994). "Race and sex differences in head size and IQ". Intelligence. 18 (3): 309–33. doi:10.1016/0160-2896(94)90032-9.
{{cite journal}}
: Invalid|ref=harv
(help) - Kamin, Leon J. (March 2006). "African IQ and Mental Retardation". South African Journal of Psychology. 36 (1): 1–9. doi:10.1177/008124630603600101.
{{cite journal}}
: Invalid|ref=harv
(help) - Kaplan, Jonathan Michael (January 2011). 'Race': What Biology Can Tell Us about a Social Construct. doi:10.1002/9780470015902.a0005857. ISBN 978-0470016176.
{{cite book}}
: Unknown parameter|encyclopedia=
ignored (help)CS1 maint: ref duplicates default (link) - Kaplan, Jonathan Michael (6 February 2014). "Race, IQ, and the search for statistical signals associated with so-called "X"-factors: environments, racism, and the "hereditarian hypothesis"". Biology & Philosophy. 30 (1): 1–17. doi:10.1007/s10539-014-9428-0.
- Kaszycka, Katarzyna A.; Štrkalj, Goran; Strzałko, Jan (2009). "Current Views of European Anthropologists on Race: Influence of Educational and Ideological Background". American Anthropologist. 111 (1): 43–56. doi:10.1111/j.1548-1433.2009.01076.x.
{{cite journal}}
: Invalid|ref=harv
(help) - Lieberman, Leonard (2001). "How "Caucasoids" got such big crania and why they shrank: from Morton to Rushton."". Current Anthropology. 42 (1): 69–95. doi:10.1086/318434. PMID 14992214.
{{cite journal}}
: Invalid|ref=harv
(help) - Loehlin, John C (2000). "Group Differences in Intelligence". In Sternberg, Robert J (ed.). The Handbook of Intelligence. Cambridge: Cambridge University Press.
{{cite book}}
: Invalid|ref=harv
(help) - Ludy, Benjamin T (2006). Brief History of Modern Psychology. Wiley-Blackwell. pp. 188–91. ISBN 978-1-4051-3206-0.
{{cite book}}
: Invalid|ref=harv
(help) - Lynn, Richard; Vanhanen, Tatu (2002). IQ and the wealth of nations. Westport, CT: Praeger. ISBN 978-0-275-97510-4.
{{cite book}}
: Invalid|ref=harv
(help) - MacEachern, Scott (March 2006). "Africanist archaeology and ancient IQ: racial science and cultural evolution in the twenty-first century". World Archaeology. 38 (1): 72–92. doi:10.1080/00438240500509918.
{{cite journal}}
: Invalid|ref=harv
(help) - Mackenzie, Brian (1984). "Explaining race differences in IQ: The logic, the methodology, and the evidence". American Psychologist. 39 (11): 1214–1233. doi:10.1037/0003-066x.39.11.1214.
{{cite journal}}
: Invalid|ref=harv
(help) - Mackintosh, NJ (1998). IQ and Human Intelligence. Oxford University Press. ISBN 978-0-19-852367-3.
{{cite book}}
: Invalid|ref=harv
(help); Unknown parameter|lay-date=
ignored (help); Unknown parameter|lay-url=
ignored (help) - Mackintosh, N. J. (2011). IQ and Human Intelligence (second ed.). Oxford: Oxford University Press. ISBN 978-0-19-958559-5.
{{cite book}}
: Invalid|ref=harv
(help); Unknown parameter|lay-date=
ignored (help); Unknown parameter|lay-url=
ignored (help) - Manly, JJ; Byrd, DA; Touradji, P; Stern, Yaakov (2004). "Acculturation, Reading Level, and Neuropsychological Test Performance Among African American Elders". Applied Neuropsychology. 11 (1): 37–46. doi:10.1207/s15324826an1101_5. PMID 15471745.
- Manly, Jennifer J; Jacobs, Diane M; Touradji, Pegah; Small, Scott A; Stern, Yaakov (2002). "Reading level attenuates differences in neuropsychological test performance between African American and White elders". Journal of the International Neuropsychological Society. 8 (3): 341–348. doi:10.1017/S1355617702813157. PMID 11939693.
- Maltby, John; Day, Liz; Macaskill, Ann (2007). Personality, Individual Differences and Intelligence. Pearson Education. pp. 334–47. ISBN 978-0-13-129760-9.
{{cite book}}
: Invalid|ref=harv
(help) - McDaniel, M. A. (2005). "Big-brained people are smarter: A meta-analysis of the relationship between in vivo brain volume and intelligence". Intelligence. 33 (4): 337–346. doi:10.1016/j.intell.2004.11.005.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Mickelson, Roslyn Arlin (2003). "When Are Racial Disparities in Education the Result of Racial Discrimination? A Social Science Perspective". Teachers College Record. 105 (6): 1052–1086. doi:10.1111/1467-9620.00277.
{{cite journal}}
: Invalid|ref=harv
(help) - Miele, Frank (2002). Intelligence, Race and Genetics: Conversations with Arthur R. Jensen. Basic Books. p. 256.
{{cite book}}
: Invalid|ref=harv
(help) - MMWR (27 May 2005). "Blood Lead Levels—United States, 1999–2002". Morbidity and Mortality Weekly Report (MMWR). 54 (20): 513–6.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Moore, Elsie G (May 1986). "Family socialization and the IQ test performance of traditionally and transracially adopted Black children". Developmental Psychology. 22 (3): 317–26. doi:10.1037/0012-1649.22.3.317.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Moore, David S.; Shenk, David (2016-12-01). "The heritability fallacy". Wiley Interdisciplinary Reviews: Cognitive Science. 8 (1–2): e1400. doi:10.1002/wcs.1400. ISSN 1939-5078. PMID 27906501.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Murray, Charles (2006). "Changes over time in the black–white difference on mental tests: Evidence from the children of the 1979 cohort of the National Longitudinal Survey of Youth". Intelligence. 34 (6): 527–540. doi:10.1016/j.intell.2006.07.004.
{{cite journal}}
: Invalid|ref=harv
(help) - Murray, Charles (July–August 2007). "The magnitude and components of change in the black–white IQ difference from 1920 to 1991: A birth cohort analysis of the Woodcock–Johnson standardizations". Intelligence. 35 (4): 305–18. doi:10.1016/j.intell.2007.02.001.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Neisser, Ulric (2004). "Serious Scientists or Disgusting Racists?". Contemporary Psychology: APA Review of Books. 49 (1): 5–7. doi:10.1037/004224.
{{cite journal}}
: Invalid|ref=harv
(help) - Neisser, Ulric; Boodoo, Gwyneth; Bouchard, Thomas J, Jr; Boykin, A. Wade; Brody, Nathan; Ceci, Stephen J; Halpern, Diane F; Loehlin, John C; Perloff, Robert; Sternberg, Robert J; Urbina, Susana (1996). "Intelligence: Knowns and unknowns" (PDF). American Psychologist. 51 (2): 77–101. doi:10.1037/0003-066X.51.2.77.
{{cite journal}}
: Invalid|ref=harv
(help)CS1 maint: multiple names: authors list (link) - Nevid, Jeffrey S. (2014-01-17). Essentials of Psychology: Concepts and Applications. Cengage Learning. ISBN 9781285751221.
{{cite book}}
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(help) - Nisbett, Richard (2005). "Heredity, environment, and race differences in IQ: A commentary on Rushton and Jensen" (PDF). Psychology, Public Policy, and Law. 11 (2): 302–10. doi:10.1037/1076-8971.11.2.302.
{{cite journal}}
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(help) - Nisbett, Richard (2009). Intelligence and How to Get It: Why Schools and Cultures Count. W. W. Norton & Company. ISBN 978-0-393-06505-3.
{{cite book}}
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(help) - Nisbett, Richard E.; Aronson, Joshua; Blair, Clancy; Dickens, William; Flynn, James; Halpern, Diane F.; Turkheimer, Eric (2012a). "Intelligence: new findings and theoretical developments" (PDF). American Psychologist. 67 (2): 130–159. doi:10.1037/a0026699. ISSN 0003-066X. PMID 22233090. Retrieved 22 July 2013.
{{cite journal}}
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ignored (help) - Nisbett, Richard E.; Aronson, Joshua; Blair, Clancy; Dickens, William; Flynn, James; Halpern, Diane F.; Turkheimer, Eric (2012b). "Group differences in IQ are best understood as environmental in origin" (PDF). American Psychologist. 67 (6): 503–504. doi:10.1037/a0029772. ISSN 0003-066X. PMID 22963427. Retrieved 22 July 2013.
{{cite journal}}
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(help) - Niu, Weihua; Brass, Jillian (2011). "Intelligence in Worldwide Perspective". In Sternberg, Robert J; Kaufmann, Scott Barry (eds.). The Cambridge Handbook of Intelligence. Cambridge University Press. ISBN 978-0-521-51806-2.
{{cite book}}
: Invalid|ref=harv
(help) - Ogbu, John (1978). Minority Education and Caste: The American System in Cross-Cultural Perspective. New York: Academic Press. ISBN 978-0-125-24250-9.
{{cite book}}
: Invalid|ref=harv
(help) - Ogbu, John U (1994). "From cultural differences to differences in cultural frames of reference". In Greenfield, PM; Cocking, RR (eds.). Cross-cultural roots of minority child development. Hillsdale, NJ: Lawrence Erlbaum Associates. pp. 365–91.
{{cite book}}
: Invalid|ref=harv
(help) - Olness, K (April 2003). "Effects on brain development leading to cognitive impairment: a worldwide epidemic". Journal of Developmental and Behavioral Pediatrics. 24 (2): 120–30. doi:10.1097/00004703-200304000-00009. PMID 12692458.
{{cite journal}}
: Invalid|ref=harv
(help) - Onwuegbuzie, A. J.; Daley, C. E. (1 May 2001). "Racial Differences in IQ Revisited: A Synthesis of Nearly a Century of Research". Journal of Black Psychology. 27 (2): 209–220. doi:10.1177/0095798401027002004.
{{cite journal}}
: Invalid|ref=harv
(help) - Pesta, Bryan J; Poznanski, Peter J (2008). "Black-White differences on IQ and grades: The mediating role of elementary cognitive tasks". Intelligence. 36 (4): 323–29. doi:10.1016/j.intell.2007.07.004.
{{cite journal}}
: Invalid|ref=harv
(help) - Pesta, Bryan J; Poznanski, Peter J (2014). "Only in America: Cold Winters Theory, race, IQ and well-being". Intelligence. 46: 271–274. doi:10.1016/j.intell.2014.07.009.
{{cite journal}}
: Invalid|ref=harv
(help) - Pickren, Wade E; Rutherford, Alexandra (2010). A History of Modern Psychology in Context. Wiley.
{{cite book}}
: Invalid|ref=harv
(help) - Plomin, R; Kennedy, J; Craig, I (2005). "The quest for quantitative trait loci associated with intelligence". Intelligence. 34 (6): 513–526. doi:10.1016/j.intell.2006.01.001.
{{cite journal}}
: Invalid|ref=harv
(help) - Plotnik, Rod; Kouyoumdjian, Haig (2011). "Intelligence". Introduction to Psychology. Cengage Learning.
{{cite book}}
: Invalid|ref=harv
(help) - Posthuma, Daniëlle; De Geus, Eco JC; Baaré, Wim FC; Hulshoff Pol, Hilleke E; Kahn, René S; Boomsma, Dorret I (February 2002). "The association between brain volume and intelligence is of genetic origin" (PDF). Nature Neuroscience. 5 (2): 83–4. doi:10.1038/nn0202-83. hdl:1871/18295. PMID 11818967.
- Qian, M; Wang, D; Watkins, WE; Gebski, V; Yan, YQ; Li, M; Chen, ZP (2005). "The effects of iodine on intelligence in children: a meta-analysis of studies conducted in China". Asia Pacific Journal of Clinical Nutrition. 14 (1): 32–42. PMID 15734706.
- Reichman, Nancy E. (2005). "Low birth weight and school readiness". The Future of Children. 15 (1): 91–116. doi:10.1353/foc.2005.0008. ISSN 1054-8289. PMID 16130543.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Reuning, Helmut (1988). "Testing Bushmen in the Central Kalahari". In Irvine, SH; Berry, JW (eds.). Human Abilities in Cultural Context. Cambridge University Press. pp. 453–486. doi:10.1017/CBO9780511574603.018. ISBN 978-0-511-57460-3.
{{cite encyclopedia}}
: Invalid|ref=harv
(help) - Richardson, K (2004). "Book Review: IQ and the Wealth of Nations". Heredity. 92 (4): 359–60. doi:10.1038/sj.hdy.6800418.
{{cite journal}}
: Invalid|ref=harv
(help) - Rindermann, Heiner; Thompson, James (November 2013). "Ability rise in NAEP and narrowing ethnic gaps?". Intelligence. 41 (6): 821–831. doi:10.1016/j.intell.2013.06.016.
{{cite journal}}
: Invalid|ref=harv
(help) - Rose, Steven (2009). "Darwin 200: Should scientists study race and IQ? NO: Science and society do not benefit". Nature. 457 (7231): 786–8. Bibcode:2009Natur.457..786R. doi:10.1038/457786a. PMID 19212384.
{{cite journal}}
: Invalid|ref=harv
(help) - Roth, PL; Bevier, CA; Bobko, P; Switzer, FS, III; Tyler, P (2001). "Ethnic group differences in cognitive ability in employment and educational settings: A metaanalysis". Personnel Psychology. 54 (2): 297–330. CiteSeerX 10.1.1.372.6092. doi:10.1111/j.1744-6570.2001.tb00094.x.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Rouvroy, Antoinette (2008). Human genes and neoliberal governance: a Foucauldian critique. Routledge. p. 86. ISBN 978-0-415-44433-0.
{{cite book}}
: Invalid|ref=harv
(help) - Rowe; David C (January 2005). Rodgers, Joseph (ed.). "Under the Skin: On the Impartial Treatment of Genetic and Environmental Hypothesis of Racial Differences". American Psychologist. 60 (1): 60–70. doi:10.1037/0003-066X.60.1.60. PMID 15641922.
- Rushton, J. Philippe (1995). Race, evolution, and Behavior. Piscataway, NJL: TransAction Books.
{{cite book}}
: Invalid|ref=harv
(help) - Rushton, J. Philippe; Jensen, Arthur R (2005). "Thirty Years of Research on Race Differences in Cognitive Ability" (PDF). Psychology, Public Policy, and Law. 11 (2): 246–8. CiteSeerX 10.1.1.186.102. doi:10.1037/1076-8971.11.2.235. Archived from the original (PDF) on 2015-11-03.
{{cite journal}}
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(help) - Rushton, J. Philippe; Jensen, Arthur R (2006). "The Totality of Available Evidence Shows the Race IQ Gap Still Remains" (PDF). Psychological Science. 17 (10): 921–2. doi:10.1111/j.1467-9280.2006.01803.x. PMID 17100794. Archived from the original (PDF) on 2010-11-05.
{{cite journal}}
: Invalid|ref=harv
(help) - Saloojee, Haroon; Pettifor, John M (December 2001). "Iron deficiency and impaired child development". BMJ. 323 (7326): 1377–8. doi:10.1136/bmj.323.7326.1377. PMC 1121846. PMID 11744547.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Scarr, S.; Weinberg, R. A. (1990). "The nature-nurture problem revisited: The Minnesota adoption studies". Methods of family research: Biographies of research projects. Vol. 1. pp. 121–151.
{{cite book}}
: Invalid|ref=harv
(help) - Scarr, S.; Weinberg, R. A. (1976). "IQ test performance of black children adopted by White families". American Psychologist. 31 (10): 726–739. doi:10.1037/0003-066x.31.10.726.
{{cite journal}}
: Invalid|ref=harv
(help) - Schacter, Daniel; Gilbert, Daniel; Wegner, Daniel (2007). Psychology. New York: Worth Publishing. ISBN 978-0-7167-5215-8.
{{cite book}}
: Invalid|ref=harv
(help) - James A. Banks (2008). "Race". In Schaefer, Richard T. (ed.). Encyclopedia of Race, Ethnicity and Society. Vol. 2. SAGE. p. 1091.
- Serpell, Robert (2000). "Intelligence and Culture". In Sternberg, Robert J. (ed.). Handbook of Intelligence. Cambridge University Press. pp. 549–577. ISBN 978-0-521-59648-0.
{{cite book}}
: Invalid|ref=harv
(help) - Sheppard, Leah D.; Vernon, Philip A. (February 2008). "Intelligence and speed of information-processing: A review of 50 years of research". Personality and Individual Differences. 44 (3): 535–551. doi:10.1016/j.paid.2007.09.015.
{{cite journal}}
: Invalid|ref=harv
(help) - Shurkin, Joel (2006). Broken Genius: The Rise and Fall of William Shockley, Creator of the Electronic Age. London: Macmillan. ISBN 978-1-4039-8815-7.
{{cite book}}
: Invalid|ref=harv
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ignored (help) - Shuttleworth-Edwards, AB; Kemp, RD; Rust, AL; Muirhead, JG; Hartman, NP; Radloff, SE (October 2004). "Cross-cultural effects on IQ test performance: a review and preliminary normative indications on WAIS-III test performance". Journal of Clinical and Experimental Neuropsychology. 26 (7): 903–20. doi:10.1080/13803390490510824. PMID 15742541.
- Smay, Diana; Armelagos, George (July 2000). "Galileo Wept: A Critical Assessment of the Use of Race in Forensic Anthropology". Transforming Anthropology. 9 (2): 19–29. doi:10.1525/tran.2000.9.2.19.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Snyderman, Mark; Rothman, Stanley (1987). "Survey of expert opinion on intelligence and aptitude testing". American Psychologist. 42 (2): 137–44. doi:10.1037/0003-066x.42.2.137.
{{cite journal}}
: Invalid|ref=harv
(help) - Sternberg, Robert J; Grigorenko, Elena L; Kidd, Kenneth K (2005). "Intelligence, Race, and Genetics" (PDF). American Psychologist. 60 (1): 46–59. CiteSeerX 10.1.1.174.313. doi:10.1037/0003-066X.60.1.46. PMID 15641921. Archived from the original (PDF) on 2011-07-20.
{{cite journal}}
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(help) - Sternberg, R. J.; Grigorenko, E. L. (2007). "The Difficulty of Escaping Preconceptions in Writing an Article About the Difficulty of Escaping Preconceptions: Commentary on Hunt and Carlson (2007)". Perspectives on Psychological Science. 2 (2): 221–223. doi:10.1111/j.1745-6916.2007.00040.x. PMID 26151963.
{{cite journal}}
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(help) - Spiro, Jonathan P. (2009). Defending the Master Race: Conservation, Eugenics, and the Legacy of Madison Grant. Univ. of Vermont Press. ISBN 978-1-58465-715-6.
{{cite book}}
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ignored (help) - Suzuki, Lisa; Aronson, Joshua (2005). "The cultural malleability of intelligence and its impact on the racial/ethnic hierarchy". Psychology, Public Policy, and Law. 11 (2): 320–327. CiteSeerX 10.1.1.1022.3693. doi:10.1037/1076-8971.11.2.320.
{{cite journal}}
: Invalid|ref=harv
(help) - Tang, Hua; Quertermous, Tom; Rodriguez, Beatriz; Kardia, Sharon L.R.; Zhu, Xiaofeng; Brown, Andrew; Pankow, James S.; Province, Michael A.; Hunt, Steven C.; Boerwinkle, Eric; Schork, Nicholas J.; Risch, Neil J. (February 2005). "Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies". American Journal of Human Genetics. 76 (2): 268–75. doi:10.1086/427888. PMC 1196372. PMID 15625622.
- Templeton, A. R. (2001), "The Genetic and Evolutionary Significance of Human Races", in Fish, J. M. (ed.), Race and Intelligence Separating Science from Myth, London: Routledge, pp. 31–55, ISBN 978-0805837575
- Thompson, Paul M.; Cannon, Tyrone D.; Narr, Katherine L.; van Erp, Theo; Poutanen, Veli-Pekka; Huttunen, Matti; Lönnqvist, Jouko; Standertskjöld-Nordenstam, Carl-Gustaf; Kaprio, Jaakko; Khaledy, Mohammad; Dail, Rajneesh; Zoumalan, Chris I.; Toga, Arthur W. (2001). "Genetic influences on brain structure" (PDF). Nature Neuroscience. 4 (12): 1253–58. doi:10.1038/nn758. PMID 11694885. Archived from the original (PDF) on 2011-05-15.
- Tizard, Barbara; Cooperman, Oliver; Joseph, Anne; Tizard, Jack (June 1972). "Environmental effects on language development: A study of young children in long-stay residential nurseries". Child Development. 43 (2): 337–58. doi:10.2307/1127540. JSTOR 1127540.
- Tucker, William H (2002). The Funding of Scientific Racism: Wickliffe Draper and the Pioneer Fund. University of Illinois Press. ISBN 978-0-252-02762-8.
{{cite book}}
: Invalid|ref=harv
(help) - Verney, Steven P.; Granholm, Eric; Marshall, Sandra P.; Malcarne, Vanessa L.; Saccuzzo, Dennis P. (26 July 2016). "Culture-Fair Cognitive Ability Assessment". Assessment. 12 (3): 303–319. doi:10.1177/1073191105276674. PMID 16123251.
- Vincent, Ken R. (March 1991). "Black/white IQ differences: Does age make the difference?". Journal of Clinical Psychology. 47 (2): 266–270. doi:10.1002/1097-4679(199103)47:2<266::aid-jclp2270470213>3.0.co;2-s. PMID 2030133.
{{cite journal}}
: CS1 maint: ref duplicates default (link) - Weinberg, Richard A.; Scarr, Sandra; Waldman, Irwin D. (1992). "The Minnesota Transracial Adoption Study: A Follow-Up of IQ Test Performance at Adolescence". Intelligence. 16 (1): 117–35. doi:10.1016/0160-2896(92)90028-P.
{{cite journal}}
: Invalid|ref=harv
(help) - Wicherts, Jelte M; Borsboom, Denny; Dolan, Conor V (2010). "Why national IQs do not support evolutionary theories of intelligence". Personality and Individual Differences. 48 (2): 91–6. doi:10.1016/j.paid.2009.05.028.
{{cite journal}}
: Invalid|ref=harv
(help) - Wicherts, Jelte M.; Borsboom, Denny; Dolan, Conor V. (2010b). "Evolution, brain size, and the national IQ of peoples around 3000 years B.C". Personality and Individual Differences. 48 (2): 104–106. doi:10.1016/j.paid.2009.08.020.
{{cite journal}}
: Invalid|ref=harv
(help) - Wicherts, Jelte M.; Dolan, Conor V.; Carlson, Jerry S.; van der Maas, Han L.J. (June 2010). "Raven's test performance of sub-Saharan Africans: Average performance, psychometric properties, and the Flynn Effect". Learning and Individual Differences. 20 (3): 135–151. doi:10.1016/j.lindif.2009.12.001.
{{cite journal}}
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(help) - Wicherts, Jelte M.; Dolan, Conor V.; van der Maas, Han L.J. (January 2010). "A systematic literature review of the average IQ of sub-Saharan Africans". Intelligence. 38 (1): 1–20. doi:10.1016/j.intell.2009.05.002.
{{cite journal}}
: Invalid|ref=harv
(help) - Witelson, S. F.; Beresh, H.; Kigar, D. L. (February 2006). "Intelligence and brain size in 100 postmortem brains: sex, lateralization and age factors". Brain. 129 (2): 386–398. doi:10.1093/brain/awh696. PMID 16339797.
{{cite journal}}
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(help) - Wooldridge, Adrian (1995). Measuring the Mind: Education and Psychology in England c. 1860-c. 1990. Cambridge University Press. ISBN 978-0-521-39515-1.
{{cite book}}
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(help) - Wroe, Andrew (2008). The Republican Party and Immigration Politics: from Proposition 187 to George W. Bush. Macmillan. p. 294. ISBN 978-0-230-60053-9.
{{cite book}}
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(help) - Zinkstok, Janneke R; De Wilde, Odette; Van Amelsvoort, Therese AMJ; Tanck, Michael W; Baas, Frank; Linszen, Don H (2007). "Association between the DTNBP1 gene and intelligence: a case-control study in young patients with schizophrenia and related disorders and unaffected siblings". Behavioral and Brain Functions. 3: 19. doi:10.1186/1744-9081-3-19. PMC 1864987. PMID 17445278.
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: CS1 maint: unflagged free DOI (link)
External links
- June 2005 issue of Psychology, Public Policy and Law, containing papers arguing various perspectives about race and intelligence.
- Debate between James Flynn and Charles Murray about whether the black/white IQ gap is shrinking or staying the same – November 2006.