Race and intelligence

This article also discusses issues regarding ethnicity and intelligence.

The study of race and intelligence is the study of how human intellectual capacities may vary among the different races. This study seeks to identify and explain the differences in manifestations of intelligence (e.g. IQ testing results), as well as the causes of such variance.

Theories about the possibility of a relationship between race and intelligence have been the subject of speculation and debate since the 16th century. The contemporary debate focuses on the nature, causes, and importance, or lack of importance, of ethnic differences in intelligence test scores and other measures of cognitive ability, and whether "race" is a meaningful biological construct with significance other than its correlation to membership of particular ethnic groups. Thus, the question of the relative roles of nature and nurture in causing individual and group differences in cognitive ability is seen as fundamental to understanding the debate.

The modern controversy surrounding intelligence and race focuses on the results of IQ studies conducted during the second half of the 20th century in the United States, Western Europe, and other industrialized nations. There are also controversies over the definition of "race", the definition of "intelligence", and whether the "intelligence quotient" is a satisfactory measure of intelligence; see the respective articles on those subjects for more information.

History

File:AverageIQ-Map-World.png

Average IQ of the original indigenous populations according to Lynn

Calculated and estimated national average IQ of people settled today.

  ≤65

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  75

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  ≥105

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Charles Darwin wrote in Descent of Man (VII, On the races of Man, published in 1871): "The races differ also in constitution, in acclimatisation and in liability to certain diseases. Their mental characteristics are likewise very distinct; chiefly as it would appear in their emotional, but partly in their intellectual faculties."

The opinion that there are differences in the brain sizes and brain structures of different racial and ethnic groups was widely held and studied during the 19th and early 20th centuries. During this time period, research on race and intelligence was often used to show that one race was superior to another, justifying the poor status and treatment of the "inferior race".

The writings of Sir Francis Galton, a British psychologist, spurred interest in the study of mental abilities, particularly as they relate to heredity and eugenics. Galton estimated from his field observations in Africa that the African people were significantly below Anglo-Saxons' position in the normal frequency distribution of general mental ability; findings that continue to spark controversy in academia today.

The scientific debate on the contribution of nature versus nurture to individual and group differences in intelligence can be traced back to at least the mid-19th century. Beginning in the 1930s, race difference research and hereditarianism — the belief that genetics are the primary cause of differences in intelligence among human groups — began to fall out of favor in psychology and anthropology after major internal debates.

Contemporary issues

The contemporary scholarly debate on race and intelligence may be traced to Arthur Jensen's 1969 publication in the Harvard Educational Review of "How Much Can We Boost IQ and School Achievement?" In this paper, he wrote on some of the major issues that characterize the genetic hypothesis of racial IQ differences, and on compensatory educational programs. Reports on Jensen's article appeared in Time, Newsweek, Life, U.S. News & World Report, and The New York Times Magazine.

William Shockley, who won the Nobel Prize in Physics for his work on the transistor, spent much of his later life focused on the questions of race, intelligence, and eugenics. He postulated that the higher reproduction rates of those with lower intelligence, especially unskilled blacks, was having a dysgenic effect on society. He donated sperm to the Repository for Germinal Choice, a sperm bank founded by Robert Klark Graham in hopes of spreading humanity's best genes, and he proposed that individuals with IQs below 100 be paid to undergo voluntary sterilization. He was harshly criticized by the media; however his involvement brought public recognition to several controversial topics and Shockley described his work on the issue as the most important of his career.

Luigi Luca Cavalli-Sforza on several occasions publicly debated Arthur Jensen and William Shockley arguing that environmental factors could explain the black-white IQ gap.

Press attention returned to the issue of race and intelligence in 1994 with the publication of The Bell Curve, which included two chapters on the subject of racial difference in intelligence and related life outcomes. In response to The Bell Curve, Stephen Jay Gould updated The Mismeasure of Man in 1996. Among other things, he criticized the IQ test as a measure of intelligence, citing what he perceived as inherent racial and social biases as well as systematic flaws in the testing process.

The Bell Curve

File:Two Curve Bell with Jobs.jpg

The social consequence of Black-White difference in IQ were discussed in The Bell Curve.

Main article: The Bell Curve

The Bell Curve is a controversial, best-selling 1994 book by the late Harvard professor of psychology Richard J. Herrnstein and American Enterprise Institute political scientist Charles Murray. Its central point is that intelligence is a better predictor of many factors including financial income, job performance, unwed pregnancy, and crime than parents' socioeconomic status or education level. Also, the book argued that those with high intelligence (the "cognitive elite") are becoming separated from the general population of those with average and below-average intelligence, and that this was a dangerous social trend. Much of the controversy concerned Chapters 13 and 14, in which the authors wrote about the enduring racial differences in intelligence and discuss implications of those differences. The authors were reported throughout the popular press as arguing that these IQ differences are genetic, although they state no position on the issue in the book, and write in the introduction to Chapter 13 that "The debate about whether and how much genes and environment have to do with ethnic differences remains unresolved."

Shortly after publication, many people rallied both in criticism and defense of the book. Some critics denounced the book and its authors as supporting scientific racism. A number of critical texts, including The Bell Curve Debate, were written in response to the book.

American Psychological Association response

Main article: Intelligence: Knowns and Unknowns

In response to the controversy surrounding The Bell Curve, the American Psychological Association's Board of Scientific Affairs in 1995 established a special task force to publish an investigative report on the research presented in the book. The report, Intelligence: Knowns and Unknowns, agreed with many of the book's statements on intelligence, however, regarding the book's genetic implications, it states:

It is sometimes suggested that the Black/White differential in psychometric intelligence is partly due to genetic differences (Jensen, 1972). There is not much direct evidence on this point, but what little there is fails to support the genetic hypothesis.

The January 1997 issue of American Psychologist published eleven critical responses to the American Psychological Association (APA) report, most of which criticized the report's failure to examine all of the evidence for or against genetic contributions to racial differences in IQ. Charles Murray, for example, responded:

Actually, there is no direct evidence at all, just a wide variety of indirect evidence, almost all of which the task force chose to ignore.

The APA report concluded with a call for more reflection in debates on intelligence and for a "shared and sustained effort" in more research to answer the many unanswered questions that remain.

"Mainstream" statement

Main article: Mainstream Science on Intelligence

A collective statement titled "Mainstream Science on Intelligence" was published in the Wall Street Journal on December 13, 1994. It was written by psychology professor Linda Gottfredson, and signed by Gottfredson and 51 other professors specializing in intelligence and related fields. It listed 25 statements which claimed to uphold findings on the subject of intelligence research discussed in the The Bell Curve. This statement was reprinted in the psychology journal Intelligence in 1997 with additional information and a bibliography. Regarding the cause of racial-ethnic group differences in IQ, the statement says:

There is no definitive answer to why IQ bell curves differ across racial-ethnic groups. The reasons for these IQ differences between groups may be markedly different from the reasons for why individuals differ among themselves within any particular group (whites or blacks or Asians). In fact, it is wrong to assume, as many do, that the reason why some individuals in a population have high IQs but others have low IQs must be the same reason why some populations contain more such high (or low) IQ individuals than others. Most experts believe that environment is important in pushing the bell curves apart, but that genetics could be involved too.

High-achieving minorities

See also: Ashkenazi intelligence

The book World on Fire notes the existence in many nations of minorities that have created and control a disproportionate share of the economy. Examples include Chinese in Southeast Asia; Whites, Indians, Lebanese and Igbo people of Western Africa; Whites in Latin America; and Jews in pre-World War II Europe, modern America, and modern Russia. These minorities are often resented and sometimes persecuted by the less successful majority.

In the United States, Jews, Japanese, and Chinese earn incomes 1.72, 1.32, and 1.12 times the American average, respectively (Sowell, 1981, p. 5). Jews and East Asians have higher rates of college attendance, greater educational attainment, and are many times overrepresented in the Ivy League and many of the United States' most prestigious schools, even though affirmative action discriminates against Asians in the admissions process (relative to Whites as well as to other minorities). At Harvard, for example, Asian American and Jewish students together make up 51% of the student body, though only constituting roughly 6% of the US population. In various Southeast Asian nations, Chinese control a majority of the wealth despite being a minority of the population and are resented by the majority, in some cases being the target of violence.

Achievement in science, a high-complexity occupation in which practitioners tend to have IQs well above average, also appears consistent with some group IQ disparity. Only 0.25% of the world population is Jewish, but Jews make up an estimated 28% of Nobel prize winners in physics, chemistry, medicine, and economics. In the U.S., these numbers are 2% of the population and 40% of winners. A significant decline in the number of Nobel prizes awarded to Europeans, and a corresponding increase in the number of prizes awarded to US citizens, occurred at the same time as Nazi persecutions of Jews during the 1930s and the Holocaust during the 1940s.

Groups vary significantly in their IQ subtest profiles. Ashkenazi Jews, for example, demonstrate verbal and mathematical scores more than one standard deviation above average, but visuospatial scores roughly one half standard deviation lower than the White average, whereas East Asians demonstrate high visuospatial scores, but average or slightly below average verbal scores. Concordantly, the professions in which these populations tend to be over-represented differ . The Asian pattern of subtest scores is found in fully assimilated third-generation Asian Americans, as well as in Inuits and Native Americans (both of Asian origin).

Policy implications

See also: Intelligence and public policy

Public policy implications of IQ and race research are one of the greatest sources of controversy surrounding this issue. Regardless of the source of the gap, most educators agree that it must be addressed. They often advocate equitable funding for education.

Some proponents of a genetic interpretation of the IQ gap, such as Template:A(Y)ref and Template:A(Y)ref, have sometimes argued that their interpretation does not in itself demand any particular policy response: while a conservative/libertarian commentator may feel the results justify, for example, reductions in affirmative action, a liberal commentator may argue from a Rawlsian point of view (that genetic advantages are undeserved and unjust) for substantial affirmative action. Since all races have representatives at all levels of the IQ curve, this means any policy based on low IQ affects members of all races.

While not specifically race-related, policies focused on geographical regions or nations may have disproportionate influences on certain racial groups and on cognitive development. Differences in health care, nutrition, regulation of environmental toxins, and geographic distribution of diseases and control strategies between the developing world and developed nations have all been subjects of policies or policy recommendations (see Health and intelligence).

Melvin Konner, professor of anthropology and associate professor of psychiatry and neurology at Emory University, called Bell Curve a "deliberate assault on efforts to improve the school performance of African-Americans". "This book presented strong evidence that genes play a role in intelligence but linked it to the unsupported claim that genes explain the small but consistent black-white difference in IQ. The juxtaposition of good argument with a bad one seemed politically motivated, and persuasive refutations soon appeared. Actually, African-Americans have excelled in virtually every enriched environment they have been placed in, most of which they were previously barred from, and this in only the first decade or two of improved but still not equal opportunity. It is likely that the real curves for the two races will one day be superimposable on each other, but this may require decades of change and different environments for different people. Claims about genetic potential are meaningless except in light of this requirement."

Finally, Gregory Stock, writes that germinal choice technology may one day be able to select or change directly alleles found to influence intelligence or racially identifying traits (such as skin color; see gene SLC24A5), making them susceptible to biotechnological intervention.

Test results

Data

Racial and ethnic groups in the U.S. show differences in average IQ test scores, but the distributions of scores overlap greatly. (Reynolds, Chastain, Kaufman, & McLean, 1987)

Long-term trends for ages 9 (light gray), 13 (dark gray), and 17 (black) on the U.S. NAEP reading achievement test for White, Black, and Hispanic children.

The gaps found between the average intelligences of races or ethnicities varies depending on the populations studied and the content of the tests used. Black and white populations in the United States are the best studied. Black-White average IQ differences appear to increase with age, averaging approximately 17 points by age 24. According to James Flynn, the overall average Black-White gap has reduced by one third over the last 30 years. Less controversially, Black-White differences on school achievement tests shrunk over the last 30 years, but some of the improvements did not continue through the 1990s. The Black-White IQ gap also varies depending on test content. For example, two subsections of the WISC IQ test, known as forward and reverse digit-span, ask children to repeat a long series of numbers either forwards or backwards. The Black-White difference on forward digit span is relatively small, while the difference on reverse digit span is relatively large. Across a battery of tests, the size of the Black-White gap is correlated with the extent to which the tests measure the psychometric factor g, which also accounts for most of the variation in interindividual differences in IQ test performance. Using a variety of statistical techniques, Dolan and colleagues have found that the Black-White IQ gap can be account for by differences in g and the other interindividual ability factors measured by IQ tests, and also that IQ tests measure roughly the same mix of abilities in both Black and white populations. Gaps are seen in other tests of cognitive ability or aptitude, including university admission exams such as the SAT and GRE as well as employment tests for corporate settings and the military.

The IQ distributions of other racial and ethnic groups in the United States are less well studied. Hispanic and Native American populations, including arctic Natives, tend to score worse on average than White populations but better on average than Black populations. East Asian populations may score higher on average than White populations in the United States as they do elsewhere. Also Ashkenazi Jewish populations tend to score substantially higher on average than other populations of European ancestry. For each of these populations, there is some evidence that the mixture of ability factors that distinguish individuals are differentially distributed between groups. For example, East Asian populations tend to outscore White populations on tests of visuospatial ability to a greater extent than on tests of verbal ability, whereas the test score differences skew towards higher verbal ability for Ashkenazi-White differences. However, the mixture of abilities within groups appears to be nearly identical across many ethnic groups.The stability of these differences is also less well studied than Black-White differences.

According to Richard Lynn, J. Philippe Rushton, and others, IQ test score differences are observed cross-culturally and around the world. Lynn has published three books summarizing IQ test scores from around the world. The accuracy of the cross cultural IQ scores is highly controversial, but many scholars use the results as an estimate of world-wide IQ scores. Lynn's meta-analysis lists East Asians (105), Europeans (99), Inuit (91), Southeast Asians and Amerindians (87 each), Pacific Islanders (85), Middle Easterners (including South Asians and North Africans) (84), sub-Saharan Africans (67), and Australian Aborigines (62). International achievement test scores, including TIMSS and PISA, have also been used to estimate average IQ world-wide with similar results where data is available. The very low IQ scores reported for sub-Saharan African populations is especially controversial. For example, Wicherts argues that the average IQ of sub-Saharan Africans is poorly measured and is more likely 78. Sternberg, a critic of Rushton and Lynn, reported an average IQ of 70 for teenagers in Kenya. All commenters agree that IQ scores in developing countries are depressed to some extent by environmental conditions, such as macronutrient and micronutrient deficiencies.

Increases in IQ scores over time

William T. Dickens and James R. Flynn write that blacks have gained 5 or 6 IQ points on non-Hispanic whites between 1972 and 2002. This graph shows the gains for various tests.

The secular, international increase in test scores, commonly called the Flynn effect, is seen by Flynn and others as reason to expect the eventual convergence of average black and white IQ scores. Flynn argues that the average IQ scores in several countries have increased about 3 points per decade during the 20th century, which he and others attribute predominantly to environmental causes. This means, given the same test, the mean black American performance today could be higher than the mean white American performance in 1920, though the gains causing this appear to have occurred predominantly in the lower half of the IQ distribution. If an unknown environmental factor can cause changes in IQ over time, they argue, then contemporary differences between groups could also be due to an unknown environmental factor. An added complication to this hypothesis is the question of whether the secular IQ gains can be predominantly a real change in cognitive ability. Flynn's face-value answer to this question is "No", and other researchers have found reason to concur. In terms of the mixture of ability factors that IQ tests were designed to measure, such as g and verbal and mathematical ability, changes in IQ scores over time are different than either within-group individual differences and between group differences. For example, there has been little increase over time in performance on either the forward digit-span or reverse digit-span subtests, and tests of school achievement have been less affected than tests of abstract reasoning.

Reaction time

In 1991, Richard Lynn tested 1,468 9-year old children consisting of Blacks from South Africa, East Asians from Hong Kong and Japan, and Whites from Britain and Ireland. The content of the tests involved flipping a switch after one or more lights came on. Lynn found that the decision times (the time taken to make a decision about what to do) had a low correlation with IQ data on Raven's Progressive Matrices tests also administered during the same study, and that movement times (the time taken to execute the decision) did not show any correlation. He found that the Asians had the fastest decision times, followed by the Whites, and then by the Blacks. He also determined that the Black children had movement times that were substantially faster than those of Whites and Asians on certain tests. Studies by Jensen have shown similar patterns in response time on tests of arithmetic and international studies by Lynn have also asserted the same trend.

Interpretations

Given the observed differences in IQ scores between certain groups, a great deal of debate revolves around the significance of these observations. Various interpretations of test data lead to a multitude of conflicting conclusions as to which specific explanations the data support.

Some people have attributed differential economic growth between nations to differences in the intelligence of their populations. One example is Richard Lynn's IQ and the Wealth of Nations. The book is sharply criticized in the peer-reviewed paper The Impact of National IQ on Income and Growth. Another peer-reviewed paper, Intelligence, Human Capital, and Economic Growth: An Extreme-Bounds Analysis, finds a strong connection between intelligence and economic growth. It has been argued that East Asian nations underachieve compared to IQ scores.

Jared Diamond's Guns, Germs and Steel instead argues that historical differences in economic and technological development for different areas can be explained by differences in geography (which affects factors like population density and spread of new technology) and differences in available crops and domesticatable animals. However,psychologist John Philippe Rushton suggests these environmental differences may operate in part by selecting for higher levels of IQ Consensus at the American Psychological Association is that a partly genetic hypothesis is as of now, inadequate in explaining differences in IQ among population groups.

Nature and nurture

The nature versus nurture debates concern the relative importance of an individual's innate qualities ("nature", i.e. nativism, or philosophical empiricism, innatism) versus personal experiences ("nurture") in determining or causing individual differences in physical and behavioral traits. The view that humans acquire all or almost all their behavioral traits from "nurture" is known as tabula rasa ("blank slate"). In a modern context, the issue often relates to estimating the relative contribution of genetic and environmental factors to difference between individuals. However, all commenters agree that these methods cannot and are not intended to distinguish genetic and environmental contributions to the development of individual people. Instead, they are meant to determine the extent to which difference between individuals, for example individual difference in IQ scores, can be attributed to genetic and environmental factors that differ between individuals. Thus, a heritability of 100% does not mean that environmental factors are unimportant for development, but rather that physical or behavioral difference between individuals are not caused by difference in environment.

There is disagreement amongst scientists, scholars, and the public over the extent to which differences in intelligence quotient (IQ) between groups of humans are the result of genetic (nature), environmental (nurture), or the interaction of both factors. The consensus among intelligence researchers is that IQ differences between individuals of the same racial-ethnic group reflect real, functionally and socially significant, and substantially heritable differences in intelligence. There is still substantial debate about the influence of various environmental factors on IQ test score differences between races and ethnic groups in a given country, and whether or not genetics may also play a role.

An environmental factor that varies between groups but not within groups can cause group differences in a trait that is otherwise 100% heritable. The height of this "ordinary genetically varied corn" is 100% heritable, but the difference between the groups is totally environmental. This is because the nutrient solution varies between populations, but not within populations.

File:TBC-BW-IQ-SES-withDiff.png

Socioeconomic status (SES) varies both between and within populations, but Black-White differences in IQ persist among the children of parents matched for SES, and the gap is largest among the children of wealthiest and best educated parents.

Much of the research on explaining group differences stems from an observation promoted first by Arthur Jensen and later James Flynn regarding an environmental explanation for group differences. Jensen and Flynn argue that the very high within-group heritability of IQ presents a problem for environmental explanations of group differences in IQ. The high heritability of IQ implies that any environmental factor that varies within populations must have little effect on IQ. This implies that factors that vary within populations cannot contribute much to IQ differences between groups, unless the groups are extremely different with respect to that environmental factor. Differences in social and economic status might fall in this category. Yet there are no environmental factors known to vary that much between groups. Alternatively then, an environmental cause of group differences must vary between groups and not within groups. Effects associated with racism might fall into this category. Based on this reasoning, both Jensen and Flynn believe that the range of plausible environmental causes of group differences is constrained. Flynn believes that a predominately environmental cause will be found. Jensen believes that genetic factors will be found to be involved.

Genetics

Main article: Genetics of intelligence

See also The genome and intelligence

A few of the notable proponents of the partly genetic hypothesis are Raymond B. Cattell, Arthur Jensen and Hans Eysenck.

Rushton and Jensen examined 10 categories of research evidence from around the world to contrast "a hereditarian model" (50% genetic-50% cultural) and a culture-only model (0% genetic-100% cultural). In the article "Thirty Years of Research on Race Differences in Cognitive Ability" published in the APA journal Psychology, Public Policy and Law they cite the following evidence to support the hereditarian model:

1. Black–White–East Asian differences in IQ, reaction time, and brain size are observed worldwide in a range of cultures and environments. In the United States, significant Black-White IQ differences are observable at every age above 3 years, within every occupation or socioeconomic level tested, in every region of the country, and at every time since the invention of ability tests.
2. Jensen and others have argued that the magnitude of race differences on different IQ subtests correlate with the extent to which those subtests measures g, which also correlates with measures of the subtests heritability. From these and other findings, they argue that race differences have a partly biological basis.
3. The rising heritability of IQ with age (within all races; studies have found on average in the developed world heritability starts at 20% in infants, rises to 40% in middle childhood, and peaks at 80% in adulthood); and studies showing the virtual disappearance (~0.0) by adulthood of shared environmental effects on IQ (for example, family income, education, and home environment), with adopted siblings partaking in the studies no more similar in IQ than with strangers From these studies, they argue that most suggested environmental explanations for IQ difference between groups do not have a strong enough effect on IQ to fully account for group differences.
4. Studies of US comparisons of both parents to children and siblings to each other finding regression to differing means for different races (85 for Blacks and 100 for Whites) across the entire range of IQs, despite the fact that siblings are matched for shared environment and genetic heritage, with regression unaffected by family socioeconomic status and generation examined

Template:A(Y)ref believe that the best explanation is that 50%-80% of the group differences in average US IQ is genetic.

Other evidence, such as transracial adoption, certain racial admixture studies, behavior genetic modeling of group differences, "life-history" traits, and evolutionary explanations have also been proposed to indicate a genetic contribution to the IQ gaps and explain how these arose.. Critics of this view, such as Robert Sternberg, argue that these studies are either flawed and thus inconclusive, or else that they support a primarily environment (<20% genetic) hypothesis. For example, Template:AYref argue that the statistical methods linking the Black-White gap to g are insufficient.

Environmental factors

Quality of education

Some researches have written that studies that find test performance gaps between races even after adjusting for education level, such as the analysis found in The Bell Curve, fail to adjust for the quality of education. Not all high school graduates or college graduates have received the same quality of education. A 2006 study reported that that years of education is an inadequate measure of the educational experience among multicultural elders, and that adjusting for quality of education greatly reduced the overall effect of racial differences on the tests. A 2004 study reported that quality of education and cultural experience influence how older African Americans approach neuropsychological tasks and concluded that adjustment for these variables may improve specificity of neuropsychological measures. Yet another study reported that, although significant differences were observed between the ethnic groups when matched for years of education, equating for literacy level eliminated all performance differences between African Americans and Whites on both cancellation tasks which assess visual scanning.(Like reaction time tests cancellation task tests are sometimes regarded as "culture free" tests of intelligence.) Eric A. Hanushek and Steven G. Rivkin wrote in their 2006 book that unequal distributions of inexperienced teachers and of racial concentrations in schools can explain all of the increased achievement gap between grades 3 and 8.

A 2004 study in South Africa found highly significant effects for both level and quality of education within the black African first language groups taking the Wechsler IQ tests. Scores black African first language groups with advantaged education were comparable with the US standardization, whereas scores for black African first language participants with disadvantaged education were significantly lower than this. The study cautioned that faulty conclusions may be drawn about the effects of ethnicity and the potential for neuropsychological misdiagnosis.

Health

Main article: Health and intelligence

Main article: Race and health

Regarding the IQ gaps in the U.S., numerous explanations beside genetics have been proposed. Joel Wiesen lists more than a hundred. Increased rates of low birth weight babies and lower rates of breastfeeding in Blacks as compared to Whites are some factors of many that have been proposed to affect the IQ gap. The Flynn effect is often cited as evidence that average IQ scores have changed greatly and rapidly, for reasons poorly understood, noting that average IQ in the US may have been below 75 before the start of this effect, and thus some argue that the IQ gap between races could change in the future or is changing, especially if the effect started earlier for Whites.

Test bias

While the existence of average IQ test score differences has been a matter of accepted fact for decades, a great deal of controversy exists among scholars over the question of whether these score differences reflected real differences in cognitive ability. Some claim that there is no evidence for test bias since IQ tests are equally good predictors of IQ-related factors (such as school performance) for U.S. Blacks and Whites. The performance differences persist in tests and testing situations in which care has been taken to eliminate bias. It has also been suggested that IQ tests are formulated in such a way as to disadvantage minorities. Controlled studies have shown that test construction does not substantially contribute to the IQ gap. However, some psychometrics are not satisfied that the question of test bias is fully answered by these results. Also, all commenters reject the common misconception that IQ is meant to measure "innate" differences in intelligence, and they agree that average IQ scores on their own say nothing about the cause of the differences.

Stereotype threat

Main article: Stereotype threat

Stereotype threat is the fear that one's behavior will confirm an existing stereotype of a group with which one identifies; this fear may in turn lead to an impairment of performance. Testing situations that highlight the fact that intelligence is being measured tend to lower the scores of individuals from racial-ethnic groups that already score lower on average. Stereotype threat conditions cause larger than expected IQ differences among groups but do not fully explain the gaps found in non-threatening test conditions.

Racism and discrimination

Researchers such as Jack Demaine find racial categorizations problematic in educational settings. Racial categorizations, Jack Demaine writes, may have adverse impacts on the education of minorities. Similarly, Alastair Bonnett, Bruce Carrington state:

The collection of ethnic and racial statistics has become common in a growing number of institutional settings. Yet contemporary approaches to race and ethnicity suggest that the very process of compelling people to assign themselves to one of a small number of racial or ethnic 'boxes' is, at best, essentialist and, at worst, racist.

Physiological responses to racism

See also: Race and health

Stereotype threat can result in physiological responses that can be measured objectively. For example, a study by Blascovich J, Spencer SJ, Quinn D and Steele C. reported that African Americans under stereotype threat exhibited larger increases in arterial blood pressure during an academic test, and performed more poorly on difficult test items. Some researchers feel this may explain the higher death rates from hypertension related disorders among African Americans. A study by Toni Schmader and Michael Johns reported that stereotype threat can effectively reduce working memory capacity, another factor in poor test performance. Stereotype threat may undermine intellectual performance by triggering a disruptive mental load. Jean-Claude Croizet, Gérard Després, Marie-Eve Gauzins, Pascal Huguet, Jacques-Philippe Leyens and Alain Méot reported increased heart rates for test subjects operating under stereotype threat.

Racial discrimination in education

Roslyn Arlin Mickelson writes that racial discrimination in education arises from actions of institutions or individual state actors, their attitudes and ideologies, or processes that systematically treat students from different racial/ethnic groups disparately or inequitably. Despite advancement in education reform efforts, to this day African American students continue to experience inequities within the educational system. Hala Elhoweris , Kagendo Mutua, Negmeldin Alsheikh and Pauline Holloway conducted a study of the effect of students' ethnicity on teachers' educational decision making. The results of this study indicated that the student's ethnicity did make a difference in the teachers' referral decisions for gifted and talented educational programs.Recently, a number of scholars have examined the issue of disproportionate representation of minority students in special education programs

Teachers' perceptions of a students cultural background may effect school achievement. African American students with African American cultural backgrounds, for example, have been found to benefit from culturally responsive teaching. In a 2003 study researchers found that teachers perceived students with African American culture-related movement styles as lower in achievement, higher in aggression, and more likely to need special education services than students with standard movement styles irrespective of race or other academic indicators.

Ellis Cose writes that low expectations may have a negative impact on the achievement of minorities. He writes that black people did not need to read The Bell Curve to be aware of the low expectations held for them by the majority culture. He recalls examples of low expectations from his teachers in school who regarded his use of AAVE as "laziness" and teachers who did not feel it was important to purchase new text books because they did not expect the students to be able to read anything complex. He contrasts these low expectations with the high expectations philosophy of Xavier University where, using the ideas Whimbey articulated in his book Intelligence can be Taught teachers created a program called SOAR. SOAR raised the performance of black students and lead Xavier to become the university that sends the greatest number of black students to medical school in the United States. The SOAR program produced gains equivalent to 120 points on an SAT test. Cose writes that "..we must treat people, whatever their color, as if they have unlimited intellectual capacity."

Caste-like minorities

The book Inequality by Design: Cracking the Bell Curve Myth claims that it is not lower average intelligence that leads to the lower status of ethnic minorities, it is instead their lower status that leads to their lower average intelligence test scores. The following table from the same book illustrates how social status or caste position is related to test scores and school success in nations around the world.

Group Differences Around the World

	Status or Caste Position		Test Scores, School Success
Country	High	Low	High	Low
United States	Whites	Blacks	Whites	Blacks
	Whites	Latinos	Whites	Latinos
	Whites	American Indians	Whites	American Indians
United Kingdom	English	Irish, Scottish	English	Irish, Scottish
Northern Ireland	Protestants	Catholics	Protestants	Catholics
Australia	Whites	Aborigines	Whites	Aborigines
New Zealand	Whites	Maoris	Whites	Maoris
South Africa	English	Afrikaaners	English	Afrikaners
Belgium	French	Flemish	French	Flemish
Israel	Jews	Arabs	Jews	Arabs
	Western Jews	Eastern Jews	Western Jews	Eastern Jews
India	Nontribals	Tribal people	Nontribals	Tribal people
	Brahmin	Harijan	Brahmin	Harijan
	High caste	Low caste	High caste	Low caste
Czechoslovakia	Slovaks	Gypsies	Slovaks	Gypsies
Japan	Non-Burakumin	Burakumin	Non-Burakumin	Burakumin
	Japanese Origin	Korean Origin	Japanese Origin	Korean Origin
South Korea	Koreans	Southeast Asians	Koreans	Southeast Asians

Viewpoints of notable scientists and researchers

See also: Snyderman and Rothman (study)

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Criticisms

Utility of research

Theories of race and intelligence have been challenged on grounds of their utility. Critics want to know what purpose such research could serve and why it has been an intense an area of focus for a few researchers. Some defend the research, saying it has egalitarian aims or that it is pure science; others say that the true motivation for the research is the same as that of the eugenics movement and other forms of scientific racism. Even supporters of intelligence research have described such research as analogous to "working with dynamite" or "dangerous play" in sports.

As to whether research in this area is desirable, John C. Loehlin wrote in 1992, "Research on racial differences in intelligence is desirable if the research is appropriately motivated, honestly done, and adequately communicated." [emphasis original] Defenders of the research suggest that both scientific curiosity and a desire to draw benefits from the research are appropriate motivations. Researchers such as Richard Lynn have suggested that conclusions from the research can help make political decisions, such as the type of educational opportunities and expectations of achievement policy makers should have for people of different races. Charles Murray, a conservative political pundit at the American Enterprise Institute has used their conclusions to criticize social programs based on racial equality that fail, he claims, to recognize the realities of racial differences.

In a book review J. Philippe Rushton called Richard Lynn's and Tatu Vanhanen's book IQ and Global Inequality which links GDP with the racial composition of nations as "the most important contribution to economic understanding since Adam Smith".

Sociologist and demographer Reanne Frank says that some race and intelligence research has been abused "The most malignant are the "true believers," who subscribe to the typological distinctions that imply hierarchical rankings of worth across different races. Although this group remains small, the members' work is often widely publicized and well known (e.g., Herrnstein and Murray 1994; Rushton 1991)"

Potential for bias

Proponents of genetic explanations of race/IQ correlation have often been criticized both of scientific misconduct and of their intimate links with groups that have historic ties to Nazis and eugenics of the early 19th century, such as the Pioneer Fund. The Pioneer Fund has been characterized by the Southern Poverty Law Center as a hate group. Beverly Daniel Tatum writes that dominant cultures often set the parameters by which minority cultures will be judged. Minority groups are labeled as substandard in significant ways: for example, blacks have historically been characterized as less intelligent than whites. Tatum suggests that the ability to set these parameters is a form of white privilege. Proponents of genetic explanations of race/IQ correlation have in turn accused their critics of suppressing scientific debate in the name of political correctness. They claim harassment and interference with both their work and funding.

The preponderance of evidence indicates that IQ tests measuring general intelligence are crossculturally valid. There is little or no evidence of population-specific cultural effects apart from the obvious example of language bias. For example, Robert Sternberg et al. found that the IQ of 12- to 15-year-old Kenyans predicted school grades at about the same level as they do in the West. IQ also predicted university performance equally well in African and non-African engineering students in South Africa in a 2004 study. Salgado et al. (2003) demonstrated the international generalizability of general mental ability across 10 member countries of the European Community and differences in a nation’s culture, religion, language, socioeconomic level or employment legislation did not affect the predictive validity of IQ tests.

The Bell Curve has often been argued to embellish the view that IQ is inheritable. (Nature argument.) However, recent studies have argued that IQ itself is in fact malleable due to conditions of nurture.

Opinion survey

Main article: Snyderman and Rothman (study)

The Snyderman and Rothman study accused the media of liberal bias in reporting on race and intelligence. Mark Snyderman and Stanley Rothman argued in their joint paper in 1988 that media coverage of intelligence-related research is often inaccurate and misleading. They surveyed the opinions of journalists and science editors and intelligence experts (not necessarily with knowledge about race), including scholars in the subfields of psychology, sociology, cognitive science, education, and genetics. They argue that media coverage of intelligence related topics was overall inaccurate and misleading. They say the media has misreported the views of the scientific community, especially about the role of genetic and environmental factors in explaining individual and group differences in IQ.

They found that the media regularly presented the views of Stephen Jay Gould and Leon Kamin as representative of mainstream opinion among experts, whereas those who stress that individual and group differences may be substantially genetic (e.g., Arthur Jensen) are characterized as a minority. According to Synderman and Rothman, their survey of expert opinion found that the opposite is true, however proportion of experts supporting these hypotheses today is unknown.

A survey was conducted in 1987 of a broad sample of 1,020 scholars (65% replied) in specialties that would give them reason to be knowledgeable about IQ (but not necessarily about race; Snyderman & Rothman, 1987). The survey was given to members of the American Education Research Association, National Council on Measurement in Education, American Psychological Association, American Sociological Association, Behavior Genetics Association, and Cognitive Science Society. Political and social opinions, reported in the same survey, accounted for less than 10% of the variation in responses. (Respondents on average called themselves slightly left of center politically.) Measures of expertise or eminence accounted for little or no variation in responses.

According to the report, regarding the question "The source of black-white difference in IQ":

This is perhaps the central question in the IQ controversy. Respondents were asked to express their opinion of the role of genetic differences in the black-white IQ differential. Forty-five percent believe the difference to be a product of both genetic and environmental variation, compared to only 15% who feel the difference is entirely due to environmental variation. Twenty-four percent of experts do not believe there are sufficient data to support any reasonable opinion, and 14% did not respond to the question. Eight experts (1%) indicate a belief in an entirely genetic determination.

A selection of survey results

Question	Responses
What heritability would you estimate for IQ differences within the White population?	Average estimate of 60 (± 17) percent.
What heritability would you estimate for IQ differences within the Black population?	Average estimate of 57 (± 18) percent.
Are intelligence tests biased against Blacks?	On a scale of 1 (not at all or insignificantly) to 4 (extremely), mean response of 2 (somewhat).
What is the source of the average Black-White difference in IQ?	Both genetic and environmental (45%, or 52% of those responding).

Robert Sternberg cautioned against supposing that the survey represented anything but opinion saying, "science isn't done by majority rule". Respondents on average called themselves slightly left of center politically, but political and social opinions accounted for less than 10% of the variation in responses. Carol Swain, author of The New White Nationalism reacted with some dismay to the survey, stating:

At least one important survey suggests that a belief in the biological inferiority of some races in regard to intelligence is more common than generally supposed. Smith College professor Stanley Rothman and Harvard researcher Mark Snyderman surveyed a sample of mostly scientific experts in the field of educational psychology in the late 1980s and found that 53 percent believed IQ differences between whites and African Americans were at least partly genetic in origin, while only 17 percent attributed the IQ differences to environmental factors alone (the remainder either believed the data was currently insufficient to decide the issue or refused to answer the question).

See also

Theories of Race and Intelligence:

• Hominid intelligence

Publications of Race and Intelligence:

• IQ and the Wealth of Nations
• IQ and Global Inequality
• The Mismeasure of Man
• Race Differences in Intelligence

Theories of other Intelligence links:

• Brain to body mass ratio
• Height and intelligence
• Neuroscience and intelligence
• Sex and intelligence

External links

Collective Statements

• APA Task Force Examines the Knowns and Unknowns of Intelligence
• Statement on "Race" and Intelligence. American Anthropological Association. Adopted December 1994.
• Mainstream Science on Intelligence. Intelligence, v24 n1 p. 13-23 Jan-Feb 1997

Review Papers

• James Flynn and Charles Murray debate - news summary
• June 2005 issue of Psychology, Public Policy, and Law, Vol. 11, No. 2.
  • Thirty Years of Research on Race Differences in Cognitive Ability J. Philippe Rushton & Arthur R. Jensen
  • There Are No Public-Policy Implications Robert J. Sternberg
  • What if the Hereditarian Hypothesis is True? Linda S. Gottfredson
  • Heredity, Environment, and Race Differences in IQ Richard E. Nisbett
  • The Cultural Malleability of Intelligence and Its Impact on the Racial/Ethnic Hierarchy Lisa Suzuki & Joshua Aronson
  • Wanted: More Race Realism, Less Moralistic Fallacy J. Philippe Rushton & Arthur R. Jensen
• Race, Genetics and IQ Richard E. Nisbett (PDF)
• The Inequality Taboo Charles Murray archived version
• The Black-White Test Score Gap (1998) online (page-image) version of ISBN 0-8157-4609-1

Others

• Crippled by Their Culture - Race doesn't hold back America's black rednecks. Nor does racism by Thomas Sowell
• Race and IQ: Part 1, Part 2, Part 3 by Thomas Sowell
• The Skeptic's Dictionary entry on IQ and race
• (Skeptic Magazine): Two book reviews, by Paul R. Gross and Alondra Oubre, of Sarich’s and Miele’s book, Race: The Reality of Human Differences
• Criticism on source material of Bell Curve book
• Poverty and Brain Development in Early Childhood 1999 report
• Miscellaneous articles by Richard Lynn et al.
• Are IQ Tests Biased?
• Scholars Provide an Overview of Explanations for Black-White Test Score Gap
• School Readiness: Closing Racial and Ethnic Gaps
• A review of the field (Jan. 2006) Kohn, Marek, "This racist undercurrent in the tide of genetic research: As taboos fall away, there's a danger that denial of racial difference will be replaced with uncritical acceptance," The Guardian.
• The Lessons of the Ashkenazim: Groups and Genes, Steven Pinker, June 2006, The New Republic.
• Are all races equally intelligent? -- Or: When is knowledge knowledge? by John J. Ray
• Black-White Gap in IQ Scores Closing, Study Finds
• Breaking Free of Nehruby Sanjeev Sabhlok : Chapter 2, section 6 of this book proposes a model of IQ determination which is strongly impacted by the level of freedom (and dignity)