Race and intelligence (research)

Race and intelligence research tries to measure the gaps between different races or ethnicities and to find the causes for these gaps. Average test scores of races or ethnicities varies depending on the method and setting used to test intelligence, the health and economic situation of the test takers, the presence of stereotype threat, and the period in history when the test was performed. Some studies have shown that gaps in test scores are closing, while other researchers write that the gaps have stopped closing in some nations.

Some explanations for the causes of the gaps found relate to cultural factors, health, testing situations, stereotype threat, and other environmental factors. Numerous researchers have shown that environment plays a large role in performance in various tests of intelligence. The importance of environment is accepted even by those researchers who suspect that genetics may play a role. In the past, disparities in performance were regarded to be genetic in nature. Today a few researchers still support such theories, though many in the flied remain either undecided, find the question of a genetic cause for gaps in the scores between races to be poorly formulated, or disagree that genetics could play a significant role at all. Based on a survey they conducted, Snyderman and Rothman (1998) write that the most common view among "intelligence experts" is that the Black-White IQ gap is caused by both genetic and environmental factors.

Explanations


Although, most intelligence researchers believe that IQ differences among individuals reflect the general intelligence factor, g. the question of whether IQ differences among groups are substantially genetic remains unsettled. Researchers, such as Richard E. Nisbett caution that the studies that are most directly relevant to the question of whether the Black/White IQ gap is genetic in origin provide no evidence for a correlation between IQ and African (rather than European) ancestry. The best modern studies, says Nisbett indicate little relation between skin color and IQ. One modern study of blood types weakly suggests African superiority; the other two suggest no difference  between the races.

According to the American Psychological Association, the difference between the average IQ scores of Blacks and Whites in the U.S. cannot be attributed to any obvious biases in test construction or cultural biases, though, it is clear, they say, that these differences, are well within the range of effect sizes that can be produced by environmental factors.

Although IQ differences between individuals is highly heritable, this does not mean that average IQ differences between racial groups are necessarily genetic in origin, because estimates of heritability depend on the range of environments tested. High heritability by itself is not informative about group differences, so any inferences made from within group heritability will depend on additional considerations. However, many scholars agree that no considerations of heritabilty are sufficient if group differences are caused by environmental factors that uniquely and uniformly affect all members of one group but not another.

Environmental explanations
Regarding the IQ gaps in the U.S., there are numerous possible explanations beside genetics. One author lists more than a hundred. It has been suggested that African-American culture disfavors academic achievement and fosters an environment that is damaging to IQ. Likewise, it is argued that the persistence of negative racial stereotypes reinforces this effect. Dr. John Ogbu writes that the condition of being a "caste-like minority" affects motivation and achievement, depressing IQ.

Arguing that IQ tests are often wrongly described as measuring "innate" rather than developed ability, conclude that this "labeling bias" causes people to inappropriately attribute the Black-White gap to "innate" differences. They assert that non-cultural environmental factors cause gaps measured by the tests, rather than any possible innate difference based on genetics, and to use these tests as a measure of innate difference is misleading and improper.

Estimates of the significance of genetics vs. environment are dependent on the strength of environmental factors. For example, schizophrenia, regarded as highly heritable, has seen increased rates in second and third generation immigrants to Western European countries which do not seem to be the result of increased genetic susceptibility, but another, as yet unidentified, environmental factor(s) that seems to have become more influential. 

Culture
Many anthropologists have argued that intelligence is a cultural category; some cultures emphasize speed and competition more than others, for example. Speculations about innate differences in intelligence between ethnic groups have occurred throughout history. Aristotle in the 4th century B.C. and Cicero in the 1st. century B.C. disparaged the intelligence of the northern Europeans of the time, as did the Moors in Iberia in the 11th century.

Ogbu elaborates on this idea suggesting that African American popular culture serves to disengage students from academic achievement by proving the wrong kind of role models.

"'What amazed me is that these kids who come from homes of doctors and lawyers are not thinking like their parents; they don't know how their parents made it,' Professor Ogbu said in an interview. 'They are looking at rappers in ghettos as their role models, they are looking at entertainers. The parents work two jobs, three jobs, to give their children everything, but they are not guiding their children.'"

The effort gap
Researchers Stephan Thernstrom and John Ogbu have suggested that black students perform poorly in part due to simple lack of effort. Stephan Thernstrom studied different kinds of schools and concluded that, while many environmental factors play a role in the achievement gap, a strong commitment to education was an essential element for academic success. Ogbu found that the black students were quite open in telling the researchers that, in general, their white classmates studied more, worked harder and cared more about getting good grades. "'In spite of the fact that the students knew and asserted that one had to work hard to succeed in Shaker schools, black students did not generally work hard. In fact, most appeared to be characterized by the low-effort syndrome ... (They) were not highly engaged in their schoolwork and homework.' --John Ogbu"

Pidgin language barriers
Sandra Lee McKay author of Sociolinguistics and Language Teaching writes that language may present a barrier for students who speak pidgin and creole languages. Unlike other languages such as Spanish and Chinese, pidgin and creole languages such as African American Vernacular English (AAVE) are not commonly recognized in classroom settings. As a result of this, students are not taught the Standard American English (SAE) used on tests as a second language in the same way as students who speak Spanish or Chinese. Students who speak AAVE face challenges similar to those learning English as a Second Language. (ESL)

John Russel Rickford author of Unequal partnership: Sociolinguistics and the African American speech community rebutts misconceptions about the cognitive limitations of the use of AAVE notes the unfair disadvantages IQ tests pose for its speakers. Geneva Smitherman writes that "80 to 90 percent of American blacks” speak AAVE “at least some of the time". The preponderance of code-switching indicates that AAVE and SAE are met with different reactions or discernments. AAVE is often perceived by members of mainstream American society as indicative of low intelligence or limited education.

The effects of test construction on minority groups, such as the use of standard English, were examined by the 1996 APA report, which wrote that "controlled studies have shown, however, that none of them contributes substantially to the Black/White differential under discussion here (Jensen, 1980; Reynolds 82 Brown, 1984; for a different view see Helms, 1992). Moreover, efforts to devise reliable and valid tests that would minimize disadvantages of this kind have been unsuccessful." However the language gap still presents a barrier to education through adverse impacts in classroom settings where the need to teach English as a second language to students who come to school speaking AAVE is not commonly recognized.

Health
In the developing world there are many factors can greatly decrease IQ scores. Examples include nutrition deficiencies in iodine and iron; certain diseases like malaria; unregulated toxic industrial substances like lead and mercury; and poor health care for pregnant women and infants. Also in the developed world there are many biological factors that can affect IQ. 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.

Exposure to violence
Exposure to violence in childhood has been associated with lower school grades. Recent research shows it may also have an impact on IQ. A group of largely African American urban first-grade children and their caregivers were evaluated using self-report, interview, and standardized tests, including IQ tests. The study found that exposure to violence and trauma-related distress in young children were associated with substantial decrements in IQ and reading achievement. Exposure to Violence or Trauma lead to a 7.5-point (SD, 0.5) decrement in IQ and a 9.8-point (SD, 0.66) decrement in reading achievement. Neighborhood risk has been related to lower school grades for African-American adolescents in another study from 2006.

The Flynn effect
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 changes in environment can cause changes in IQ over time, they argue, then contemporary differences between groups could also be due to an unknown environmental factor. On the supposition that the effect started earlier for whites, because their social and economical conditions began to improve earlier than did those of blacks, they anticipate that the IQ gap among races might change in the future or is even now changing. 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. Responding to such concerns, have proposed a solution which rests on genotype-environment correlation, hypothesizing that small initial differences in environment cause feedback effects which magnify into large IQ differences. Such differences would need to develop before age 3, when the black-white IQ gap can be first detected.

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 (Aronson, Wilson, & Akert, 2005). Stereotype threat was first articulated and documented by the social psychologists Claude Steele, Joshua Aronson, and Steven Spencer, who have conducted several studies on this topic.

"'When capable black college students fail to perform as well as their white counterparts, the explanation often has less to do with preparation or ability than with the threat of stereotypes about their capacity to succeed.' - Claude M. Steele, The Atlantic Monthly, August 1999 Thin Ice: Stereotype Threat and Black College Students"

It is suggested that reduced performance from "stereotype threat" could be a contributing factor to the gaps in IQ test scores. found that making race salient when taking a test of cognitive ability negatively affected high-ability African American students. point out that these findings are widely misinterpreted to mean that eliminating stereotype threat eliminated the Black-White performance gap.

Other Factors
Many studies that attempt to test for heritability find results that do not support the genetic hypothesis. They include studies on IQ and skin color, self-reported European ancestry, children in post WWII Germany born to black and white American soldiers, blood groups, and mixed-race children born to either a black or a white mother. Many intervention and adoption studies also find results that do not support the genetic hypothesis. Non-hereditarians have argued that these are direct tests of the genetic hypothesis and of more value than indirect variables, such as skull size and reaction time. Hereditarians argue that these studies are flawed due to their age, lack of replication, problems with their sample population, or that they do in fact support the genetic hypothesis.

, with data from "the first large, nationally representative sample" of its kind, report finding only a very small racial difference when measuring mental function for children aged eight to twelve months, and that even these differences disappear when including a "limited set of controls". They argue that their report poses "a substantial challenge to the simplest, most direct, and most often articulated genetic stories regarding racial differences in mental function." They conclude that "to the extent that there are any genetically-driven racial differences in intelligence, these gaps must either emerge after the age of one, or operate along dimensions not captured by this early test of mental cognition."

Another recent theory hypothesizes that fluid cognition (gF') may be separable from general intelligence, and that gF' may be very susceptible to environmental factors, in particular early childhood stress. Some IQ tests, especially those used with children, are poor measures of gF', which means that the effect of the environment on intelligence regarding racial differences, the Flynn effect, early childhood intervention, and life outcomes may have been underestimated in many studies. The article has received numerous peer commentaries for and against.

Genetic explanation

 * See also: Inheritance of intelligence

Arthur Jensen and others have concluded that the US IQ gap is partially genetic. Rushton and Jensen say that while plausible environmental explanation for the lower mean IQ in Blacks in the U.S. can be offered in many cases, these explanations are less capable of explaining the higher average IQ of East Asians than Whites.

To support their theory, they often cite several arguments and observations:


 * 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
 * 5) Evidence against test construction and cultural bias: the internal consistency of item difficulty for all groups, the equivalent validity of tests in predicting academic and occupational outcomes for all groups, and the persistence of the IQ gap on relatively culture-free tests.

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, argue that the statistical methods linking the Black-White gap to g are insufficient.

Test data


The modern controversy surrounding intelligence and race focuses on the results of IQ studies conducted during the second half of the 20th century, mainly in the United States and some other industrialized nations. In almost every testing situation where tests were administered and evaluated correctly, a difference of approximately one standard deviation was observed in the US between the mean IQ score of Blacks and Whites. Attempted world-wide compilations of average IQ by race generally place Ashkenazi Jews at the top, followed by East Asians and Whites, other Asians, Arabs, Blacks and Australian Aborigines. See IQ and the Wealth of Nations for an attempted compilation of average IQ for different nations and a discussion of associated measurement problems. The IQ scores vary greatly among different nations for the same group. Blacks in Africa score much lower than Blacks in the US. Some reports indicate that the Black–White gap is smaller in the UK than in the U.S. Many studies also show large differences in IQ between different groups of Whites. For example, in Northern Ireland the IQ gap between Protestants and Catholics are as large as that between Blacks and Whites in the US. For example, in Israel, large gaps in test scores and achievement separate Ashkenazi Jews from other groups such as the Sephardi.

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 (Roth et al. 2001). Measures of school achievement correlate fairly well with IQ, especially in younger children. In the United States, achievement tests find that by 12th grade Black students are performing on average only as well as White students in 10th grade, and Asian students in 8th grade; Hispanic students do only slightly better than Blacks. Whether the gaps are narrowing or not is debated.

Interpretations of measured group IQ differences

 * See also: Practical importance of IQ

Given the observed differences in IQ scores between certain groups, a great deal of debate revolves around the significance of these observations. Some believe that these differences indicate a natural genetic hierarchy of races, with East Asians being the most genetically superior, Whites slightly below, and Blacks the most genetically inferior, and suggest that attempts to close the gaps are doomed to fail. Others believe that these differences are direct evidence of the social oppression of minority groups.