THIRTY YEARS OF RESEARCH ON RACEDIFFERENCES IN COGNITIVE ABILITY
J. Philippe Rushton Arthur R. Jensen
Psychology, Public Policy, and Law 2005, Vol. 11, No. 2, 235–294
The culture-only (0% genetic–100% environmental) and the hereditarian (50% genetic–50% environmental) models of the causes of mean Black–White differences in cognitive ability are compared and contrasted across 10 categories of evidence:
the worldwide distribution of test scores, g factor of mental ability, heritability, brain size and cognitive ability, transracial adoption, racial admixture, regression, related life-history traits, human origins research, and hypothesized environmental variables.
The new evidence reviewed here points to some genetic component in Black–White differences in mean IQ.
Section 1: Background
Jensen’s (1969) article was covered in Time, Newsweek, Life, U.S. News & World Report, and New York Times Magazine. His conclusions, the theoretical issues they raised, and the public policy recommendations that many saw as stemming directly from them were dubbed “Jensenism,” a term which entered the dictionary.
【Jensenismに関しては、現在では否定的見解が、主流である。英文ウキペディアから
Despite such defenses, however, the current scientific consensus is that genetics do not explain IQ differences between racial groups.[14][15][16][17][18]
】
Section 2: The Two Conflicting Research Programs
Here, we review the research on Black–White difference in average IQ published since Jensen’s (1969) now 36-year-old article.
Section 3: Mean Race–IQ Differences: A Global Perspective
Around the world, the average IQ for East Asians centers around 106; that for Whites, about 100; and that for Blacks, about 85 in the United States and 70 in sub-Saharan Africa.
On the Differential Aptitude Battery, by age 6, however, the average IQ of East Asian children is 107, compared with 103 for White children and 89 for Black children (Lynn, 1996).
The correlations between IQ and reaction times for the five countries are summarized in Table 1.
Table1
Note.
Data in this table are reconfigured from IQ and the Wealth of Nations (p. 67, Table 6.2), by R. Lynn and T. Vanhanen, 2002, Westport, CT: Praeger. Copyright 2002 by R. Lynn and T. Vanahanen. Adapted with permission. a r reliability. * p .05.
Figure 2.
Mean response times of 10-year-old Black, White, and East Asian children on the Math Verification Test for Multiplication, Subtraction, and Addition. Redrawn by A. R. Jensen from data in Jensen (1993;
Section 5: Gene–Environment Architecture and Mean Black–White IQ Differences
Dozens of twin, adoption, and family studies have confirmed the high heritability of intellectual and behavioral traits, and even reaction time tasks, within a race (Bouchard, 1996; Bouchard & Loehlin, 2001; Deary, 2000; Plomin et al., 2001).
Jensen & Whang, 1994). Copyright 2002 by A. R. Jensen. Reprinted with permission.
Figure 3. Estimated proportions of the total IQ variance attributable to genetic and environmental (shared and nonshared) effects. Note that only the nonshared (or within-family) environmental variance remains relatively constant across the entire age range. From “Behavioral Genetics of Cognitive Ability: A Life-Span Perspective,” by M. McGue, T. J. Bouchard, Jr., W. G. Iacono, and D. T. Lykken, in R. Plomin and G. E. McClearn (Eds.), Nature, Nurture, and Psychology (p. 64), edited by R. Plomin and G. E. McClearn, 1993, Washington, DC: American Psychological Association. Copyright 1993 by the American Psychological Association. Reprinted with permission.
Section 6: Race, Brain Size, and Cognitive Ability
Section 7: Mean Race–IQ Differences and Transracial Adoption Studies
Section 8: Mean Race–IQ Differences and Racial Admixture
Section 9: Mean Race–IQ Differences and Regression to the Mean
Section 10: The Race–Behavior Matrix
Note. From Race, Evolution, and Behavior: A Life History Perspective (p. 5), by J. P. Rushton, 2000, Port Huron, MI: Charles Darwin Research Institute. Copyright 2000 by J. P. Rushton. Adapted with permission.
Section 11: Mean Race–IQ Differences and Human Origins
The currently most commonly accepted view of human origins, the “Out-ofAfrica” theory, posits that Homo sapiens arose in Africa about 150,000 years ago, expanded northward beyond Africa about 100,000 years ago, with a European– East Asian split about 41,000 years ago (Cavalli-Sforza et al., 1994; Stringer & McKie, 1996). In Cavalli-Sforza’s (2000) maximum likelihood tree devised on the basis of molecular genetic markers, the most distant group was the Africans, with Europeans and Asians being closer.
r. It has been proposed that the farther north the populations migrated out of Africa, the more they encountered the cognitively demanding problems of gathering and storing food, gaining shelter, making clothes, and raising children successfully during prolonged winters (Rushton, 2000).
As these populations evolved into present-day Europeans and East Asians, the ecological pressures selected for larger brains, slower rates of maturation, and lower levels of testosterone—with concomitant reductions in sexual potency, aggressiveness, and impulsivity; increases in family stability, advanced planning, self-control, rule following, and longevity; and the other characteristics listed in Table 3.
The fact that the three-way pattern in IQ, brain size, and other traits is not unique to the United States but occurs internationally is consistent with a single, general (genetic–evolutionary) theory, whereas culture-only theory must invoke a number of highly localized, specific explanations.
Section 12: How Well Have Culture-Only Theories of Mean Race–IQ Differences Held Up?
Culture-only hypotheses have not explained the mean Black–White group differences in IQ. (They have especially not explained the findings on East Asians.)
One early view was that the mean Black–White group difference in IQ was due to the then obvious differences in (segregated) school facilities (Myrdal, 1944).
Section 13: Evaluating the Culture-Only and the Hereditarian Research Programs
Section 15: Implications for Public Policy
J. Philippe Rushton Arthur R. Jensen
Psychology, Public Policy, and Law 2005, Vol. 11, No. 2, 235–294
注目されるのは、この論文の引用数の多さである。2022年4月時点で783もある。
①黒人と白人・東アジア人のIQの差は、事実として認めざるを得ない。反面、白人・東アジア人の差は？である。何故なら、16世紀頃以降の歴史と完全に矛盾する。事実と仮定すれば、IQの分布が異なるはずである。
しかし、「我々は優秀な民族」という極めて奇妙な自己陶酔型パーソナリティー障害者集団である韓国人ども場合には、外国人によるIQテストを小学生に行う場合には、ほぼ確実に前日に事前にIQテストを行い低い者を欠席させるであろう。この論文では、香港が異様に高い数値であるが、同様のことが行われている可能性がある。日本人については、多分されてはいない。
②IQの相違の原因として、この論文メモで赤字にしておいた箇所が著者らの主張である。
出アフリカ後の自然環境の差に起因するというあまりにも、粗雑かつ乱暴な根拠に過ぎない。
①黒人と白人・東アジア人のIQの差は、事実として認めざるを得ない。反面、白人・東アジア人の差は？である。何故なら、16世紀頃以降の歴史と完全に矛盾する。事実と仮定すれば、IQの分布が異なるはずである。
しかし、「我々は優秀な民族」という極めて奇妙な自己陶酔型パーソナリティー障害者集団である韓国人ども場合には、外国人によるIQテストを小学生に行う場合には、ほぼ確実に前日に事前にIQテストを行い低い者を欠席させるであろう。この論文では、香港が異様に高い数値であるが、同様のことが行われている可能性がある。日本人については、多分されてはいない。
②IQの相違の原因として、この論文メモで赤字にしておいた箇所が著者らの主張である。
出アフリカ後の自然環境の差に起因するというあまりにも、粗雑かつ乱暴な根拠に過ぎない。
The culture-only (0% genetic–100% environmental) and the hereditarian (50% genetic–50% environmental) models of the causes of mean Black–White differences in cognitive ability are compared and contrasted across 10 categories of evidence:
the worldwide distribution of test scores, g factor of mental ability, heritability, brain size and cognitive ability, transracial adoption, racial admixture, regression, related life-history traits, human origins research, and hypothesized environmental variables.
The new evidence reviewed here points to some genetic component in Black–White differences in mean IQ.
Section 1: Background
Jensen’s (1969) article was covered in Time, Newsweek, Life, U.S. News & World Report, and New York Times Magazine. His conclusions, the theoretical issues they raised, and the public policy recommendations that many saw as stemming directly from them were dubbed “Jensenism,” a term which entered the dictionary.
【Jensenismに関しては、現在では否定的見解が、主流である。英文ウキペディアから
Despite such defenses, however, the current scientific consensus is that genetics do not explain IQ differences between racial groups.[14][15][16][17][18]
- Ceci, Stephen; Williams, Wendy M. (1 February 2009). "Should scientists study race and IQ? YES: The scientific truth must be pursued". Nature. 457 (7231): 788–789. Bibcode:2009Natur.457..788C. doi:10.1038/457788a. PMID 19212385. S2CID 205044224.
There is an emerging consensus about racial and gender equality in genetic determinants of intelligence; most researchers, including ourselves, agree that genes do not explain between-group differences.
- ^ Hunt, Earl (2010). Human Intelligence. Cambridge University Press. p. 447. ISBN 978-0-521-70781-7.
- ^ Mackintosh, N. J. (2011). IQ and human intelligence (2nd ed.). Oxford: Oxford University Press. pp. 334–338, 344. ISBN 978-0-19-958559-5. OCLC 669754008.
- ^ Nisbett, Richard E.; Aronson, Joshua; Blair, Clancy; Dickens, William; Flynn, James; Halpern, Diane F.; Turkheimer, Eric (2012). "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.
- ^ Kaplan, Jonathan Michael (January 2015). "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. ISSN 0169-3867. S2CID 85351431.
Section 2: The Two Conflicting Research Programs
Here, we review the research on Black–White difference in average IQ published since Jensen’s (1969) now 36-year-old article.
Section 3: Mean Race–IQ Differences: A Global Perspective
Around the world, the average IQ for East Asians centers around 106; that for Whites, about 100; and that for Blacks, about 85 in the United States and 70 in sub-Saharan Africa.
On the Differential Aptitude Battery, by age 6, however, the average IQ of East Asian children is 107, compared with 103 for White children and 89 for Black children (Lynn, 1996).
The correlations between IQ and reaction times for the five countries are summarized in Table 1.
Table1
Note.
Data in this table are reconfigured from IQ and the Wealth of Nations (p. 67, Table 6.2), by R. Lynn and T. Vanhanen, 2002, Westport, CT: Praeger. Copyright 2002 by R. Lynn and T. Vanahanen. Adapted with permission. a r reliability. * p .05.
Figure 2.
Mean response times of 10-year-old Black, White, and East Asian children on the Math Verification Test for Multiplication, Subtraction, and Addition. Redrawn by A. R. Jensen from data in Jensen (1993;
Section 5: Gene–Environment Architecture and Mean Black–White IQ Differences
Dozens of twin, adoption, and family studies have confirmed the high heritability of intellectual and behavioral traits, and even reaction time tasks, within a race (Bouchard, 1996; Bouchard & Loehlin, 2001; Deary, 2000; Plomin et al., 2001).
Jensen & Whang, 1994). Copyright 2002 by A. R. Jensen. Reprinted with permission.
Figure 3. Estimated proportions of the total IQ variance attributable to genetic and environmental (shared and nonshared) effects. Note that only the nonshared (or within-family) environmental variance remains relatively constant across the entire age range. From “Behavioral Genetics of Cognitive Ability: A Life-Span Perspective,” by M. McGue, T. J. Bouchard, Jr., W. G. Iacono, and D. T. Lykken, in R. Plomin and G. E. McClearn (Eds.), Nature, Nurture, and Psychology (p. 64), edited by R. Plomin and G. E. McClearn, 1993, Washington, DC: American Psychological Association. Copyright 1993 by the American Psychological Association. Reprinted with permission.
Section 6: Race, Brain Size, and Cognitive Ability
Section 7: Mean Race–IQ Differences and Transracial Adoption Studies
Section 8: Mean Race–IQ Differences and Racial Admixture
Section 9: Mean Race–IQ Differences and Regression to the Mean
Section 10: The Race–Behavior Matrix
Note. From Race, Evolution, and Behavior: A Life History Perspective (p. 5), by J. P. Rushton, 2000, Port Huron, MI: Charles Darwin Research Institute. Copyright 2000 by J. P. Rushton. Adapted with permission.
Section 11: Mean Race–IQ Differences and Human Origins
The currently most commonly accepted view of human origins, the “Out-ofAfrica” theory, posits that Homo sapiens arose in Africa about 150,000 years ago, expanded northward beyond Africa about 100,000 years ago, with a European– East Asian split about 41,000 years ago (Cavalli-Sforza et al., 1994; Stringer & McKie, 1996). In Cavalli-Sforza’s (2000) maximum likelihood tree devised on the basis of molecular genetic markers, the most distant group was the Africans, with Europeans and Asians being closer.
r. It has been proposed that the farther north the populations migrated out of Africa, the more they encountered the cognitively demanding problems of gathering and storing food, gaining shelter, making clothes, and raising children successfully during prolonged winters (Rushton, 2000).
As these populations evolved into present-day Europeans and East Asians, the ecological pressures selected for larger brains, slower rates of maturation, and lower levels of testosterone—with concomitant reductions in sexual potency, aggressiveness, and impulsivity; increases in family stability, advanced planning, self-control, rule following, and longevity; and the other characteristics listed in Table 3.
The fact that the three-way pattern in IQ, brain size, and other traits is not unique to the United States but occurs internationally is consistent with a single, general (genetic–evolutionary) theory, whereas culture-only theory must invoke a number of highly localized, specific explanations.
Section 12: How Well Have Culture-Only Theories of Mean Race–IQ Differences Held Up?
Culture-only hypotheses have not explained the mean Black–White group differences in IQ. (They have especially not explained the findings on East Asians.)
One early view was that the mean Black–White group difference in IQ was due to the then obvious differences in (segregated) school facilities (Myrdal, 1944).
Section 13: Evaluating the Culture-Only and the Hereditarian Research Programs
Section 15: Implications for Public Policy
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