Bell Curve

Notes to pages 30 1-303 725Psychology, Counseling Psychology, and Industrial and OrganizaticlnalPsychology), the Behavior Genetics Association, the Cognitive ScienceSociety, and the education division of the American Sociological Association.69. Brody 1992, p. 309.70. Gould 1984, pp. 26-27.71. Gould 1984, p. 32. See Lewontin, Rose, and Kamin 1984, p. 127, for a similarargument.72. Gould 1984, p. 33.73. The ramifications for public policy are dealt with in detail in Chapters 19and 20, concerning affirmative action.74. We do not include in the text any discussion of Phillipe Rushton's intenselycontroversial writings on the differences among Asian, white, and blackpopulations. For a brief account, see Appendix 5.75. A similar example can be found in Lewontin 1970, one of the most outspokencritics of the IQ enterprise in all its manifestations.76. The calculation proceeds as follows: The standard deviation of 1Q being15, the variance is therefore 225. We are stipulating that environment accountsfor .4 of the variance, which equals 90. The standard deviation ofthe distribution of the environmental component of IQ is the square rootof 90, or 9.49. The difference between group environments necessary toproduce a fifteen-point difference in group means is 1519.49, or 1.58, andthe difference necessary to produce a three-point difference is 319.49, or.32. The comparable figures ifheritability is assigned the lower bound valueof .4 are 1.28 and .26. If heritability is assigned the upper-hound value of.8, then the comparable figures are 2.24 and .45.77. Stevenson et al. 1985.78. Lynn 1987a.79. Frydman and Lynn 1989.80. Iwawaki and Vernon 1988; McShane and Berry 1988.81. Vernon, 1982 p. 28. It has been argued that the 1 10 figure is too high, buta verbal-visuospatial difference among Asian Americans is not disputed(Flynn 1989).82. Supplemental evidence has been found among Chinese students living inChina who were given the SAT. Several hundred Chinese students inShanghai between the ages of 11 and 14 scored extremely high on the MathSAT, despite an almost total lack of familiarity with American cognitiveability testing. As a proportion of the total population, this represented afar greater density of high math scorers in Shanghai than in the UnitedStates. Further attempts to find high scorers in Chinese schools confirmedthe original results in Shanghai (Stanley, Feng, and Zhu 1989).83. The SAT data actually provide even more of a hint about genetic ortginsfor the test-score pattern, though a speculative one. The College Board reportsscores for persons whose first language learned is English and for thosewhose first language is "English and another." It is plausible to assume thatAsian students whose only "first language" was English contain a disproportionatenumber of children of mixed parentage, usually Asian andwhite, compared to those in whose homes both English and an Asian languagewere spoken from birth. With that hypothesis in mind, consider thatthe discrepancy between the Verbal and Math SATs was (in IQ points)only 1.7 points for the "English only" Asians and 5.3 points for the "Englishand another" first-language Asians. Nongenetic explanations areavailable. For example, one may hypothesize that although English and anotherlanguage were both "first languages," English wasn't learned as wellin those homes; hence the Verbal scores for the "English and another"homes were lower. But then one must also explain why the Math scores ofthe "English and another" Asians were twenty-one SAT points higher thanthe "English-only" homes. Here one could hypothesize that the "Englishonly"Asians were second- and third-generation Americans, more assimilated,and therefore didn't study math as hard as their less assimilatedfriends (although somehow they did quite well in the Verbal test). Butwhile alternative hypotheses are avaitable, the consistency with a geneticexplanation suggests that it would be instructive to examine the scores ofchildren of full and mixed Asian parentage.84. A related topic that we do not review here is the comparison of blacks andwhites on Level I and Level 11 abilities, using Jensen's two-level theory ofmental abilities (Jensen and Figueroa 1975; Jensen and Inouye 1980). Thefindings are consistent with those presented under the discussion of WISC-R profiles and Spearman's hypothesis.85. "Spearman's hypothesisw is named after an observation made by CharlesSpearman in 1927. Noting that the black-white difference varied systematicallyfor different kinds of tests, Spearman wrote that the mean difference"was most marked in just those [tests] which are known to be mostsaturated withg" (Spearman 1927, p. 379). Spearman himself never triedto develop his comment into a formal hypothesis or to test it.86. Jensen and Reynolds 1982.87. Jensen and Reynolds actually compared large sets of IQ scores with thefull-scale IQ score held constant statistically.88. Jensen and Reynolds 1982, p. 427; Reynolds and Jensen 1983.89. Jensen and Reynolds 1982, pp. 428-429.90. Jensen 1985,1987a.91. Jensen 1993b.92. Braden 1989.93. Jensen 1993b.