Bell Curve

292 The National Context Ethnic Differences in Cognitive Ability 293The first published breakdowns of SAT scores by ethnicity appear for1976, when the downward trend in SAT scores nationwide after 1963was nearing its bottom (see Chapter 18). From 1976 to 1993, the whiteblackgap in SAT scores narrowed from 1.16 to .88 standard deviationin the verbal portion of the test and from 1.27 to .92 standard deviationin the mathematics portion of the test.f541 Comparable narrowing hasalso brought black and white achievement test scores closer, as presentedin Appendix 5. Because the ethnic self-identification of SAT testtakers contains some anomalies55 and because the SAT pool is unrepresentativeof the general population, the numbers should he interpretedwith caution. But even so, the SAT data indicate a narrowing gap. BlackSAT test takers improved substantially more in scores than white SATtest takers, and neither the changes in the pool of test takers nor thewell-advertised national decline in SAT scores was responsihle, for reasonsexplained in the notes.'56'EX~LAINING THE CONVERGENCE. Let us assume that during the past twodecades black and white cognitive ability as measured hy IQ has in factconverged by an amount that is consistent with the convergence in educationalaptitude measures such as the SAT or NAEP-a narrowing ofapproximately .l5 to .25 standard deviation units, or the equivalent oftwo to three IQ points Why have the scores converged? Theanswer calls for speculation.We take for granted that individual variations in cognitive ability dependon both genes and environment (see Chapter 4). In ;I pertodas short as twenty years, environmental changes are likely to providethe main reason for the narrowing racial gap in scores.15" Real and importantthough the problems of the underclass are, and acknowledgingthat the underclass is disproportionately black, living conditions haveimproved for most African-Americans since the 1950s-socially, economically,and educationally.Consider the schools that blacks attend, for example. Some schoolsin the inner cities are worse than they were thirty years ago, hut proportionatelyfew blacks live in these worst-of-the-worst areas.59Throughout the South and in much of the rest of the country, manyblack children as recently as the 1950s attended ramshackle schoolswith undertrained teachers and meager teaching materials. Any comparisonbetween the schools that most blacks attend now and the onesthey attended in the 1950s favors contemporary schools. Assuming thateclucat~on affects cognitive capacity, the rising investment in educationdisproportionately benefits the cognitive levels at the lower end of thesocioeconomic spectrum.The argument can be repeated for public health. If nutrition, shelter,and health care affect intellectual development, then rising standardsof living are disproportionately going to show up in rising scores for theeconomically disadvantaged rather than for the upper classes. For traveland its educational henefits, the argument also applies. Not so long ago,many less advantaged people spent their lives within a few miles of theirb~rthplaces. Today, Americans of nearly all walks of life crowd the interstateroads and the airports. Finally, for that most contemporary formof vicarious travel-the popular media-the leveling is still more dramatic.The modern media can bring the world to everyone in ways thatwere once open only to the rich.Because blacks are shifted toward the lower end of the socioeconomicrange, such improvements benef~them, on average, more than whites.If the improvements affect cognitive development, the black-white gapshould have contracted. Beyond this socioeconomic leveling, theremight also have been a leveling due to diminishing racism. The legacyof historic racism may still be taking its toll on cognitive development,hut we must allow the possibility that it has lessened, at least for newgenerations. This too might account for some narrowing of the blackwhitegap.LCXIKINC; TO THE FUTURE. The question that remains is whether blackand white test scores will continue to converge. If all that separatesblacks from whites are environmental differences and if fertilitypatterns for different socioeconomic groups are comparable, there isno reason why they shouldn't. The process would be very slow,however. If it continues at the pace observed over the last twentyyears, then we could expect black and white SAT scores to reachequality sometime in the middle of the twenty-first century, hut linearextrapolations over such long periods are not worth much.'w1If black fertility is loaded more heavily than white fertility towardlow-IQ segments of the population, then at some point convergencemay be expected to stop, and the gap could even hegin to widen again.We take up the fertility issue in Chapter 15. A brief summary statementconcerning fertility patterns is that the news is not good. For now, thetest score data leave open the possibility that convergence has already