The Bell Curve: Intelligence and Class Structure in American Life (130 page)

12
Later children are on the average born into larger families, which tend to be of lower average IQ. Hence, there is a decline with successive births that is a by-product of family size in and of itself. However, even after the family size effect is extracted, there may be a decline with birth order. The classic demonstration of declining scores with successive births independent of family size is a study based on a large sample of Dutch men (Belmont and Marolla 1973; Belmont, Stein, and Zybert 1978). Since then, subsequent studies have both confirmed and failed to confirm the basic relationship (e.g., Blake 1989; Retherford and Sewell 1991; Zajonc 1976). At present, there is no resolution of the varying findings.

13
Representative findings, on Japanese twins, are in Takuma 1966, described in Iwawaki and Vernon 1988.

14
For a review of the literature on twin differences in birth weight in relation to IQ as well as of other evidence that the uterine environment affects intelligence, see Storfer 1990.

15
Achenbach et al. 1990. This study compared two dozen low-birth-weight babies whose mothers received training in mothering with comparably small groups of normal-weight babies and low-birth-weight babies whose mothers did not receive the training. The encouraging outcome is that when the children were 7 years old, the usual deficit seems to have been forestalled by having trained the mothers in infant nurturing. However, the small scale of the study, the lack of random assignment to the three groups, and the puzzling near identity in scores for the underweight children whose mothers had been trained and the normal children suggest that the next step should to attempt to replicate the finding, as the authors themselves say.

16
For a helpful and balanced introduction to aptitude-treatment interactions, see Snow 1982.

17
Hativa 1988.

18
Atkinson 1974.

19
Cook et al. 1975.

20
Coleman et al. 1966. The report talked about educational “aptitude,” but the measures used—vocabulary scores, reading comprehension, mathematical reasoning tasks, etc.—were taken from standard group tests of IQ.

21
See Mosteller and Moynihan 1972 for a collection of more or less critical articles; included also is Coleman’s response to the most intense methodological criticisms (Coleman 1972). The combatants were often trying to answer different questions, with Coleman mostly interested in whether the objective differences among schools were responsible for the observed differences in abilities and his critics more interested in characterizing the objective differences in the schools. We cannot do justice to the range of issues that surfaced in the report and the subsequent commentary, but one of them deserves mention: The report uncovered evidence that the ethnic and socioeconomic mix of students in a school had a larger impact than the more standard investments in per pupil expenditures, teacher salaries, quality of physical plant, and the like. This, in turn, became a major argument for school busing. Soon after, school busing itself became a battleground for social researchers, a tale we will not tell here except to say that having a beneficial effect on intelligence is no longer used as an argument in favor of busing.

22
Coleman and Hoffer 1987.

23
It isn’t hard to find what seems to be the opposite conclusion in educational writings (e.g., the Coleman report is “no longer taken seriously,” Zigler and Muenchow 1992, p. 62) but no one has been able to show that the variables
examined in the report account for much of the variation in cognitive ability among American public school students. If they are in any sense not taken seriously, it is presumably because educational variables other than the ones that Coleman studied have been found to be significant. This chapter reviews the evidence about those other variables as well.

24
See Kozol 1992 for a passionate argument that disparities in school funding are a major cause of disparities in educational outcomes.

25
Husén and Tuijnman 1991.

26
The quantitative details of the study are not germane to contemporary times, but even then, when schooling varied so broadly, the direct link between IQ at the age of 10 and at 20 was a minimum of five times stronger than that between amount of schooling and IQ at 20, in terms of variance accounted for in a path analysis.

27
Flynn himself does not believe that educational equalization per se accounts for much of the rise in IQ in some countries such as Holland (Flynn 1987a), but then Flynn also does not believe that the rising national averages in IQ really reflect rising intelligence.

28
Stephen Ceci (1991) has summarized evidence, much of it from earlier in the century, for an impact of schooling on intelligence.

29
National Center for Education Statistics 1981, Table 161, 1992, Table 347.

30
McLaughlin 1977, p. 55.

31
McLaughlin 1977, p. 53 The failure of such compensatory efforts antedated the Great Society by many years, however. An early educational researcher writing of similar compensatory efforts in 1938 concluded that “whatever the number of years over which growth was studied; whatever the number of cases in the several groups used for comparisons; whatever the grade groups in which the IQs were obtained; whatever the length of the interval between initial and final testing; in short, whatever the comparison, no significant change in IQs has been found” (Lamson 1938, p. 70).

32
Office of Policy and Planning 1993.

33
For more on this distinction, see Adams 1989; Brown and Campione 1982; Jensen 1993a; Nickerson, Perkins, and Smith 1985.

34
“Chicago educator pushes common sense,” St. Louis Post Dispatch, Dec. 2, 1990, p. 5D; “Marva Collins still expects, gets much,” St. Petersburg Times, July 23, 1989, p. 6A; “Pioneering educator does not want post in a Clinton cabinet,”
Minneapolis Star Tribune,
Oct. 25, 1992, p. 22A.

35
Spitz 1986. See also “Chicago schools get an education in muckraking,”
Chicago Tribune,
May 8, 1989, p. 1C.

36
“Fairfax principal, 4 other educators disciplined in test-coaching,”
Washington Post,
Aug. 7, 1987, p. C1.

37
“Pressure for high scores blamed in test cheating,”
Los Angeles Times,
Sept. 18, 1988, p. 1.

38
“S.I. principal said to fudge school scores,”
New York Times,
July 19, 1991, p. B1.

39
For a sense of the magnitude of the cheating problem, see “Schools for Scandal,”
U.S. News & World Report,
April 27, 1992, p. 66.

40
The minister was Luis Alberto Machado, a high official in the ruling party at the time.

41
Based on estimates in the preceding years, the children in the two groups were chosen to be of comparable cognitive ability. For descriptions of the experiment, see Herrnstein et al. 1986; Nickerson 1986.

42
The teachers’ manual for most of the lessons, translated into English, is available as Adams 1986.

43
See Brigham 1932 for the relevant background. Briefly, the SAT was originally designed to be an intelligence test targeted for the college-going population and was originally validated against existing intelligence tests. For a modern source showing how carefully the College Board avoids saying the SAT measures intelligence while presenting the evidence that it does, see Donlon 1984.

44
Fallows 1980; Slack and Porter 1980; Messick 1980; DerSimonian and Laird 1983; Dyer 1987; Becker 1990.

45
Messick and Jungeblut 1981.

46
From 1980 to 1992, the SAT-V standard deviation varied from 109 to 112 and the SAT-M standard deviation varied from 117 to 123. For the calculations, we assumed SDs of 110 and 120, respectively.

47
McCall 1979.

48
McCall 1987.

49
Alexander Pope (in his
Moral Essays)
is the poet, and the entire couplet is “Tis education forms the common mind; / Just as the twig is bent the tree’s inclined.”

50
See Mastropieri 1987 for a review of the expert consensus on this point.

51
For a sympathetic rendition of the program and its history, see Zigler and Muenchow 1992. For a more critical account, see Spitz 1986. We try to keep our account as close to what these two have in common as we can.

52
“Project Rush-Rush” was what Head Start was called by those in Washington who thought that it was plunging ahead with more speed than deliberation (quoted in Caruso, Taylor, and Detterman 1982, p. 52).

53
Zigler and Muenchow 1992, reporting the conclusions of Leon Eisenberg and C. Keith Connors after the first summer program. Only slightly less grandiose were the claims of raising IQ scores “a point a month” that were often cited by enthusiasts.

54
Sargent Shriver, brother-in-law of the late president, John Kennedy, and former head of the Peace Corps.

55
The first comprehensive evaluation was the so-called Westinghouse study,
which the Office of Economic Opportunity sponsored. Its conclusion was that there were few or no cognitive benefits of Head Start within three years after the child completed it (Cicarelli, Evans, and Schiller 1969). Soon there was a mini-industry picking over the Westinghouse study, in addition to the one picking over Head Start. The consensus is now clear: Cognitive gains vanish before the end of primary school, e.g., Haskins 1989; McKey 1985; Spitz 1986; Zigler and Muenchow 1992. The new consensus has recently surfaced in the popular media (e.g., J. DeParle, “Sharp criticism for Head Start, even by friends,”
New York Times,
Mar. 19, 1993, p. A1).

56
For a range of views, see Gamble and Zigler 1989; McKey 1985; Zigler and Muenchow 1992.

57
E.g. Haskins 1989.

58
Zigler and Muenchow 1992. Edward Zigler, one of the early research directors of Head Start and a professor at Yale, argues in his book that it was a mistake from the beginning to promise gains in intelligence to the public. The more general shift away from making increases in IQ the target of preschool programs is discussed in Garber and Hodge 1991; Locurto 1991; Schweinhart and Weikart 1991, pro and con.

59
Among the people promising gains in the 300 percent range is the president of the United States, as reported by Jason DeParle (“Sharp criticism for Head Start, even by friends,”
New York Times,
Mar. 19, 1993). Even more of an optimist is economist Alan Blinder, who once promised a return of $4.75 for every dollar spent on preschool education (Blinder 1987).

60
For a review of such benefits from Head Start programs, see Haskins 1989, who concludes that the results “call for humility” (p. 280). The Head Start literature, he says, “will not support the claim that a program of national scope would yield lasting impacts on children’s school performance nor substantial returns on the investment of public dollars” (p. 280). In short, there are no sleeper effects from Head Start. Even the evidence of cost-effective returns in the more intensive educational programs is highly restricted. For a literature review, see Barnett and Escobar 1987.

61
Most of the children were 3 years old and spent two years in the program; the 22 percent who were 4 spent only one year in it (Barnett 1985; Berrueta-Clement et al. 1984.

62
Half a school day, or about two and a half hours.

63
The lack of effect was indirectly confirmed in a subsequent study by the same group of workers. They failed to find any differential effect on IQ of three different forms of preschool: their own cognitive enrichment program, a language-enhancing program, and a conventional nursery school program (Weikart et al. 1978). There was no control group in this follow-up, so we cannot say how much, if at all, preschool per se influenced IQ.

64
For a critical reading of just how minimal these other effects of preschool may have been, see Spitz 1986.

65
Lazar and Darlington 1982.

66
Similar estimates can be found in a study of the early effects of Head Start and the consortium sample (Lee et al. 1990).

67
Lazar and Darlington 1982, p. 47 The people who do these studies often argue that other positive effects are not being picked up in the formal measurements (e.g., Ramey, MacPhee, and Yeates 1982).

68
Many publications have flowed from the project; useful summaries are in Ramey 1992; Ramey, MacPhee, and Yeates 1982.

69
Personal communication from Ron Haskins.

70
Ramey 1992.

71
These differences are clearer in the critical accounts of the project in Spitz 1986 and 1992 than in the report by Ramey, MacPhee, and Yeates 1982.

72
Herrnstein 1982; Sommer and Sommer 1983.

73
Page 1972; Page and Grandon 1981.

74
Garber 1988; Garber and Hodge 1991.

75
Jensen 1989; Locurto 1991. The problem of “teaching to the test” recurs in educational interventions. It is based on the test’s being less than a perfect measure of intelligence (or g), so that it is possible to change the score without changing the underlying trait (see further discussion in Jensen 1993a).