The Bell Curve: Intelligence and Class Structure in American Life (115 page)

Abbreviations

1
Galton 1869.

2
Forrest 1974.

3
For a brief history of testing from Galton on, see Herrnstein and Boring 1965.

4
In Introina, civil service examinations that functioned de facto as intelligence tests—though overweighted with pure memory questions—had been in use for more than a thousand years.

5
Spearman 1904.

6
Galton 1888; Stigler 1986.

7
A correlation matrix is the set of all pairs of correlations. For example, in a 20-item test, each item will have 19 unique correlations with the other items, and the total matrix will contain 190 unique correlations (of Item 1 with Item 2, Item 1 with Item 3, etc.).

8
We are glossing over many complexities, including the effects of varying reliabilities for the items or tests. Spearman understood, and took account of, the contribution of reliability variations.

9
Buck
v.
Bell,
1927.

10
This was Harry Laughlin, whose story is told in Kevles 1985.

11
Brigham 1923; Kevles 1985.

12
The stories have been most influentially told by Fallows 1980; Gould 1981; Kamin 1974.

13
Snyderman and Herrnstein 1983.

14
Snyderman and Herrnstein 1983.

15
Lippmann 1922 p. 10.

16
Lippmann, 1923 p. 46.

17
Snyderman and Herrnstein 1983.

18
Maier and Schneirla 1935.

19
Skinner 1938.

20
Skinner 1953; Skinner 1971.

21
Jensen 1969.

22
Hirsch 1975, p. 3.

23
Pearson 1992.

24
Herrnstein 1971.

25
Griggs et al.
v.
Duke Power
Co., 1971.

26
Quoted in Jensen 1980, p. 13.

27
Elliott 1987.

28
Kamin 1974, p. 3.

29
O. Gillie. 1976. Crucial data faked by eminent psychologist.
Sunday Times
(London), Oct. 24, pp. 1-2.

30
Joynson 1989; Fletcher 1991.

31
Bouchard et al. 1990.

32
Gould 1981.

33
Gould 1981, pp. 27-28.

34
Snyderman and Rothman 1988.

35
Binet himself had died by the time Piaget arrived at the Sorbonne in 1919, but the work on intelligence testing was being carried forward by his collaborator on the first Binet test, Thèophile Simon (see Piaget 1952).

36
Sternberg 1988, p. 8.

37
Sternberg 1985, p. 18.

38
Block and Dworkin 1974.

39
Gardner 1983, pp. 60-61. Emphasis in the original.

40
Gardner 1983, p. 278.

41
Gardner 1983, p. xi. Emphasis in original.

42
Gardner 1983, p. 17. In fact, Gardner’s claim about the arbitrariness of factor analysis is incorrect.

43
Gardner 1983, pp. xi-xii.

44
Gardner 1983, p. 17.

45
Although some of the accomplishments of mental calculators remain inexplicable, much has been learned about how they are done. See Jensen 1990; O’Connor and Hermelin 1987.

46
Ceci and Liker 1986.

47
An accurate and highly readable summary of the major points is Seligman 1992. For those who are prepared to dig deeper, Jensen 1980 remains an authoritative statement on most of the basic issues despite the passage of time since it was published.

1
Reuning 1988.

2
Robert Laird Collier, quoted in Manchester 1983, p. 79.

1
Bender 1960, p. 2.

2
The national SAT-V in 1952 was 476, a little more than a standard deviation lower than the Harvard mean. Perhaps the average Harvard student was much farther ahead of the national average than the text suggests because the national SAT-taking population was so selective, representing only 6.8 percent of high school graduates. But one of the oddities of the 1950s, discussed in more detail in Chapter 18, is that the SAT means remained constant through the decade and into 1963, even as the size of the test-taking population mushroomed. By 1963, when SAT scores hit their all-time high in the post-1952 period, the test-taking population had grown to 47.9 percent of all high school graduates. Thus there is reason to think that the comparison is about the same as the one that would have been produced by a much larger number of test takers in 1952.

3
Bender 1960, p. 4.

4
In the 1920s, fewer than 30 percent of all young people graduated from high school, and the differences between the cognitive ability of graduates and nongraduates were small, as discussed in Chapter 6. Something between 60 and 75 percent of the 18-year-olds in the top IQ quartile never even made it into the calculations shown in the figure on page 34. From the early 1960s on, 70 percent of the nation’s youth have graduated from high school, and we know that the difference between the ability of those who do and do not graduate has been large. More concretely, of a nationally representative sample of youth who were administered a highly regarded psychometric test in 1980 when they were 15 and 16 years old, 95 percent of those who scored in the top quartile subsequently graduated from high school, and another 4 percent eventually got a general equivalency diploma. The test was the Armed Forces Qualification Test, and the sample was the 1964 birth cohort of the National Longitudinal Survey of Youth (NLSY), discussed in detail in the introduction to Part II. The figure for the proportion entering colleges is based on the NLSY cohorts and students entering colleges over 1981-1983.

5
The top IQ quartile of the NLSY that first attended college in 1981-1983 was split as follows: 21 percent did not continue to college in the first year after graduation, 18 percent went to a two-year college, and 61 percent attended a four-year college.

6
O’Brien 1928. These percentages are based on high school graduates,
which accounts for the high percentages of students shown as going to college in the 1920s. If the estimates had been based on the proportion of the 18-year-olds who have been graduating from high school since the 1970s, those proportions would have been much smaller. The shape of the curve, however, would be essentially unchanged (because the IQ distribution of students who did not complete high school was so close to the distribution of those who did; see Finch 1946).

7
Another excellent database from the same period, a nationally representative sample tested with the Preliminary SAT in 1960 and followed up a year later, confirms results from Project TALENT, a large, nationally representative sample of high school youths taken in 1960 (Seibel 1962). Among those who scored in the bottom quartile, for example, only 11 percent went to college; of those in the top quartile, 79 percent went to college; of those in the top 5 percent, more than 95 percent went to college.

8
These data are taken from Project TALENT in 1960.

9
From the NLSY, described in the introduction to Part II.

10
The test was Form A of the Otis. Brigham 1932, Table XVIII, p. 336.

11
The schools are Brown, Bryn Mawr, Columbia, Harvard, Mount Holyoke, Princeton, Radcliffe, Smith, University of Pennsylvania (with separate means for men and women), Vassar, Wellesley, Williams, and Yale.

12
Learned and Wood 1938.

13
Not including the University of Pennsylvania, one of the elite schools.

14
Between the earliest SAT and 1964, the SAT had divided into a verbal and a math score. It is a moot question whether the modern overall SAT or the verbal SAT is more comparable to the original SAT. In the comparisons being made here, we rely on the Educational Testing Service norm studies, which enable us to place an SAT value on the
national
18-year-old cohort, not just the cohort who takes the test. We explain the norm studies in Chapter 18.

15
This is not the usual SAT distribution, which is ordinarily restricted to college-bound seniors, but rather shows the distribution for a nationally representative sample of all high school seniors, based on the norm studies mentioned in note 14. It is restricted to persons still in high school and does not include the 34 percent of 18-year-olds who were not.

16
We know how high the scores were for many schools as of the early 1960s. We know Harvard’s scores in the early 1950s. We can further be confident that no school was much more selective than Harvard as of 1952 (with the possible exception of science students going to Cal Tech and MIT). Therefore means for virtually all of the other schols as of 1952 had to be near or below Harvard’s, and the dramatic changes for the other elite schools had to be occurring in the same comparatively brief period of time concentrated in the 1950s.

17
Bender 1960, p. 6.

18
This percentage is derived from 1960 data reported by Bender 1960, p. 15, regarding the median family income of candidates who applied for scholarship aid, were denied, but came to Harvard anyway. Total costs at Harvard in 1960 represented 21 percent of that median.

19
The families for whom a year at Harvard represented less than 20 percent of their income constituted approximately 5.8 percent of families in 1950 and 5.5 percent of families in 1960. Estimated from U.S. Bureau of the Census 1975, G-1-15.

20
The faculty’s views were expressed in Faculty of Arts and Sciences 1960.

21
Bender 1960, p. 31.

22
For an analysis of the ascriptive qualities that Harvard continued to use for admissions choices in the 1980s, see Karen 1991.

23
The increase in applications to Harvard had been just as rapid from 1952 to 1958, when the size of the birth cohorts was virtually constant, as in 1959 and 1960, when they started to increase.

24
For an analysis of forces driving more recent increases in applications, see Clotfelter 1990 and Cook and Frank 1992.

25
Cook and Frank 1992.

26
Harvard, MIT, Princeton, Stanford, and Cal Tech were in the top seven in all three decades. Columbia and Chicago were the other two in the 1960s, Yale and Cornell in the 1970s and 1980s. Cook and Frank 1992, Table 3.

27
Cook and Frank 1992, Table 4. The list of “most competitive” consists of the thirty-three schools named by
Barron’
s in its 1980 list. The Cook and Frank analysis generally suggests that the concentration of top students in a few schools may have plateaued during the 1970s, then resumed again in the 1980s.

28
U.S. News & World Report,
October 15, 1990, pp. 116-134. It is not necessary to insist that this ranking is precisely accurate. It is enough that it includes all the schools that most people would name if they were asked to list the nation’s top schools, and the method for arriving at the list of fifty seems reasonable.

29
The College Board ethnic and race breakdowns for 1991, available by request from the College Board. There is also reason to believe that an extremely high proportion of high school students in each senior class who have the potential to score in the high 600s and the 700s on the SAT actually take the test. See Murray and Herrnstein 1992.

30
See Chapter 18 for where the SAT population resides in the national context.

31
These represent normal distributions based on estimates drawn from the Learned data that the mean IQ of Pennsylvania graduates in 1930 was approximately
two-thirds of a standard deviation above the mean (the mean of incoming freshmen was .48 SDs above the mean), and from the Brigham data that the graduates of the Ivy League and Seven Sisters were approximately 1.25 SDs above the mean (they were 1.1 SDs above the mean as freshmen, and the Ivy League graduated extremely high proportions of the incoming students).

32
The distributions for the main groups are based on the NLSY, for youths who came of college age from 1981 to 1983 and have been followed through the 1990 interview wave. The top dozen universities are those ranked 1 through 12 in the
U.S. News & World Report
survey for 1990.
U.S. News & World Report,
October 15, 1990, pp. 116-134. The analysis is based on published distribution of SAT-Verbal scores, which is the more highly g-loaded of the SAT subtests. The estimated verbal mean (weighted by size of the freshman class) for these twenty schools, based on their published SAT distributions, is 633. The estimated mean for graduates is 650 (dropout rates for these schools are comparatively low but highly concentrated among those with the lowest entering scores). This compares with a national SAT-Verbal norm estimated at 376 with an SD of 102 (Braun, Centra, and King, 1987, Appendix B). The distribution in the figure on page 46 converts the SAT data to standardized scores. The implicit assumption is that AFQT (Armed Forces Qualification Test, an intelligence test discussed in Appendix 3) and SAT-Verbal measure the same thing, which is surely wrong to some degree. Both tests are highly g-loaded, however, and it is reasonable to conclude that youths who have a mean 2.5 SDs above the mean on the SAT would have means somewhere close to that on a full-fledged mental test.