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psycoloquy.99.10.058.intelligence-g-factor.8.fancher Sat Dec 4 1999
ISSN 1055-0143 (7 paragraphs, 13 references, 194 lines)
PSYCOLOQUY is sponsored by the American Psychological Association (APA)
Copyright 1999 Raymond E. Fancher
A HISTORIAN'S LOOK AT THE G FACTOR
Book Review of Jensen on Intelligence-g-Factor
Raymond E. Fancher
Department of Psychology
York University
Toronto, Ontario
M3J 1P3 Canada
fancher@yorku.ca
ABSTRACT: The historical sections of Jensen's (1998, 1999) "The g
Factor" do not mention the strong connections between the origins
of intelligence testing and eugenics. They also fail to acknowledge
some of Jensen's major critics, and certain changes in his own
views as expressed over the past 30 years. This failure to deal
with his critics and with the troubling history of aspects of
intelligence testing may make it difficult for Jensen to convince
an audience not already converted to his views.
1. As a historian of psychology my attention was naturally drawn to the
book's opening chapter of Jensen (1998), "A Little History." The
adjective is accurate, as the account is not only brief but also
surprisingly incomplete. While Jensen correctly features Francis Galton
(1822-1911) as the founding father of intelligence testing and modern
behavior genetics, he omits to mention the crucial historical fact that
virtually all of Galton's key contributions arose in the service of his
vision for eugenics. The reader is not told that Galton created and
named the eugenics movement, which he viewed as a literally "religious"
enterprise, worthy of the same devotion and resources as were normally
afforded to traditional faiths. Almost everything Galton did in the
second half of his life was related in one way or another to this
cause, and his prototype intelligence tests were specifically intended
as a means of selecting the most hereditarily able young men and women
to be the parents of the future eugenic society. Thus intelligence
testing and hereditarian theory were inextricably linked from the very
beginning.
2. Jensen portrays Galton quite unequivocally as a hero, characterized
by "what Hollywood calls 'star quality,'" along with a variety of
"charming eccentricities" (p. 7). Although he acknowledges that Galton
wrote unflatteringly about the "comparative worth" of non-European
ethnic groups, Jensen excuses this style of writing as "common among
nineteenth-century intellectuals, without the slightest implication
that they were mean-spirited, unkindly, or at all unfriendly toward
people of another race" (p. 15). I would suggest that this lets Galton
off too easily. His published accounts of African native groups (e.g.,
Galton, 1889) were rife with decidedly "unfriendly" characterizations,
likening natives to baboons, pigs and dogs; and some of the suggestions
in The Art of Travel on the "Management of Savages" (Galton, 1872, pp.
308-310) hardly betray "kindly" sentiments. Elsewhere I have shown that
although some of Galton's contemporary explorers and ethnographers
(e.g., Richard Burton and Robert Knox) were similar to Galton in their
outspoken racism, others including David Livingstone and John Hanning
Speke were considerably more moderate (Fancher, 1983). Galton's cousin
Charles Darwin was also notably less harsh in his racial attitudes. In
general then, while some Victorians expressed crude racial views
similar to Galton's, others did not.
3. In one sense these are minor issues with little direct bearing on
the larger content of Jensen's book. In another sense, however, they
seem reflective of a general disinclination to acknowledge the more
disturbing aspects of the social history of the intelligence testing
movement. It is true that Galton himself generally promoted positive as
opposed to negative eugenics: i.e., the encouragement of breeding by
the able, rather than its prevention by the "unfit." He died before
negative eugenics became a popular movement, leading to the involuntary
sterilization of thousands of people diagnosed as mentally deficient in
the U.S. and Canada. Galton cannot be held personally responsible for
those practices, much less for the atrocities perpetrated in the name
of "race hygiene" in Nazi Germany. But still there were indubitable
historical links between his writings and these later enormities
(Weindling, 1989), and it is precisely because of this disturbing
history that so many people are nervous about hereditarian theories of
intelligence. To ignore or to sugarcoat this history seems nave at
best.
4. Jensen's coverage of more recent history is also spotty. He never
even mentions the names of Stephen Jay Gould (1981) and Leon Kamin
(1974), two of his most visible opponents in the IQ controversy.
Neither does he explicitly acknowledge some changes in his own own
views over the years, which may have been partly inspired by his
critics. In 1969, for example, Jensen declared that "the best single
overall estimate of the heritability of measured intelligence" was .81;
in 1980 this estimate fell to "probably near .75," and in 1981 (p. 103)
to "a central tendency around .70" (Jensen, 1969, 1980, 1981; pp. 51,
244, 103). The present book states, "the broad heritability of IQ is
about .40 to .50 when measured in children, about .60 to .70 in
adolescents and young adults, and approaches .80 in later maturity"
(p. 169). Clearly, Jensen's heritability estimates have been drifting
lower and becoming more nuanced over the years.
5. Jensen's highest estimate, in 1969, rested heavily on the work of
Cyril Burt, which he authoritatively declared to be "a 'must' for
students of individual differences" (1969, p. 33). In the present book
he deals with the intervening "Burt Scandal" only briefly and
allusively in a single footnote (pp. 198-199). Somewhat disingenuously,
he cites only himself as having "brought into question" the accuracy
and authenticity of Burt's reported findings on separated identical
twins. Completely overlooked is Kamin's crucial role in discrediting
the Burt results, a role that is well known to all who followed the
scandal closely. Jensen's footnote also attempts to minimize the effect
of excluding Burt's data from current analyses, on the grounds that
Burt's results "are so closely in line with those of other studies"
that their inclusion "would make little difference." Jensen neglects to
mention that the feature that had made Burt's study seem so important
to him in 1969 was not the magnitude of the reported IQ correlation,
but rather the claim for completely random placement of his twins in a
full socioeconomic range of foster homes. Kamin's (1974) analysis not
only demolished Burt's credibility, but also showed that no other
separated twin study published to that date could come close to
claiming random placement.
6. The results of the more recent and highly touted "Minnesota study"
of separated twins have not yet been published in great detail, but it
seems unlikely that they will support such a claim either. The
Minnesota investigators have summarized their findings as indicating,
"In the current environments of the broad middle class, in
industrialized societies, two-thirds of the observed variance in IQ can
be traced to genetic variation." They explicitly advise that their
results "should not be extrapolated to the extremes of environmental
disadvantage still encountered in society" (Bouchard et al., 1990, p.
227). Here is a heritability estimate substantially lower than Burt's
.81, and explicitly restricted to the middle class of the population.
(The effect of the restriction, of course, is to inflate the
heritability estimate.) Jensen's statement that the loss of the Burt
study makes "little difference" to the hereditarian case is highly
questionable.
7. Given Jensen's own rough and sometimes inappropriate treatment at
the hands of his less temperate critics, he may understandably feel at
times as if he is engaged in a war. His neglect of his critics and of
the less savory aspects of the history of intelligence testing may be
the result of a "take no prisoners" mentality. But however
understandable such a response might be, its main effect is
counterproductive. It would be far better to adopt an attitude similar
to that expressed by E. O Wilson when he described himself as having
been "blessed with brilliant enemies" whose critiques "redoubled my
energies and drove me in new directions" (Wilson, 1994, p. 218). Until
Jensen explicitly and respectfully addresses the arguments of his
numerous responsible opponents, and acknowledges the socially fraught
history of intelligence testing and the fact that even the most
authoritative-seeming knowledge of one generation is provisional and
liable to being superseded in the next, he will be preaching primarily
to the converted. And that is too bad, because he is an accomplished
scholar with much to say that deserves wide and serious debate.
REFERENCES
Bouchard, T. J, Lykken, D. T., McGue, M., Segal, N. L. & Tellegen, A.
(1990). Sources of human psychological differences: The Minnesota study
of twins reared apart. Science, 250, 223-228.
Fancher, R. E. (1983). Francis Galton's African ethnography and its
role in the development of his psychology. British Journal for the
History of Science, 16, 67-79.
Galton, F. (1872). The art of travel, 5th edition. London: Murray.
Galton, F. (1889). Narrative of an explorer in tropical South Africa.
London: Ward, Lock and Company.
Gould, S.J., (1981). The Mismeasure of Man. Penguin, London.
Jensen, A. R. (1969). How much can we boost IQ and scholastic
achievement? In Environment, heredity and intelligence, compiled from
the Harvard Educational Review (pp. 1-123). Cambridge, MA: Harvard
Educational Review.
Jensen, A. R. (1980). Bias in mental testing. New York: Free Press.
Jensen, A. R. (1981). Straight talk about mental testing. New York:
Free Press.
Jensen, A. (1998). The g Factor: The Science of Mental Ability. Praeger
Jensen, A. (1999). Precis of: "The g Factor: The Science of Mental
Ability" PSYCOLOQUY 10 (23).
ftp://ftp.princeton.edu/pub/harnad/Psycoloquy/1999.volume.10/
psyc.99.10.023.intelligence-g-factor.1.jensen
http://www.cogsci.soton.ac.uk/cgi/psyc/newpsy?10.23
Kamin, L. (1974). The science and politics of IQ. Potomac MD: Erlbaum.
Weindling, P. (1989). Health, race and German politics between national
unification and Nazism, 1870-1945. Cambridge: Cambridge University
Press.
Wilson, E. O. (1994). Naturalist. Washington, DC: Island Press.
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