[evol-psych] Reply to Fancher on Jensen on Intelligence-g-Factor
- psycoloquy.00.11.017.intelligence-g-factor.30.jensen Wed Feb 2 2000
ISSN 1055-0143 (9 paragraphs, 6 references, 194 line)
PSYCOLOQUY is sponsored by the American Psychological Association (APA)
Copyright 2000 Arthur R Jensen
MIXING UP EUGENICS AND GALTON'S LEGACY TO RESEARCH ON INTELLIGENCE
Reply to Fancher on Jensen on Intelligence-g-Factor
Arthur R. Jensen
School of Education
University of California
Berkeley, CA 94720-1670
ABSTRACT: The fact that Sir Francis Galton coined the word
'eugenics' and promoted the concept during the latter part of his
long life is hardly a disgrace, but it is apparently thought by
some to sully his contributions as the founding father of
differential psychology as an empirical science and to cast
subsequent developments of Galton's original ideas in this sphere
in a sinister light.
1. My aim in writing "The g Factor" (Jensen, 1998; 1999) was not to
compile a history of the 'IQ controversy', or to recapitulate my
earlier and often elaborate replies to critics of my former books and
articles. I wanted to present as clear a picture as I could of the g
factor, which has figured so prominently in the research on human
abilities, and to explicate recent developments in empirical research
on g. I believe that the Galton-Spearman line of thought about human
abilities is now the mainline research in differential psychology, and
I hope my book contributes to its advancement. My critics have been
largely either ideological or scientifically technical. I pay little
attention to the former but much attention to the latter.
2. Galton (1822-1911) is one of the most biographed figures in the
history of psychology. Only the psychoanalyst has had more written
about him. The variety and durability of Galton's ideas are truly
remarkable and can't be diminished by the fact that there are currently
some disapproving observations and reactions about the experiences
gained in his extensive explorations in subSaharan Africa in the 1840s
(Burt, 1962). But among biographies of famous scientists, particularly
such near-psychopaths as Newton and Leibniz, Galton's personal conduct
and ethical ideals seem exemplary by comparison. In any case, in
science, unlike politics, a scientist's personality, beliefs, and
convictions, although possibly of biographical and historical interest,
are wholly separate from the objective validity of the scientist's
discoveries, empirically testable theories, and methodological
3. Fancher (1999, par. #3) is waving a red flag by bringing up that
fashionably vilifying word "eugenics" in the context of my book, which
deals exclusively with the science of individual differences in mental
abilities. The aspect of Galton's career that is most relevant to the
subject of my book is not eugenics, which was a benign conception as
initiated by Galton, but rather his extraordinary curiosity,
inventiveness, and investigative zeal, which generated empirical
discoveries of historic scientific importance and laid the foundations
for differential psychology, psychometrics, and behavior genetics.
True, he later promoted eugenics as a secular religion, with the
express goal of increasing the future well-being of humanity. Galton
took it for granted that superior mental and behavioral capacities as
well as physical health and stamina are beneficial both to individuals
and to the whole society.
4. In Galton's later years (he lived to 90) his scientific
contributions became so amalgamated with his enthusiasm for eugenics as
to have contributed to the disfavor in which Galtonian lines of
research on human intelligence have been held in the latter half of the
20th century, during which we have seen a systematic inculcation in the
public's mind of a link between the humane conception Galton termed
'eugenics,' on the one hand, and the fanatical political abuses and
terrible acts committed in its name that were exposed at the end of
World War II, on the other. This confusion has contributed to
stigamatizing biological and genetical research on intelligence to a
degree not seen in scientific research for any other natural phenomena,
save perhaps for evolution as perceived by Biblical Fundamentalists.
5. What does not seem to be entirely clear, perhaps even to Galton
himself, and to Fancher (1999), is that prescriptive eugenics falls not
in the province of science, but in that of ethics or moral philosophy.
Despite Galton's humanitarian aims, the desirability of eugenics is an
ethical question rather than a scientific one. Science deals with what
is, not with what anyone thinks ought to be. This critical distinction
in no way discredits the eugenics concept or suggests that its aims,
means, or feasibility should be divorced from scientific scrutiny. The
same distinction must be made between medical science and medical
practice, especially as biomedical technology advances. Galton himself
mainly advocated negative eugenics, which today, in fact, is a
principal aim of genetic counseling as respectably practiced in many
medical centers around the world.
6. Galton's conception of eugenics is probably best expressed in his
own words: "Individuals appear to me as partial detachments from the
Infinite ocean of Being, and this world is a stage on which Evolution
takes place, principally hitherto by means of Natural Selection, which
achieves the good of the whole with scant regard to that of the
individual. Man is gifted with pity and other kindly feelings; he has
also to power of preventing many kinds of suffering. I conceive it to
fall well within his province to replace Natural Selection by other
processes that are more merciful and not less effective. This is
precisely the aim of Eugenics. Its first object is to check the
birth-rate of the Unfit, instead of allowing them to come into being,
though doomed in large numbers to perish prematurely. The second object
is the improvement of the race by furthering the productivity of the
Fit by early marriages and healthful rearing of their children. Natural
Selection rests upon excessive production and wholesale destruction;
Eugenics on bringing no more individuals into the world than can be
properly cared for, and those only of the best stock" (Galton, 1908, p.
7. My critics have had no effect on the estimates of IQ heritability
that I have reported at different times in various references, contrary
to Fancher's (1999, par. #4) surmise. These estimates, like all
statistical estimates of population parameters, vary in different
samples and studies for a multitude of reasons - sample characteristics
(e.g., age and range of ability), and psychometric characteristics of
the tests. I discovered, for example, that the degree of heritability
of mental tests is directly related to the tests' g loadings, further
indicating that it is g, more than any other factor, that reflects the
biological basis of individual differences in IQ. Whenever I have
reported heritability estimates, they have been based on the average of
the existing data at the time I am writing, but omitting, since 1975,
the questionable data of Burt's studies of MZ twins reared apart. The
overall average estimate of heritability based on monozygotic twins
reared apart (excluding Burt's data) is .75. Burt's estimate was .77.
Hence, averaging in Burt's figure with that of other studies or
omitting it makes hardly any difference. In recent years, it has been
discovered that IQ heritability increases with age, ranging from about
.40 in childhood to about .65 -.70 in middle age and about .80 in the
elderly. I have accordingly concluded that an overall average value of
the broad heritability is rather uninformative compared to values which
specify the age group, the types of kinship samples used, and the
g-loadedness of the test scores used.
8. More is known about the genetic component of IQ variance than about
the environmental component, most of which, by late adolescence, is NOT
attributable to differences between family environments, but consists
of nongenetic variance WITHIN families. It appears that most of this
nongenetic variance results from what I call micro-environmental
influences, which may consist largely of a multitude of virtually
random small prenatal, perinatal, and postnatal environmental variables
that have effects on the nongenetic but biological basis of mental
development (Jensen, 1997). If this is true, it helps explain the
failure of psychological and educational interventions to importantly
and durably effect increases of the level of the g component of IQ
tests. The secular increase in IQ (or Flynn Effect)would accordingly be
explainable largely in terms of the intergenerational elimination of
many of the most undesirable effects of the microenvironment by means
that have affected virtually the whole population of the industrialized
world, such as improved nutrition, advances in obstetrics, and
inoculations that have virtually eliminated many childhood diseases.
9. I have always taken it for granted that the state of knowledge at
the cutting edge of any science is provisional, as Fancher (1999, par.
#7) points out, and that continual hypothesis testing is the
scaffolding by which the theoretical structures for explaining
empirical phenomena become generally accepted as true in a scientific
sense. This has never implied any kind of Eternal Truth, which may
exist only in pure mathematics and religion. While recognizing the
provisional character of empirical knowledge at any given time, I doubt
that equivocation on every point in its exposition is the most
effective strategy for the advancement of research. Of what use to the
development of a field is a book without an argument? The Science
Citation Index and the Social Science Citation Index would seem to
indicate that much of my work over the past three decades has indeed
received, in Fancher's words, "wide and serious debate."
Burt, C. (1962). Francis Galton and his contributions to psychology.
British Journal of Statistical Psychology, 15, 1-49.
Fancher, R.E. (1999). A historian's look at The g Factor. PSYCOLOQUY
Galton, F. (1908). Memories of my life. London: Methuen.
Jensen, A.R. (1997). The puzzle of nongenetic variance. In R.J.
Sternberg & E.L. Grigorenko (Eds.), Heredity, intelligence, and
environment (pp. 42-88). Cambridge: Cambridge University Press.
Jensen, A.R. (1998). The g factor: The science of mental ability.
Westport, CT: Praeger.
Jensen, A.R. (1999). Precis of: "The g Factor: The Science of Mental
Ability" PSYCOLOQUY 10(23).
- From: "C. Loring Brace" <clbrace@...>
Sent: 04 February 2000 21:56
Subject: Re: [evol-psych] Reply to Fancher on Jensen on Intelligence-g-Factor
> psycoloquy.00.11.017.intelligence-g-factor.30.jensen Wed Feb 2 2000Both here and in his comment on my review of The g Factor
> ISSN 1055-0143 (9 paragraphs, 6 references, 194 line)
> PSYCOLOQUY is sponsored by the American Psychological Association (APA)
> Copyright 2000 Arthur R Jensen
> MIXING UP EUGENICS AND GALTON'S LEGACY TO RESEARCH ON INTELLIGENCE
> Reply to Fancher on Jensen on Intelligence-g-Factor
> Arthur R. Jensen
> Educational Psychology
> School of Education
> University of California
> Berkeley, CA 94720-1670
> ABSTRACT: The fact that Sir Francis Galton coined the word
> 'eugenics' and promoted the concept during the latter part of his
> long life is hardly a disgrace, but it is apparently thought by
> some to sully his contributions as the founding father of
> differential psychology as an empirical science and to cast
> subsequent developments of Galton's original ideas in this sphere
> in a sinister light.
> 1. My aim in writing "The g Factor" (Jensen, 1998; 1999) was not to
> compile a history of the 'IQ controversy', or to recapitulate my
> earlier and often elaborate replies to critics of my former books and
> articles. I wanted to present as clear a picture as I could of the g
> factor, which has figured so prominently in the research on human
> abilities, and to explicate recent developments in empirical research
> on g. I believe that the Galton-Spearman line of thought about human
> abilities is now the mainline research in differential psychology, and
> I hope my book contributes to its advancement. My critics have been
> largely either ideological or scientifically technical. I pay little
> attention to the former but much attention to the latter.
psycoloquy.00.11.009.intelligence-g-factor.25.jensen) Jensen has maintained
that he pays much attention to the "scientifically technical" but little to
the "ideological" (psycoloquy.00.11.017.intelligence-g-factor.30.jensen). Yet
his "default position" is a classic manifestation of ideology. He is quite
right to say that it is "not a lone rootless hypothesis coming from out of the
blue" (psycoloquy.00.11.012.intelligence-g-factor.27.jensen). It is a
continuing thread from Plato's assumption a priori that some people are "born
slaves." That in turn underlay the justification for the enslavement of
people of African ancestry in America prior to the Civil War; it continued in
the subsequent century-long enforcement of "segregation"; and it survives in
the legacy euphemistically referred to as "states' rights."
The common link that ties these together, however, is not a "null hypothesis"
in the proper sense of the word. Instead it is the historical assumption that
group differences in innate worth are inevitable and that "we" are better than
"they." The only scientific way to test a true "null hypothesis" is to
generate conditions that are demonstrably equal and then to measure the
performance of members of different groups who have been raised under those
conditions. Until that is done, no measurement depicting differences can
count as scientific. For the same reason, the technicalities to which Jensen
is pleased to pay "much attention" cannot properly count as "scientifically"
C. L. Brace