I found the excerpt below in the comments
here.
Mega Questions for Renowned Psychologist Dr._Arthur R. Jensen
- Interview by Christopher Michael Langan and Dr. Gina LoSasso and
members of the Mega Foundation, Mega Society East and Ultranet
Question #1:
Christopher Langan for the Mega Foundation: It is reported that one of
this century’s greatest physicists, Nobelist Richard Feynman, had an IQ of
125 or so. Yet, a careful reading of his work reveals amazing powers of
concentration and analysis…powers of thought far in excess of those
suggested by a z score of well under two standard deviations above the
population mean. Could this be evidence that something might be wrong with
the way intelligence is tested? Could it mean that early crystallization
of intelligence, or specialization of intelligence in a specific set of
(sub-g) factors – i.e., a narrow investment of g based on a lopsided
combination of opportunity and proclivity - might put it beyond the reach
of g-loaded tests weak in those specific factors, leading to deceptive
results?
Arthur Jensen: I don’t take anecdotal report of the IQs of famous persons
at all seriously. They are often fictitious and are used to make a point
- typically a put-down of IQ test and the whole idea that individual
differences in intelligence can be ranked or measured. James Watson once
claimed an IQ of 115; the daughter of another very famous Nobelist claimed
that her father would absolutely “flunk” any IQ test. It’s all
ridiculous.
Furthermore, the outstanding feature of any famous and
accomplished person, especially a reputed genius, such as Feynman, is
never their level of g (or their IQ), but some special talent and some
other traits (e.g., zeal, persistence). Outstanding achievements(s)
depend on these other qualities besides high intelligence. The special
talents, such as mathematical musical, artistic, literary, or any other of
the various “multiple intelligences” that have been mentioned by Howard
Gardner and others are more salient in the achievements of geniuses than
is their typically high level of g. Most very high-IQ people, of course,
are not recognized as geniuses, because they haven’t any very outstanding
creative achievements to their credit. However, there is a threshold
property of IQ, or g, below which few if any individuals are even able to
develop high-level complex talents or become known for socially
significant intellectual or artistic achievements. This bare minimum
threshold is probably somewhere between about +1.5 sigma and +2 sigma from
the population mean on highly g-loaded tests.
Childhood IQs that are at
least above this threshold can also be misleading. There are two famous
scientific geniuses, both Nobelists in physics, whose childhood IQs are
very well authenticated to have been in the mid-130s. They are on record
and were tested by none other than Lewis Terman himself, in his search for
subjects in his well-known study of gifted children with IQs of 140 or
above on the Stanford-Binet intelligence test. Although these two boys
were brought to Terman’s attention because they were mathematical
prodigies, they failed by a few IQ points to meet the one and only
criterion (IQ > 139) for inclusion in Terman’s study. Although Terman was
impressed by them, as a good scientist he had to exclude them from his
sample of high-IQ kids. Yet none of the 1,500+ subjects in the study ever
won a Nobel Prize or has a biography in the Encyclopedia Britannica as
these two fellows did. Not only were they gifted mathematically, they had
a combination of other traits without which they probably would not have
become generally recognized as scientific and inventive geniuses.
So-called intelligence tests, or IQ, are not intended to assess these
special abilities unrelated to IQ or any other traits involved in
outstanding achievement. It would be undesirable for IQ tests to attempt
to do so, as it would be undesirable for a clinical thermometer to measure
not just temperature but some combination of temperature, blood count,
metabolic rate, etc. A good IQ test attempts to estimate the g factor,
which isn’t a mixture, but a distillate of the one factor (i.e., a unitary
source of individual differences variance) that is common to all cognitive
tests, however diverse.
I have had personal encounters with three Nobelists in
science, including Feynman, who attended a lecture I gave at Cal Tech and
later discussed it with me. He, like the other two Nobelists I’ve known
(Francis Crick and William Shockley), not only came across as extremely
sharp, especially in mathematical reasoning, but they were also rather
obsessive about making sure they thoroughly understood the topic under
immediate discussion. They at times transformed my verbal statements into
graphical or mathematical forms and relationships. Two of these men knew
each other very well and often discussed problems with each other. Each
thought the other was very smart. I got a chance to test one of these
Nobelists with Terman’s Concept Mastery Test, which was developed to test
the Terman gifted group as adults, and he obtained an exceptionally high
score even compared to the Terman group all with IQ > 139 and a mean of 152.
I have written an essay relevant to this whole question:
“Giftedness and genius: Crucial differences.” In C. P. Benbow & D.
Lubinski (Eds.) Intellectual Talent: Psychometric and Social Issues, pp.
393-411. Baltimore: Johns Hopkins University Press.
See
here for data relevant to this topic and the discussion in the comments.