Thanks for the substantive post.
On IQ: Fractionating Human Intelligence
, the largest intelligence study on record with more than 100,000 participants, concludes that IQ tests and scores only measure certain aspects of intelligence, ignoring others. (When the article is discussed elsewhere, an analogy is suggested: existing IQ tests only test one part of intelligence, like testing basketball players' ability based on height; yes, being tall is an asset for basketball, but you can be tall and still suck at basketball, and you can be short and still be a skilled player. Height alone is not a good measure of basketball ability, and IQ tests alone are not a good measure of intelligence.)
Unfortunately, this paper was a mess, as explained by Richard Haier (editor-in-chief of the journal Intelligence
, author of The Neuroscience of Intelligence
) et al.:
"Hampshire and Owen maintain that their original paper was flawless, but doubts remain about their factor analysis methods and related assumptions. Failure to cite relevant papers, poor sampling and restricted ranges also remain problematic for the definitive conclusions they drew. The editorial review process for investigating the serious issues we raised prior to publication in Neuron remains a mystery. We stand by the opinion expressed in our preview: the Hampshire et al. paper is an interesting but flawed exercise and their conclusions are not as definitive, or original, as they believe."Haier, R.J., etal., Yes, but ﬂaws remain, Intelligence (2014)
The Cambridge Handbook of Intelligence
concurs that "there is no single definition of intelligence" (p. 88). It states that intelligence is substantially malleable (changeable as a consequence of environmental factors).
So far so good.
On IQ and race: the real problem is that both IQ and race are vague and elusive, with scientists contesting whether each are even meaningful categories on their own, let alone together.
Race is vague in the same way languages are. The boundaries are fuzzy, like the one between Dutch and German. If you keep that limitation in mind, it's not particularly difficult to use the concept productively. There's nothing elusive about it.
Let's look at some more scientific evidence. I'm citing from the Cambridge Handbook of Intelligence (CHI) again because it's a convenient way to cite numerous scientific, peer-reviewed journal articles at once. Measured IQ differences between black and white 12 year olds in the US dropped significantly from 1979-2009. (If IQ is genetic, then such a change shouldn't occur; if we assume IQ to be the result of educational opportunities, then it becomes understandable). When socioeconomic status is taken into account, the mean difference in IQ among US blacks and whites also drops. (CHI 283-284).
No one said IQ is purely genetic.
Its section on race and intelligence concludes:
CHI 301 wrote:So, what we have is a strong relationship between two weak phenomena (race and intelligence), one of which – intelligence – is reported to be measurable with IQ tests that happen to correlate with socioeconomic status and that represent a narrowly defined set of cognitive skills which, not surprisingly, predict similarly defined academic skills and therefore, occupational success and wealth, which in turn predict intelligence as represented by an IQ score. Flawed constructs, flawed instruments, and flawed relationships yield flawed inferences and flawed educational and social policies."
CHI 302 wrote:We need to be clear that IQ is not synonymous with intelligence and to continue in our efforts to reach a consensus on the substance of this elusive construct. In this regard, the authors are impressed with the work of Fagan and Holland (2002, 2007, 2009) who argue that intelligence is information processing and that cultural differences in the provision of information appear to account for observed racial differences in IQ. Specifically, what Fagan and Holland’s research demonstrates is that differences in knowledge between Blacks and Whites for intelligence test items can be erased when equal opportunity is provided for exposure to the information to be tested.
The two editors of the CHI fail to give a representative overview of IQ research. See for example this editorial signed by 52 experts explaining Mainstream Science on Intelligence
. It states among other things that:
"Intelligence is a very general mental capability ... it reflects a broader and deeper capability for comprehending our surroundings ..."
"Intelligence, so defined, can be measured, and intelligence tests measure it well. They are among the most accurate (in technical terms, reliable and valid) of all psychological tests and assessments."
"IQ is strongly related, probably more so than any other single measurable human trait, to many important educational, occupational, economic, and social outcomes ... Whatever IQ tests measure, it is of great practical and social importance"
"The practical advantages of having a higher IQ increase as life’s settings become more complex"
"Differences in intelligence certainly are not the only factor affecting performance in education, training, and complex jobs ... but intelligence is often the most important"
"Heritability estimates range from 0.4 to 0.8 ... indicating genetics plays a bigger role than environment in creating IQ differences"
"There is no persuasive evidence that the IQ bell curves for different racial-ethnic groups are converging"
"Racial-ethnic differences in IQ bell curves are essentially the same when youngsters leave high school as when they enter first grade ... black 17-year-olds perform, on the average, more like white 13-year-olds"
The editorial predates the CHI publication by 15 years, but I have seen no indication that the field has been turned on its head in the meantime, which the CHI section on IQ would imply.
Ein Buch muß die Axt sein für das gefrorene Meer in uns. - Kafka