Is Psychometric g a Myth?

http://humanvarieties.org/2013/04/03/is-psychometric-g-a-myth/?2

by gwern • 12 years ago

26 11 12 years ago

verteu3• 12 years ago

The scientific consensus on intelligence in 1997 was quite clear on this issue: http://en.wikipedia.org/wiki/Mainstream_Science_on_Intellige... . (See conclusion #3.)

Has the consensus changed since '97? I frequently hear people dispute #2 ("Intelligence can be measured, and intelligence tests measure it well") and #5 ("Intelligence tests are not culturally biased"). However, I'm not aware of a revolution in IQ testing which overturns the old findings.

pessimizer• 12 years ago

That was the consensus of scientists who specialized in studying general intelligence, not the consensus of scientists, and was controversial at the time. It did help to fight myths that were being promulgated by popular writers and politically-motivated cranks about what the consensus of scientists who studied general intelligence actually was.

Asking scientists who specialize in Spearman's g whether g is real is like asking astrologers whether astrology works.

verteu3• 12 years ago

Asking scientists who specialize in Spearman's g whether g is real is like asking astrologers whether astrology works.

Climate change deniers use the same argument -- "Of course people who professionally study global warming will claim it's real!"

Why is your claim valid while the above is specious? It depends on the rigor of the subfield in question.

murbard22• 12 years ago

I don't know of any field where there is a larger gap between mainstream science's position and what the public think this position is. It's "common knowledge" among a certain educated elite that IQ has been debunked.

keketi• 12 years ago

What educated elite is that?

avatarlite• 12 years ago

tl;dr - a refutation of statistician Cosma Shalizi’s essay at http://vserver1.cscs.lsa.umich.edu/~crshalizi/weblog/523.htm... in three parts:

(1) "Shalizi’s first error is his assertion that cognitive tests correlate with each other because IQ test makers exclude tests that do not fit the positive [correlation matrix]. In fact, more or less the opposite is true. ... Cognitive tests correlate because all of them truly share one or more sources of variance."

(2) "Shalizi’s second error is to disregard the large body of evidence that has been presented in support of g as a unidimensional scale of human psychological differences. The g factor is not just about the positive [correlation matrix]. A broad network of findings related to both social and biological variables indicates that people do in fact vary, both phenotypically and genetically, along this continuum that can be revealed by psychometric tests of intelligence and that has has widespread significance in human affairs."

(3) "Shalizi’s third error is to think that were it shown that g is not a unitary variable neurobiologically, it would refute the concept of g. However, for most purposes, brain physiology is not the most relevant level of analysis of human intelligence. What matters is that g is a remarkably powerful and robust variable that has great explanatory force in understanding human behavior. Thus g exists at the behavioral level regardless of what its neurobiological underpinnings are like."

Conclusion: "In many ways, criticisms of g like Shalizi’s amount to “sure, it works in practice, but I don’t think it works in theory”. Shalizi faults g for being a “black box theory” that does not provide a mechanistic explanation of the workings of intelligence, disparaging psychometric measurement of intelligence as a mere “stop-gap” rather than a genuine scientific breakthrough. However, the fact that psychometricians have traditionally been primarily interested in validity and reliability is a feature, not a bug. Intelligence testing, unlike most fields of psychology and social science, is highly practical, being widely applied to diagnose learning problems and medical conditions and to select students and employees. What is important is that IQ tests reliably measure an important human characteristic, not the particular underlying neurobiological mechanisms."

andreasvc• 12 years ago

Please, can we just call it a "summary" instead of invoking the anti-intellectual air of "tl;dr"?

nhoven• 12 years ago

There is a good discussion of the relative merits of both articles(the linked blog post, and the post it criticizes) on the LessWrong forums: http://lesswrong.com/r/discussion/lw/h6p/g_a_statistical_myt...

Is Psychometric g a Myth?

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