Intelligence Redux

I was disappointed recently after reading Life’s Extremes: Smart vs. Dumb on LiveScience. Based upon the comments of American psychologist Richard Haier, the article presented a one-sided view of human intelligence research: a view largely consistent with Herrnstein & Murray‘s The Bell Curve. In this brief blog post, I’m going to don my contrarian hat and advance the flip side of the intelligence coin.

Quite a gulf exists between the extremes in innate human intelligence.

“Everybody would like to think there are environmental interventions to overcome biology. We know in medicine it’s true – you can overcome certain genetic predispositions by exercise or changing diet,” Haier told LiveScience. “But we haven’t found such things on cognition.”

Not all intelligence research subscribes to such biological determinism. To the interested reader, I suggest perusing:

“A generation ago, people were arguing over the definition of intelligence, and that argument is now done,” said Richard Haier, professor emeritus in the School of Medicine at the University of California, Irvine. “Intelligence is something that’s real and exists, and it can be measured.”

Regarding intelligence, I explored the twin problems of its definition and its measurement in a previous blog post, Questioning Everything Includes Questioning Yourself. In that piece, I examined the question of whether or not Mark Zuckerberg is a genius.

The best-known index of smarts is an intelligence quotient (IQ) test, which probes spatial ability, memory, speed of processing information and more. “In the last hundred years of studying intelligence, there have been pretty constant results that several different intelligence factors, like these, relate to how smart people are,” said Haier.

IQ tests are indicative of IQ-test-taking ability. They also tend to be predictive of academic performance. Beyond that, however, their use in conclusively assessing the breadth of mental capacity is questionable. As Mary-Elaine Jacobsen so eloquently asserted in her book, The Gifted Adult: A Revolutionary Guide for Liberating Everyday Genius: “As we have seen, we have been indoctrinated with the notion that a single IQ number, such as 109, 123, or 145, is a true indicator of ability from which we can determine the limits of our potential, including giftedness. However, we now know that a single IQ rating (1) does not validly describe the intelligence of many individuals, (2) is a finite measure of performance that can change over time, (3) cannot claim to measure the multifaceted factors of ability proposed by current research on intelligence, (4) all but ignores creativity and other specialized aspects of human potential.”

When discussing intelligence, researchers tend to cite a general factor of intelligence, or g, the common factor across a battery of intelligence tests. “Think of the really smart kids you knew in school — they were kind of generally smart, not just in one subject,” said Haier. “It’s that general ability that’s reflected in the g score.”

In Norse mythologyVíðarr, son of Odin, avenged his father by smiting the monstrous wolf, Fenrir, at Ragnarök. Likewise, Cosma Shalizi divinely judged and utterly decimated the abstraction of g in his article, g, a Statistical Myth.

“The question of why are people smarter than others is a question we now have the scientific means to investigate,” Haier said.

Intelligence research still seems to exude the trappings of pseudoscience. Perhaps one day—once neuroscience has progressed to the point where the brain’s neurocircuitry can be mapped in detail—it will graduate to the level of a hard science, such as physics. I’ll impart the last word of this post to The Skeptic Encyclopedia of Pseudoscience, Volume 2, edited by Michael Shermer: “Volumes have been written on problems with intelligence tests, and I will not repeat them here. Suffice it to say that one problem with such tests is what they purport to measure. Rather than measuring some qualitatively distinct structure or process as defenders of such tests would have us believe, intelligence tests literally measure only the correctness of a variety of learned behaviors—answers to questions on the test—in a contrived context—the test taking situation (Schlinger, 1992). Alfred Binet knew this when he developed the first modern intelligence test (although he eschewed the use of the term ‘intelligence’ in favor of the more descriptive and neutral ‘intellectual level’). The challenge for serious scientists is to ask about the variables that affect the broad range of behaviors we describe as intelligent; and only an experimental analysis can answer such questions.”

2 thoughts on “Intelligence Redux

  1. Steinberg

    Just looking at your comment on Cosma Shalizi & IQ.

    As Steve Hsu (involved in the Cognitive Genomics Project) has pointed out, anyone who understands factor analysis realises that you can have correlations and a single largest factor even if there are no underlying causal reasons (i.e., it is just an accident). Nonetheless, these models may still be useful.

    Prior to the availability of molecular studies the heritability of type II diabetes was estimated at 0.25 using all those methods. Now molecular studies have identified at least 9 loci involved in the disease. There are other examples in relation to height. So you can’t say that heritability studies, with all their seemingly ridiculous assumptions, are worthless.

    In fact, reading Shalizi closely, you’ll see that he doesn’t think they are either. For instance, he says:

    ***If you put a gun to my head and asked me to guess [whether there are genetic variants that contribute to IQ], and I couldn’t tell what answer you wanted to hear, I’d say that my suspicion is that there are, mostly on the strength of analogy to other areas of biology where we know much more. ***

    Also, in his article on g he seems to accept in the footnotes that intelligence or cognitive ability, as operationally defined by psychologists, is important for economic development.

    His criticism of g is also met here. Still just 1 g: Consistent results from five test batteries Johnson et al
    Intelligence Volume 36, Issue 1, January–February 2008, Pages 81–95

  2. Steinberg

    Also note that Gould was exposed last year as a charlatan in terms of his treatment of Morton’s data (see NY Times article). Very little of Mismeasure stands up to scrutiny.

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