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Three Recent Environmentalist Books that Perpetuate the “IQ-As-A-Measure-of-Intelligence” Myth

2500 words

The hereditarian-environmentalist debate has been ongoing for over 100 years. In this time frame, many theories have been forwarded to explain the disparity between individuals and groups. In one camp you have the hereditarians who claim that any non-zero heritability for IQ scores means that hereditarianism is true (eg Warne, 2020); while in the other camp you have the environmentalists who claim that differences in IQ are explained by environmental factors. This debate has been raging since the 1870s when Francis Galton coined the “nature-nurture” dichotomy still rages today. Unfortunately, the environmentalists lend credence to IQ-ist claims that, however imperfect, IQ tests are “measures” of intelligence.

Three recent books on the matter are A Terrible Thing to Waste: Environmental Racism and its Assault on the American Mind (Washington, 2019), Making Kids Cleverer: A Manifesto for Closing the Advantage Gap (Didau, 2019), and Young Minds Wasted: Reducing Poverty by Enhancing Intelligence in Known Ways (Schick, 2019). All three of these authors are clearly environmentalists and they accept the IQ-ist canard that IQ—however crudely—is a “measure” of “intelligence.”

There are, however, no sound arguments that IQ tests “measure” intelligence and there is no response to the Berka/Nash measurement objection for the claim that IQ tests are a “measure” since no hereditarian can articulate the specified measured object, the object of measurement and the measurement unit for IQ; there is, also, no accepted definition or theory of “intelligence”. So how can we say that some”thing” is being “measured” with a certain instrument if we have no satisfactorily defined what we claim to be measuring with a well-accepted theory of what we are measuring (Richardson and Norgate, 2015; Richardson, 2017), with a specified measured object, object of measurement, and measurement unit (Berka, 1983a, 1983b; Nash, 1990; Garrison, 2003, 2009) for the construct we want to measure?

But the point of this article is that environmentalists push the hereditarian canard that IQ is equal to, however crudely, intelligence. And though the authors do have great intentions and are pointing to things that we can do to attempt to ameliorate differences between individuals in different environments, they still lend credence to the hereditarian program.

A Terrible Thing to Waste

Washington (2019) discusses the detrimental effects (and possible effects of others) of lead, mercury and other metals that are more likely to be found in low-income black and “Hispanic” communities along with iodine deficiencies. These environmental exposures retard normal brain development. But, one is not justified in claiming that they are measures of “intelligence”—at best, as Washington (2019) argues, we can claim that they are indexes of environmental polluters on the brains of developing children.

Intelligence is a product of environment and experience that is forged, not inherited; it is malleable, not fixed. (Washington, 2019: 20)

While it is true, as Washington claims, that we can mitigate these problems from the toxic metals and lack of other pertinent nutrients for brain development by addressing the problems in these communities, it does not follow that IQ is a “biological” thing. Yes, IQ is malleable (contra hereditarian claims), and Headstart does work to improve life outcomes, even though such gains “fade out” after the child leaves the enriched environment. Lead poisoning, for example, has led to a decrease in 23 million IQ points per year (Washington, 2019: 15). But I am not worried about lost IQ points (even though by saving the IQ points from being lost, we would then be directly improving the environments that lead to such a decrease). I am worried about the detrimental effects of these toxic chemicals on the developing minds of children; lost IQ points are an outcome of this effect. At best, IQ tests can track cognitive damage due to pollutants in these communities (Washington, 2019) but they do NOT “measure” intelligence. (Also note that lead consumption is associated with higher rates of crime so this is yet another reason to reduce the consumption of lead in these communities.)

Speaking of “measuring intelligence”, Washington (2019: 29) noted that Jensen (1969: 5) stated that while “intelligence” is hard to define, it can be measured… But how does that make any sense? How can you measure what you can’t define? (See arguments (i), (ii), and (iii) here.)

Big Lead, though, “actively encouraged landlords to rent to families with vulnerable young children by offering financial incentives” (Washington, 2019: 55). This was in reference to the researchers who studied the deleterious effects of lead consumption on developing humans. “The participation of a medical researcher, who is ethically and legally responsible for protecting human subjects, changes the scenario from a tragedy to an abusive situation. Moreover, this exposure was undertaken to enrich landlords and benefit researchers at the detriment of children” (Washington, 2019: 55). We realized that lead had deleterious effects on development as early as the 1800s (Rabin, 2008), but Big Lead pushed back:

[Lead Industries Association’s] vigorous “educational” campaign sought to rehabilitate lead’s image, muddying the waters by extolling the supposed virtues of lead over other building materials. It published flooding guides and dispatched expert lecturers to tutor architects, water authorities, plumbers, and federal officials in the science of how to repair and “safely” install lead pipes. All the while the [Lead Industries Association] staff published books and papers nd gave lectures to architects and water authorities that downplayed lead’s dangers. 11 (Washington, 2019: 60)

In any case, Washington’s book is a good read into the effects of toxic metals on brain development, and while we must do what we can to ameliorate the effects of these metals in low-income communities, IQ increases are a side effect of ameliorating the toxic metals in these communities.

Making Kids Cleverer

Didau (2019: 86) outright claims that “intelligence is measured by IQ tests”—he is outright pushing the hereditarian view that IQ tests “measure intelligence.” (A strange claim since on pg 95-96 he says that IQ tests are “a measure of relative intelligence.”)

In the book, Didau accepts many hereditarian premises—like the claim IQ tests measure intelligence, that heritability can partition genetic and environmental variation. Further, Didau says in the Acknowledgements (pg 11) that Ritchie’s (2015) Intelligence: All That Matters forms the backbone for much of the information in Chapters 3 and 5.” So we can see here how the hereditarian IQ-ist stance colors his view on the relationship between “IQ” and “intelligence.” He also makes the bald claims that “intelligence is a good candidate for being the best researched and best understood characteristic of the human brain” and that it’s “also probably the most stable construct in all psychology” (pg 81).

Didau takes the view that intelligence is both a way to acquire knowledge as well as what type of knowledge we know (pg 83)—basically, it’s what we know and what we do with what we know along with ways to acquire said knowledge. What one knows is obviously a product of the environment they find themselves growing up in, and what we do with the knowledge we have is similarly down to environmental factors. Didau states that “Possibly the strongest correlations [with IQ] are those with educational outcomes” (pg 92). But Didau, it seems, fails to realize that this strong correlation is built into the test since IQ tests and scholastic achievement tests are different versions of the same test (Schwartz, 1975, Richardson, 2017).

In one of the “myths of intelligence” (Myth 3: Intelligence cannot be increased, pg 102) he discusses, Didau uses a similar analogy as myself. In an article on “the fade-out effect“, I argued that if one goes to the gym, works out and gets bigger and then stops going, we can then say that going to the gym is useless since once they leave the enriched environment they lose their gains. The direct parallels to Headstart, then, is clear with my gym/muscle-building analogy.

In another myth (Myth 4: IQ tests are unfair), Didau claims that if you get a low IQ score then you are probably unintelligent, while if you get a high one, it means you know the answers to the questions—which is obviously true. Of course, to know the answers to the questions (and to be able to reason the answers for some of the questions), one must be exposed to the knowledge that is contained in that test, or they won’t score high.

We can reject the use of IQ scores by racists, he says, who would use it to justify the superiority of their own groups and the inferiority of “the other”, all while not rejecting that IQ tests are valid (where have they been validated?). “Something real and meaningful” is being measured by these tests, and we have chosen to call this “intelligence” (pg 107). But we can say this about anything. Imagine having a test Y for X. But we don’t really know what X is, nor that Y really measures it. But because it accords with our a priori biases and since we have constructed Y to get the results we think we should see, even though we have no idea what X is, we assume that we are measuring what we set out to all without the basic requirements of measurement.

While Didau does seem to agree with some of the criticisms I’ve levied on IQ tests over the years (cross-cultural testing is pointless, IQ scores can be changed), he is, obviously, pushing a hereditarian IQ-ist agenda, cloaked as an environmentalist. He contradicts himself by saying that intelligence is measured by IQ tests without then saying what he says later about them—and I don’t think one should assume that he meant they are an “imperfect measure” of intelligence. (Imagine an imperfect measure of length—would we still be using it to build houses if it was only somewhat accurate?) Didau also agrees with the g theorists, in that there is a “general cognitive ability”, as well. He also agrees with Ritchie and Tucker-Drob (2018) and Ceci (1996) that schooling can and does increase IQ scores (as summer vacations show that IQ scores do decrease without schooling) (see Didau, 2018: Chapter 5). So while he does agree that IQ isn’t static and that education can and does increase it, he is still pushing a hereditarian IQ-ist model of “intelligence”—even though, as he admits, the concept of “intelligence” has yet to be satisfactorily defined.

Young Minds Wasted

In the last book, Young Minds Wasted (Schick, 2019), while he does dispense with many hereditarian myths (such as the myth of the normal distribution, see here), he still—through an environmentalist lens—justifies the claims that IQ tests test intelligence. While he masterfully dispenses with the “IQ is normally distributed” claim (see discussion in pg 180-186), the tagline of the book is “reducing poverty by increasing intelligence, in known ways.”

The poor’s intelligence is wasted, he says, by an intelligence-depressing environment. We can see the parallels here with Washington’s (2019) A Terrible Thing to Waste. Schick claims that “the single most important and widespread cause of poverty is the environmental constraints on intelligence” (pg 12, Schick’s emphasis). Now, like Washington, Schick says that a whole slew of chemicals and toxins decrease IQ (a truism) and by identity, intelligence. Of course, living in a deprived environment where one is exposed to different kinds of toxins and chemicals can retard brain development and lead to deleterious life outcomes down the line. But this fact does not mean that intelligence is being measured by these tests; it only shows that there are environments that can impede brain development which then is mirrored in a decrease in IQ scores.

Schick says that as intelligence increases, societal problems decrease. But, as I have argued at length, this is due to the way the tests themselves are constructed, involving the a priori biases of the test’s constructors. If we can construct a test with any kind of distribution we want to, and if the items emerge arbitrarily from the heads of the test’s constructors who then try them out on a standardized sample (Jensen, 1980: 71) looking for the results they want and assume a priori, then we can make it so that what we accept as truisms regarding the relationship between IQ and life events can be turned on their head, with no logical reason to accept one set of items over another, other than that one set has a bias in which it upholds a test constructor’s previously-held biases.

Schick does agree that “intelligent behavior” can change throughout life, based on one’s life experiences. But “Human intelligence is based on several genetically determined capabilities such as cognitive functions” (pg 39). He also claims that genetic factors determine while environmental factors influence cognitve functions, memory, and universal grammar.

Along with his acceptance that genetic factors can influence IQ scores and other aspects of the mind, he also champions heritability estimates as being able to partition genetic and environmental variation in traits (even though it can do no such thing; Moore and Shenk, 2016). He—uncritically—accepts the 80/20 genetic environmental heritability from Bouchard and the 60/40 genetic environmental heritability from Jensen and Murray and Herrnstein. These “estimates”—drawn mostly from family, twin, and adoption studies (Joseph, 2015)—though, are invalid due to the false assumptions the researchers hold, neverminding the conceptual difficulties with the concept of heritability (Moore and Shenk, 2016).


While Washington and Schick both make important points—that those who live in poor environments are at-risk of being exposed to certain things that disrupt their development—they both, along with Didau, accept the hereditarian claim that IQ tests are tests of intelligence. While each author has their own specific caveats (some of which I agree with, and other I do not), they keep the hereditarian claim alive by lending credence to their arguments, but not looking at it through a genetic lens.

While the authors have good intentions in mind and while the research they discuss is extremely important and interesting (like the effects of toxins and metals on the development of the brain and the development of the child), they—like their intellectual environmentalist ancestors—unwittingly lend credence to hereditarian claims that IQ tests measure intelligence but they go about the causes of individual and group differences in completely different ways. These authors, with their assertions, then, accept the claim that certain groups are less “intelligent” than others. But it’s not genes that are the cause—it’s the differences in environment that cause it. And while that claim is true—that the deleterious effects Washington and Schick discuss can and do retard normal development—it, in no way shape or form, means that “intelligence” is being measured.

Normal (brain) development is indeed a terrible thing to waste; we can teach kids more by exposing them to more things, and young minds are wasted by poverty. But by accepting these premises, one does not need to accept the hereditarian dogma that IQ tests are measures of some undefined thing with no theory. That poverty and the environments that those in poverty live in impedes normal brain development which is then reflected in IQ scores, it does not follow that these tests are “measuring” intelligence—they, at best, show environmental challenges that change the brain of the individual taking the test.

One needs to be careful with the language they use, lest they lend credence to hereditarian pseudoscience.