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Strengthening my Argument to Ban IQ Tests

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Over three years ago I provided an argument with the ultimate conclusion that IQ tests should be banned. The gist of the argument is that if we believed the hereditarian hypothesis is true and we make policy ascription based on the hereditarian hypothesis and the results that were derived from IQ tests, then a policy could be enacted that would harm a group, and if the policy were enacted, then it would do harm to a group. Thus we should ban whatever led to the policy in question, and so if IQ tests led to the policy in question then IQ tests should be banned. In this article, I will strengthen each premise and then I will provide another argument for why IQ tests should be banned. Here’s the argument:

(P1) The Hereditarian Hypothesis is false
(P2) If the Hereditarian Hypothesis is false and we believed it to be true, then policy A could be enacted.
(P3) If Policy A is enacted, then it will do harm to group G.
(C1) If the Hereditarian Hypothesis is false and we believed it to be true and policy A is enacted, then it will do harm to group G (HypotheticaSyllogismP2, P3).
(P4) If the Hereditarian Hypothesis is false and we believed it to be true and it would harm group G, then we should ban whatever led to policy A.
(P5) If Policy A is derived from IQ tests, then IQ tests must be banned.
(C2) Therefore, we should ban IQ tests (Modus Ponens, P4P5).

Premise 1: The truth or falsity of this premise would divide people. On the one hand, there are proponents of the hereditarian hypothesis who believe that the hereditarian hypothesis is true, and so by banning their main “measurement tool”, then we would be censoring “the truth of human biodiversity.” But what entails “the hereditarian hypothesis”? The hereditarian hypothesis can also be called the generic theory of intelligence. It’s main claim is that the observed differences in IQ between groups and individuals are largely attributed to genetic factors. For example, Rushton and Jensen (2005) claim to take the middle ground in arguing that it’s 50/50 genes and environment that lead to the IQ phenotype. But Rushton and Jensen (2005: 279) claim that the 50/50 estimate of heritability is too low—80 percent G and 20 percent E is what we should assume:

A conundrum for theorists of all persuasions, however, is that there is too little evidence of any environmental effects. The hereditarian model of Black–White IQ differences proposed in Section 2 (50% genetic and 50% environmental), far from precluding environmental factors, requires they be found. Although evidence in Sections 3 to 11 provided strong support for the genetic component of the model, evidence from Section 12 was unable to identify the environmental component. On the basis of the present evidence, perhaps the genetic component must be given greater weight and the environmental component correspondingly reduced. In fact, Jensen’s (1998b, p. 443) latest statement of the hereditarian model, termed the default hypothesis, is that genetic and cultural factors carry the exact same weight in causing the mean Black–White difference in IQ as they do in causing individual differences in IQ, about 80% genetic–20% environmental by adulthood.

I have spent the better part of 3 years since publishing my original article to ban IQ tests arguing against the falsity of the hereditarian hypothesis on many grounds. The hereditarian hypothesis largely relies on heritability estimates derived from twin and adoption studies (and now shifting to neuroscience, like they have been since the 80s) and this is where the “laws of behavioral genetics” came from, but the “laws” fail. Important for the hereditarian position is the claim that science can study the mind. However, science is third-personal while mind is first-personal and subjective. Thus it follows that what is third-personal cannot study what is first-personal. Most important for the hereditarian position is the irreducibility of the mental—for if the claim is that the hereditarian hypothesis is true, then the mental would need to reduce to the physical. Humans have minds which means we have the ability for intentional states and propositional attitudes which implies that humans aren’t fully physical. If the argument there holds then science can’t study what’s immaterial, so there is a part of our constitution that can’t be studied by science. So at the end of the day, the hereditarian hypothesis is a physicalist position on the mind-body problem, but empirical evidence is irrelevant to conceptual arguments so the hereditarian position can’t help us understand the mind-body problem since it is an empirical position based on a supposed relationship between mind (“IQ”) and genes/brain/brain structure. Finally, the claim that there is a “general intelligence” is false; we don’t need a nonexistent, reified thing to explain the intercorrelations on IQ scores between individuals and groups. IQ tests are mere knowledge tests—and since knowledge is class-dependent, then different classes have different psychological and cultural tools, and so they would have different knowledge. Basically, IQ is an arbitrary notion especially due to the fact that tests can and have changed in the past for different social groups like men and women (Rosser, 1989), and two white South African groups (Hilliard, 2012) while Kidder and Rosner (2002) showed unconscious bias in the SAT favoring whites due to how the questions were selected. All of these considerations combine to show that the hereditarian hypothesis is false and that we should not accept conclusions from anyone who uses the hereditarian hypothesis as a guide.

Premise 2: But if we believed the hereditarian hypothesis to be true even when it’s false, then we may harm a group. For example, Jensen espoused some eugenic-type ideas in his infamous 1969 paper, stating:

“Is there a danger that current welfare policies, unaided by eugenic foresight, could lead to the genetic enslavement of a substantial segment of our population?” – Jensen, 1969: 95How Much Can We Boost IQ and Scholastic Achievement?

“What the evidence on heritability tells us is that we can, in fact, estimate a person’s genetic standing on intelligence from his score on an IQ test.” – Jensen, 1970, Can We and Should We Study Race Difference?

“… the best thing the black community could do would be to limit the birth-rate among the least-able members, which of course is a eugenic proposal.” – A Conversation with Arthur Jensen, American Reinnasance, 1992

What Jensen wrote in his 1969 paper is similar to what Herrnstein and Murray (1994: 548) wrote:

We can imagine no recommendation for using the govemment to manipulate fertility that does not have dangers. But this highlights the problem: The United States already has policies that inadvertently social-engineer who has babies, and it is encouraging the wrong women. If the United States did as much to encourage high-IQ women to have babies as it now does to encourage low-lQ women, it would rightly be described as engaging in aggressive manipulation of fertility. The technically precise description of America’s fertility policy is that it subsidizes births among poor women, who are also disproportionately at the low end of the intelligence distribution. We urge generally that these policies, represented by the extensive network of cash and services for low-income women who have babies, be ended.

While these propositions don’t directly stem from hereditarian ideas, they are a direct consequence of such thinking. Like Shockley and Cattell’s beliefs and how their a priori racist ideas influenced the “science” they performed. So premises 2 and 3 presume a causal link between the hereditarian hypothesis, policy A and harm to group G. One specific example that immediately comes to mind is the sterilization or “morons”, “idiots”, and “imbeciles” in the 1900s even continuing up until the late 1970s. Perhaps the most famous case of this was the case of Carrie Buck, to which a judge famously stated, “Three generations of imbeciles are enough.” Premise 3 clearly has historical support.

Conclusion 1: So, since I’ve argued that P2 and P3 are true, then it follows that C1 is true as well. In the original article, I showed that blacks were disproportionately affected by IQ test rulings. Along with the fact that low IQ people were sterilized, this provides yet more support for the premises and the conclusion of this part of the argument.

Premise 4: I have already given the example above about the eugenics movement of the 1900s in America sterilizing thousands of people for having low IQs (this also occurred around the world). The Tuskegee Syphilis Experiment also lends credence to this premise. The US Public Health Service conducted a study from 1932 to 1972 on black Americans where they were observed with syphilis but they weren’t treated after penicillin became available. Segregation laws were based on the belief that the races were inherently different and shouldn’t mix. So in an attempt to prevent mixing, segregation was based on a false belief that blacks were inferior to whites. This is what Darby and Rury (2018) refer to as “the color of mind.”

The Color of Mind [the idea that”blacks were not equal to whites in intelligence, character, or conduct”] has served to rationalize racially exclusionary school practices and unequal educational opportunities, and the effects of these..have worked to sustain this racial ideology

Premise 5: Furthermore, government policies such as redlining and discriniminatory housing policies have led to segregation and inequalities/inequities in education (Rothstein, 2017). These example lend credence to the claim in P4 and P5—policies and practices derived from IQ or other standardized tests can be harmful if they contribute to existing inequalities and disparities. It is quite clear that IQ tests have been used to justify discriminatory polices in the past. Historical and recent considerations point to the fact that IQ tests can and have been used to perpetuate harm on individuals and groups (with the best example being the eugenics movement sterilizing low IQ people, sometimes without their knowledge). The other considerations that weren’t directly related to IQ tests like Tuskegee and Japanese Americans in WW2 show that beliefs that are false that are held to be true can and do lead to devestating consequences for groups of people. The arbitrariness of IQ can also be seen with the death penalty—there are literally life or death consequences riding on the results of a biased test. Moreover, IQ tests have been used to bar immigrants into America in the 1920s (Gould, 1981; Allen, 2006; Richardson, 2011).

Even if IQ tests haven’t been used to enact harmful policies in the past (they quite obviously have), potential future harm is enough. For example, IQ tests are biased in virtue of their item content. So if, say, an employer decides to use IQ tests to select job applicants, they will be necessarily biased by race and class. (Even though IQ tests don’t really have any predictive power for job performance, and whatever relationship between school performance is built in due to the relationship between the items on the tests.)

Thus, the conclusion of the argument that we should ban IQ tests follows. I have argued for the truth of premises 4 and 5 so it then follows that we should ban IQ tests. The argument is valid and I hold it to be sound. So we should ban IQ tests. Nevertheless, here is another argument that we should ban IQ tests:

P1: If IQ tests are not culturally biased and do not perpetuate social inequalities, then they should not be banned.
P2: IQ tests are culturally biased and perpetuate social inequalities.
P3: If IQ tests are culturally biased and perpetuate social inequalities, then IQ tests should be banned.
C: Therefore IQ tests should be banned.


I defended the premises in my original argument more in depth, giving more examples go each premise to justify and strengthen the overall argument. I then gave a new argument stating that since IQ tests at culturally biased, and perpetuate social inequalities then they should be banned. I will now close with a final argument that we should ban IQ tests (hypothetical syllogism):

P1: If IQ tests are biased and have a negative impact on people’s lives, then they should be banned.
P2: If IQ tests are banned, then they will no longer have a negative impact on people’s lives.
C: Therefore, if IQ tests are biased and have a negative impact on people’s lives, then IQ tests should be banned to eliminate  that harm.

All you need to do to see the goal of IQ-ists is to merely read what they write. IQ-ists like Jensen and Lynn have outright stated that we should in Jensen’s case limit the birthrate of the “least-able” while there is a danger that “current welfare policies unaided by eugenic foresight” could lead to a “genetic enslavement” of a substantial portion of the population. While in Lynn’s case, he was much more coy about it that we need to “phase out” such cultures (but he claimed it isn’t genocidal, though the term “phase out” of course tells you his real aims). Nevertheless, IQ-ists like Jensen, Lynn, Shockley, and Cattell have told us exactly what their views are. And their views are derived from, ultimately, heritability estimates derived from research with false assumptions. There is also the case that Pygmalion seems to be in the genes—the act of classifying one based on their polygenic score could have feedback effects based on how they view themselves and how society views them: “Through possible mechanisms of stigma and self-fulfilling prophecies, our results highlight the potential psychosocial harms of exposure to low-percentile polygenic scores for educational attainment” (Matthews et al, 2021).

I don’t even think it makes sense to claim that genes contribute to the ontogeny and differences in psychological traits between individuals. Genes only contribute to physical traits. Genes also don’t work how hereditarians need them to work. This is yet another reason why we should reject the hereditarian hypothesis and, along with it, stop using and banning IQ tests. The claim that genes contribute to the differences in psychological traits between people is not only false, but it has caused much harm since the argument has been mounted. Hereditarians have a ton of work to do on the conceptual front if they ever hope to have a sound basis for their beliefs. I’ve argued for a long time that it’s just not possible.

I don’t think we need a moratorium on these matters, such as behavioral genetics. I will be much more specific:

We need to outright cease and ban behavioral genetic research and IQ testing since they lead to avoidable harms. Since these things are based on flawed assumptions, and since these hardly have an evidentiary basis, the only recourse we should take on the matter is to outright ban them. The arguments given here definitively show that to be the case. If someone tells you who they are, then you listen to them. The main actors in the hereditarian sphere have told us who they are and what they stand for for decades, so we should listen to them and ban behavioral genetic and IQ tests. It’s only right to do so.


1 Comment

  1. “Genes only contribute to physical traits.”

    Yes, that is what the brain is, physical.

    Just like the opposable thumb, and the vocal cords.

    Without the brain, we would not be human.

    And humans ARE different, in the brain, body, and mind.


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