2000 words

Introduction

Jensen’s default hypothesis proposes that individual and group differences in IQ are primarily explained genetic factors. But Fagan and Holland (2002) question this hypothesis. For if differences in experience lead to differences in knowledge, and differences in knowledge lead to differences in IQ scores, then Jensen’s assumption that blacks and whites have the same opportunity to learn the content is questionable, and I’d think it false. It is obvious that there are differences in opportunity to acquire knowledge which would then lead to differences in IQ scores. I will argue that Jensen’s default hypothesis is false due to this very fact.

In fact, there is no good reason to accept Jensen’s default hypothesis and the assumptions that come with it. Of course different cultural groups are exposed to different kinds of knowledge, so this—and not genes—would explain why different groups score differently on IQ tests (tests of knowledge, even so-called culture-fair tests are biased; Richardson, 2002). I will argue that we need to reject Jensen’s default hypothesis on these grounds, because it is clear that groups aren’t exposed to the same kinds of knowledge, and so, Jensen’s assumption is false.

Jensen’s default hypothesis is false due to the nature of knowledge acquisition

Jensen (1998: 444) (cf Rushton and Jensen, 2005: 335) claimed that what he called the “default hypothesis” should be the null that needs to be disproved. He also claimed that individual and group differences are “composed of the same stuff“, in that they are “controlled by differences in allele frequencies” and that these differences in allele frequencies also exist for all “heritable” characters, and that we would find such differences within populations too. So if the default hypothesis is true, then it would suggest that differences in IQ between blacks and whites are primarily attributed to the same genetic and environmental influences that account for individual differences within each group. So this implies that genetic and environmental variances that contribute to IQ are therefore the same for blacks and whites, which supposedly supports the idea that group differences are a reflection of individual differences within each group.

But if the default hypothesis were false, then it would challenge the assumption that genetic and environmental influences in IQ between blacks and whites are proportionally the same as seen in each group. Thus, this allows us to talk about other causes of variance in IQ between blacks and whites—factors other than what is accounted for by the default hypothesis—like socioeconomic, cultural, and historical influences that play a more substantial role in explaining IQ differences between blacks and whites.

Fagan and Holland (2002) explain their study:

In the present study, we ensured that Blacks and Whites were given equal opportunity to learn the meanings of relatively novel words and we conducted tests to determine how much knowledge had been acquired. If, as Jensen suggests, the differences in IQ between Blacks and Whites are due to differences in intellectual ability per se, then knowledge for word meanings learned under exactly the same conditions should differ between Blacks and Whites. In contrast to Jensen, we assume that an IQ score depends on information provided to the learner as well as on intellectual ability. Thus, if differences in IQ between Blacks and Whites are due to unequal opportunity for exposure to information, rather than to differences in intellectual ability, no differences in knowledge should obtain between Blacks and Whites given equal opportunity to learn new information. Moreover, if equal training produces equal knowledge across racial groups, than the search for racial differences in IQ should not be aimed at the genetic bases of IQ but at differences in the information to which people from different racial groups have been exposed.

There are reasons to think that Jensen’s default hypothesis is false. For instance, since IQ tests are culture-bound—that is, culturally biased—then they are biased against a group so they therefore are biased for a group. Thus, this introduces a confounding factor which challenges the assumption of equal genetic and environmental influences between blacks and whites. And since we know that cultural differences in the acquisition of information and knowledge vary by race, then what explains the black-white IQ gap is exposure to information (Fagan and Holland, 2002, 2007).

The Default Hypothesis of Jensen (1998) assumes that differences in IQ between races are the result of the same environmental and genetic factors, in the same ratio, that underlie individual differences in intelligence test performance among the members of each racial group. If Jensen is correct, higher and lower IQ individuals within each racial group in the present series of experiments should differ in the same manner as had the African-Americans and the Whites. That is, in our initial experiment, individuals within a racial group who differed in word knowledge should not differ in recognition memory. In the second, third, and fourth experiments individuals within a racial group who differed in knowledge based on specific information should not differ in knowledge based on general information. The present results are not consistent with the default hypothesis.(Fagan and Holland, 2007: 326)

Historical and systematic inequalities could also lead to differences in knowledge acquisition. The existence of cultural biases in educational systems and materials can create disparities in knowledge acquisition. Thus, if IQ tests—which reflect this bias—are culture-bound, it also questions the assumption that the same genetic and environmental factors account for IQ differences between blacks and whites. The default hypothesis assumes that genetic and environmental influences are essentially the same for all groups. But SES/class differences significantly affect knowledge acquisition, so if challenges the default hypothesis.

For years I have been saying, what if all humans have the same potential but it just crystallizes differently due to differences in knowledge acquisition/exposure and motivation? There is a new study that shows that although some children appeared to learn faster than others, they merely had a head start in learning. So it seems that students have the same ability to learn and that so-called “high achievers” had a head start in learning (Koedinger et al, 2023). They found that students vary significantly in their initial knowledge. So although the students had different starting points (which showed the illusion of “natural” talents), they had more of a knowledge base but all of the students had a similar rate of learning. They also state that “Recent research providing human tutoring to increase student motivation to engage in difficult deliberate practice opportunities suggests promise in reducing achievement gaps by reducing opportunity gaps (63, 64).”

So we know that different experiences lead to differences in knowledge (it’s type and content), and we also know that racial groups for example have different experiences, of course, in virtue of their being different social groups. So these different experiences lead to differences in knowledge which are then reflected in the group IQ score. This, then, leads to one raising questions about the truth of Jensen’s default hypothesis described above. Thus, if individuals from different racial groups have unequal opportunities to be exposed to information, then Jensen’s default hypothesis is questionable (and I’d say it’s false).

Intelligence/knowledge crystalization is a dynamic process shaped by extensive practice and consistent learning opportunities. So the journey towards expertise involves iterative refinement with each practice opportunity contribute to the crystallization of knowledge. So if intelligence/knowledge crystallizes through extensive practice, and if students don’t show substantial differences in their rates of learning, then it follows that the crystalization of intelligence/knowledge is more reliant on the frequency and quality of learning opportunities than on inherent differences in individual learning rates. It’s clear that my position enjoys some substantial support. “It’s completely possible that we all have the same potential but it crystallizes differently based on motivation and experience.” The Fagan and Holland papers show exactly that in the context of the black-white IQ gap, showing that Jensen’s default hypothesis is false.

I recently proposed a non-IQ-ist definition of intelligence where I said:

So a comprehensive definition of intelligence in my view—informed by Richardson and Vygotsky—is that of a socially embedded cognitive capacity—characterized by intentionality—that encompasses diverse abilities and is continually shaped by an individual’s cultural and social interactions.

So I think that IQ is the same way. It is obvious that IQ tests are culture-bound and tests of a certain kind of knowledge (middle-class knowledge). So we need to understand how social and cultural factors shape opportunities for exposure to information. And per my definition, the idea that intelligence is socially embedded aligns with the notion that varying sociocultural contexts do influence the development of knowledge and cognitive abilities. We also know that summer vacation increases educational inequality, and that IQ decreases during the summer months. This is due to the nature of IQ and achievement tests—they’re different versions of the same test. So higher class children will return to school with an advantage over lower class children. This is yet more evidence in how knowledge exposure and acquisition can affect test scores and motivation, and how such differences crystallize, even though we all have the same potential (for learning ability).

Conclusion

So intelligence is a dynamic cognitive capacity characterized by intentionality, cultural context and social interactions. It isn’t a fixed trait as IQ-ists would like you to believe but it evolves over time due to the types of knowledge one is exposed to. Knowledge acquisition occurs through repeated exposure to information and intentional learning. This, then, challenges Jensen’s default hypothesis which attributes the black-white IQ gap primarily to genetics.Since diverse experiences lead to varied knowledge, and there is a certain type of knowledge in IQ tests, individuals with a broad range of life experiences varying performance on these tests which then reflect the types of knowledge one is exposed to during the course of their lives. So knowing what we know about blacks and whites being different cultural groups, and what we know about different cultures having different knowledge bases, then we can rightly state that disparities in IQ scores between blacks and whites are suggested to be due to environmental factors.

Unequal exposure to information creates divergent knowledge bases which then influence the score on the test of knowledge (IQ test). And since we now know that despite initial differences in initial performance that students have a surprising regularity in learning rates, this suggests that once exposed to information, the rate of knowledge acquisition remains consistent across individuals which then challenges the assumption of innate disparities in learning abilities. So the sociocultural context becomes pivotal in shaping the kinds of knowledge that people are exposed to. Cultural tools environmental factors and social interactions contribute to diverse cognitive abilities and knowledge domains which then emphasize the contextual nature of not only intelligence but performance in IQ tests. So what this shows is that test scores are reflective of the kinds of experience the testee was exposed to. So disparities in test scores therefore indicate differences in learning opportunities and cultural contexts

So a conclusive rejection of Jensen’s default hypothesis asserts that the black-white IQ gap is due to exposure to different types of knowledge. Thus, what explains disparities in not only blacks and whites but between groups is unequal opportunities to exposure of information—most importantly the type of information found on IQ tests. My sociocultural theory of knowledge acquisition and crystalization offers a compelling counter to hereditarian perspectives, and asserts that diverse experiences and intentionality learning efforts contribute to cognitive development. The claim that all groups or individuals are exposed to similar types of knowledge as Jensen assumes is false. By virtue of being different groups, they are exposed to different knowledge bases. Since this is true, and IQ tests are culture-bound and tests of a certain kind of knowledge, then it follows that what explains group differences in IQ and knowledge would therefore be differences in exposure to information.