With approximately half of variance in cognitive task performance having non-g sources of variance, we believe that other traits may be important in explaining cognitive performance of both non-Western and Western groups.

Although we believe that this study establishes the presence of g in data from these non-Western cultures, this study says nothing about the relative level of general cognitive ability in various societies, nor can it be used to make cross-cultural comparisons. For this purpose, one must establish measurement invariance of a test across different cultural groups (e.g., Holding et al., 2018) to ensure that test items and tasks function in a similar way for each group.

This is because most authors usually did not report a plausible theoretical model for the structure of their observed variables, and there was often insufficient information for us to create our own plausible non-g models that could be compared with a theory of the existence of Spearman’s g in the data

Two peer reviewers raised the possibility that developmental differences across age groups could be a confounding variable because a g factor may be weaker in children than adults.

some of these data sets were collected by individuals who are skeptical of the existence or primacy of g in general or in non-Western cultures (e.g., Hashmi et al., 2010; Hashmi, Tirmizi, Shah, & Khan, 2011; O’Donnell et al., 2012; Pitchford & Outhwaite, 2016; Stemler et al., 2009; Sternberg et al., 2001, 2002). One would think that these investigators would be most likely to include variables in their data sets that would form an additional factor. Yet, with only three ambiguous exceptions (Grigorenko et al., 2006; Gurven et al., 2017), these researchers’ data still produced g.

the strongest first factor accounted for 86.3% of observed variable variance

The weakest first factor accounted for 18.3% of variance

The mean sample size of the remaining data sets was 539.6 (SD = 1,574.5). The large standard deviation in relationship to the mean is indicative of the noticeably positively skewed distribution of sample sizes, a finding supported by the much smaller median of 170 and skewness value of 6.297. There were 16,559 females (33.1%), 25,431 males (48.6%), and 10,350 individuals whose gender was unreported (19.8%). The majority of samples—62 of 97 samples (63.9%)—consisted entirely or predominantly of individuals below 18. Most of the remaining samples contained entirely or predominantly adults (32 data sets, 33.0%), and the remaining 3 datasets (3.1%) had an unknown age range or an unknown mix of adults and children). The samples span nearly the entire range of life span development, from age 2 to elderly individuals.

This information was not explicitly stated in either article, but the sample and community description makes it clear that the participants of these studies are the same people, though the sample sizes differ slightly (ns = 85 and 86). However, this redundancy did not produce any analysis problems because the correlation matrix in the Grigorenko et al. (2001) article was not positive definite.

This is one of the most important decisions in an EFA (Thompson, 2004; Warne & Larsen, 2014), and these decisions can make g artificially easier or harder to identify.

For the sake of transparency, we find it important to explicitly state deviations from our preregistration protocol. First, in our preregistration, we stated that we would search for (cognitive OR intelligence) AND the name of a continent or population. However, searching for a continent was not feasible in finding data sets. We also had difficulty generating a list of population groups (e.g., ethnic groups, tribal groups) that would be useful for our search procedures.

Alternatively, one could postulate that a general cognitive ability is a Western trait but not a universal trait among humans, but this would require an evolutionary model where this general ability evolved several times independently throughout the mammalian clade, including separately in the ancestors of Europeans after they migrated out of Africa and separated from other human groups. Such a model requires (a) a great deal of convergent evolution to occur across species occupying widely divergent environmental niches and (b) an incredibly rapid development of a general cognitive ability while the ancestors of Europeans were under extremely strong selection pressures that other humans did not experience (but other mammal species or their ancestors would have experienced at other times). We find the more parsimonious model of an evolutionary origin of the general cognitive ability in the early stages of mammalian development to be the more plausible one, and thus we believe that it is reasonable to expect a general cognitive ability to be a universal human trait.

Researchers studying the cognitive abilities of animals have identified a general factor in cognitive data from many mammal species

The same logic that researchers use to argue that a folk belief regarding intelligence provides evidence of the nature of intelligence could also be used to argue that widespread cultural beliefs in elves, goblins, or angels provide evidence of the existence of supernatural beings. Survey methodology regarding layman beliefs cannot substitute for collecting data on individuals’ performance on mental tasks.

Investigating cultural beliefs about intelligence may be mildly interesting from an anthropological perspective, but it sheds little light on the nature of intelligence. One undiscussed methodological problem in many studies of cultural perspectives on intelligence is the reliance on surveys of laymen to determine what people in a given culture believe about intelligence. This methodology says little about the actual nature of intelligence.

Panga Munthu test of intelligence

Berry (1986)

We believe that members of the public likely learn some inaccurate information about intelligence in their psychology courses. The good news about this implication is that reducing the public’s mistaken beliefs about intelligence will not take a massive public education campaign or public relations blitz. Instead, improving the public’s understanding about intelligence starts in psychology’s own backyard with improving the content of undergraduate courses and textbooks.

This means that it is actually easier to measure intelligence than many other psychological constructs. Indeed, some individuals trying to measure other constructs have inadvertently created intelligence tests

Lewontin’s fallacy

many psychologists simply accept an operational definition of intelligence by spelling out the procedures they use to measure it. . . . Thus, by selecting items for an intelligence test, a psychologist is saying in a direct way, “This is what I mean by intelligence.” A test that measures memory, reasoning, and verbal fluency offers a very different definition of intelligence than one that measures strength of grip, shoe size, hunting skills, or the person’s best Candy Crush mobile game score. (p. 290)

Minnesota Transracial Adoption Study

the Stanford-Binet intelligence test

The introductory psychology textbook is difficult to produce with uniform accuracy, as authors have only a limited area of expertise, yet must write chapters that discuss the entire breadth of psychology.

Mayson C. Astle

Some readers will also be surprised to find that The Bell Curve is not as controversial as its reputation would lead one to believe (and most of the book is not about race at all).

Gardner’s multiple intelligences

Most frequently this appeared in the form of a tacit acknowledgment that IQ test scores correlate with academic success, followed by a quick denial that the scores are important for anything else in life

this study highlights the mismatch between scholarly consensus on intelligence and the beliefs of the general public

In recent years, the evidence that genes are at least a partial influence of every human behavior and psychological trait has mounted so quickly that the early 21st century may be the dawn of a behavioral genetics revolution in psychology. Such a revolution may be as important—or more important—for psychology than the cognitive revolution was in the mid-20th century.

Judged solely by the number of factually inaccurate statements, the textbooks we examined were mostly accurate.

We found that 79.3% of textbooks contained inaccurate statements and 79.3% had logical fallacies in their sections about intelligence.

Neisser et al.’s (1996) article is the official report of an APA committee to produce a summary of intelligence research.

Gottfredson’s (1997a) mainstream statement on intelligence

Warne, R. T., Astle, M. C., & Hill, J. C. (2018). What do undergraduates learn about human intelligence? An analysis of introductory psychology textbooks. Archives of Scientific Psychology, 6(1), 32-50. http://dx.doi.org/10.1037/arc0000038

What Do Undergraduates Learn About Human Intelligence? An Analysis of Introductory Psychology Textbooks

ABSTRACT

Figure 3.