It seems like every day something new comes out that attempts to discredit the reality of g (This paper came out in 2012.). Steven Jay Gould (in)famously wrote in The Mismeasure of Man:
The argument begins with one of the fallacies—reification, or our tendency to convert abstract concepts into entities (from the Latin res, or thing). We recognize the importance of mentality in our lives and wish to characterize it, in part so that we can make the divisions and distinctions among people that our cultural and political systems dictate. We therefore give the word “intelligence” to this wondrously complex and multifaceted set of human capabilities. (emphasis mine)
“The results disprove once and for all the idea that a single measure of intelligence, such as IQ, is enough to capture all of the differences in cognitive ability that we see between people,”
“Instead, several different circuits contribute to intelligence, each with its own unique capacity. A person may well be good in one of these areas, but they are just as likely to be bad in the other two,”
Just like The Mismeasure of Man is “the definitive refutation to the argument of The Bell Curve”, right?
In the above paper, they cite Gould twice writing:
It remains unclear, however, whether population differences in intelligence test scores are driven by heritable factors or by other correlated demographic variables such as socioeconomic status, education level, and motivation (Gould, 1981; . . .
They have been shown over numerous studies that population differences in intelligence are driven by heritable factors (Rushton and Jensen, 2005; Lynn and Vanhanen, 2006; Winick, Meyer, and Harris, 1975; Frydman and Lynn, 1988; Rushton, 2005)
More relevantly, it is questionable whether they relate to a unitary intelligence factor, as opposed to a bias in testing paradigms toward particular components of a more complex intelligence construct (Gould, 1981;
I will prove the existence of g in this article. There is also an empirical basis for the g factor.
It’s getting old now that researchers still think that they can “disprove g”, as a multitude of studies have already corroborated Spearman’s hypothesis as an empirical fact. That is, applying the scientific method, using the same hypothesis over a multitude of different studies and testing those predictions by experiment or further observation and modify the hypothesis when new information comes to light. Then, repeat the aforementioned steps until there are no discrepancies between the theory and experiment/observations.Then when consistency is obtained it then becomes a theory that provides a coherent set of premises that explain a class of events.
How many times has the Hampshire et al hypothesis been corroborated? I doubt it has been corroborated as many times as Spearman’s hypothesis has.
As I said the other day, Jensen tested Spearman’s hypothesis on 25 large independent samples, with each sample confirming Spearman’s hypothesis. Even matching blacks and whites for SES didn’t diminish the effect. Jensen then concludes that the overall chance for Spearman’s hypothesis being wrong is over 1 in a billion. Pretty high odds.
Even then, if this study were to be replicated the amount of times that Spearman’s hypothesis has, it still wouldn’t disprove g.
He (Gould) continues: “The fact that Herrnstein and Murray barely mention the factor-analytic argument forms a central indictment around The Bell Curve and is an illustration of its vacuousness.” Where, Gould asks, is the evidence that g “captures a real property in the head?
Murray states that they “barely brought up the factor-analytical argument” because it was out of date; Gould was using statistics on g that were 50 + years old. Also, a reviewer of his book for the journal Nature said that Gould’s “discussion of the theory of intelligence stops at the stage it was more than a quarter of a century ago.” Gould was using old arguments, and, as Arthur Jensen states in his response to Gould:
Of all the book’s references, a full 27 percent precede 1900. Another 44 percent fall between 1900 and 1950 (60 percent of those are before 1925); and only 29 percent are more recent than 1950.
More than half of Gould’s references in The Mismeasure of Man are outdated by more than 50 years. Clearly, he was attempting to denigrate the old studies of intelligence, i.e., phrenology, even though this recent paper in the journal Nature recently said:
The genomic regions identified include several novel loci, some of which have been associated with intracranial volume
So, we have several loci that are associated with intracranial volume; this shows that those skull studies of yesteryear weren’t crazy. Moreover, the fact that Rushton and Ankney (1996) “reviewed 32 studies correlating measures of external head size with IQ scores or with measures of educational and occupational achievement, and they found a mean r .20 for people of all ages, both sexes, and various ethnic backgrounds, including African Americans” shows that there is a correlation of .20, albeit not too high but there, with external head size and IQ. This shows that Gould’s argument on phrenology is bunk, as modern studies confirm that there is a slight correlation between head size and IQ, and therefore g.
The fact that researchers are still bringing up Gould’s arguments on g show that there really is no good argument to discount it. Basically, any and all arguments that attempt to discredit g are bunk as Spearman’s hypothesis has been empirically verified:
Conclusion: Mean group differences in scores on cognitive-loaded instruments are well documented over time and around the world. A meta-analytic test of Spearman’s hypothesis was carried out. Mean differences in intelligence between groups can be largely explained by cognitive complexity and the present study shows clearly that there is simply no support for cultural bias as an explanation of these group differences. Comparing groups, whether in the US or in Europe, produced highly similar outcomes.
Along with Jensen’s 25 large independent studies that showed that the probability that Spearman’s hypothesis is false is 1 in a billion, this proves that Spearman’s hypothesis is an empirical scientific fact.
Newman and Just, (2005) state in verbal and spatial conditions that the frontal cortex revealed greater activation for high-g in comparison to low-g, supporting the idea that g reflects functions of the frontal lobe. The “seat” of general intelligence is the prefrontal cortex (Cole, et al, 2011, Roth, 2011). This can also be verified with MRI scans that show that those who have higher g have bigger prefrontal cortexes than those with lower g.
Moreover, the fact that Colom, et al (2006) show that in their sample that neuroanatomic areas underlying the g factor could be found across the entire brain including the frontal, parietal, temporal and occipital lobes, shows that this factor is present throughout the brain and all are correlated with g and work together in concert to manifest intellectual ability.
Other researchers have also used the method of correlated vectors on functional Magnetic Resonance Imaging (fMRI), which measures brain activity by detecting changes associated with blood flow. This technique is proven useful due to the fact that cerebral blood flow and neuronal action are correlated. Lee, et al write:
In conclusion, we suggest that higher order cognitive functions, such as general intelligence, may be processed by the coordinated ability may be attributable to the functional facilitation rather than the structural peculiarity of the neural network for g. In addition, our results demonstrated that the posterior parietal regions including bilateral SPL and right IPS could be the neural correlates for superior general intelligence. These findings would be the early step toward the development of biological measures of g which leads to new perspectives for behavior interventions improving general cognitive ability.
They also used the MCV to find that the frontal and parietal lobes are associated with g. Even these studies show that g shows up throughout the brain and not in one solitary spot (though, the PFC is still the seat of intelligence), this shows yet another biological basis for g.
Hampshire, et al write:
Thus, these results provide strong evidence that human intelligence is a construct that emerges from the functioning of anatomically dissociable brain networks.
However, with the above studies confirming that the seat of intelligence is the prefrontal cortex, along with great g ability possibly be attributable to the functional facilitation rather than the structural peculiarity of the neural network for g, this shows, along with the study proving Spearman’s hypothesis, that g is a real and measurable thing. g’s seat is the prefrontal cortex, and exceptional g may possibly be attributed to the functional facilitation of the neural network for g . What all of these studies show is that all though the Hampshire paper showed how they “demonstrate that different components of intelligence have their analogs in distinct brain networks.” that a) higher order cognitive functions may be processed by the coordinated activation of widely distributed brain areas (disproving the above quote), b) the seat of g is the prefrontal cortex, c) those with more g have bigger prefrontal cortexes and therefore bigger brains since the prefrontal cortex is the ‘seat’ of intelligence and d) Spearman’s hypothesis has been corroborated numerous times by many different researchers not named Arthur Jensen.
Highfield (one of the researchers in the study) ends the article as follows:
“We already know that, from a scientific point of view, the notion of race is meaningless. Genetic differences do not map on to traditional measurements of skin colour, hair type, body proportions and skull measurements.
This is something that never ends; it always comes up no matter how many times it’s been said. People can say “race is a social construct” all they want, it doesn’t make it true as there is a biological reality to race.
Now we have shown that IQ is meaningless too,” Dr Highfield said.
When will people learn not to cite men who have smeared their legacy in an attempt to defame men who they disagreed with ideologically? Citing Steven Jay Gould in 2016 shows a bias to want to discredit g as a main factor for many things in life including SES, educational attainment, wealth attainment and so forth. The g factor is a measurable thing, with the seat of the factor being the prefrontal cortex. No amount of attempting to dispute this factor can be done, as it’s been empirically verified numerous times.