The IQ Conundrum

Cato Unbound has a set of essays about the issue of general intelligence, its measurement, the Flynn Effect, and racial inequalities. I don’t have any commentary to add. I just wanted to post some quotes from two of the essays, both by Eric Turkheimer. I appreciate intelligent exchanges such as this, and I hope it raises the level of public debate.

Race and IQ
By Eric Turkheimer

“But the intuitive view turns out to be incoherent on more than superficial examination. A point of view that is sometimes called developmentalism points out that absolutely no aspect of biology or genetics comes into being automatically without rich interaction with the environment. Ducks raised in the complete absence of auditory input from other ducks don’t quack, and in general organisms raised in the absence of environmental inputs don’t do anything at all. So the difference between learning to play the oboe and learning to walk is not that the former requires environmental input while the other does not, being in principle innate. They both emerge from a complex interplay of genetics and environment, and thinking of walking as innate is a distraction from the real scientific question of how the extraordinarily complex process actually comes about. Once you start to think this way, it gets difficult to say that any difference between two organisms is innate. The contention about Africans and IQ has to be that their genetic makeup is such that they will be lower than other races in IQ not only in the current environment, but in all imaginable alternative environments, and how could we possibly know that? [ . . . ]

“If the question of African IQ is a matter of empirical science, exactly what piece of evidence are we waiting for? What would finally convince the racialists that they are wrong? Nothing, it seems to me, except the arrival of the day when the IQ gap disappears, and that is going to take a while. The history of Africans in the modern West is roughly as follows: Millennia of minding their own business in Africa, followed by 200 years of enslavement by a foreign civilization, followed by 100 years of Jim Crow oppression, followed by fifty years of very incomplete equality and freedom. And now the scientific establishment, apparently even the progressive scientific establishment, is impatient enough with Africans’ social development that it seems reasonable to ask whether the problem is in the descendants of our former slaves’ genes. If that isn’t offensive I don’t know what is.”

The Fundamental Intuition
By Eric Turkheimer

“So let’s return to Flynn. He thinks that g used to hold together, as long as our focus was on relations among tests at a single point of time, and has only come apart once he started to examine differential changes in the components of ability over time. But the coherence of g was an illusion, founded on the false intuition that positivity of relations among ability tests was sufficient evidence of unidimensionality, In fact, pace Gottfredson, it would be possible to define separate ability domains for abstract thinking and practical knowledge within a single time point, and these traits would then correspond closely to the courses of generational change that interest Flynn. Such traits would not be the correct way to divide up ability, any more than g is. They would be a plausible solution in a domain where a certain amount of indeterminacy is part of the scientific landscape, and they would be a convenient tool for studying the Flynn effect. In the same way, g is useful for many things, especially for broad-stroke prediction of outcomes like job performance. The trick is not to get hooked on any particular way of dividing up the pie, because it is a short step from there to trying to find the Greenwich Meridian at the bottom of the North Atlantic.

“Actually, psychologists don’t look for lines of longitude in the seabed; they look for mental factors in the brain and genome. Flynn’s over-commitment to the reality of g leads him to be distressingly cavalier about how human ability might be represented neurologically or genetically. “General intelligence or g,” he says, “has something to do with brain quality, and good genes have a lot to do with having an above average brain.” That sounds safe enough, but wait a minute: How do we know a quality brain or a good gene when we see one? And presumably not only general intelligence but abstract reasoning ability has something to do with the brain, the environmental Flynn effect notwithstanding. When we start looking for human intelligence in the brain and the genes, what exactly should we look for? General intelligence? Specific abilities? Morality? Which way do those lines really run again?

“There is nothing wrong with studying the neurology or genetics of differences in ability, but these investigations will proceed on their own neurological and genetic terms, and we should not look to them for biological vindication of the psychological expediencies that help us tame the nearly overwhelming complexity of human behavior. Literal-mindedness about the details of psychological statistics may seem harmless when the discussion is just about what goes with what and when, but history has shown us only too clearly what can happen when simplistic views of human ability make poorly informed contact with biology and genetics. I am by training a behavioral geneticist, and as such I am too well-acquainted with the ugly places oversimplified thinking about human ability and genetics can lead to let the phrase “good genes” pass without a shiver. It is best to be careful from the beginning.”