More about Intelligence

Do genes matter? You betcha! See geneticist Gregory Cochran’s “Everything Is Different but the Same” and “Missing Heritability — Found?” (Useful Wikipedia articles for explanations of terms used by Cochran: “Genome-wide association study,” “Genetic load,” and “Allele.”) Snippets:

Another new paper finds that the GWAS hits for IQ – largely determined in Europeans – don’t work in people of African descent.

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There is an interesting new paper out on genetics and IQ. The claim is that they have found the missing heritability – in rare variants, generally different in each family.

Cochran, in typical fashion, ends the second item with a bombastic put-down of the purported dysgenic trend, about which I’ve written here.

Psychologist James Thompson seems to put stock in the dysgenic trend. See, for example, his post “The Woodley Effect“:

[W]e could say that the Flynn Effect is about adding fertilizer to the soil, whereas the Woodley Effect is about noting the genetic quality of the plants. In my last post I described the current situation thus: The Flynn Effect co-exists with the Woodley Effect. Since roughly 1870 the Flynn Effect has been stronger, at an apparent 3 points per decade. The Woodley effect is weaker, at very roughly 1 point per decade. Think of Flynn as the soil fertilizer effect and Woodley as the plant genetics effect. The fertilizer effect seems to be fading away in rich countries, while continuing in poor countries, though not as fast as one would desire. The genetic effect seems to show a persistent gradual fall in underlying ability.

But Thompson joins Cochran in his willingness to accept what the data show, namely, that there are strong linkages between race and intelligence. See, for example, “County IQs and Their Consequences” (and my related post). Thompson writes:

[I]n social interaction it is not always either possible or desirable to make intelligence estimates. More relevant is to look at technical innovation rates, patents, science publications and the like…. If there were no differences [in such] measures, then the associations between mental ability and social outcomes would be weakened, and eventually disconfirmed. However, the general link between national IQs and economic outcomes holds up pretty well….

… Smart fraction research suggests that the impact of the brightest persons in a national economy has a disproportionately positive effect on GDP. Rindermann and I have argued, following others, that the brightest 5% of every country make the greatest contribution by far, though of course many others of lower ability are required to implement the discoveries and strategies of the brightest.

Though Thompson doesn’t directly address race and intelligence in “10 Replicants in Search of Fame,” he leaves no doubt about dominance of genes over environment in the determination of traits; for example:

[A] review of the world’s literature on intelligence that included 10,000 pairs of twins showed identical twins to be significantly more similar than fraternal twins (twin correlations of about .85 and .60, respectively), with corroborating results from family and adoption studies, implying significant genetic influence….

Some traits, such as individual differences in height, yield heritability as high as 90%. Behavioural traits are less reliably measured than physical traits such as height, and error of measurement contributes to nonheritable variance….

[A] review of 23 twin studies and 12 family studies confirmed that anxiety and depression are correlated entirely for genetic reasons. In other words, the same genes affect both disorders, meaning that from a genetic perspective they are the same disorder. [I have personally witnessed this effect: TEA.]…

The heritability of intelligence increases throughout development. This is a strange and counter-intuitive finding: one would expect the effects of learning to accumulate with experience, increasing the strength of the environmental factor, but the opposite is true….

[M]easures of the environment widely used in psychological science—such as parenting, social support, and life events—can be treated as dependent measures in genetic analyses….

In sum, environments are partly genetically-influenced niches….

People to some extent make their own environments….

[F]or most behavioral dimensions and disorders, it is genetics that accounts for similarity among siblings.

In several of the snippets quoted above, Thompson is referring to a phenomenon known as genetic confounding, which is to say that genetic effects are often mistaken for environmental effects. Brian Boutwell and JC Barnes address an aspect of genetic confounding in “Is Crime Genetic? Scientists Don’t Know Because They’re Afraid to Ask.” A small sample:

The effects of genetic differences make some people more impulsive and shortsighted than others, some people more healthy or infirm than others, and, despite how uncomfortable it might be to admit, genes also make some folks more likely to break the law than others.

John Ray addresses another aspect of genetic confounding in “Blacks, Whites, Genes, and Disease,” where he comments about a recent article in the Journal of the American Medical Association:

It says things that the Left do not want to hear. But it says those things in verbose academic language that hides the point. So let me translate into plain English:

* The poor get more illness and die younger
* Blacks get more illness than whites and die younger
* Part of that difference is traceable to genetic differences between blacks and whites.
* But environmental differences — such as education — explain more than genetic differences do
* Researchers often ignore genetics for ideological reasons
* You don’t fully understand what is going on in an illness unless you know about any genetic factors that may be at work.
* Genetics research should pay more attention to blacks

Most of those things I have been saying for years — with one exception:

They find that environmental factors have greater effect than genetics. But they do that by making one huge and false assumption. They assume that education is an environmental factor. It is not. Educational success is hugely correlated with IQ, which is about two thirds genetic. High IQ people stay in the educational system for longer because they are better at it, whereas low IQ people (many of whom are blacks) just can’t do it at all. So if we treated education as a genetic factor, environmental differences would fade way as causes of disease. As Hans Eysenck once said to me in a casual comment: “It’s ALL genetic”. That’s not wholly true but it comes close

So the recommendation of the study — that we work on improving environmental factors that affect disease — is unlikely to achieve much. They are aiming their gun towards where the rabbit is not. If it were an actual rabbit, it would probably say: “What’s up Doc?”

Some problems are unfixable but knowing which problems they are can help us to avoid wasting resources on them. The black/white gap probably has no medical solution.

I return to James Thompson for a pair of less incendiary items. “The Secret in Your Eyes” points to a link between intelligence and pupil size. In “Group IQ Doesn’t Exist,” Thompson points out the fatuousness of the belief that a group is somehow more intelligent that the smartest member of the group. As Thompson puts it:

So, if you want a problem solved, don’t form a team. Find the brightest person and let [him] work on it. Placing [him] in a team will, on average, reduce [his] productivity. My advice would be: never form a team if there is one person who can sort out the problem.

Forcing the brightest person to act as a member of a team often results in the suppression of that person’s ideas by the (usually) more extroverted and therefore less-intelligent members of the team.

Added 04/05/17: James Thompson issues a challenge to IQ-deniers in “IQ Does Not Exist (Lead Poisoning Aside)“:

[T]his study shows how a neuro-toxin can have an effect on intelligence, of similar magnitude to low birth weight….

[I]f someone tells you they do not believe in intelligence reply that you wish them well, but that if they have children they should keep them well away from neuro-toxins because, among other things, they reduce social mobility.

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