Missing Heritability and Missing Malleability

Do people really have strong stereotypes about how smart and dumb people look?

An interesting phenomenon is that while the new GWAS studies of the human genome have documented some heritability of IQ, they haven’t yet come up with the very high levels of heritability for IQ seen in twin, twins raised apart, and adoption studies over the last century.

Is this because there is something radically wrong with twin and adoption studies that nobody has been able to prove? Possibly, although anti-hereditarians never seem to do much work of their own to generate new knowledge.

My attitude toward GWAS during its short lifespan has been positive but cautioning patience. In 2018, for example, I wrote:

Racimo has come up with a hypothesis somewhat similar to that of Davide Piffer’s that we can already guess the findings of the next decade or so of racial genomics research by looking at the genetic-driven traits already discovered to have been under different selection pressures among different populations and assume that we will discover more such DNA to have been selected for by the same selection pressures.

I find that theory interesting, but I’m also perfectly happy to wait out the decade or whatever it will take to find out for sure through ever more accurate huge sample size brute force genomic studies. For instance, we saw the first one million sample size study of the genetic correlates of educational attainment published in July.

The Racimo-Piffer theory might turn out to be a brilliant shortcut, or it might turn out to be mostly wrong because, for example, it could be that blacks are so different from whites genetically that studying how white genomes work doesn’t tell you much about how black genomes work. (That would be ironic.) …

Anyway, time will tell.

And in a commentary that accompanied the paper in the journal Genetics, Dr. Novembre warned that such research is “wrapped in numerous caveats” that are likely to get lost in translation.

I linked to Dr. Novembre’s commentary in my iSteve blog last May [2018].

“Great care,” his commentary concludes, “should be taken in communicating results of these studies to general audiences.”

As I blogged in response, endorsing Novembre’s caution, “This seems like a pretty reasonable way to proceed.” On the other hand, it’s important that the public keeps an eye out for explicit or tacit agreements among scientists not to investigate major questions, such as the genetics of racial differences in intelligence, for reasons of political correctness. …

We will know more about genetic racial differences and their relation to IQ and educational attainment, if any, with a higher degree of certainty soon enough, so I’m content to wait.

Besides the problem of the Missing Heritability, there's also the problem over the last six decades of the Missing Malleability. The 1964 Civil Rights Act allocated one ... million ... dollars (seriously, a really large amount of money for a social science project back then) for a study of how the racial gap in school achievement was due to discrimination, lack of school spending on blacks, and other environmental factors. It was something of a shock when the Coleman Report in 1966 reported it couldn't find much evidence for the basic assumptions of the Great Society. What seemed more important, it found, was whatever it was that students brought to school from home.

Enormous amounts of money have been spent on social programs since then, but, so far, people don't appear to be as malleable as assumed in the Blank Slate 1960s.

On the other hand, some countries, such as Japan and South Korea, seem to have climbed the IQ charts over the generations, just as 6’4” Shohei Ohtani is a lot taller than the average Japanese man in 1950. But from the Japanese and South Korean examples it’s hard to figure out the One Weird Trick for increasing IQ, since their societies tended to get better at pretty much everything (except having babies).

In the U.S., raw IQ scores rose considerably along with height over the course of the 20th Century, although Americans were always fairly tall and smart due to our favorable land to population ratio meaning that life was better for our masses than in most places in human history.

Elite American opinion tended to assume, not all that unreasonably, that blacks would quickly catch up in IQ once Jim Crow was abolished a couple of generations ago.

And indeed, blacks did seem to get better at sports over the third and perhaps fourth quarters of the 20th Century. For example, by the turn of the century, the best American male golfer and female tennis player were black.

As for IQ, though, well, everybody tended to get higher raw IQ scores, while school achievement scores tended to go up or down a little for everybody dependent upon whether conservative or progressive ideas were dominant in education. The main exception was that Asians kept scoring higher.

Now, it could turn out that heritability actually is lower than seen in twin and adoption studies for subtle unknown reasons.

But an important question about these kind of theories is whether more social welfare spending can then do much about it. So far, we haven't stumbled upon too many magic bullet social programs over the last 60 years.

For example, twin studies are based on the notion that identical twins and fraternal twins experience the same socio-economic status.

But what if, one of Scott Alexander’s commenters suggests, what really matters is how people treat you based on your looks? Sure, your wealthy parents may provide both of you with the finest nutrition and education, but what if people look at you different if you look different, and that’s what determines your IQ? So then identical twins would be treated the same while fraternal twins would be treated differently, and thus fraternal twins differ a lot more in IQ than identical twins because it’s not genes, it’s how people look at you.

That’s a pretty interesting idea, but I have to wonder how much people really have strong opinions on intelligence based on looks. I was thinking about this lately because I was trying to come up with an actor who looks extremely smart to play in a sketch for Saturday Night Live.

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