Tuesday, November 29, 2011

no, I'm not an IQ guy myself

Since some have asked, in response to my recent post on IQ and race-- no, I'm not a booster of IQ. You can read far smarter and more qualified people than I describing why a measure like IQ (or g) is deeply insufficient to approximate intelligence, or indeed why even "intelligence" as a static, comprehensive, or meaningful term is deeply problematic. (Although there are of course those who will insist that these perspectives are merely the product of well-intentioned sentimentality.)

Additionally, "race" and "black" have never been defined to my satisfaction in these discussions. Again, this is the kind of stance that is commonly dismissed as politically correct or romantic, but I find it simply a sensible consideration of the facts. When we're talking about ancestry and heredity we're talking about complex genealogical lines that are particularly tangled when you're talking about black Americans. Using terms like "of African ancestry" is deeply problematic when talking about black Americans, who represent a totally unique group and who have a genetic heritage loaded with the influence of other groups such as white Americans and Native Americans. It seems to me, from a common sense (read: inexpert) position, that "black" can't mean much if it includes both a first-generation Somalian who now lives in Los Angeles and can trace his lineage to the same town going back hundreds of years, and also someone whose family in Cleveland came by way of Alabama via Haiti via being captured as a slave from what is now Liberia, and whose lineage includes a Greek grandfather and a Cherokee great-grandmother and the slaveholders who raped their way into his background. I'm willing to be educated on why the term is still useful despite this lack of common background, but I keep not hearing that argument.

I engage on this issue using those terms and those assumptions because I want to critique the arguments that flow from their assumptions. And even accepting their assumptions that intelligence is one quantity that can be distilled down to individual numerical scores, and that broad designations of race and ethnicity are meaningful categories for making informed assumptions, their arguments strike me as a comprehensive failure. Again, show me the actual mechanism at work here. Point to the genes, the chromosomes, the alleles, demonstrate how those affect gestation, and prove that they lead to the phenotypical outcomes of lower IQ.

I'll show my cards and say that I don't think that will happen, because I don't believe intelligence, whatever that means, is like having lobed ears or blue eyes. Even if it were, I don't think it can be boiled down to a measure like g. But even if I did, I'd need to see the mechanism. Call me a stickler.


FredR said...

"Point to the genes, the chromosomes, the alleles, demonstrate how those affect gestation, and prove that they lead to the phenotypical outcomes of lower IQ."

Wasn't Bruce Lahn working on this until, for mysterious reasons, he stopped?


sweet tooth said...

Ingold poses a simple question every scientist hung up on the circular logic of neo-Darwinism ought to ask: ‘where is the genotype?' ‘[I]f genes are to be understood, as the theory requires, as the carriers of a formal design specification, shaped up through natural selection, from one locus of development to another, then there must be some systematic correspondance between the elements of this specification and the actual DNA of the genome that is independent of any developmental process.’ Ingold notes, damningly, that ‘such a correspondance has been generally assumed, but never demonstrated.’ After noting that DNA ‘never exists on its own, except when artificially isolated in the laboratory,’ that DNA ‘exists within cells, which are the part of organisms, themselves situated within wider environments,’ and that ‘the remarkably inert molecules’ of DNA ‘do not, unaided, make copies of themselves or construct proteins, let alone build entire organisms,’ Ingold concludes that it must therefore be the case that ‘the DNA is not an agent but a reactant, and the particular reactions it sets in train depend upon the total organismal context in which it is situated.’


'What happens in practice…is that biologists seek to redescribe the observed phenotypic characteristics of organisms as the outputs of a formal system of epigenetic rules. These are then ‘read in’ to the genome, so that development can be seen as the ‘reading off’ of a programme or specification that is already there, and that is imported with the genome into the site of inauguration of a new life-cycle. In short, as an account of the evolution of form, Darwinian theory rests on a simple circularity. That is one reason, of course, why it has proved so hard to refute.
At root, the issue comes down to one about copying. The orthodox account has it that the formal design features of the incipient organism are copied along with the DNA, in advance of its interaction with the environment, so that they can then ‘interact’ with the environment to produce the organism. I would argue to the contrary…that copying is itself a process that goes on within the context of organism-environment interaction. In other words, the ‘missing link’ between the genome and the formal characteristics of the organism is none other than the developmental process itself. There is, then, no design for the organism, no genotype – except, of course, as this might be constructed by the biologist. Organic form, in short, is generated, not expressed, in development, and arises as an emergent property of the total system of relations set up by virtue of the presence of the organism in its environment.'

Interested readers are directed to Chapters Twenty-one and Twenty-two of Ingold’s seminal The Perception of the Environment. I cannot resist quoting the delicious skirmish that concludes the former.

'Nothing better illustrates the transferral, onto the organism, of the principles of the observer’s external relation to it, than the fate of the concept of biology itself. Referring initially to the procedures involved in the scientific study of organic forms, ‘biology’ has come to be seen as a framework of rational principles – literally a bio-logos – supposedly residing in the organisms themselves, and orchestrating their construction. For any particular organism, its bio-logos is, of course, its genotype. Herein, then, lies the explanation for the identification…of ‘biology’ with genetics. In the final analysis, this identification betrays a logocentrism that biology shares with the entire enterprise of Western natural science: the assumption that the manifest phenomena of the physical world are underwritten by the work of reason. But the reason that science sees at work there is its own, reflected in the mirror of nature.'

J. Otto Pohl said...

Well racial categories are arbitrary. They don't have any real biological meaning. What they do have is legal and social meanings. Black in the US has traditionally meant anybody with any Black ancestry. So yes it is a very broad category in terms of the exact composition of this ancestry. For most purposes it is meaningless. It really is only meaningful for how the White majority has historically treated people with phenotypes associated with Africa. There you see this diverse group treated rather uniformly badly.

Fake Herzog said...

Mr. Pohl (and Freddie),

Actually, racial categories are not arbitrary and exist as biological realities as explained in this wonderful paper by Neven Sesardic:


Anonymous said...

"Again, show me the actual mechanism at work here. Point to the genes, the chromosomes, the alleles, demonstrate how those affect gestation, and prove that they lead to the phenotypical outcomes of lower IQ."

You could say the same for just about any common disease!

It's a good habit to criticize these eugenicist arguments when they come into vogue periodically, but you can do so without muddying the scientific waters. The fact is, we can measure the heritability of IQ just as if it were any other quantitative trait (and heritability analysis has many tricks in place to account for shared environment, dominance effects, age of onset, etc). Likewise, we've seen both a diversity in heritability and in prevalence of complex phenotypes in different populations; so it's not unreasonable to assume the same would be true of IQ. That and a few more putative causal variants is about how far we've come to "proving" phenotypic outcomes in common disease ... and yet few would call the field a "comprehensive failure". You seemed to acknowledge all of this in the previous post and then lose the point in this one.

Minnesota Derek said...

It's totally unnecessary to understand all the genes that affect intelligence, the mechanism of these genes, and how they are distributed in different populations just to solve the Race/IQ problem. You only have to gather a sample of African Americans, assess what percent of each person's genome is European, and see if the fraction of white admixture is positively correlated with their IQs. This study could be begun tomorrow if there were scientists with the will and funding to do it.

Take a similar case for example: there's been a long running dispute among a small number of people as to whether the extremely short stature of central African pygmies (sometimes the average male is five feet tall or less) is attributable to genetics or poor nutrition. A few months back some anthropologists, using a sample of 213 pygmies, normal Africans, and mixes of the two found that: "Overall, we show that a Pygmy individual exhibiting a high level of genetic admixture with the neighboring Non-Pygmies is likely to be taller." GNXP has a good writeup of the study here: http://blogs.discovermagazine.com/gnxp/2011/05/the-pygmies-are-short-because-nature-made-them-so/

An earlier 2003 study used the same technique on African Americans and discovered increased African ancestry in AAs was positively associated with BMI http://www.nature.com/oby/journal/v11/n7/abs/oby2003124a.html

For a decade now geneticists have had the tools at their disposal to once and for all solve this heavily debated issue and yet strangely, they seem to place a much higher priority on solving the age-old question of where Central African Pygmies come from. It is not a mystery why.

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The2GirlsTeachSex said...

they say that my IQ might be kinda high, I say no :)