Saturday, August 11, 2018

The Plastic Brain


I got kind of legitimately excited by this story from Northeastern University, the home of neuroscientist Lisa Feldman Barrett, who has come up with what sounds like an extremely well-supported hypothesis of a kind I've been waiting for for a very long time, for how the brain might go about organizing itself between birth and toddlerhood, with the necessary help of the people the child interacts with, like, I would say, a natural-selection system inside an ecosystem, constantly nourishing and reinforcing the adaptive neuronal connections and allowing the non-adaptive ones to die, in the general way described by the late Gerald Edelman in the 1980s and 1990s (here's a review of his most accessible book by the also late Oliver Sacks), but with a good deal more attention than Edelman gave to the importance of the child's social connections and a pretty simple biological concept of what the brain cells are looking for: Bill Ibelle, the Northeastern News science writer, explains,

At the center of this biological survival instinct is a process called allostasis: a sort of biological efficiency that must be achieved in order to survive in a gamut of stressful situations. Allostasis rewards behavior that replenishes energy and, in response to stressors, allocates those resources efficiently. During early development, infants rely on caregivers to maintain allostasis for them, by providing the proper food, temperature, and social contact.
Barrett contends that the brain’s primary function is not thinking, but anticipating the needs of the body and meeting those needs before they arrive. This is how allostasis is maintained efficiently.
And that concept of allostasis provides the cybernetic (self-regulating control-system) element for what drives it to change, the presence of a stressor. (Dumb old child-development joke about the kid who seems unable to learn to talk until suddenly one day at breakfast, when he says, "Mom, my oatmeal's cold!"—"Albert," says Mom, thunderstruck, "you can talk! How come you never said anything before?" "Up until now," says the kid, "everything was perfect.")

What I'm really excited about is the detail I can fill in for myself into this picture. Because if thinking is not the "primary function" of the brain, you have to ask where does it come from, and the answer must be that it comes from the baby's social interactions, inscribed inside the language system that the baby and her interlocutors build for her in the plasticity of the cortex—thinking (second-order cognition) comes from learning how to talk (a step Edelman was unable to take).

Another thought is about human individuality: because the human neonate is so radically incomplete and incompetent, compared to other mammals, so much formed by the social circumstances of after he's born, that the idea of human uniqueness more or less explains itself, and you can see how unimportant the genetic component really is in that. This is why the heritability of "IQ" and arguments like Charles Murray's that it's a significant fact about particular ethnically or economically defined populations are always doomed to wither:

  • The black-white IQ gap is decreasing, and is now closer to 10 points than the widely cited one standard deviation (15 points), which is the erroneous value Murray cites in the interview. Academic achievement of blacks has also improved by about one-third standard deviation in recent decades.
  • The Flynn effect, named for the political scientist and IQ researcher James Flynn, is the term many scholars use to describe the remarkable rise in IQ found in many countries over time. There has been an 18-point gain in average IQ in the US from 1948 to 2002. One way to put that into perspective is to note that the IQ gap between black and white people today is only about half the gap between America as a whole now and America as a whole in 1948. When asked about the Flynn effect by Harris, Murray responds with some hand-waving about g, a response that does not make the extraordinary fact of the Flynn effect go away.
  • Murray’s assertion that it is hard to raise the IQs of disadvantaged children leaves out the most important data point. Adoption from a poor family into a better-off one is associated with IQ gains of 12 to 18 points.
  • It is true (and unsurprising) that poor children exposed to special educational programs such as Head Start tend to regress once the program ends and environmental disadvantages reassert themselves. But the gain in social and intellectual capital from the best available early childhood education can result in an increase of one-third in the likelihood of graduating from high school, can triple the rate of college attendance, can produce a two-year advantage in reading ability of young adults, and can result in a two-thirds increase in the likelihood that they will be either gainfully employed or enrolled in higher education. The best available K-12 programs also result in substantial gains in intellectual and social capital.
  • The heritability of intelligence, although never zero, is markedly lower among American children raised in poverty. Several interpretations of this fact are possible. The one we find most persuasive is that children raised in those circumstances are unable to take full advantage of their genetic potential because they do not have access to the high-quality environments that could support it (Eric Turkheimer, Kathryn Paige Harden, and Richard E. Nisbett, writing for Vox).
Whatever it is, it isn't anything except as the social surroundings allow it to express itself, and Murray's agenda, which is to enforce the thought that certain people—certain groups of people—will never amount to anything and aren't worth the expense of fostering and cultivating, is not just evil but also incorrect.

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