Shaping the brain and humans as complex systems

I linked to this interview with Robert Sapolsky a couple of weeks ago, but after glancing through it again, I felt it worth highlighting two paragraphs (both for your interest and so I can find them again). First, on the evolutionary purpose of the teenage brain:

What I’ve been thinking might actually be going on is that adolescence is something unavoidable that emerges not because it’s so cool and adaptive, but because the adaptive thing is wait a long, long time before you have fully wired up your frontal cortex. Why might that be the case? Alright, so we’re born with our genome, the combination of your mother and father’s genes, that wind up in that first fertilized egg and that’s it. That’s your genetic legacy. Every cell in your body is destined to have that exact same genome. That turns out not to be true in all sorts of interesting ways, but what that also means is that when you’re thinking about what genes have to do with the brain behavior, by definition critically, if the frontal cortex is the last part of the brain to develop it’s the part of the brain least shaped by genes, and most sculpted by the environment and experience. And I think basically the only way you can have a species that is as complex and socially resilient and socially context dependent and all those amazing things we do, the only way you can pull that off is to have a frontal cortex whose development just bears the imprint of everything you experienced along the way—in effect, that’s been freed from whatever extent the genes are deterministic, which is not very. I think ironically what the evolution of the frontal cortex has been about is genetic evolution to free it as much as possible from the straight jacket of genes.

Second, on reductionism in neurobiology:

[R]eductionism doesn’t actually tell you a whole lot about how this stuff works. I mean reductionism is perfect for like telling you why your clock is broken. What you do is you break it down to its component parts. You find the part that’s got a tooth missing from the gear. I guess there’s not a clock on earth that works this way anymore, but your Renaissance clock. You fix the missing tooth, you put it back, you add the pieces back together and it works. The way to understand a complicated system is to understand its component parts. The way in which that steps away from the ideology is the component parts of the genes and the nerve transmitters and the hormones and the early experience. Okay, so that’s a more sophisticated version of reductionism. You got to be reductive about lots of different domains. But nonetheless, even that more multidisciplinary version of reductionism isn’t going to work because that’s not how complex systems work and humans are a complex system. You got these emergent non-linear chaotic properties. What’s that another way of saying? If you knew every individual’s genome and exactly which gene was active at which point, are you going to be able to predict who’s going to do what next? Absolutely not. If you added in knowing the levels of every hormone in their body at that point, if you added in… it doesn’t work that way. The reductionism breaks down because the reductionism breaks down in the same way that like a cloud that isn’t producing enough rain during a drought or something, the solution isn’t to study half the cloud and then get a research grant to study a quarter of the cloud and smaller, smaller pieces and finally understand the reductive basis of the non-rain and add it up together. That’s not how clouds work when they don’t rain. Humans are more like clouds than they are like clocks. We’re not reductive in that way, which is the case for any complex system.

And if you haven’t read the full interview, do it.

One comment

  1. “the adaptive thing is wait a long, long time before you have fully wired up your frontal cortex”

    Long, long time? Adolescence is a really short span of time compared with the whole lifespan of an individual, even in previous environments where the expected medium lifespan was probably much shorter.

    Childhood is longer than adolescence. At least, in normal non-hikikomori societies.

    I’m a really big fan of Ockham’s Razor. Maybe it takes “so long” just because it is difficult to wire.

    The later you evaluate human individuals in their psychometric characteristics, the most they seem to follow the genetic script, not the other way around. That’s well established.

    “by definition critically, if the frontal cortex is the last part of the brain to develop it’s the part of the brain least shaped by genes, and most sculpted by the environment and experience.”

    Genes-environment dualism, rebooted. Again and again. Put a 80 IQ child through the most enriching and demanding environment, surrounded of smart caring children and teens, leave him or her live through the most varied, experience-filled and longer adolescence possible and wait the adult genius to emerge. You know what? It won’t happen. Never ever.

    Moreover, surround a child who leans socially to the Right (according to the tests he’s or she’s been put through) with a far-Left environment. He will be socially leftist at 18. And socially rightist at 25, or 30.

    “in effect, that’s been freed from whatever extent the genes are deterministic, which is not very.”

    And that’s why I have six arms and I change my skin color depending on my mood. Because I chose so.

    Well, this text, to me, tells me a whole lot more about Robert Sapolsky and his feelings than about the brain or evolution. His response is filled with “free this”, “freed that”, “socially dependent”, “the genes are a straight jacket” (!), etc. Throughout the entire text you feel that classical typical familiar obsession with “freeing you from yourself”. American (europoid) über-individualism, delusions of absolute freedom, personal will as supreme master and old-school ambientalism. The same old same old.

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