Peter—I think ‘hard coding’ and ‘hard wiring’ is a very misleading way to think about brain evolution and development; it’s based way too much on the hardware/software distinction in computer science, and on 1970s/1980s cognitive science models inspired by computer science.
Apparently it’s common in some AI alignment circles to view the limbic system as ‘hard wired’, and the neocortex as randomly initialized? Interesting if true. But I haven’t met any behavior geneticists, neuroscientists, evolutionary psychologists, or developmental psychologists who would advocate for that view, and I don’t know where that view originated.
Anyway, I cited some work by the Human Connectome Project, the Allen Human Brain Atlas, and other research programs that analyze gene expression patterns in neocortex—which seem highly complex, nuanced, evolved, adaptive, and very far from ‘randomly initialized’.
The cortex/cerebellum are definitely randomly initialized at birth in terms of most synaptic connectivity[1]. The evidence for this from neuroscience is enormous, overwhelming, and by virtue of being closer to physics—trumps the weak contradictory evidence from all other softer fields (behavior genetics, dev psych, and especially especially evo psych). See this 2015 post which shows how the ev psych evolved modularity hypothesis was rather decisively disproven, and the evidence has only grown stronger since.
Peter—I think ‘hard coding’ and ‘hard wiring’ is a very misleading way to think about brain evolution and development; it’s based way too much on the hardware/software distinction in computer science, and on 1970s/1980s cognitive science models inspired by computer science.
Apparently it’s common in some AI alignment circles to view the limbic system as ‘hard wired’, and the neocortex as randomly initialized? Interesting if true. But I haven’t met any behavior geneticists, neuroscientists, evolutionary psychologists, or developmental psychologists who would advocate for that view, and I don’t know where that view originated.
Anyway, I cited some work by the Human Connectome Project, the Allen Human Brain Atlas, and other research programs that analyze gene expression patterns in neocortex—which seem highly complex, nuanced, evolved, adaptive, and very far from ‘randomly initialized’.
The cortex/cerebellum are definitely randomly initialized at birth in terms of most synaptic connectivity[1]. The evidence for this from neuroscience is enormous, overwhelming, and by virtue of being closer to physics—trumps the weak contradictory evidence from all other softer fields (behavior genetics, dev psych, and especially especially evo psych). See this 2015 post which shows how the ev psych evolved modularity hypothesis was rather decisively disproven, and the evidence has only grown stronger since.
That does not mean some low frequency components of the wiring distribution are not genetically predetermined—obviously they must be.