We can also see this when brain areas are recruited for tasks they were not specifically designed for. For instance visual processing areas can be recruiited for other tasks in the blind.
So while there is specialisation in brain tissue, rather than there being circuits designed at a low level for certain cognitive tasks, it is more that the connectivity and kinds of neurons within an area are tuned to excel at a specific class of problems.
It is softer and more diffuse organ than a "grammar gland". Rather it is a kind of soil within the mind that permits the growth of certain kinds of cognitive structures. Rather than being computer like and existing prior to the input of data, it is merely a capability expressed by the tuning of an overall system.
Chomsky's universals in this view become rather less important. It is merely the statement that brain tissue is tuned in such a way that it encourages, among other things, certain specific kinds of linguistic structure.
It's similar to noticing that the human hand is good stirring soup and then describing it as a soup stirring organ. Yes the hand has properties that allow it to be easily used as a soup stirring organ, but those same properties make it useful for some other things as well.
Hasn't there been a lot of recent work showing similar circuits between songbirds and humans that seem to have independently evolved?
If only I had one more upvote.
Chomsky says there are universal, physiologically-based manifestations which are universal across humans. That is not really demonstrates but would not be surprising any more than the universality of the human visual system (as well as individual variation).
He claims to have identified some such universals, and that they are relatively high level. THAT is a bold claim, hard both to verify or falsify. But in principle not absurd.
I don’t believe it, but I no longer mock him with the phrase “grammar gland”. There is some insight there.