apeiron
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bohm2 said:What science? I thought there is very little science in this area.
Why do you think that? There are journals, conferences, turf battles over whether you belong to paleolinguistics, biolinguistics or historical linguistics. Every semblance of an active academic domain

If his papers and that of people like Ian Tattersall, Hauser, etc. aren't convincing then it's unlikely that a non-expert like myself can do justice to their arguments but two very good papers giving these arguments are the following:
OK, what is it that Tattersall is claiming here in your view? I'm not sure where the significant dispute might be?
Apparently the major biological reorganization at the origin of Homo sapiens involved some neural innovation that “exapted” the already highly evolved human brain for symbolic thought. This potential then had to be “discovered” culturally, plausibly through the invention of language. Emergence rather than natural selection is thus implicated in the origin of human symbolic consciousness, a chance coincidence of acquisitions having given rise to an entirely new and unanticipated level of complexity. This observation may undermine claims for “adaptedness” in modern human behaviors.
So as I argue, the brain is exapted for grammar/syntax. And then this possibility had to be "discovered" culturally.
Tattersall's gloss is in error I would say for not treating cultural evolution as an actual form of evolutionary change (he calls this second stage emergence rather than evolution).
But really, he is not addressing the points that I was raising. He does not deal with the vocal tract (though elsewhere he has said he is more swayed by the evidence that an articulate tract arose only in sapiens - something that is quite possibly true, indeed what I would prefer to believe, and doesn't change anything here except the timings).
And so far as "major brain reorganisation" goes, Tattersall is not presenting any evidence of such.
He says...
What exactly this change was, is beyond my expertise to speculate, although numerous suggestions have been made: one intriguing suggestion is that a neural system linking the basal ganglia and other subcortical structures with the cortex, and initially adapted for motor control,
was coopted to cognitive functions (Lieberman, 2006, 2007); another possibility is of a mutation affecting working memory or phonological storage capacity in the prefrontal cortex (Coolidge and Wynn, 2005).
He then goes on to say that this change was like the keystone of an arch - a small but significant change. So not in fact anything major in morphology, just retrospectively major in consequence.
At this point, it would be worth turning to a better authority like Lieberman - the original vocal tract theorist! Whose "intriguing suggestion" is precisely that the critical shift was from a low-level autonomic control over the vocal tract to a high-level one, setting up the ability to actually plan complex and novel vocalisations.
Vocalisation became more complex because of considerable change to the vocal tract. And because of the fine-tuning of top-down neural connectivity that created more "oversight" of the motor control of that tract.
It does pay to understand brain evolution in some detail here. The top-down connections already existed. So you could say the brain was exapted - but then it has connections in every direction so it is exapted to do just about anything on this score. All that had to actually happen was an adjustment of ratios. More widespread top-downness, more plasticity of motor control.
That is not to say a whole lot of other fine-grain twiddling of neurodevelopmental settings were not going on. Rather than a single hopeful monster genetic change, you would expect many millenia of fine-tuning that continued even for the next 40k years after symbolic speech definitely existed.
So did you see something critical in the Tattersall paper that I've missed? It's certainly not an argument against the possible importance of the vocal tract as a new constraint on expressive communication, or the likely fine-grain and cumulative nature of any related "brain reorganisation", or the need for the later cultural evolution of language itself, as far as I can see.