Over at Babel’s Dawn, Edmund Blair Bolles has written several blog posts about the recent Evolang 2010 conference. They’re all worth reading, just to get a gist of the varying approaches taken to language evolution, with Bolles singling out talks by Morten Christiansen and Terrence Deacon as being particular highlights. Not too surprisingly, Deacon is discussing his latest idea (which I mentioned here) about relaxed selection. In Bolles’ own words:
The strength of Deacon’s presentation was that it described a mechanism for the brain changes that support language. The old view that language functions are confined to a few regions like Broca’s area and Wernicke’s area, or even the left hemisphere can no longer stand. Language processing involves complex coordination between multiple systems. But the modern human brain is a relatively recent acquisition. How did all that complexity evolve and become coordinated?
Deacon proposes a three-phase scenario:
- Standard primate brain in which midbrain areas (older parts of the brain) control vocal emotional communications.
- A duplication of a section of the genome leads to “relaxed selection” and extensive cross talk between many cerebral cortical systems (newer parts of the brain).
- “Unmasked selection” fixes new functional coordination and drives the brain’s anatomical reorganization.