In the comments section of the recent post on the evolution of language Michael Farris states:
My own working theory is that language evolved mostly visuo-gesturally (as in natural sign languages) perhaps with simultaneous vocalizations and the vocalizations took over as the hands became needed for more and more everyday tasks.
This theory is of course not provable….
I’ve stumbled upon the “gesture => vocalization” theory before. I find it interesting that Michael thinks that this theory is not “provable,” for if the gesture => vocalization hypothesis is correct it seems likely that their will be a neurological footprint in the hardware of the brain that we could detect.
The reason I have some hope that these hypotheses might be testable in some sense is that similar ideas have been bounced around in the simpler field of the study of numeracy. In The Number Sense: How the Mind Creates Mathematics, Stanislas Dehaene tells of how some cognitive scientists suggested mental counting was an abstraction of the ticking off of fingers. Years later neuroscientists discovered that some individuals who had suffered brain damage no longer had the ability to manipulate their fingers also lost the ability to count!
The moral of the story is that hypotheses might seem pie-in-the-sky when one is viewing the situation from within one discipline, but future synthesis of knowledge with other fields might change that perception in unpredictable ways. While evolutionary anthropologists theorize about language in the context of ultimate ends, and cognitive scientists posit mental models and paradigms that explain the proximate phenomena, neuroscientists will map and explore the very physical structure of the brain itself, where both evolution and modular concepts will be tested and explicated.
Here is a review of The Number Sense from a few years back. If you liked The Language Instinct, it will be a good addition to your library.
Addendum: To my mind, all language theories must grapple with FOXP2, this locus is implicated in vocalization in birds as well, and the fact that it has mutated considerably in humans in comparison to how conserved it is in other mammal lineages is very suspicious.
Posted by razib at 01:17 PM