Terrence Deacon’s ‘The Symbolic Species’ also argumes that Broca’s area is not as constant across individuals as the other subsections being discussed are; interpretations of Broca’s area in particular are shaky (argues Deacon) because this region is immediately adjacent to the motor controls for the equipment needed to produce speech. I have seen no studies attempting to falsify this claim, though, so unless anyone knows of actual evidence for it, we can safely shuffle this one into the realm of hypothesis for now.
In any case, Wernicke’s and Broca’s areas may not be the best examples of specialization in brain regions; I think we have a much clearer understanding (as these things go) of the sensory processing areas.
The citations in this comment are new science, so please take them with at least a cellar of salt:
There are recent studies, especially into Wernicke’s area, which seem to implicate alternate areas for linguistic processing : http://explore.georgetown.edu/news/?ID=61864&PageTemplateID=295 (they don’t cite the actual study, but I think it might be here http://www.pnas.org/content/109/8/E505.full#xref-ref-48-1); and this study (http://brain.oxfordjournals.org/content/124/1/83.full) is also interesting.
Terrence Deacon’s ‘The Symbolic Species’ also argumes that Broca’s area is not as constant across individuals as the other subsections being discussed are; interpretations of Broca’s area in particular are shaky (argues Deacon) because this region is immediately adjacent to the motor controls for the equipment needed to produce speech. I have seen no studies attempting to falsify this claim, though, so unless anyone knows of actual evidence for it, we can safely shuffle this one into the realm of hypothesis for now.
In any case, Wernicke’s and Broca’s areas may not be the best examples of specialization in brain regions; I think we have a much clearer understanding (as these things go) of the sensory processing areas.