As a central activity promoting this encephalization, language evolved to help hominids adapt better to their environment by making possible a complex level of cooperation.
Current thinking maintains that a significant number of changes occurred within homo sapiens, including changes in bone structure, stature, and vocal cords, with the most momentous being encephalization, which is significant increase in the size of the cerebral cortex.
Gould then has only to argue for a single genetic mutation involving the massive encephalization that occurred once.
For instance, there is even evidence for specific regions for problem-solving, at least for some tasks, in the parietal lobes (Iacoboni, 2000), which presumably constitutes a significant part of the general intellectual competence that Gould sees as the single product of encephalization.
Ecology and energetics of encephalization in hominid evolution, Philosophical Transactions of the Royal Society (London) Series B 334: 223-2.
Body mass and encephalization in Pleistocene Homo, Nature 387: 173-7.
Elizabeth Whitcombe looks at the implications of language for functional anatomy and suggests that language may have evolved at least in part as a consequence of changing cranial anatomy related to encephalization.
Lee returns to the use of at least some data with a discussion of how social behaviour might influence and be influenced by encephalization.
The pivotal innovation of increased brain size, or encephalization
, illustrates a concept that is a major theme of the book, that both costs and benefits must be considered when explaining adaptations.