This review was written for a senior-level philosophy course at The College of William & Mary in Virginia back in 2007. It was my take, at the time, on Cheney & Seyfarth’s ‘social intelligence hypothesis‘ and how it applies to language. To summarize quickly, the authors suggest that primates developed the capacity to represent information hierarchically (e.g. the complex social relationships among group members) and developed a rudimentary theory of mind (necessary for communication) largely in response to the social pressures that come from living in a larger group size. They then suggest that this hierarchical mental representation of social relationships among the group, in conjunction with a flowering theory of mind, gave rise to the language capacity in humans.
My review takes issue with this approach due to the fact that the authors too readily equate social hierarchies with syntactic ones, often implying the development of the latter out of the former. While the capacity to relate information and mental representations to each other hierarchically is an important requisite for language, it seems strange to suggest that sentence structures somehow developed out of social structures.
Of course, language evolution is not the primary interest of the book. For that, I would recommend The Symbolic Species (Deacon 1998), which does an excellent job integrating the findings of Cheney & Seyfarth into a theory of language evolution.
My views on this topic have become more refined over the past several years, especially in light of having read Deacon’s book, but my overall position is still largely the same, and this shows in my review.