An evolutionary context for the emergence of language

Abstract

Modern human beings process information symbolically, rearranging mental symbols according to rules to envision multiple potential realities. They also express the ideas they form using structured articulate language. No other living creature does either of these things, reflecting a qualitative cognitive gulf between modern Homo sapiens and all the other species – including their own closest living relatives – that compose the Great Tree of Life. Yet it is evident that we are descended from a non-symbolic and non-linguistic ancestor. How did this astonishing transformation occur? Scrutiny of the fossil and archaeological records suggests that the transition to symbolic reasoning happened very late in hominid history – indeed, within the tenure of anatomically recognizable Homo sapiens. It was evidently not simply a passive result of the increase in brain size that typified multiple lineages of the genus Homo over the Pleistocene. I thus propose that a brain exaptively capable of complex symbolic manipulation and Universal Grammar was acquired as a byproduct of the major developmental reorganization that gave rise to the anatomically distinctive species H. sapiens, and that this new capacity was later recruited through the action of a cultural stimulus. In evolutionary terms this would have been a rather routine happening: after all, structures must necessarily be in place before they can be used for new purposes. Given the intimate interdependence of modern cognition and language – both are intrinsically symbolic activities – the most plausible cultural trigger for symbolic thought processes was the invention of language in an African isolate of H. sapiens at (very approximately) 100,000 years ago. I enumerate several advantages that language has in this role relative to other putative stimuli such as theory of mind.