Biocultural evolution and human language diversity

The turn of the century witnessed key developments in biological sciences with profound implications both for biological theory and for the sciences of language. The decoding of the human genome showed that humans share with their closest living relatives, chimpanzees and bonobos, between 95% and 98% of their genes, depending on the methodology for establishing similarity. This finding threw doubt on the plausibility of the claim that the human language capacity is a consequence of a species-unique, genetically determined neurobiological innovation. Around the same time, it was shown that cultural variation is not unique to the human species; this was initially demonstrated with reference to chimpanzees, but it has since been shown that cultural variation and cultural transmission occurs in a variety of mammalian and avian species. In theoretical biology, the ‘Central Dogma’ of Neo-Darwinism was challenged by the (re-)emergence of epigenetic and ecologically based niche construction approaches. These developments have led to an increasing acceptance of the Extended Evolutionary Synthesis originally called for by C.H. Waddington, that goes beyond, and in some crucial respects contradicts, the Neo-Darwinian modern synthesis of the mid-twentieth century. Together, these developments of recent decades compel the recognition that biology and culture cannot be seen, as they largely were in the last century, as competing ‘causes’ of human cognition and language. This recasting of evolutionary theory cannot fail to impact the foundations of biolinguistics. A 21st century biolinguistics needs to accommodate contemporary findings in biology and related disciplines through the elaboration of a biocultural language science that is fundamentally interdisciplinary, situated in contemporary accounts of human evolution, and recognizes the biocultural foundations of cultural and linguistic diversity.