Lithic morphological variability as a proxy for Palaeolithic linguistic ability: a knapping training study exploring cultural transmission, theory of mind and language

The identification of Palaeolithic symbolic material culture has often been taken as an indication of cognitive complexity, which limits interpretations to rare, late and localised events. This thesis develops an alternative method of interpretation through an empirical and psychologically supported chain of inference which avoids these limitations. It tests a hypothesis which predicts that material culture produced by varying methods of social learning will differ in their range of relative morphological variability due to varying levels of copy error. For Palaeolithic assemblages, high levels of standardisation might only be possible with the high fidelity transmission involved in complex social learning methods which utilise theory of mind (the ability to think about thoughts). Theory of mind, in turn, is highly correlated to linguistic ability; as both these abilities are gradient, using theory of mind as a proxy for language ability means Palaeolithic communities can be attributed with not just a binary presence or absence of language, but semantic and syntactic abilities which correlate with stages of theory of mind acquisition in modern humans. This thesis presents a knapping experiment where participants replicate model handaxes in different simulated social learning environments. Results show that different levels of morphological variation in the tools they produce support that high fidelity social learning methods produce a lower range of morphological variability. Results suggest that the origins of language lie somewhere before the origins of Acheulean technology, and that teaching and grammatical language were in the behavioural repertoires of Middle Palaeolithic hominins