Did chimpanzee-like nut-cracking act as a direct precursor to Pliocene stone knapping? A techno-evolutionary critique and preliminary experimental programme

<p>Stone tools are regularly utilised by certain populations of West African chimpanzees in order to crack open hard-shelled nuts. Primatological, and more recently archaeological, observations have shown that chimpanzee percussive technology can result in the detachment of lithic by-products. It has been proposed that these inadvertent stone detachments often share affinities to those recovered from the earliest (Mode 1) archaeological sites in East Africa.</p> <p>Based on these observations, a theory linking the two activities has been proposed, with nut-cracking being a direct precursor to deliberate stone knapping. Specifically, it has been speculated that once Pliocene hominids recognised the functionality of accidentally-produced stone flakes, the production of lithic technology transferred from unintentional to intentional; as early hominins picked up nut-cracking anvils and began striking them directly, thus turning a (passive) anvil into an (active) core. As part of this hypothesis, it is argued that skill was transferred from one activity to the other, with little cognitive or physiological difference between the two stone technologies.</p> <p>The research reported here provides a critique of this theory, highlighting that a simple transfer of skills, from nut-cracking to stone knapping, would have been unlikely to create comparable stone tools as those seen at Gona, Ethiopia, 2.6 million years ago. Supported by preliminary experimental data, and chimpanzee behavioural data, it is suggested that nut-cracking rarely provides the functional stone flakes that would have been crucial for the uptake of stone tool-making, and even if there is a link between the two activities then significant cognitive and physiological advances would have been necessary for nut-cracking to have stimulated the innovation of stone knapping.</p> <p>Produced as MSc dissertation project, 2009.