Early Stone Age populations living between 1.8 - 1.2 million years ago engineered their stone tools in complex ways to make optimised cutting tools, according to a new study by University of Kent and UCL.
The research, published in the Journal of Royal Society Interface, shows that Palaeolithic hominins selected different raw materials for different stone tools based on how sharp, durable and efficient those materials were. They made these decisions in conjunction with information about the length of time the tools would be used for and the force with which they could be applied. This reveals previously unseen complexity in the design and production of stone tools during this period.
Alastair Key et al, Raw material optimization and stone tool engineering in the Early Stone Age of Olduvai Gorge (Tanzania), Journal of The Royal Society Interface (2020).
For more than 1.8 million years hominins at Olduvai Gorge were faced with a choice: whether to use lavas, quartzite or chert to produce stone tools. All are available locally and all are suitable for stone tool production. Using controlled cutting tests and fracture mechanics theory we examine raw material selection decisions throughout Olduvai's Early Stone Age. We quantify the force, work and material deformation required by each stone type when cutting, before using these data to compare edge sharpness and durability. Significant differences are identified, confirming performance to depend on raw material choice. When combined with artefact data, we demonstrate that Early Stone Age hominins optimized raw material choices based on functional performance characteristics. Doing so flexibly: choosing raw materials dependent on their sharpness and durability, alongside a tool's loading potential and anticipated use-life. In this way, we demonstrate that early lithic artefacts at Olduvai Gorge were engineered to be functionally optimized cutting tools.