Early Stone Age people engineered stone tools in complex ways between 1.8 and 1.2 million years ago, based on evidence from Olduvai Gorge in Tanzania - one of the world's most important sites for understanding human origins. New research shows Palaeolithic hominins selected raw materials for tools based on sharpness, durability, and efficiency, according to the length of time the tools would be used and the force applied - previously unseen complexity in the design and production of stone tools during this period.
     Experimental methods more commonly used in modern engineering research reveal that Hominins preferentially selected quartzite - the sharpest but least durable stone type at Olduvai - for flake tools thought to have been used for expedient, short-lived cutting activities. Chert - highly durable and nearly as sharp as quartzite - was favoured for a variety of stone tool types due to its extended cutting performance, but was only available to hominins for a 200,000 year period. Some stone types such as including lavas and quartzite were always available.
     Previous research has demonstrated that Early Stone Age populations in Kenya selected highly durable stone types for tools, but the new study is the first to find evidence of cutting-edge sharpness being considered. The team hopes researchers at other sites will apply similar tests and techniques to help understand the behaviour of Stone Age populations.

Edited from EurekAlert! (8 January 2020), Cosmos (9 January 2020)