Early humans optimised stone tool use at Tanzania’s Olduvai Gorge

Early Stone Age populations living up to 1.8 million years ago made complex decisions in selecting different types of stone to optimise a variety of cutting tools, according to a new study by UCL, University of Kent and the Centre for Human and Social Sciences, Spain. The study, published in the Journal of Royal Society Interface , offers new insight into the complexity of stone tool use, design and production. The researchers suggest that the hominins selected raw materials based on their sharpness and durability while also factoring in how long a tool was intended to be used for, their relative functional performance and the distance hominins had to travel to raw material sources. The research is based on evidence from mechanical testing of the raw materials and artefacts found at Olduvai Gorge in Tanzania, one of the world's most important sites for human origins research. Dr Tomos Proffitt (UCL Archaeology), co-author on the study, said: "The decision processes underlying raw material selection behaviours represents a major element of Palaeolithic research, and is often vital to interpreting the behaviour and cognitive capabilities of early hominins." Lead author, Dr Alastair Key (University of Kent), said: 'Why Olduvai populations preferentially chose one raw material over another has puzzled archaeologists for more than 60 years. This has been made all the more intriguing given that some stone types, including lavas and quartzite, were always available. "What we've been able to demonstrate is that our ancestors were making quite complex decisions about which raw materials to use, and were doing so in a way that produced tools optimised for specific circumstances.