New research published in the journal PeerJ demonstrates that a technique used to produce ‘Late Acheulean’ handaxes is likely to have needed a modern human-like hand. The study, led by University of Kent archaeologist and paleoanthropologist Alastair Key, is the first to link a stone tool production technique known as ‘platform preparation’ to the biology of human hands.

Platform preparation is essential for making many different types of advanced prehistoric stone tool, with the earliest known occurrence observed at the early Middle Pleistocene Acheulean site of Boxgrove in West Sussex, the United Kingdom.

Dr. Key and his colleagues at the University of Kent, Christopher Dunmore, investigated how hands are used during the production of different types of early stone technology.

Using sensors attached to the hand of skilled flint knappers (stone tool producers), they were able to identify that platform preparation behaviors required the hand to exert significantly more pressure through the fingers when compared to all other stone tool activities studied.

The study demonstrates that Boxgrove hominins would have needed significantly stronger grips compared to earlier populations who did not perform this behavior.

It further suggests that highly modified and shaped stone tools, such as the handaxes discovered at the Boxgrove site and stone spear points found in later prehistory, may not have been possible to produce until humans evolved the ability to perform particularly forceful grips.

This discovery is particularly important because human hand bones rarely survive in the fossil record.

“Hand bones from before 300,000 years ago are rare, particularly when compared to other human fossils such as teeth, so the fact we can study the manipulative capabilities of our early ancestors from the stone tools they produced is incredibly exciting,” Dr. Key said.

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A.J.M. Key & C.J. Dunmore. 2018. Manual restrictions on Palaeolithic technological behaviours. PeerJ 6: e5399; doi: 10.7717/peerj.5399