Hominins evolved a strong grip similar to modern human hands at least 500,000 years ago, reveals a study of ancient stone tools. The findings demonstrated that without the ability to perform highly forceful precision grips, our ancestors would not have been able to produce advanced types of stone tools like spear points. The technique involves preparing a striking area on a tool to remove specific stone flakes and shape the tool into a pre-conceived design.
This research is the first to link a stone tool production technique known as “platform preparation” to the biology of human hands, said researchers from the Britian’s University of Kent. Platform preparation is essential for making many different types of advanced prehistoric stone tool, with the earliest known occurrence observed at the 500,000-year-old site of Boxgrove in West Sussex (UK).
“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,” said lead author Alastair Key from the varsity.
For the study, detailed in the journal PeerJ, the team 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), the researchers were able to identify that platform preparation behaviours required the hand to exert significantly more pressure through the fingers when compared to all other stone tool activities studied.
The research demonstrates that the Boxgrove hominins (early humans) would have needed significantly stronger grips compared to earlier populations who did not perform this behaviour. It further suggests that highly modified and shaped stone tools, such as the handaxes, discovered at Boxgrove 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, the researchers said.