Could woodworking have influenced variation in the form of Acheulean handaxes?

The relationship between tool form and function is fundamental to hominin behaviour and evolution. Acheulean handaxes are known for their general consistency across more than a million years and three continents, albeit with some variation in size and shape. However, the influence of this variation on cutting has only rarely been studied, mostly in either butchery or generalized cutting tasks. Yet evidence indicates that handaxes were used for woodworking by at least 1.5 mya. Here, we experimentally tested whether woodworking could have exerted selective pressures on handaxe form. Additionally, these data were compared with a previous experiment that tested flakes during woodworking. For handaxes, no significant relationships were detected in woodworking efficiency. Accordingly, woodworking likely did not exert strong selective pressures on handaxe variability. However, the effectiveness shown by handaxes further demonstrates the functional flexibility of this technology, which is likely a factor contributing to their use over broad temporal, geographical and ecological spans. When comparing handaxes with flakes, only the smallest flakes were found to be significantly less efficient than handaxes. Therefore, the functional demands of woodworking were likely influencing hominin technological decisions about flake morphology, or the selection of flakes for woodworking, more than they were handaxe morphology.