Pronounced increase in biface knapping skill half a million years ago in Britain

• 3D scans of 795 handaxes used to extract variables related to knapping skill. • Comparison of skill from the first two waves of Acheulean occupation in Britain. • Highly significant differences in handaxe thinness, symmetry, and edge regularity. • There was a pronounced increase in hominin skill between MIS15 and MIS13/12. • Increased motor control may have implications for the emergence of speech. Flake scar patterning indicates Acheulean knappers were attempting to make thin, symmetrical handaxes with regular edges. In this study we quantify these elements of handaxe form and test the variation between the first two waves of Acheulean occupation in Britain. The results show a marked contrast between these groups in thinness, symmetry, and edge regularity. Handaxes from sites such as Fordwich dated to > 0.56 Ma are crude, whereas those from sites including Boxgrove dated to ∼0.48 Ma are highly refined. This contrast in biface skill outcomes seems to have been facilitated by the use of soft-hammers and platform preparation, both of which are evident at Boxgrove. Furthermore, it suggests an increase in hominin motor control around half a million years ago that may have implications for the emergence of speech.