From side to side: Symmetry in handaxes in the British Lower and Middle Palaeolithic

The Acheulean is defined by its iconic tool type, the handaxe, and a suite of other large cutting tools (LCTs). These tools retain information on technical and procedural practices concerned with the manufacture of these butchery tools and carcass processing knives. The Acheulean straddles the period in which more ancient hominin species (H. erectus and H. heidelbergensis) give way to archaic H. sapiens (sensu lato) amongst whom the ancestor of modern humans may be found. The roots of modern behaviour may be present in these handaxe making hominin species, and the handaxes themselves, through proxy data such as bilateral symmetry, may chart hominin cognitive evolution as researchers such as T. Wynn and F. Coolidge (2016), amongst others, have argued. But the search for the earliest consistent application of symmetry, and its persistence thereafter has been hampered by the lack of large datasets, spanning the temporal extent of the Acheulean, and analysed through a single consistent methodology.