Skill and efficiency in Acheulian giant core reduction.

The beginning of the Chibanian age (0.774-0.129 Ma) is characterized by a proliferation of giant core (GC) reduction strategies across the Acheulian world, which were used to produce standardized large flake blanks for shaping large cutting tools (LCTs), such as handaxes and cleavers. Archaeological analyses of GCs have revealed that flaking strategies were often tailored to the lithological and morphological properties of boulders, while experimental research has demonstrated challenges in managing and exploiting their volumes. These insights emphasize the importance of technological skill in reducing GCs efficiently to maximize the production of standardized blanks. However, examining skill in Acheulian contexts has focused on shaping LCTs almost exclusively, while the early phases of these manufacturing chains, including raw material acquisition and blank production, have received less attention. Here, we document the role of technological skill in reducing giant quartzite cores to manufacture large flake blanks through a set of actualistic experiments that contrast expert, intermediate and novice performances. Our results show that knapping expertise is correlated with increased efficiency in exploiting core volume and creating blanks with morphometric features that are ideal for shaping LCTs. We further argue that economizing LCT shaping processes through front-loading time investment in blank production probably involved expert cognition and may have had social implications for skill development in the deep past.