Thermal engineering of stone increased prehistoric toolmaking skill

Intentional heat treating of toolstone has been documented to have begun at least by 70 K BP; however, the advantages of such treatment have been debated for decades. There are two schools of thought with regard to its purpose. One, is that it merely reduces the force required for flake propagation. A second is that it also alters flake morphological properties. We systematically tested these hypotheses by generating flakes from cores exposed to...