Stone tools provide some of the best remaining evidence of behavioral change over long periods, but their cognitive and evolutionary implications remain poorly understood. Here, we contribute to a growing body of experimental research on the cognitive and perceptual-motor foundations of stone toolmaking skills by using a flake prediction paradigm to assess the relative importance of technological understanding vs. accurate action execution in Late Acheulean–style handaxe production. This experiment took place as part of a larger, longitudinal study of knapping skill acquisition, allowing us to assemble a large sample of predictions across learning stages and in a comparative sample of experts. By combining group and individual-level statistical analyses with predictive modeling, we show that understanding and predicting specific flaking outcomes in this technology is both more difficult and less important than expected from previous work. Instead, our findings reveal the critical importance of perceptual motor skills needed to manage speed-accuracy trade-offs and reliably detach the large, invasive flakes that enable bifacial edging and thinning. With practice, novices increased striking accuracy, flaking success rates, and (to an extent) handaxe quality by targeting small flakes with acute platform angles. However, only experts were able to combine percussive force and accuracy to produce results comparable with actual Late Acheulean handaxes. The relatively intense demands for accurate action execution documented in our study indicate that biomechanical properties of the upper limb, cortical and cerebellar systems for sensorimotor control, and the cognitive, communicative, and affective traits supporting deliberate practice would all have been likely targets of selection acting on Late Acheulean toolmaking aptitude.

石制工具提供了长期最佳的行为变化证据，但对它们的认知和进化影响仍然知之甚少。在这里，我们通过使用片状预测范例评估技术理解与准确的动作执行在Acheulean式手斧生产后期的相对重要性，为石材工具制造技能的认知和知觉运动基础的实验研究不断发展做出贡献。这项实验是大型的纵向学习技巧研究的一部分，它使我们能够在学习阶段和比较专家样本中收集大量的预测样本。通过将小组和个人级别的统计分析与预测建模相结合，我们表明，与以前的工作相比，了解和预测此技术中的特定剥落效果既困难又重要。取而代之的是，我们的发现揭示了感知运动技能对控制速度精度的权衡并可靠地分离大型侵入性薄片（使双面磨边和变薄）所需的至关重要。通过练习，新手可以通过瞄准具有锐平台角的小薄片来提高打击精度，剥落成功率以及（一定程度上）手斧质量。但是，只有专家才能将冲击力和精确度相结合，以产生与实际的晚安琪兰手斧相当的结果。在我们的研究中，对准确执行动作的要求相对较高，这表明上肢的生物力学特性，