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Category: Project

Description: Investments in stone tool skill learning constitute an oft-neglected cost in the evaluation of alternative adaptive strategies. Studies show that the most salient neural and cognitive demands of stone tool-making should occur during learning rather than expert performance. However, the behavioral complexity and extensive learning requirements that make stone knapping skill acquisition an interesting object of study are the very features that make it so challenging to reconstruct. Here we present results from a new study of Late Acheulean handaxe-making skill acquisition involving twenty-six naïve subjects and up to 90 hours training over several months, accompanied by psychometric testing and regular behavioral assessments. Our study’s main objectives were to derive a robust quantitative skill metric for the experimental handaxes using machine learning algorithms, to reconstruct a handaxe-making learning curve, and to explore sources of variation in handaxe making and learning outcomes. The objective, artifact-based model performed well in predicting handaxe making skill levels, in forecasting future performance and rating out-of-sample expert handaxes. The overall learning curve for subjects follows a characteristic power law showing that with training practice performance generally improves. Extrapolations of our individual learning curves suggest that experimental studies of such refined technologies should plan for at least 200 hrs. of training to achieve archaeological validity. We also find that performance in early stages of training correlates with differences in executive function (as tracked by widely-used psychometric measures) whereas performance during subsequent learning was associated with practice density. Our results highlight the significance of technologically focused teaching for achieving high-level skill in handaxe production, the importance of motivation, persistence, and self-control in knapping skill acquisition, and how these processes can be reliably reconstructed from archaeological evidence.