Counting rather than weighing: metrological analysis and machine learning reveal the monetary potential of pre-contact Ecuadorian axe-monies

Abstract

This article investigates the potential monetary function of axe-monies from pre-contact Ecuador (500–1532 CE), a widely diffused and morphologically consistent copper-alloy artifact. Drawing on a dataset of 3,588 specimens, we employ a multidisciplinary approach combining metrological analysis, computer vision, and machine learning techniques to evaluate the presence of weight-based or dimensional standardization and morphological regularities. Our findings challenge the hypothesis that these objects were regulated by weight, as no metrological clusters emerge from the data. Instead, we identify two distinct dimensional classes and a high degree of typological consistency, suggesting intentional standardization based on form rather than mass, with triangular axes being the smallest and lightest, and those with a broad cutting edge and quadrangular heel the largest and heaviest.These results support the interpretation of Ecuadorian axe-monies as fiduciary currency, counted rather than weighed, and contribute to broader discussions on the emergence of money, measurement systems, and economic behaviour in pre-modern societies