An experimental approach to the generation of copying error during the manufacture of material culture: Implications for cultural evolution

Cultural evolutionary models are marked by an increased understanding that sources of variation such as cultural mutations, or copying error, form an integral part in generating population-level patterns of artefactual variation. Despite recognition that the manual manufacturing process is a fundamental component of material culture in the archaeological record, little is known about exactly how factors related to the manual manufacturing process affect rates of copying error, which potentially influence population-level trends. In addition, only a few studies have incorporated the study of shape variation into cultural evolutionary models even though artefactual shape is affected by evolutionary processes. Utilising an empirical framework that combined methods from the ‘psychology laboratory’ and morphometric shape data, it was shown on the basis of experimentally produced 3D cultural artefacts that a variety of manufacture-related components significantly impact rates of shape variation produced. Individual experiments confirmed hypotheses stating that differences in components of manufacture, such as contrasting manufacturing traditions, social learning mechanisms, economic factors associated with constraints placed on production time and distinct traditions of ‘equipment’ employed to produce material artefacts, all influence patterns of shape variation at statistically significant levels. The studies conclude that high mutation loads represent a potential cause for the ‘disintegration’ of shape traditions over repeated bouts of cultural transmission. Where shape traditions matter in the long-term (e.g., in the case of functional tools such as Acheulean handaxes or projectile points) high fidelity transmission mechanisms may become targets of selection processes associated with manual manufacture. A strong implication for cultural evolutionary models is that the study of the evolution of material culture may, therefore, not be fully characterised solely as the study of cultural transmission, but that it can be partly re-conceptualised as the study of the ‘management’ of the continuous production of mutation loads by various populations of artefact producers.