Flake selection and scraper retouch probability: an alternative model for explaining Middle Paleolithic assemblage retouch variability

Abstract

It has been proposed that the relative abundance of retouched objects in Paleolithic assemblages can serve as a measure for artifact transport and by extension a proxy for site occupation duration. This approach is based on the assumption that retouch represents curatory effort for extending the service time of transported artifacts when raw material access is uncertain or limited, a condition that could arise when groups move frequently over long distances across the landscape. This paper proposes an alternative model that explains retouch as a probabilistic outcome of an expedient, on-site flake selection process. A simulation illustrates that the model is capable of producing assemblage retouch configurations akin to those commonly observed in Paleolithic settings. The simulation also indicates that the threshold applied by past individuals for selecting particular artifacts is an important parameter for explaining assemblage retouch variability. Using artifact weight as a proxy for flake selection criteria, several Middle Paleolithic assemblages exhibit patterns that support predictions made from the model simulation. Findings suggest that variation in scraper frequency among the studied assemblages can be accounted for by an interaction between the abundance of artifact production events and shifting artifact selection criteria, without appealing to higher-level behaviors of technological and mobility strategies.