Technological and behavioural complexity in expedient industries: The importance of use-wear analysis for understanding flake assemblages

Abstract Expedient lithic technology has been described as unchanging and without or very limited presence of formal tool types. However, this premise seems to limit the discussion on technological and behavioural complexity when studying amorphous flake industries. To address this issue, we employed multi-stage use-wear analysis to identify features that are not detectable through macroscopic approach. Our analysis of chert tools from Leang Sarru, North Sulawesi indicated the use of both unmodified flakes and retouched tools for plant processing, and we detected evidence for the manufacture of composite tools. Microscopic wear traces on unretouched flakes show that these were attached to shafts for possible use as hafted tools, but not necessarily as projectiles. Our results suggest that simple flake assemblages can be part of complex tool production and present an alternative view on the seemingly unchanging lithic technology from the Late Pleistocene to the Holocene. Furthermore, our current understanding of expedient lithic technology should be reassessed as features that are not observable with standard morphological and technological analyses may be detected through use-wear analysis. Overall, the applied methodology and results of this study are relevant to Pleistocene and Early Holocene archaeological sites and assemblages that exhibit the dilemma of inferring technological and behavioural complexity through the analysis of simple stone tools.