Does point size matter? How morphometric arguments impact evolutionary models of Palaeolithic weaponry

The invention of long-range weaponry has been a pivotal technological change with significant implications for Palaeolithic subsistence strategies and is assumed to have been a crucial factor facilitating the spread of anatomically modern humans while migrating out of Africa. Over the last years, a prevailing hypothesis seems to have emerged that long-range weaponry appeared somewhere at the end of the Middle Stone Age and dispersed over the rest of the world together with modern humans. However, organic remains testifying to the use of long-range weaponry are far more recent and the early-appearance model is therefore inferred primarily from morphometric analyses of the stone points. Metrics such as tip cross-sectional area (TCSA) and tip cross-sectional perimeter (TCSP) are argued to be reliable proxies for inferring the penetration capacity of points and the diameter of the shaft and have been used to hypothesise the use of a particular weapon system. Despite the popularity of TCSA/TCSP in projectile studies, the reliability of using morphometric values to infer a particular weapon system remains insufficiently explored through experimental approaches. To further assess the validity of these proxies, we use the results of a comprehensive multiparameter shooting experiment, the design of which permits to test the reliability of using TCSA/TCSP values as proxies for weapon technology. Our results indicate that the TCSA/TCSP value of a point does not correlate with its penetration depth, which proves more influenced by other morphological parameters and by the hafting system and propulsion mode. Additionally, we show that small points, often interpreted as arrow tips, can effectively function with larger shafts across different propulsion modes thereby disproving an exclusive relation between small points and the use of arrows. These findings raise important concerns regarding the reliability of the arguments that are currently used to support an early appearance of long-distance weaponry. We encourage an approach that draws more from use-wear studies and sequential experimental programs, to permit the development of more fine-grained models for the emergence of long-range weapon systems.