The handaxe reloaded: a morphometric reassessment of Acheulian and Middle Paleolithic handaxes.

This paper examines shape and size variability in Mousterian of Acheulian Tradition (MTA) handaxes and compares the observed patterns to those in the Lower Paleolithic Acheulian, both to better understand variability in MTA handaxes and to test whether or not this variability, particularly as it relates to resharpening and reduction, is structured similarly to that in the Acheulian. The Acheulian data set is based on previously published data with the addition here of a study of the handaxes from the site of Boxgrove, England. The MTA data set is based on four classic sites from southwest France with large handaxe collections. Both standard caliper-based morphometrics and Elliptical Fourier Analysis applied to coordinate data taken from digitized images of handaxes are used to assess shape. The result is that, contrary to expectations based on assumptions of evolving technological skill, handaxes in the MTA are as or more variable in shape than Acheulian ones. This variation is allometric in Acheulian handaxes, and is linked to resharpening from the tip down to the base, but is not related to size in the MTA samples. These results suggest that the goals and constraints of handaxe manufacture, but particularly handaxe reduction as a result of reworking during use, were quite different in the MTA and Acheulian, implying that conclusions about hominin cognition drawn from patterns in shape variability in handaxes must be understood in the context of artifact life histories.