Identifying, analyzing, and explaining trends in the development of material culture is one of the major concerns in prehistoric archaeology. The traditional recording of data in typologies, however, is not optimal for answering the question of diachronic change because typological data capture variability poorly and are often incompatible with multivariate statistics. To overcome these problems, we present PyREnArA (Python-R-Environment for Artifact Analysis), a trait-based tool that allows for a systematic recording of diversity and variability in a way that is applicable to quantitative analysis and multivariate statistics. Using Gravettian assemblages from Lower Austria and Moravia as a case study, we analyze changes in the morphology as well as the design of lithic projectiles and statistically determine the amount of variation that correlates with the progression of time. We identify a slow trend towards slenderer and more pointed projectiles and a shift from laterally to latero-frontally hafted implements. Most of the analyzed traits, however, appear not to experience selective pressure and seem to be unrelated to the passage of time. We discuss these results with regard to different scales of selection, in particular individual choice vs. macroevolutionary group selection over longer periods of time and thus beyond the realm of individual intend, and we raise questions for future research.
