A Statistical Examination of Flake Edge Angles Produced During Experimental Lineal Levallois Reductions and Consideration of Their Functional Implications

Recent studies have indicated that Levallois-style core reduction offered potential practical benefits to hominin populations. However, none of these studies have yet considered one of the most important functional attributes of flake tools, which is edge angle. To address this shortcoming, we statistically examined flakes produced experimentally during “classic” or “lineal” Levallois core production and reduction. The primary aim of our analyses was to statistically test the null hypothesis of “no difference” between the edge angles of “Levallois” products and the flakes involved in their production. We employ existing edge angle analytical techniques and develop new comparative methodologies to assess flake blank standardization through the case of Levallois core reduction. Having determined the statistical properties of our experimental Levallois reductions, we thereafter evaluated to what extent edge angles produced may, or may not, have been useful to prehistoric hominins. Our analyses demonstrated that the experimentally produced Levallois edge angles were indeed statistically different from the flakes involved in their production. These differences were evident both in terms of relatively higher (i.e., more obtuse) edge angles than debitage flakes and in being significantly less variable around their higher mean edge angles compared to debitage flakes. However, based on current knowledge of how flake edge angle properties relate to issues of functionality, such differences would not have been detrimental to their functionality. Indeed, the edge angle properties they possess would have provided distinct benefits to hominins engaged in their manufacture. Most notably, Levallois-style core organization and reduction would have provided hominins with a reliable means of consistently producing flakes (i.e., “Levallois flakes”) possessing average flake angles that are beneficial in terms of providing a viable cutting edge yet not being so acute as to be friable upon application. Hence, edge angle properties join an array of other features that provide logical motive for why hominins may have organized core production and reduction around Levallois-style patterns at various times and places during the Mid-Late Pleistocene.