Are Upper Paleolithic blade cores more productive than Middle Paleolithic discoidal cores? A replication experiment.

It is widely believed that the change from discoidal flake production to prismatic blade-making during the Middle-Upper Paleolithic transition in Europe led to enhanced technological efficiency. Specifically, blade-making is thought to promote higher rates of blank production, more efficient and complete reduction of the parent core, and a large increase in the total length of cutting edge per weight of stone. Controlled replication experiments using large samples, computer-assisted measurements, and statistical tests of several different measures failed to support any of these propositions. When resharpened, the use-life of flake edges actually surpasses that of blades of equivalent mass because the narrower blades are more rapidly exhausted by retouch. Our results highlight the need to replace static measurements of edge length that promote an illusion of efficiency with a more dynamic approach that takes the whole reduction sequence into account. An unexpected by-product of our replications was the discovery that real gains in cutting-edge length per weight of stone are linked to surface area. There is now a need to test the proposition that all the perceived advantages currently bestowed upon blades only occurred during the shift from macroblade to bladelet production. If our results are duplicated in further experiments, the notion of "economical" blades will have to be rejected and alternative explanations sought for their appearance in the early Upper Paleolithic. While Aurignacian bladelet (Dufour) production could signal the advent of composite tool technology (wooden handles or shafts with bladelet inserts), this does not help to explain why macroblades were also produced in large numbers. We may need to reexamine the notion that macroblades were of more symbolic than functional significance to their makers.