Bifacial Cores and Flake Production Efficiency: An Experimental Test of Technological Assumptions

Many researchers assume that the greater flake tool production efficiency of bifacial versus amorphous cores helps explain the prevalence of bifacial core technology among mobile populations. This paper describes experiments that test whether bifacial cores are more efficient carriers of flake cutting edge than amorphous cores. The first experiment established a size threshold of flake cutting efficiency. The second experiment reduced ten bifacial and ten amorphous cores to exhaustion and calculated the amount of usable and total flake edge produced by each core type, excluding flakes beneath the size threshold. Results indicate that bifacial cores are not significantly more efficient producers of usable or total flake edge than amorphous cores. Bifaces do produce flakes with significantly higher edge-to-weight ratios than do amorphous cores, but more of the weight of bifacial cores is lost to waste during the flake production process. Flake production efficiency therefore does not explain the use of bifacial cores among mobile populations.