Looking for behavioral modernity in Pleistocene northwestern China

The Paleolithic record of the southwestern Ordos Loop region of northwestern China suggests settlement variability, increased occupational intensity, and the intrusion or development of blade-based technology ca. 41,000-37,000 cal BP. These phenomena are also associated with equivocal evidence for ornamentation. More substantial changes in hominin behavior, however, are evident during and immediately after the Last Glacial Maximum (LGM), this marked by the development or intrusion of microblade technologies, perhaps groundstone technologies, and reductions in hominin population density. While changes in technology and settlement at approximately 40,000 cal BP arguably equate with some qualitative descriptors of modern human behavior and are contemporaneous with some estimates for the arrival of anatomically modern humans in the region, at present it is unclear whether these changes represent the expression of truly modern human behaviors. In part, this is because the East Asian Paleolithic record is so different from Europe and Africa and because the critical changes leading to the unequivocally modern human behaviors of the Terminal Pleistocene and Early Holocene appeared fairly late, during the LGM. Consequently, we argue that the LGM provided the environment of selection for modern human behaviors in northwestern China, whether their origins were ultimately the result of immigration, diffusion, in situ development, or some combination thereof.