Bayesian analyses of direct radiocarbon dates reveal geographic variations in the rate of rice farming dispersal in prehistoric Japan

Abstract

The adoption of rice farming during the 1st millennium BC was a turning point in Japanese prehistory, defining the subsequent cultural, linguistic, genetic variation in the archipelago. Here we employ a suite of novel Bayesian techniques to estimate the regional rates of dispersal and arrival time of rice farming using radiocarbon dates on charred rice remains. Our results indicate substantial variations in the rate of dispersal of rice within the Japanese islands, hinting at the presence of a mixture of demic and cultural diffusion, geographic variations in the suitability of its cultivation, as well as the possible role of existing social networks in facilitating or hindering the adoption of the new subsistence economy.