A. C. MacWilliams

The diffusion of maize to the southwestern United States and its impact

Our understanding of the initial period of agriculture in the southwestern United States has been transformed by recent discoveries that establish the presence of maize there by 2100 cal. B.C. (calibrated calendrical years before the Christian era) and document the processes by which it was integrated into local foraging economies. Here we review archaeological, paleoecological, linguistic, and genetic data to evaluate the hypothesis that Proto-Uto-Aztecan (PUA) farmers migrating from a homeland in Mesoamerica introduced maize agriculture to the region. We conclude that this hypothesis is untenable and that the available data indicate instead a Great Basin homeland for the PUA, the breakup of this speech community into northern and southern divisions ≈6900 cal. B.C. and the dispersal of maize agriculture from Mesoamerica to the US Southwest via group-to-group diffusion across a Southern Uto-Aztecan linguistic continuum.

Reply to Hill and Brown: Maize and Uto-Aztecan cultural history

The hypothesis that Proto-Uto-Aztecan (PUA) speakers cultivated maize in or near Mesoamerica rests primarily on Jane H. Hills argument (1) that a maize-related vocabulary can be reconstructed for PUA, based on cognates in Northern Uto-Aztecan (NUA) and Southern Uto-Aztecan (SUA) languages. In our essay (2), we noted that Hill fails to demonstrate the existence of this PUA vocabulary, because the NUA words she identifies as cognates of maize-related words in SUA languages lack the expected phonological forms or the expected meanings. The same characterization applies to the additional evidence from three California NUA languages that she cites in her reply.