Methodological Challenges to Tracking Zea mays (Maize) Historical Pathways Through Macrobotanical, Microbotanical, and Stable Isotope Evidence: Maize’s Adoption and Consumption by Precontact Populations in the North American Midcontinent

The process of plant domestication and subsequent adoption of agriculture have long been viewed by archaeologists as key factors in the emergence of social and political complexity. Ongoing research by botanists, archaeobotanists, and archaeologists, with ever-improving methodologies and technologies, reveal that the adoption of agriculture varies significantly in terms of chronologies, dietary intensity, and social impacts. It has become clear that broad-sweeping theories of agricultural adoption obscure meaningful micro-historical variations. Nowhere is this more true than in the Western Hemisphere, where the dates of the adoption of maize may differ in even geographically adjacent regions — thus the importance of focused regional studies of the history of maize consumption. In this review, we examine in detail the various methodological approaches employed in micro- and macro-botanical and isotopic studies and, importantly, appraise ongoing challenges to interpreting the findings of such research. We undertake this evaluation in the context of the northern midcontinent USA where these methodologies have produced regional maize histories that differ by as much as a thousand years in terms of both the presence of maize and the ultimate adoption of maize agriculture. We conclude that incorporating multiple refined methodological approaches is a key to understanding this variability.