An evolutionary model of social change in the Middle Ohio Valley: Was social complexity impossible during the late woodland but mandatory during the late prehistoric?

We present an evolutionary model of social change in the Middle Ohio Valley during the Fort Ancient period (AD 1000–1650), primarily relying on an application of Winterhalder’s (1986) and Kelly’s (1995) evolutionary ecology model of cultural responses to environmental variability. We predict changes in social organization, political complexity, and patterns of stylistic similarity. As the environmental background for our model we employ recently published moisture data. By iteratively applying the synchronic Winterhalder–Kelly model we are able to predict a sequence of general trends that agree with much current interpretation of Fort Ancient development. Specifically, the model leads us to expect increasing village size, the development of regional traditions, and the development of leadership roles and a region-wide style Horizon around AD 1400. However, our model provides the ability to make testable predictions that deviate from the accepted cultural history and predicts that the Middle Ohio Valley and the groups referred to as Fort Ancient were far from homogenous.