Hunter-gatherer societies held sway in midwestern North America for at least 11,000 years. Those at the end of this period were more complex and less mobile, and they supported larger populations than those at the beginning, but there are relatively few general conceptions as to when and how this took place. Here we examine the fit of gradual, one-way social change as it relates to the size and shape of lithic supply zones for Upper Mercer and Flint Ridge flint as well as the inflow of exotic materials. Our results show no singular cline either in the size of successive lithic supply zones or in the inflow of exotic materials. Hunter-gatherer societies can make remarkable behavioral changes through time and not necessarily in any consistent (unilineal) direction. Such differences impose more contingency—and less directionality—into particular historical sequences.
