Upper Palaeolithic Settlement and Mobility in the Armenian Highlands: Agent-Based Modeling, Obsidian Sourcing, and Lithic Analysis at Aghitu-3 Cave

Abstract

Excavations at Aghitu-3 Cave in Armenia revealed stratified Upper Palaeolithic archaeological horizons (AHs), spanning from 39 to 36,000 cal BP (AH VII) to 29–24,000 cal BP (AH III) and from which we identified the sources of 1120 obsidian artifacts. Not only does AH III—deposited at the onset of the Last Glacial Maximum—have the most artifacts from non-regional sources but also the artifacts originate from the greatest variety of sources, including two ≥ 270 km on foot in different directions. The amount of retouch and density of lithics—as expressed by whole assemblage behavioral indicators (WABI)—suggest a trend from more expediency to more curation between the deposition of AHs VII and IV. This was followed by a substantial shift back to expediency during the deposition of AH III, corresponding to greater logistical mobility. Here, we use agent-based modeling (ABM) to interpret these data. Greater interactions between foraging groups are not an unavoidable outcome of a shift from residential to logistical mobility. Some variables (i.e., lithic stock, use intensity, provisioning strategy) can be ruled out, while other variables (i.e., decreased source abundance, a shift to direct procurement) appear inconsistent with the archaeological data. Territory spacing, in contrast, has a clear and predictable effect. A small decrease in territory spacing can yield notable increases in inter-group contact opportunities and can be explained by an increase in population densities as the climate cooled. Following this scenario, we assume that, as AH III accumulated, the cave’s occupants not only moved farther distances but also more frequently encountered neighboring groups.