Volcanic climate forcing, extreme cold and the Neolithic Transition in the northern US Southwest

The impacts on global climate of the AD 536 and 541 volcanic eruptions are well attested in palaeoclimatic datasets and in Eurasian historical records. Their effects on farmers in the arid uplands of western North America, however, remain poorly understood. The authors investigate whether extreme cold caused by these eruptions influenced the scale, scope and timing of the Neolithic Transition in the northern US Southwest. Archaeological tree-ring and radiocarbon dates, along with settlement survey data suggest that extreme cooling generated the physical and social space that enabled early farmers to transition from kin-focused socio-economic strategies to increasingly complex and widely shared forms of social organisation that served as foundational elements of burgeoning Ancestral Pueblo societies.

Contextualizing Ancestral Pueblo Turkey (Meleagris gallopavo spp.) Management

Penning turkeys (Meleagris gallopavo spp.) in the Ancestral Pueblo American Southwest/Mexican Northwest (SW/NW) involved the creation or use of a variety of spaces and contexts throughout AD 1–1600 and into the post-contact era. Turkey pens, or captivity, occur through simple tethering, reuse of abandoned pit houses or surface rooms, or creation of pens within villages, plazas, and elsewhere. Turkey dung, droppings, and eggshells are fundamental for determining the presence or absence of pens at archaeological sites. In this paper, I review the archaeological record for turkey pens and focus on three main questions: (1) how are turkey pens identified in the SW/NW, (2) if turkey pen construction or evidence for turkey captivity shifts through time, and (3) what the record of turkey penning informs us regarding the long-term human management of these birds and global perspectives on human–bird/human–animal management. Ancestral Pueblo peoples created an adaptive and flexible strategy for turkey penning, which successfully integrated these birds into ceremonial and socioeconomic processes for approximately 1600 years.

Colour and Directional Symbolism in Ancestral Pueblo Radial Offerings from Chaco Canyon

Dedicatory offerings of small colourful objects are often found in pre-Hispanic architectural contexts in the Ancestral Pueblo region of the American Southwest. These deposits are particularly numerous in the roof support pillars of circular ritual structures (kivas) at the site of Pueblo Bonito, Chaco Canyon, which served as the ceremonial hub of the Chacoan regional system between the tenth and twelfth centuries ce. Based on the importance of directionality and colour in traditional Pueblo worldviews, archaeologists speculate that the contents of these radial offerings may likewise reference significant Chacoan cosmographic elements. In this paper, I explore this idea by examining the distribution of colours and materials in kiva pilaster repositories in relation to directional quadrants, prominent landscape features, and raw material sources. I discuss the results in the context of Pueblo cosmology and assemblage theory, arguing that particular colours were polyvalent and relational, deriving their meanings from their positions within interacting and heterogenous assemblages.

Evolutionary model discovery of causal factors behind the socio-agricultural behavior of the Ancestral Pueblo

Agent-based modeling of artificial societies allows for the validation and analysis of human-interpretable, causal explanations of human behavior that generate society-scale phenomena. However, parameter calibration is insufficient to conduct data-driven explorations that are adequate in evaluating the importance of causal factors that constitute agent rules that match real-world individual-scale generative behaviors. We introduce evolutionary model discovery, a framework that combines genetic programming and random forest regression to evaluate the importance of a set of causal factors hypothesized to affect the individual’s decision-making process. With evolutionary model discovery, we investigated the farm plot seeking behavior of the Ancestral Pueblo of the Long House Valley simulated in the Artificial Anasazi model. We evaluated the importance of causal factors unconsidered in the original model, which we hypothesized to have affected the decision-making process. Our findings, concur with other archaeological studies on the Ancestral Pueblo communities during the Pueblo II period, which indicate the existence of cross-village polities, hierarchical organization, and dependence on the viability of the agricultural niche. Contrary to the original Artificial Anasazi model, where closeness was the sole factor driving farm plot selection, selection of higher quality land, distancing from failed farm plots, and desire for social presence are found to be more important. Finally, models updated with farm selection strategies designed by incorporating these insights showed significant improvements in accuracy and robustness over the original Artificial Anasazi model.