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Human lifestyles vary enormously over time and space and so understanding the origins of this diversity has always been a central focus of anthropology. A major source of this cultural variation is the variation in institutional complexity: the cultural packages of rules, norms, ontologies and expectations passed down through societies across generations. In this article, we study the emergence of institutions in small-scale societies. There are two primary schools of thought. The first is that institutions emerge top-down as rules are imposed by elites on their societies in order to gain asymmetrical access to power, resources and influence over others through coercion. The second is that institutions emerge bottom-up to facilitate interactions within populations as they seek collective solutions to adaptive problems. Here, we use Bayesian networks to infer the causal structure of institutional complexity in 172 small-scale societies across ethnohistoric western North America reflecting the wide diversity of indigenous lifestyles across this vast region immediately prior to European colonization. Our results suggest that institutional complexity emerges from underlying socioecological complexity because institutions are solutions to coordination problems in more complex environments where human–environment interactions require increased management. [ABSTRACT FROM AUTHOR]

This study examines the fluting of two well‐known Late Pleistocene fluted point types in North America: Clovis and Folsom. Using scaling analyses, we assess the changing relationship between flute length and point length in a large sample of each type. Researchers use scaling to investigate the physical constraints of an object and determine how its dimensions change with size. We compare the strength and consistency of the scaling relationships between the older Clovis and the younger Folsom with the aim of shedding light on scaling differences, if any, over their temporal span. Our results show that there is a significant difference in the relationship of fluting length to point length between these types. In Folsom point manufacture, flute length increases nearly twice as fast with increasing point length than in Clovis. Importantly, the scaling of flute length to point length relationship is isometric (linear) in the Folsom sample, whereas it is allometric (sublinear) in the Clovis sample. In other words, Folsom flintknappers maintained a constant ratio of flute length to point length. Clovis flintknappers were less concerned about maintaining this ratio. We attribute this difference to a potentially increasing, or changing, functional role of fluting in Folsom. [ABSTRACT FROM AUTHOR]

Bullet ricochets are common occurrences during shooting incidents and can provide a wealth of information useful for shooting incident reconstruction. However, there have only been a small number of studies that have systematically investigated bullet ricochet impact site morphology. Here, this study reports on an experiment that examined the plan-view morphology of 297 ricochet impact sites in concrete that were produced by five different bullet types shot from two distances. This study used a random forest machine learning algorithm to classify bullet types with morphological dimensions of the ricochet mark (impact) with length and perimeter-to-area ratio emerging as the top predictor variables. The 0.22 LR leaves the most distinctive impact mark on the concrete, and overall, the classification accuracy using leave-one-out cross-validation is 62%, considerably higher than a random classification accuracy of 20%. Adding in distance to the model as a predictor increases the classification accuracy to 66%. These initial results are promising, in that they suggest that an unknown bullet type can potentially be determined, or at least probabilistically assessed, from the morphology of the ricochet impact site alone. However, the substantial amount of overlap this study documented among distinct bullet types' ricochet mark morphologies under highly controlled conditions and with machine learning suggests that the human identification of ricochet marks in real-world shooting incident reconstructions may be on occasion, or perhaps regularly, in error. Key points Bullet ricochet impact sites can help with shooting incident reconstruction. A random forest machine learning algorithm classified bullet type from ricochet morphology. Results suggest that unknown bullets can potentially be determined from ricochet impact site morphology. Human identification of bullet types from ricochet sites may be erroneous. [ABSTRACT FROM AUTHOR]

Amazonia is an invaluable global asset for all its ecological and cultural significance. Indigenous peoples and their lands are pivotal in safeguarding this unique biodiversity and mitigating global climate change. Understanding the causal structure behind variation in the degree of environmental conservation across different indigenous lands–each with varying institutional, legal, and socioenvironmental conditions–is an essential source of information in the struggle for long-term sustainable management of Amazonian ecosystems. Here, we use data from the Instituto Socioambiental for 361 indigenous lands in the Brazilian Amazon coded for environmental integrity, territorial integrity, legal stability, indigenous governance, and threats due to infrastructure projects. Using Bayesian networks to learn the causal structure amongst these variables reveals two causal pathways leading to environmental integrity. One causal pathway starts with territorial integrity and is mediated by infrastructure projects, while the other is directly from legal stability. Hence, safeguarding indigenous lands from exploitation is best accomplished via legal land rights and stricter enforcement instead of placing the onus on indigenous governance, which is also a direct outcome of legal stability. [ABSTRACT FROM AUTHOR]

Researchers use a variety of target materials, and sometimes combinations of materials, in their archaeological experiments to examine thrust‐spear or projectile penetration, impact angle, durability, and other issues involving prehistoric hunting weaponry. This variety of target materials is beneficial to archaeological science in several ways, but it may also hinder the comparison of results because many of these target materials do not necessarily share similar physical properties. Here, we assess the penetration properties of four different target materials—store‐bought meat, clay, and two types of gelatin—via static penetration tests of a modern broadhead‐tipped arrow and a stone‐tipped projectile attached to an Instron Universal Materials Tester. Our analyses of load‐deflection curves, peak load, and work energy demonstrate how the four target materials are similar in some ways but different in others, which suggests that researchers may strategically employ one or several depending on the question asked or hypothesis tested. [ABSTRACT FROM AUTHOR]

Amazonia has as least two major centers of ancient human social complexity, but the full geographic extents of these centers remain uncertain. Across the southern rim of Amazonia, over 1,000 earthwork sites comprised of fortified settlements, mound villages, and ditched enclosures with geometric designs known as geoglyphs have been discovered. Qualitatively distinct and densely located along the lower stretches of major river systems and the Atlantic coast are Amazonian Dark Earth sites (ADEs) with deep anthropogenic soils enriched by long-term human habitation. Models predicting the geographic extents of earthworks and ADEs can assist in their discovery and preservation and help answer questions about the full degree of indigenous landscape modifications across Amazonia. We classify earthworks versus ADEs versus other nonearthwork/ non-ADE archaeological sites with multi-class machine learning algorithms using soils, climate, and distances to rivers of different types and sizes as geospatial predictors. Model testing is done with spatial cross-validation, and the best model at the optimal spatial scale of 1 km has an Area Under the Curve of 0.91. Our predictive model has led to the discovery of 13 new geoglyphs, and it pinpoints specific areas with high probabilities of undiscovered archaeological sites that are currently hidden by rainforests. The limited, albeit impressive, predicted extents of earthworks and ADEs means that other non-ADE/non-earthwork sites are expected to predominate most of Western and Northern Amazonia. [ABSTRACT FROM AUTHOR]

Stone‐tipped weaponry was important for the survival of past peoples, and many functional and non‐functional factors likely influenced their design. Two functional factors that past peoples likely considered in the design of their stone tips are durability (whether or not a stone tip breaks) and robusticity (how much damage is incurred upon breakage). Many factors have been shown experimentally to influence stone tip influence durability and robusticity, including stone raw material. Here, we further explore the relationship between stone raw material and stone tip durability and robusticity via controlled experiments comparing chert and obsidian. We first demonstrate with semi‐static fracture strength analyses that obsidian stone tips require less force to break than do chert stone tips. We then show with dynamic ballistics impact testing that obsidian stone tips are less durable and robust than chert stone tips. Our results are entirely consistent with previous experimental comparisons of chert versus obsidian stone tips, and support the hypothesis that past peoples, when presented with multiple raw materials, likely weighed their costs and benefits in the process of selection. [ABSTRACT FROM AUTHOR]

Stone that fractured conchoidally was an important resource for prehistoric hunter‐gatherers. In recent years, archaeologists have come to realize that rather than defining stone "quality" simply and implicitly as "high" or "low," a stone's quality can be best defined in several different explicit and often quantitative ways involving production, function, or social benefits. Here, we examine the stone quality—defined as "fracture predictability"—of Upper Mercer chert when it is locally versus nonlocally acquired by prehistoric people in Ohio, USA. By quantitatively assessing silicon dioxide (SiO2) content and loss on ignition, we compared stone tools from a site at the Upper Mercer outcrop (n = 42) to those found at archaeological sites over 100 km north of it (n = 126). Our results showed that the former on average were of significantly higher quality than the latter. We conclude with a consideration of factors that could cause this difference in quality, suggesting that the lower quality of Upper Mercer chert in northern Ohio might be explained by northern people's decreased familiarity with it during the Archaic period and by their decreased access to it during the Woodland and Late Precontact periods. [ABSTRACT FROM AUTHOR]

James Savage's article 'Where's the Pork?' (Issues, Spring 1993) is a timely commentary on the issue of academic pork barrel. His analysis of the various definitions of earmarking clearly and […]

Human societies exhibit a diversity of social organizations that vary widely in size, structure, and complexity. Today, human sociopolitical complexity ranges from stateless small-scale societies of a few hundred individuals to complex states of millions, most of this diversity evolving only over the last few hundred years. Understanding how sociopolitical complexity evolved over time and space has always been a central focus of the social sciences. Yet despite this long-term interest, a quantitative understanding of how sociopolitical complexity varies across cultures is not well developed. Here we use scaling analysis to examine the statistical structure of a global sample of over a thousand human societies across multiple levels of sociopolitical complexity. First, we show that levels of sociopolitical complexity are self-similar as adjacent levels of jurisdictional hierarchy see a four-fold increase in population size, a two-fold increase in geographic range, and therefore a doubling of population density. Second, we show how this self-similarity leads to the scaling of population size and geographic range. As societies increase in complexity population density is reconfigured in space and quantified by scaling parameters. However, there is considerable overlap in population metrics across all scales suggesting that while more complex societies tend to have larger and denser populations, larger and denser populations are not necessarily more complex. [ABSTRACT FROM AUTHOR]

Combining scattered federal research efforts in a single agency would enhance the visibility and the coherence of science programs. As chairman of the House Committee on Science, I have the […]