The author analyzes 440 Sub-Saharan African societies to test whether trade across ecologically diverse zones is predictive of degree of state centralization (state capacity or strength of state) in pre-colonial Africa. The author finds that diverse ecology is predictive of state capacity and that trade supports class stratification. The author also emphasizes the importance of historical contingency and ethnographic data consultation in understanding mechanisms in individual cases.

This study asks the following research questions: What are the dynamics of land ownership norms over time? Do these changes follow predetermined trajectories? The authors utilize biogeographical and evolutionary analyses to explore temporal and spatial patterns in land ownership norms within a sample of 73 Bantu societies. For the first component of the research, they test three prominent hypotheses regarding evolutionary trajectories: rectilinear, unilinear, and shift without restriction. For the second component, they use a multi-model inference approach to evaluate three hypotheses regarding the possible spatial patterns of land ownership. The results show evidence for the unilinear trajectory in type, but not with a consistent decrease in group ownership in size. Land ownership is more likely in areas with neighboring landowners and predictable resource productivity, while subsistence type is not significantly correlated with type of land ownership.

Using a cross-cultural sample of 91 societies, this paper draws on ecological theory to test if unpredictable environments will favor subsistence diversification. The general hypothesis is that societies with high climate unpredictability and resource stress would exhibit more subsistence diversity than societies in more stable climates. The authors examined four environmental and resource stress variables while controlling for temperature variance, subsistence activity, and phylogeny. Support was found for 2 of the 4 variables--chronic scarcity and environmental instability. In the discussion they suggest that more commonly observed events (e.g. annual hunger and climate unpredictability) may give people more motivation to change subsistence than rarer events (e.g. natural hazards and famine).

Using a cross-cultural sample of 91 societies, this paper draws on ecological theory to test if unpredictable environments will favor subsistence diversification. The general hypothesis is that societies with high climate unpredictability and resource stress would exhibit more subsistence diversity than societies in more stable climates. The authors examined four environmental and resource stress variables while controlling for temperature variance, subsistence activity, and phylogeny. Support was found for 2 of the 4 variables--chronic scarcity and environmental instability. In the discussion they suggest that more commonly observed events (e.g. annual hunger and climate unpredictability) may give people more motivation to change subsistence than rarer events (e.g. natural hazards and famine).

Using a cross-cultural sample of 91 societies, this paper draws on ecological theory to test if unpredictable environments will favor subsistence diversification. The general hypothesis is that societies with high climate unpredictability and resource stress would exhibit more subsistence diversity than societies in more stable climates. The authors examined four environmental and resource stress variables while controlling for temperature variance, subsistence activity, and phylogeny. Support was found for 2 of the 4 variables--chronic scarcity and environmental instability. In the discussion they suggest that more commonly observed events (e.g. annual hunger and climate unpredictability) may give people more motivation to change subsistence than rarer events (e.g. natural hazards and famine).

Using a cross-cultural sample of 91 societies, this paper draws on ecological theory to test if unpredictable environments will favor subsistence diversification. The general hypothesis is that societies with high climate unpredictability and resource stress would exhibit more subsistence diversity than societies in more stable climates. The authors examined four environmental and resource stress variables while controlling for temperature variance, subsistence activity, and phylogeny. Support was found for 2 of the 4 variables--chronic scarcity and environmental instability. In the discussion they suggest that more commonly observed events (e.g. annual hunger and climate unpredictability) may give people more motivation to change subsistence than rarer events (e.g. natural hazards and famine).

In this study, the authors analyze subsistence economies to better understand their variability and success, the role of the environment in different subsistence choices, and the relevance of fishing, specifically in mixed economies. They find regular subsistence patterns, suggesting that not all subsistence combinations are successful. Their findings also indicate that environment influences subsistence choice, mixed economies are common, and that fishing plays a key role in mixed economies.

Using t-test, generalized linear models (GLMs) and Bayesian regression models in a sample of 1188 pre-industrial societies, this study explores the research question: Why have foraging, horticulture, and pastoralism persisted into the 20th and 21st century? The authors test the marginal hypothesis and the oasis hypothesis of agricultural intensification. The first hypothesis suggests that foragers persisted because foragers predominantly inhabited marginal habitats that were typically unsuitable for agricultural purposes. The second hypothesis suggests that intensive agriculture emerged in regions characterized by limited biodiversity and a dependable water supply not reliant on local rainfall. In addition, the authors test whether specific kinds of biodiversity (elephants, malaria, and tsetse flies) correlate with agricultural intensification in African societies. The results support the marginal and oasis hypotheses, but only marginally support the African hypothesis, since only tsetse fly has a significant negative correlation to agricultural intensification.

This article presents a representative theoretical model of the transition to agriculture. Empirical results from a cross-cultural sample provide support for the model. Results suggest that agriculture is associated with population density, technological sophistication, environment, and proximity to agricultural hearths, such as the Fertile Crescent.

Using t-test, generalized linear models (GLMs) and Bayesian regression models in a sample of 1188 pre-industrial societies, this study explores the research question: Why have foraging, horticulture, and pastoralism persisted into the 20th and 21st century? The authors test the marginal hypothesis and the oasis hypothesis of agricultural intensification. The first hypothesis suggests that foragers persisted because foragers predominantly inhabited marginal habitats that were typically unsuitable for agricultural purposes. The second hypothesis suggests that intensive agriculture emerged in regions characterized by limited biodiversity and a dependable water supply not reliant on local rainfall. In addition, the authors test whether specific kinds of biodiversity (elephants, malaria, and tsetse flies) correlate with agricultural intensification in African societies. The results support the marginal and oasis hypotheses, but only marginally support the African hypothesis, since only tsetse fly has a significant negative correlation to agricultural intensification.