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We report functional relationships between humans and canines based on observations in the village of Santa Cruz (Toledo District, Belize), emphasizing the cultural ecology of dogs in this lowland tropical rainforest setting and milpa agriculture subsistence system. Dogs pursue animals threatening field crops; they deter forest herbivores by leaving their scent along the myriad trails from the village to the milpa field plots; and they guard the homestead and foods stored there. Dogs also aid in daytime hunts for species that can be cornered. They are less useful in pursuits of fast species like deer and are protected from pursuing especially dangerous species like anteater or warri. Litter survival rates are low, and the lifespan of hunting dogs is significantly shorter than that of guard dogs due to hazards of forest pursuit. Explicit training for hunting is limited and maintenance costs are low as dogs are fed a partial ration of tortillas and otherwise scavenge for their diet. The village population of dogs appears not to be under genetic selection for hunting skills. Our results advance the comparative ethnographic study of this important domesticate; they should aid in the formulation and assessment of hypotheses about dog domestication and co-evolution with human society.

Cesario et al. argue that benchmarking the relative counts of killings by police on relative crime rates, rather than relative population sizes, generates a measure of racial disparity in the use of lethal force that is unbiased by differential crime rates. Their publication, however, lacked any formal derivation showing that their benchmarking methodology has the statistical properties required to establish such a claim. We use the causal model of lethal force by police conditional on relative crime rates implicit in their analyses and prove that their benchmarking methodology does not, in general, remove the bias introduced by crime rate differences. Instead, it creates strong statistical biases that mask true racial disparities, especially in the killing of unarmed noncriminals by police. Reanalysis of their data using formally derived criminality-correcting benchmarks shows that there is strong and statistically reliable evidence of anti-Black racial disparities in the killing of unarmed Americans by police in 2015–2016.

Author(s): Winterhalder, Bruce P.; Puleston, Cedric O. | Abstract: We adopt an imagined exchequer, the functionary responsible in an early polity for securing resources from its agrarian subjects, and we develop a feature-rich demographic and environmental model to explore the population ecology of agricultural production in the context of population growth, Malthusian constraints and economic exploitation. The model system allows us to (i) identify and characterize a peak of surplus production early in population growth, prior to density-dependent constraints and (ii) characterize the taxation potential of a population at its Malthusian equilibrium. For a fixed total level of taxation the exchequer has two options: a small population taxed at a high rate, unstable to small perturbations, or a larger population taxed at a lower rate, which is stable. In a small and growing population it is more effective to tax goods; as the population approaches its density-dependent equilibrium it becomes more effective to tax labor. We likewise show that early agrarian states afflicted by stochastic variation in agronomic output face an extinction risk dependent on the level of taxation and magnitude of yield variation. Successful agrarian states balanced resource exploitation against dynamic population ecology constraints; we propose that fiscal mismanagement should be among the hypotheses for polity failure.

Tl\X/ENTY An Ecological Model for the Emergence of Institutionalized Social Hierarchies qon California’s Northern Channel Islands Douglas]. Kennett, Bruce Winterhaldergjacob Bartruflf - and_/on A/I. Erlandson 0 N E O F T H E central questions in anthro- pological archaeology is how and why insti- tutionalized social hierarchies evident in ranked societies and chiefdoms developed indepen- dently i.n multiple locations around the world during the Holocene (Feinman and Manzanjlla zooo; Flannery I998)._ Status competition and social inequality exist in all human groups, re- gardless of size or mode of production (Fried I967; Boehm zooo; Diehl 2.000). However, ar- chaeological evidence for significant and institu- tionalized intragroup differences in status and wealth are confined to the last I3,ooo years, well after the first evidence for anatomically modern humans in Afiica (ca. 150,000 years ago) and their subsequent appearance throughout much of the Old and New Worlds (Klein 2.004). The preponderance of archaeological evidence sug- gests that for the majority of human history groups remained small, occupied relatively large territories at low. densities, and moved periodi- cally to adapt to spatial and temporal fluctuations ir1 resources. The record also indicates that group fissioning, environmental infilling, and emigra- tion to diverse habitats were generally favored over localized increases in group size and density or other forms of intensification. Under these conditions, institutionalized hereditary leader- ship and significant differences in status and wealth rarely emerged or persisted. Archaeological evidence for ranked societies is often found in conjunction with clear indications of localized population aggregation, economic intensification, and territorial circumscription (Blake and Clark 1999; Cameiro 1970; Clark and Blalce I994; Hayden I98I). In some instances, ranking follows heightened commitrnent to agri- culture (Price and Gebauer 1995), but similar de- velopments occurred among hunter-gatherers in areas where wild resources are concentrated, such as in marine and other aquatic habitats (Erlandson 2.001; Kennett 2oo5; Palsson I988; Yesner 1980). ‘In these contexts, certain group members were able to acquire greater wealth and status by (I) manipulating economic, social, and political relationships to their own benefit (Earle 1987); (2.) controlling the flow'of exotic goods used to signal status (Flannery I972) ,' (3) monop- olizing the labor of other group members (Earle I987; Arnold 2.ooI); and (4) creating ideologies 397

Archaeology’s broad engagement with the long-term evolution of human subsistence systems and social forms hinges on understanding relationships among environment, demography, production, and society. Semiquantitative narrative accounts of interactions among these factors by Malthus and later by Boserup currently are being updated with more explicitly quantitative analytical and simulation models. We describe one of these approaches, food-limited demography, and present examples of how it is being used to interpret archaeological data on subsistence, settlement, and the sociopolitical evolution of Pacific and North American societies. We note that dynamic modeling can reveal system properties that run counter to commonly held beliefs about population ecology. In agrarian societies the weight of Malthusian constraints on population develop not gradually, but abruptly, with severe consequences for human welfare; inter-annual food storage mitigates some instances of famine but makes others more severe; the potential for surplus production is greatest when populations are relatively small; low tax rates applied to a large population of producers are more stable than a high rate applied to a smaller population; and, at population equilibrium, a tax on labor may be more efficient than one on agrarian goods. These and other insights from contemporary modeling of linkages among human demography, behavior, economy, and environment allow us to examine the consequences of assumptions about rates of birth and death, the allocation of wealth and power, and how resources and labor are utilized in the evolution of early agricultural societies.

© 2018 The Author(s) Published by the Royal Society. All rights reserved. Monogamy appears to have become the predominant human mating system with the emergence of highly unequal agricultural populations that replaced relatively egalitarian horticultural populations, challenging the conventional idea - based on the polygyny threshold model - that polygyny should be positively associated with wealth inequality. To address this polygyny paradox, we generalize the standard polygyny threshold model to a mutual mate choice model predicting the fraction of women married polygynously. We then demonstrate two conditions that are jointly sufficient to make monogamy the predominant marriage form, even in highly unequal societies. We assess if these conditions are satisfied using individual-level data from 29 human populations. Our analysis shows that with the shift to stratified agricultural economies: (i) the population frequency of relatively poor individuals increased, increasing wealth inequality, but decreasing the frequency of individuals with sufficient wealth to secure polygynous marriage, and (ii) diminishing marginal fitness returns to additional wives prevent extremely wealthy men from obtaining as many wives as their relative wealth would otherwise predict. These conditions jointly lead to a high population-level frequency of monogamy.

We present a quantitative account based on ethnographic and documentary research of the prevalence of female genital modification (FGMo) in the African diaspora and indigenous populations of Colombia. We use these data to test hypotheses concerning the cultural evolutionary drivers of costly trait persistence, attenuation, and intergroup transmission. The uptake of FGMo by indigenous populations in Colombia is consistent with frequency-dependent hypotheses for the social transmission of the FGMo trait from the African diaspora population in the period following the era of slavery in Colombia. The prevalence and severity of practices related to FGMo decline with level of sociocultural integration into mainstream Colombian culture. Our results provide empirical support for the cultural evolutionary models proposed by Ross et al. (2015) to describe the transmission dynamics of FGMo and other costly traits. Analysis of costly trait dynamics contributes knowledge useful to applied anthropology and may be of interest in policy design and human rights monitoring in Colombia and elsewhere.

Using complementary behavioural and population ecological models, we explore the role of production risk, normal surplus and inter-annual food storage in the adaptations of societies dependent on seasonal agriculture. We find that (a) household-level, risk-sensitive adaption to unpredictable environmental variation in annual agricultural yields is a sufficient explanation for the origins of normal agrarian surplus and, consequently, of household-level incentives for inter-annual food storage; and, (b) at the population level, density-dependent Malthusian processes tightly constrain the circumstances under which this same mechanism can be effective in smoothing inter-annual fluctuations in household food availability. Greater environmental variation and higher levels of fixed set-asides such as seed requirements or transfer obligations to political authorities lead to more severe, periodic famines; however, outside of famine events, these same factors improve average population welfare by suppressing population density to levels at which Malthusian constraints have lessened impact. The combination of behavioural and population ecological modelling methods has broad and complementary potential for illustrating the dynamic properties of complex, coupled human–natural systems.

Using a sample of 40 sources reporting milpa and mucuna-intercropped maize yields in Mesoamerica, we test Boserup’s (1965) prediction that fallow is reduced as a result of growing population density. We further examine direct and indirect effects of population density on yield. We find only mixed support for Boserupian intensification. Fallow periods decrease slightly with increasing population density in this sample, but the relationship is weak. Controlling for other covariates, fallow-unadjusted maize yields first rise then fall with population density. Fallow-adjusted maize yields peak at 390 kg/ha/yr for low population densities (8 persons / km2) and decline to around 280 kg/ha/yr for the highest population densities observed in our dataset. Fallow practices do not appear to mediate the relationship between population density and yield. The multi-level modeling methods we adopt allow for data clustering, accurate estimates of group-level variation, and they generate conditional predictions, all features essential to the comparative study of prehistoric and contemporary agricultural yields.

This chapter provides an introduction to the main theoretical principles employed throughout this volume. It presents an overview of contemporary evolutionary theory, emphasizing the explanatory logic of natural selection. The chapter describes the complexities imposed by the hierarchical organization of living systems and the techniques currently used to analyze the evolution of social interactions. It examines selected theoretical and methodological issues in the social sciences. The chapter gives methodological individualism and rational choice, topics that provide natural avenues for linking social theory and evolutionary ecology. It summarizes the general principles of simple optimization analysis, a framework commonly employed in both evolutionary ecology and the social sciences. The chapter pays special attention to problems that can arise in applying optimization methods in an evolutionary context. Natural selection results from the interaction between a population of organisms and the environment.

© 2017 Elsevier Ltd and INQUA. Changes in social organization accelerated on California's northern Channel Islands beginning around 1300 cal BP. These changes were associated with shifts in settlement and subsistence patterns related in part to drought conditions during the Medieval Climatic Anomaly (MCA; 1150-600 cal BP). By the end of the MCA, settlement patterns demonstrate evidence for territoriality and can be described by the ideal despotic distribution. The occupants of the most productive habitats prevented new settlers from moving in and accessing the available resources. We use faunal data from five sites on western Santa Rosa Island (CA-SRI-15, -31, -97, -313, and -333) to trace changes in settlement and population aggregation through this period. Fishing, which can support higher population densities than harvesting shellfish, increased overall from the Middle (2550-800 cal BP) to Late Period (650-168 cal BP), but there were fewer settlement sites on western Santa Rosa Island. In the centuries before the Middle to Late Period Transition (MLT; 800-650 cal BP), people occupied sites geographically dispersed along the west coast of the island. After the MLT, fishing was restricted to fewer large coastal villages. We argue that environmental stress and an increase in warfare on the northern Channel Islands drove the growth of more permanent consolidated villages, the development of territoriality, and settlement patterns consistent with greater resource defense and therefore a more despotic distribution.

© 2016 Elsevier Inc. Evolutionary ecological models of human fertility predict that: (1) parents will bias investment toward the sex with the highest fitness prospects in a particular socio-ecological context; (2) fertility is subject to quantity–quality trade-offs; and (3) fertility decisions will be sensitive to both predictable and stochastic mortality risk and the relative fitness value of differently sized sib-sets (the variance compensation hypothesis). We test these predictions using demographic records from the Agta, an indigenous population from the Philippines, who, as a result of disruption by loggers, miners, and settlers, are undergoing a demographic and social/ecological transition from foragers to peasant laborers. Leveraging the spatial and temporal variation in the Agta Demographic Database, we conduct an analysis of Agta life-history traits across this transition. Specifically, we compare the Casiguran Agta (CA) with the more isolated peninsular San Ildefonso Agta (SIA) sub-population from before (phase 1) and after (phase 2) encroachment. We find: (1) evidence of a decline in overall survival from phase 1 to phase 2, coupled with increased parental investment in first-born daughters compared to first-born sons in the CA population, and increased parental investment in sons versus daughters in the SIA population; (2) evidence of a moderate quantity–quality trade-off in CA and SIA fertility in phase 1; and (3) support for predictions of the variance compensation hypothesis as a driver of the lowered relative fertility in the CA. Our customized methods, comparative framework, and simultaneous focus on fertility and mortality allow us to show how heterogeneity in mortality and fertility are linked to life history trade-offs and environmental context in a manner consistent with the predictions of evolutionary ecological models.

The prehistoric establishment and expansion of permanent settlements on the Northern Channel Islands of southern California generally follows a pattern predicted by the population ecology model, the ideal free distribution (IFD). We determine this by comparing the abundant archaeological record of these Islands against a careful quantification of habitat suitability using areal photography, satellite imagery, and field studies. We assess watershed area, length of rocky intertidal zone, length of sandy beach for plank canoe pull-outs and area of off-shore kelp beds, for 46 coastal locations. A simple descriptive analysis supports key IFD predictions. A Bayesian model fitted with the Gibbs sampler allows us to reconstruct the Native assessment of habitat that appears to underlie this process. Use of the Gibbs sampler mitigates the impact of missing data, censored variables, and uncertainty in radiocarbon dates; it allows us to predict where new settlements may yet be discovered. Theoretically, our results support a behavioral ecology interpretation of settlement history, human population expansion, and economic intensification in this region. They also demonstrate Bayesian analytical methods capable of making full use of the information available in archaeological datasets.

Since despotism is a common evolutionary development in human history, we seek to understand the conditions under which it can originate, persist, and affect population trajectories. We describe a general system of population ecology equations representing the Ideal Free and Despotic Distributions for one and two habitats, one of which contains a despotic class that controls the distribution of resources. Using analytical and numerical solutions we derive the optimal concession strategy by despots with and without subordinate migration to an alternative habitat. We show that low concessions exponentially increase the time it takes for the despotic habitat to fill, and we discuss the trade-offs despots and subordinates confront at various levels of exploitation. Contrary to previous hypotheses, higher levels of despotism do not necessarily cause faster migration to alternative habitats. We further show how, during colonization, divergent population trajectories may arise if despotic systems experience Allee-type economies of scale.

Analysis of a natural fertility agrarian society with a multi-variate model of population ecology isolates three distinct phases of population growth following settlement of a new habitat: (1) a sometimes lengthy copial phase of surplus food production and constant vital rates; (2) a brief transition phase in which food shortages rapidly cause increased mortality and lessened fertility; and (3) a Malthusian phase of indefinite length in which vital rates and quality of life are depressed, sometimes strikingly so. Copial phase duration declines with increases in the size of the founding group, maximum life expectancy and fertility; it increases with habitat area and yield per hectare; and, it is unaffected by the sensitivity of vital rates to hunger. Transition phase duration is unaffected by size of founding population and area of settlement; it declines with yield, life expectancy, fertility and the sensitivity of vital rates to hunger. We characterize the transition phase as the Malthusian transition interval (MTI), in order to highlight how little time populations generally have to adjust. Under food-limited density dependence, the copial phase passes quickly to an equilibrium of grim Malthusian constraints, in the manner of a runner dashing over an invisible cliff. The three-phase pattern diverges from widely held intuitions based on standard Lotka-Verhulst approaches to population regulation, with implications for the analysis of socio-cultural evolution, agricultural intensification, bioarchaeological interpretation of food stress in prehistoric societies, and state-level collapse.

Child survival is probabilistic, but the unpredictability in family formation and completed family size has been neglected in the fertility literature. In many societies, ending the family cycle with too few or too many surviving offspring entails serious social, economic, or fitness consequences. A model of risk- (or variance-) sensitive adaptive behavior that addresses long-term fertility outcomes is presented. The model shows that under conditions likely to be common, optimal, risk-sensitive reproductive strategies deviate systematically from the completed family size that would be expected if reproductive outcome is were predictable. This is termed the "variance compensation hypothesis." Variance compensation may be either positive or negative, resulting in augmented or diminished fertility. Which outcome obtained is a function of identifiable social, economic, and environmental factors. Through its effect on fertility behavior, variance compensation has a direct bearing on birth spacing and completed fertility, and thereby on problems in demography and human population biology ranging from demographic transitions to maternal depletion and child health. Risk-sensitive models will be a necessary component of a general theory of fertility.

Anthropological views on the labour effort required of hunter-gatherers have flip-flopped between stereotypic positions depicting either very limited subsistence work or long exertion. A computer simulation using evolutionary and population ecology models shows that at equilibrium foraging efficiency is a declining function of work effort, whereas population density responds to work effort by first increasing and then decreasing. This and other foraging theory models provide a framework which can explain observations of routine sharing, modest effort and limited material accumulation in hunter-gatherer societies, leads us to expect diversity in the expression of these characteristics and, is consistent with neo-Darwinian and neoclassical economic theory. Evolutionary ecology theory thus obviates the need for a "Zen' economics as proposed by Sahlins. -from Author

Hutchinson (1975) has recently suggested that the study of population cycles is one area of ecological inquiry where theory and data have not always interacted to produce satisfactory explanations. One difficulty may be that a major part of the data available, fur trade statistics, provides evidence of a different kind than has been, until recently, assumed. In this paper I have attempted to substantiate in qualified form a hypothesis presented by Weinstein (1977) and independently by Winterhalder (1977) pertinent to this difficulty. It states that cyclic or fluctuating pelt counts of boreal region species are partially a result of differential foraging by native trappers, and for many species are not directly indicative of population fluctuations. Three conditions necessary to this interpretation were established: (1) Hare were important in the diet of the Cree-Ojibwa, (2) they could be effectively and efficiently obtained when abundant, and (3) the quest for food-producing species, including hare, had p...

In this paper we combine foraging theory and population biology models to simulate dynamic relationships between hunter-gatherers and their prey resources. Hunter-gatherer population growth responds to the net marginal rate of foraging; prey population growth responds logistically to exploitation. Thus conceived, the relationship between forager and prey biomass is time-dependent and nonlinear. It changes from stable equilibrium to damped and stable cycles with modest adjustments of input parameters. And, it produces the largest sustainable human population at intermediate levels of individual work effort. At equilibrium the forager takes all prey types with a pursuit and handling rate greater than or equal to its maintenance foraging rate. The structural properties of the model compel us to reject standard anthropological interpretations of the carrying capacity concept; they provide new insights on old issues such as original affluence and intensification. Analysis of the interaction of human population, diet selection, and resource depletion requires microecological models in part because the relevant processes occur on time scales largely invisible to both ethnography and archaeology.