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Despite agreement that humans have evolved to be unusually fat primates, adipose patterning among hunter–gatherers has received little empirical consideration. Here we consider the development of adiposity among four contemporary groups of hunter–gatherers, the Aka, Savanna Pumé, Ju’/Hoansi and Agta using multi-level generalized additive mixed modelling to characterize the growth of tricep skinfolds from early childhood through adolescence. In contrast to references, hunter–gatherers show several consistent patterns: (i) children are lean with little fat accumulation; (ii) no adiposity rebound at 5 years is evident; (iii) girls on average have built 90% of their body size, and reach menarche when adiposity is at its maximum velocity; and (iv) a metabolic trade-off is evident in young, but not older children, such that both boys and girls prioritize skeletal growth during middle childhood, a trade-off that diminishes during adolescence when height velocity increases in pace with fat accumulation. Consistent results across hunter–gatherers living in diverse environments suggest that these patterns reflect a general forager pattern of development. The findings provide a valuable baseline for adipose development not apparent from reference populations. We emphasize both generalized trends among hunter–gatherers, and that inter-populational differences point to the plasticity with which humans organize growth and development. 

Little is known about the potential for reproductive conflict among hunter–gatherer populations, who are characterized by bilateral kinship ties, flexible residential mobility, and high offspring mortality. To assess the potential for reproductive conflict, we use longitudinal residence and reproductive history data for two bands of South American foragers. Using multilevel logistic regressions (N= 44 women,N= 712 person years), we examine how yearly measures of (i) camp composition, (ii) distribution of female kin and (iii) a woman's position in a female kinship network impact the likelihood of giving birth or experiencing a child's death. We compare conflict models to a demographic model that accounts for the proportion of women giving birth in a given year. Contrary to conflict models, results show that the odds of giving birth increase with the presence of highly related women. However, the odds of experiencing an offspring death are insensitive to the presence of coresident women. Network measures of closeness and centrality in the female kin network also show no significant effect on reproductive outcomes. Furthermore, chances of both births and deaths increase in years when proportionally more women are giving birth. We argue that demographic stochasticity relating to ecological conditions best predicts reproductive outcomes for women. This article is part of the theme issue ‘Cooperation among women: evolutionary and cross-cultural perspectives’. 

Abstract ObjectivesThe extreme condition that we address in this special issue is how people adapt to rapid change, which in this case study is instigated by globalization and the process of market integration. Although market integration has been underway for centuries in some parts of the world, it often occurs precipitously in small‐scale societies, initiating an abrupt break with traditional ways of life and fostering a keen sense of uncertainty. MethodsUsing cross sections from 30‐years of data collected in a Yucatec Maya subsistence farming community, we test the expectation that when payoffs to pursue new livelihood and reproductive options are uncertain, variance in social, economic, and reproductive traits will increase in the population. Our data span the transition from subsistence farming to a mixed economy, and bridge the transition from natural to contracepting fertility. Exposure to globalizing and market forces occurred when a paved road was built in the early 2000s. ResultsWe find that livelihood traits (a household's primary economic strategy, amount of land under cultivation, amount of maize and honey sold), become more variable as new, but uncertain options become available. Variance in levels of education and family size likewise immediately increase following the road, but show signs of settling back down a decade later. Rather than replacing one way of life with another, Maya farmers conservatively adopt some new elements (family planning, wage labor), until the tradeoffs to commit to smaller families and the labor market become clearer. ConclusionOur findings highlight that in rapidly changing environments when the payoffs to assimilate new options are uncertain, some households and individuals intensify what they know best, while others adopt new opportunities, driving variance up in the population. 

Abstract Social scientists have increasingly used asset‐based wealth scores, like the Demographic and Health Survey (DHS) wealth index, to assess economic disparities. However, current indices primarily capture wealth in globalized market economies, thus ignoring other forms of prosperity, such as success in agricultural activities. Using a simple extension to the standard estimation of the DHS wealth index, we describe procedures for estimating an agricultural wealth index (AWI) that complements market‐based wealth indices by capturing household success in agricultural activities. We apply this procedure to household data from 129 DHS surveys from over 40 countries with sufficient land and livestock data to estimate a reliable and consistent AWI. We assess the construct validity of the AWI using benchmarks of growth in both adults and children. This alternative measure of wealth provides new opportunities for understanding the causes and consequences of wealth inequality, and how success along different dimensions of wealth creates different social opportunities and constraints for health and well‐being. 

Abstract Studies have shown mixed associations between wealth and fertility, a finding that has posed ongoing puzzles for evolutionary theories of human reproduction. However, measures of wealth do not simply capture economic capacity, which is expected to increase fertility. They can also serve as a proxy for market opportunities available to a household, which may reduce fertility. The multifaceted meaning of many wealth measures obscures our ability to draw inferences about the relationship between wealth and fertility. Here, we disentangle economic capacity and market opportunities using wealth measures that do not carry the same market-oriented biases as commonly used asset-based measures. Using measures of agricultural and market-based wealth for 562,324 women across 111,724 sampling clusters from 151 DHS surveys in 64 countries, we employ a latent variable structural equation model to estimate (a) latent variables capturing economic capacity and market opportunity and (b) their effects on completed fertility. Market opportunities had a consistent negative effect on fertility, while economic capacity had a weaker but generally positive effect on fertility. The results show that the confusion between operational measures of wealth and the concepts of economic capacity can impede our understanding of how material resources and market contexts shape reproduction. 

Abstract ObjectivesWith our diverse training, theoretical and empirical toolkits, and rich data, evolutionary and biological anthropologists (EBAs) have much to contribute to research and policy decisions about climate change and other pressing social issues. However, we remain largely absent from these critical, ongoing efforts. Here, we draw on the literature and our own experiences to make recommendations for how EBAs can engage broader audiences, including the communities with whom we collaborate, a more diverse population of students, researchers in other disciplines and the development sector, policymakers, and the general public. These recommendations include: (1) playing to our strength in longitudinal, place‐based research, (2) collaborating more broadly, (3) engaging in greater public communication of science, (4) aligning our work with open‐science practices to the extent possible, and (5) increasing diversity of our field and teams through intentional action, outreach, training, and mentorship. ConclusionsWe EBAs need to put ourselves out there: research and engagement are complementary, not opposed to each other. With the resources and workable examples we provide here, we hope to spur more EBAs to action. 

Abstract ObjectivesHuman responses to climate variation have a rich anthropological history. However, much less is known about how people living in small‐scale societies perceive climate change, and what climate data are useful in predicting food production at a scale that affects daily lives. MethodsWe use longitudinal ethnographic interviews and economic data to first ask what aspects of climate variation affect the agricultural cycle and food production for Yucatec Maya farmers. Sixty years of high‐resolution meteorological data and harvest assessments are then used to detect the scale at which climate data predict good and bad crop yields, and to analyze long‐term changes in climate variables critical to food production. ResultsWe find that (a) only local, daily precipitation closely fits the climate pattern described by farmers. Other temporal (annual and monthly) scales miss key information about what farmers find important to successful harvests; (b) at both community‐ and municipal‐levels, heavy late‐season rains associated with tropical storms have the greatest negative impact on crop yields; and (c) in contrast to long‐term patterns from regional and state data, local measures show an increase in rainfall during the late growing season, indicating that fine‐grained data are needed to make accurate inferences about climate trends. ConclusionOur findings highlight the importance to define climate variables at scales appropriate to human behavior. Course‐grained annual, monthly, national, and state‐level data tell us little about climate attributes pertinent to farmers and food production. However, high‐resolution daily, local precipitation data do capture how climate variation shapes food production. 

A major goal in Engineering training in the U.S. is to continue to both grow and diversify the field. Project- and service-based forms of experiential, problem-based learning are often implemented with this as a goal, and Engineering Projects in Community Service (EPICS) High is one of the more well-regarded and widely implemented. Yet, the evidence based on if and how participation in such programs shapes student intentions and commitment to STEM pathways is currently limited, most especially for pre-college programming. This study asks: How do high school students’ engineering mindsets and their views of engineering/engineers change as they participate in project–service learning (as implemented through an EPICS High curriculum)? This study employed a mixed method design, combining pre- and post-test survey data that were collected from 259 matched students (63% minority, 43% women) enrolling in EPICS High (total of 536 completed pre-tests, 375 completed post-tests) alongside systematic ethnographic analysis of participant observation data conducted in the same 13 socioeconomically diverse schools over a two-year period. Statistical analyses showed that participants score highly on engineering-related concepts and attitudes at both pre- and post-test. These did not change significantly as a result of participation. However, we detected nuanced but potentially important changes in student perspectives and meaning, such as shifting perceptions of engineering and gaining key transversal skills. The value of participation to participants was connected to changes in the meaning of commitments to pursue engineering/STEM.