A key issue distinguishing prominent evolutionary models of human life history is whether prolonged childhood evolved to facilitate learning in a skill- and strength-intensive foraging niche requiring high levels of cooperation. Considering the diversity of environments humans inhabit, children’s activities should also reflect local social and ecological opportunities and constraints. To better understand our species’ developmental plasticity, the present paper compiled a time allocation dataset for children and adolescents from twelve hunter-gatherer and mixed-subsistence forager societies (n = 690; 3–18 years; 52% girls). We investigated how environmental factors, local ecological risk, and men and women’s relative energetic contributions were associated with cross-cultural variation in child and adolescent time allocation to childcare, food production, domestic work, and play. Annual precipitation, annual mean temperature, and net primary productivity were not strongly associated with child and adolescent activity budgets. Increased risk of encounters with dangerous animals and dehydration negatively predicted time allocation to childcare and domestic work, but not food production. Gender differences in child and adolescent activity budgets were stronger in societies where men made greater direct contributions to food production than women. We interpret these findings as suggesting that children and their caregivers adjust their activities to facilitate the early acquisition of knowledge which helps children safely cooperate with adults in a range of social and ecological environments. These findings compel us to consider how childhood may have also evolved to facilitate flexible participation in productive activities in early life.

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Understanding how socioecology affects contemporary children’s learning and work opportunities can help researchers better model the selection pressures which have shaped the evolution of human life history and social organization. Here, we compiled a global time allocation dataset for children and adolescents from hunter-gatherer and mixed-subsistence societies. We investigated how society-level variables including adult sexual division of labour, ecological risk, and climate related to variation in childcare, food production, domestic work, and play. We found that adult sexual division of labour predicted increased sex differences in time allocation, especially childcare. Children in safer ecologies allocated more time to childcare and domestic work, but ecological risk did not strongly predict participation in food production. Climate did not predict child and adolescent time allocation. We argue that by coordinating labour across age and sex, children may simultaneously learn to navigate challenges in their environment while safely participating in productive activities.

Yearly, development-induced displacement affects some 20 million people, a disproportionate share of whom are indigenous. Within the diverse category of indigenous peoples, hunter-gatherers are especially vulnerable to displacement as they form the least powerful sectors of society. While displacement poses a major threat to the few remaining hunter-gatherer peoples, case studies of how this process unfolds are scarce. This ethnographic study details how two decades of indigenous land rights legislation have been ineffective in preventing displacement of indigenous communities in the Philippines, through the case of Agta hunter-gatherers of Dimasalansan. The paper demonstrates how procedural inconsistencies, institutional competition and a development paradigm focused on commodification of land have undermined the legal titling process. We argue that the ensuing land-rush that currently displaces Agta is symptomatic for how the implementation of indigenous land rights legislation is undermined by business interests, thereby creating more uncertainty than certainty for the least powerful.

Background and objectives How do new ideas spread in social groups? We apply the framework of cultural evolution theory to examine what drives change in perinatal care norms among Himba women in the Kunene region of Namibia. Access to formal medical care is on the rise in this region, and medical workers regularly visit communities to promote WHO-recommended perinatal care practices. This study investigates how various forms of social transmission affect women’s uptake of medical recommendations concerning perinatal care. Methodology Based on interviews with one hundred Himba mothers, we used Bayesian multi-level logistical regression models to examine how perceptions of group preferences, prestige ascribed to outgroup conformers, interaction with the outgroup, and access to resources affect norm adoption. Results Women who perceive medical recommendations as common in their group prefer, plan and practice these recommendations more often themselves. We observed a shift towards medical recommendations regarding birth location and contraception use that was in line with conformity bias predictions. Practices that serve as cultural identity markers persist in the population. Conclusions and implications Norm changes, and the cultural evolutionary processes that can lead to them, are not uniform, either in process or pace. Empirical studies like this one provide important examples of how these changes reflect local culture and circumstance, and are critical for better understanding the models that currently predominate in cultural evolution work. These cases can also help bridge the gap between evolutionary anthropology and public health by demonstrating where promotion and prevention campaigns might be most effective. Lay summary The recent promotion of WHO-recommended perinatal care practices in Namibia provides an opportunity to empirically study norm change using a cultural evolution framework. We found women adopt medical recommendations when they believe these are common in their social group. Local norms that were not discouraged persisted in the study group.