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The fate of hunting and gathering populations following the rise of agriculture and pastoralism remains a topic of debate in the study of human prehistory. Studies of ancient and modern genomes have found that autochthonous groups were largely replaced by expanding farmer populations with varying levels of gene flow, a characterization that is influenced by the almost universal focus on the European Neolithic.1-5 We sought to understand the demographic impact of an ongoing cultural transition to farming in Southwest Ethiopia, one of the last regions in Africa to experience such shifts.6 Importantly, Southwest Ethiopia is home to several of the world's remaining hunter-gatherer groups, including the Chabu people, who are currently transitioning away from their traditional mode of subsistence.7 We generated genome-wide data from the Chabu and four neighboring populations, the Majang, Shekkacho, Bench, and Sheko, to characterize their genetic ancestry and estimate their effective population sizes over the last 60 generations. We show that the Chabu are a distinct population closely related to ancient people who occupied Southwest Ethiopia >4,500 years ago. Furthermore, the Chabu are undergoing a severe population bottleneck, which began approximately 1,400 years ago. By analyzing eleven Eastern African populations, we find evidence for divergent demographic trajectories among hunter-gatherer-descendant groups. Our results illustrate that although foragers respond to encroaching agriculture and pastoralism with multiple strategies, including cultural adoption of agropastoralism, gene flow, and economic specialization, they often face population decline.

We examine from whom children learn in mobile hunter-gatherers, a way of life that characterized much of human history. Recent studies on the modes of transmission in hunter-gatherers are reviewed before presenting an analysis of five modes of transmission described by Cavalli-Sforza and Feldman [L. L. Cavalli-Sforza, M. W. Feldman, Cultural Transmission and Evolution: A Quantitative Approach (1981)] but not previously evaluated in hunter-gatherer research. We also present two modes of group transmission, conformist transmission, and concerted transmission, seldom mentioned in hunter-gatherer social learning research, and propose a unique mode of group transmission called cumulative transmission. The analysis of the additional modes of transmission indicated that cultural evolutionary signatures of vertical transmission, such as the conservation of cultural traits, have been underestimated because previous studies have seldom considered remote generations or distinguished intrafamilial from extrafamilial horizontal and oblique transmission. However, field data also indicate that hunter-gatherer children interacted with and learned from many nongenetically related individuals; about half of children’s and adolescents’ horizontal and oblique social learning came from nongenetically related individuals. Intimate living conditions of hunter-gatherers provide opportunities for group transmission, and ethnographic evidence presented demonstrates that at least three types of group transmission exist. All three forms of group transmission theoretically contribute to the conservation of culture, homogeneity of intracultural diversity, and high intercultural diversity. Analysis of additional modes of oblique and horizontal transmission and discussion of previous and unique modes of group transmission demonstrate the various mechanisms by which hunter-gatherer children learn and how cultures are conserved and contribute to cumulative culture. [ABSTRACT FROM AUTHOR]

Humans are an exceptionally cooperative species, but there is substantial variation in the extent of cooperation across societies. Understanding the sources of this variability may provide insights about the forces that sustain cooperation. We examined the ontogeny of prosocial behavior by studying 326 children 3-14 y of age and 120 adults from six societies (age distributions varied across societies). These six societies span a wide range of extant human variation in culture, geography, and subsistence strategies, including foragers, herders, horticulturalists, and urban dwellers across the Americas, Oceania, and Africa. When delivering benefits to others was personally costly, rates of prosocial behavior dropped across all six societies as children approached middle childhood and then rates of prosociality diverged as children tracked toward the behavior of adults in their own societies. When prosocial acts did not require personal sacrifice, prosocial responses increased steadily as children matured with little variation in behavior across societies. Our results are consistent with theories emphasizing the importance of acquired cultural norms in shaping costly forms of cooperation and creating cross-cultural diversity.

Compared everyday infant experiences among central Africa's Aka hunter-gatherers and Ngandu farmers. Found that Aka were more likely to be held, fed, and asleep or drowsy. Ngandu were more likely to be alone and to fuss or cry, smile, vocalize, or play. Crying, soothing, feeding, and sleeping declined over time for both; distal social interaction increased among the Ngandu. (EV)

Cultural learning is a key feature of culture and our humanity. Although studies exist on children's learning in subsistence farmers and hunter-gatherers, comparable cross-cultural studies have not been conducted for pastoralists. The purpose of this paper is to identify and describe patterns of cultural learning in pastoralists and to compare these patterns to what we know about cultural learning in hunter-gatherers. The study utilizes 13 cultures coded as pastoralists in eHRAF World Cultures. The search located 198 texts in ethnographies with precise information on how pastoral children learn. Overall, we found that children acquired most pastoral skills and knowledge in early childhood, children were most likely to learn from parents (vertical transmission) and non-parental adults (oblique transmission), a relationship between age and specific modes of transmission did not exist, various forms of teaching were the most frequently mentioned processes of learning, and the frequency of teaching did not vary by the child's age. When hunter-gatherer's and pastoralist's patterns of cultural learning were compared several similarities emerged: most accounts of learning occurred in early childhood, children were most likely to learn from parents and non-parental adults, and various forms of teaching were the most frequently mentioned processes of learning. Several differences in cultural learning between the two groups were identified: pastoralist ethnographers were less likely than hunter-gatherer ethnographers to mention learning from peers and more likely to mention learning via local enhancement and stimulus enhancement. [ABSTRACT FROM AUTHOR]