Suchergebnisse

The demographic success of humans compared with other closely related species can be attributed to the relatively rapid pace of reproduction and improved chances of survival. The assistance that mothers receive from others to help raise children is a common theme in explaining this gain in surviving fertility. Cooperative breeding in its broad definition describes such a social system in which nonmaternal helpers support offspring who are not their own. In traditional societies, kin and nonkin of different ages and sex contribute both to child care and to provisioning older children. This review discusses empirical evidence for human cooperative breeding and its demographic significance and highlights the ways in which humans are similar to and different from other cooperative breeders. An emphasis is placed on cross-cultural comparison and variability in allocare strategies. Because helping in humans occurs within a subsistence pattern of food sharing and labor cooperation, both kin selection and mutualism may explain why children are often raised with nonmaternal help. Cooperative breeding is relevant to debates in anthropology concerning the evolution of human life history, sociality, and psychology and has implications for demographic patterns in today's world as well as in the past.

"Foraging persists as a viable economic strategy both in remote regions and within the bounds of developed nation-states. Given the economic alternatives available, why do some groups choose to maintain their hunting and gathering lifeways? Through a series of detailed case studies, the contributors to this volume examine the decisions made by modern-day foragers to sustain a predominantly hunting and gathering way of life. What becomes clear is that hunter-gatherers continue to forage because the economic benefits of doing so are high relative to the local alternatives and, perhaps more importantly, because the social costs of not foraging are prohibitive; in other words, hunter-gatherers value the social networks built through foraging and sharing more than the potential marginal gains of a new means of subsistence. Why Forage? shows that hunting and gathering continues to be a viable and vibrant way of life even in the twenty-first century."

National census data show that the modern demographic transition—the recent trend toward declining mortality and fertility—is well underway in most countries. A different picture emerges when data from small‐scale societies in unindustrialized parts of the world are considered. Many of these small‐scale societies are also adapting to rapid changes in their subsistence economies. In this article, we examine the relationship between the pace of acculturation, infant mortality, and fertility levels among Pumé foragers and horticulturalists, two related groups of native South Americans. During the earliest stages of acculturation, Pumé horticulturalists experience not only a rapid drop in infant mortality but also a rise in birth rates. An anthropological view of demographic transitions provides important insight into how small‐scale societies are affected by exposure to the labor market economy and has practical applications to effective development initiatives and public health policies.

This article examines the relationship between household demographic pressure and interage transfers for a group of Maya subsistence agriculturists in Yucatán, Mexico. The authors use data from a field study conducted in 1992–93 on individual time allocation, relative productivity by age and sex, and caloric costs of activities to estimate age schedules of average consumption and production. Using these, they investigate the net costs of children to their parents and find that children have a negative net asset value up to the time they leave home. The direction of net wealth flows in this group is downward, from older to younger, and in economic terms the internal rate of return to children is highly negative up to the time they leave home. Nonetheless, children play a critically important role in the family's economic life cycle. On average, girls offset 76 percent of their consumption costs before leaving home at age 19, and boys offset 82 percent before leaving home at 22. Without the contributions from children as a group, parents would have to double or triple their work effort during part of the family life cycle if they were to raise the same number of children. By the thirteenth year of the family life cycle, children as a group produce more than half of what they consume in every year, and after the twentieth year children produce more than 80 percent of what they as a group consume. The authors also find that the elderly in the sample, ages 50 to 65, produce more than they consume. Thus while children have a negative net asset value to parents, the timing of their children's economic contribution across the family life cycle plays a key role in underwriting the cost of large families.

Postmarital residence patterns in traditional human societies figure prominently in models of hominid social evolution with arguments for patrilocal human bands similar in structure to female-dispersal systems in other African apes. However, considerable flexibility in hunter-gatherer cultures has led to their characterization as primarily multilocal. Horticulturalists are associated with larger, more sedentary social groups with more political inequality and intergroup conflict and may therefore provide additional insights into evolved human social structures. We analyze coresidence patterns of primary kin for 34 New World horticultural societies (6,833 adults living in 243 residential groupings) to show more uxorilocality (women live with more kin) than found for hunter-gatherers. Our findings further point to the uniqueness of human social structures and to considerable variation that is not fully described by traditional postmarital residence typologies. Sex biases in coresident kin can vary according to the scale of analysis (household vs. house cluster vs. village) and change across the life span, with women often living with more kin later in life. Headmen in large villages live with more close kin, primarily siblings, than do nonheadmen. Importantly, human marriage exchange and residence patterns create meta-group social structures, with alliances extending across multiple villages often united in competition against other large alliances at scales unparalleled by other species.

From a comparative perspective, human life histories are unique and raising offspring is unusually costly: humans have relatively short birth intervals compared to other apes, childhood is long, mothers care simultaneously for many dependent children (other apes raise one offspring at a time), infant mortality is high in natural fertility/mortality populations, and human females have a long post-reproductive lifespan. These features conspire to make child raising very burdensome. Mothers frequently defray these costs with paternal help (not usual in other ape species), although this contribution is not always enough. Grandmothers, elder siblings, paid allocarers, or society as a whole, help to defray the costs of childcare, both in our evolutionary past and now. Studying offspring care in a various human societies, and other mammalian species, a wide range of specialists such as anthropologists, psychologists, animal behaviorists, evolutionary ecologists, economists and sociologists, have contributed to this volume, offering new insights into and a better understanding of one of the key areas of human society