Data on the frequency of non-reproductive adults in a cross-cultural sample of small-scale human societies

Ross, Cody T.; Hooper, Paul L.; Borgerhoff, M Mulder

doi:10.1101/032318

Cited by 4 publications

(5 citation statements)

References 17 publications

(9 reference statements)

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“…Human groups contain multiple breeding pairs within the same social group, and much lower degrees of reproductive skew. A recent compilation of demographic data from 13 small scale societies shows that a minority of adults never reproduce [76]. -Levels of relatedness within cooperatively breeding groups are high.…”

Section: Convergent Social Preferencesmentioning

confidence: 99%

The evolution of altruistic social preferences in human groups

Silk

House

2016

Phil. Trans. R. Soc. B

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One contribution of 18 to a theme issue 'The evolution of cooperation based on direct fitness benefits'. In this paper, we consider three hypotheses to account for the evolution of the extraordinary capacity for large-scale cooperation and altruistic social preferences within human societies. One hypothesis is that human cooperation is built on the same evolutionary foundations as cooperation in other animal societies, and that fundamental elements of the social preferences that shape our species' cooperative behaviour are also shared with other closely related primates. Another hypothesis is that selective pressures favouring cooperative breeding have shaped the capacity for cooperation and the development of social preferences, and produced a common set of behavioural dispositions and social preferences in cooperatively breeding primates and humans. The third hypothesis is that humans have evolved derived capacities for collaboration, group-level cooperation and altruistic social preferences that are linked to our capacity for culture. We draw on naturalistic data to assess differences in the form, scope and scale of cooperation between humans and other primates, experimental data to evaluate the nature of social preferences across primate species, and comparative analyses to evaluate the evolutionary origins of cooperative breeding and related forms of behaviour.

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Section: Convergent Social Preferencesmentioning

confidence: 99%

The evolution of altruistic social preferences in human groups

Silk

House

2016

Phil. Trans. R. Soc. B

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“…Humans exhibit high degrees of cooperation-encompassing proactive food sharing and cooperative child care [1,2], teaching and cultural learning [3], collaborative foraging [4], and extensive division of labour [5,6]-in groups characterized by low average genetic relatedness [7] and low frequencies of non-reproductive individuals [8]. This propensity toward 'hyper-cooperation' [9] takes place within an unusual life history integrating short interbirth intervals and large birth size with a highly dependent juvenile period and a prolonged post-reproductive lifespan, as compared to other primates [10,11].…”

Section: Introductionmentioning

confidence: 99%

Harsh environments promote alloparental care across human societies

et al. 2020

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Alloparental care is central to human life history, which integrates exceptionally short interbirth intervals and large birth size with an extended period of juvenile dependency and increased longevity. Formal models, previous comparative research, and palaeoanthropological evidence suggest that humans evolved higher levels of cooperative childcare in response to increasingly harsh environments. Although this hypothesis remains difficult to test directly, the relative importance of alloparental care varies across human societies, providing an opportunity to assess how local social and ecological factors influence the expression of this behaviour. We therefore, investigated associations between alloparental infant care and socioecology across 141 non-industrialized societies. We predicted increased alloparental care in harsher environments, due to the fitness benefits of cooperation in response to shared ecological challenges. We also predicted that starvation would decrease alloparental care, due to prohibitive energetic costs. Using Bayesian phylogenetic multilevel models, we tested these predictions while accounting for potential confounds as well as for population history. Consistent with our hypotheses, we found increased alloparental infant care in regions characterized by both reduced climate predictability and relatively lower average temperatures and precipitation. We also observed reduced alloparental care under conditions of high starvation. These results provide evidence of plasticity in human alloparenting in response to ecological contexts, comparable to previously observed patterns across avian and mammalian cooperative breeders. This suggests convergent social evolutionary processes may underlie both inter- and intraspecific variation in alloparental care.

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“…Here we provide a brief introduction to the methods for measuring inequality, intended to introduce the reader to what is an extensive body of literature in economics. Distributions can differ from pure equality in numerous ways [20,[28][29][30]. When empirical wealth distributions are well-described by the functional form of one or more distributions, inequality can be described analytically via the parameters specifying the distribution [21].…”

Section: Boxmentioning

confidence: 99%

“…Finally, it is important to note that most of these methods were developed to describe inequality in large nation-states, and methodological challenges remain to facilitate comparative approaches to inequality in smaller societies such as those found in non-human systems [28,29,36].…”

Section: Boxmentioning

confidence: 99%

The ecology of wealth inequality in animal societies

Strauss¹,

Shizuka²

2021

Preprint

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Individuals vary in their access to resources, social connections, and phenotypic traits, and a central goal of behavioral ecology is to understand how this variation influences reproductive success and longevity. Parallel research on human societies has focused on the causes and consequences of variation in material possessions, opportunity, and health among individuals. At the core in both fields of study is that unequal distribution of benefits is an important component of social structure, but an explicit study of inequality is largely missing from evolutionary biology and ecology. Here we advance a research framework and agenda for studying inequality within an ecological and evolutionary context, drawing upon work in the human-oriented literature where applicable. We present four broad arguments for the ecological study of inequality: (1) wealth and inequality are taxonomically broad features of societies, (2) feedback loops link inequality to individual and societal outcomes, (3) very little is known about what makes some societies more unequal than others, and (4) inequality is dynamic, and these dynamics are relevant for social evolution. We hope that this framework will motivate a cohesive interdisciplinary approach to understanding inequality as a widespread and diverse biological phenomenon.

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Data on the frequency of non-reproductive adults in a cross-cultural sample of small-scale human societies

Cited by 4 publications

References 17 publications

The evolution of altruistic social preferences in human groups

The evolution of altruistic social preferences in human groups

Harsh environments promote alloparental care across human societies

The ecology of wealth inequality in animal societies

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