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Abstract BackgroundSocial isolation is a key risk factor for the onset and progression of age-related disease and mortality in humans. Nevertheless, older people commonly have narrowing social networks, with influences from both cultural factors and the constraints of senescence. We evaluate evolutionarily grounded models by studying social aging in wild chimpanzees, a system where such influences are more easily separated than in humans, and where individuals are long-lived and decline physically with age. MethodologyWe applied social network analysis to examine age-related changes in social integration in a 7+ year mixed-longitudinal dataset on 38 wild adult chimpanzees (22 females, 16 males). Metrics of social integration included social attractivity and overt effort (directed degree and strength), social roles (betweenness and local transitivity) and embeddedness (eigenvector centrality) in grooming networks. ResultsBoth sexes reduced the strength of direct ties with age (males in-strength, females out-strength). However, males increased embeddedness with age, alongside cliquishness. These changes were independent of age-related changes in social and reproductive status. Both sexes maintained highly repeatable inter-individual differences in integration, particularly in mixed-sex networks. Conclusions and implicationsAs in humans, chimpanzees appear to experience senescence-related declines in social engagement. However, male social embeddedness and overall sex differences were patterned more similarly to humans in non-industrialized versus industrialized societies. Such comparisons suggest common evolutionary roots to ape social aging and that social isolation in older humans may hinge on novel cultural factors of many industrialized societies. Lastly, individual and sex differences are potentially important mediators of successful social aging in chimpanzees, as in humans.Lay summary: Few biological models explain why humans so commonly have narrowing social networks with age, despite the risk factor of social isolation that small networks pose. We use wild chimpanzees as a comparative system to evaluate models grounded in an evolutionary perspective, using social network analysis to examine changes in integration with age. Like humans in industrialized populations, chimpanzees had lower direct engagement with social partners as they aged. However, sex differences in integration and older males’ central positions within the community network were more like patterns of sociality in several non-industrialized human populations. Our results suggest common evolutionary roots to human and chimpanzee social aging, and that the risk of social isolation with age in industrialized populations stems from novel cultural factors.
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Kinship Practices Among Alternative Family Forms in Western Industrialized Societies
Abstract ObjectiveThis article discusses how kinship is construed and enacted in diverse forms of the family that are now part of the culturally pluralistic family system of Western societies. BackgroundThis study is the second in a pair documenting changes over the past century in the meaning and practice of kinship in the family system of Western societies with industrialized economies. While the first paper reviewed the history of kinship studies, this companion piece shifts the focus to research explorations of kinship in alternative family forms, those that depart from the standard nuclear family structure. MethodThe review was conducted running multiple searches on Google Scholar and Web of Science directly targeting nonstandard family forms, using search terms such as “cohabitation and kinship,” “same‐sex family and kinship,” and “Artificial Reproductive Technology and kinship,” among others. About 70% of studies focused on the United States, while the remaining 30% focused on other industrialized Western societies. ResultsWe identified three general processes by which alternative family forms are created and discussed how kinship practices work in each of them. Thefirstcluster of alternative family forms comes about throughvariations of formal marriage or its absence, including sequential marriages, plural marriages, consensual unions, single parenthood, and same‐sex marriages and partnerships. Thesecondcluster is formed as a result ofalterations in the reproduction process, when a child is not the product of sexual intercourse between two people. Thethirdcluster results from theformation of voluntary bondsthat are deemed to be kinship‐like, in which affiliation rests on neither biological nor legal bases. ConclusionFindings from this study point to a broad cultural acceptance of an inclusive approach to incorporating potential kin in “family relationships.” It is largely left to individuals to decide whether they recognize or experience the diffuse sense of emotional connectedness and perceived obligation that characterize the bond of kinship. Also, family scripts and kinship terms often borrow from the vocabulary and parenting practices observed in the standard family form in the West. Concurrently, the cultural importance of biology remains strong. ImplicationsThis study concludes by identifying important gaps in the kinship literature and laying out a research agenda for the future, including building ademography of kinship.
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- Award ID(s):
- 1729185
- PAR ID:
- 10456816
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of Marriage and Family
- Volume:
- 82
- Issue:
- 5
- ISSN:
- 0022-2445
- Page Range / eLocation ID:
- p. 1403-1430
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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