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Why Old Age: Non-Material Contributions and Patterns of Aging Among Older Adult Tsimane'

Little is known about why humans have an extended juvenile development and long post-reproductive lifespan. While older adults’ non-material contributions to younger generations can help explain human life history, even less is known about development of skills and abilities in small-scale society, and whether older adults suffer from social depreciation as traditional skills become replaced with novel skills related to market interactions. As the relative size of older aged populations burgeons across cultures, so does prevalence of increased health risk, abuse, neglect, and discrimination. Solutions to these problems are not well understood. This study among the Tsimane' of the Bolivian Amazon, focusing on development of special skills and older adults’ roles in the enculturation process, provides evidence of positive intergenerational contributions and the circumstances that both threaten and contribute to wellbeing of older adults. Three components of these contributions have been investigated: a) knowledge and expertise; b) development and transmission of important skills over the lifecourse; c) roles as social mediators, child-rearers, skill transmitters, and informal leaders. Data has also been collected on psychological well-being, social support, and health of older adults, to see if those who contribute more are better off. Results indicate that complex skills essential to survival take decades to learn. Wellbeing of older Tsimane' is contingent on their roles in culture transmission; they specialize in storytelling, increase involvement in kin affairs, and are most identified as experts and transmitters. Variance in market acculturation found among study villages shows that adults in more acculturated villages are valued less, as difficult traditional skills become replaced with convenient novel skills. These findings, which help explain when and why older Tsimane' are supported, also support the hypothesis that large brains and delayed development, with relatively late onset of adult productivity, enable the long and slow life history that characterizes humans. Payoffs of sustained early life learning among foragers are realized only later in life, but such an investment is only worthwhile given the long lifespan, health improvements, and important cultural transmission contributions to younger kin made by older adults in the context of a kin-based society with relatively stable traditions.