Age-related social selectivity: An adaptive lens on a later life social phenotype

Age-related social selectivity is a process in which older humans reduce their number of social partners to a subset of positive and emotionally fulfilling relationships. Although selectivity has been attributed to humans' unique perceptions of time horizons, recent evidence demonstrates that these social patterns and processes occur in other non-human primates, suggesting an evolutionarily wider phenomenon. Here, we develop the hypothesis that selective social behavior is an adaptive strategy that allows social animals to balance the costs and benefits of navigating social environments in the face of age-related functional declines. We first aim to distinguish social selectivity from the non-adaptive social consequences of aging. We then outline multiple mechanisms by which social selectivity in old age may enhance fitness and healthspan. Our goal is to lay out a research agenda to identify selective strategies and their potential benefits. Given the importance of social support for health across primates, understanding why aging individuals lose social connections and how they can remain resilient has vital applications to public health research.