In modern human societies, social interactions and pro-social behaviours are associated
with better individual and collective health, reduced mortality, and increased longevity.
Conversely, social isolation is a predictor of shorter lifespan. The biological processes
through which sociality affects the ageing process, as well as healthspan and lifespan,
are still poorly understood. Unveiling the physiological, neurological, genomic, epigenomic,
and evolutionary mechanisms underlying the association between sociality and longevity
may open new perspectives to understand how lifespan is determined in a broader socio/evolutionary
outlook. Here we summarize evidence showing how social dynamics can shape the evolution
of life history traits through physiological and genetic processes directly or indirectly
related to ageing and lifespan. We start by reviewing theories of ageing that incorporate
social interactions into their model. Then, we address the link between sociality
and lifespan from two separate points of view: (i) considering evidences from comparative
evolutionary biology and bioanthropology that demonstrates how sociality contributes
to natural variation in lifespan over the course of human evolution and among different
human groups in both pre-industrial and post-industrial society, and (ii) discussing
the main physiological, neurological, genetic, and epigenetic molecular processes
at the interface between sociality and ageing. We highlight that the exposure to chronic
social stressors deregulates neurophysiological and immunological pathways and promotes
accelerated ageing and thereby reducing lifespan. In conclusion, we describe how sociality
and social dynamics are intimately embedded in human biology, influencing healthy
ageing and lifespan, and we highlight the need to foster interdisciplinary approaches
including social sciences, biological anthropology, human ecology, physiology, and
genetics.
