Evolution, Relationships, and Health: The Social Shaping Hypothesis

D ealing with environmental stressors such as predators, aggressive rivals, and the divergent interests of conspecifics is one of the primary evolutionary challenges faced by all creatures. In this respect, nature has often been ingenious in its solutions: thick skin, sharp teeth, quick reflexes, and even camouflage. Humans, like many other primate species, have adapted group living and deep investment in social bonds as a primary solution to the problems of survival and reproduction (Caporeal, 1997; Dunbar, 1998). This observation has long been acknowledged in both evolutionary biology and evolutionary psychology but until recently, few scholars have recognized how important social relationships are for managing stress, for health, and for longevity. Recent converging evidence from biology and psychology reveals the manifold benefits of social relationships. Social relationships are vital resources for managing the demands of the environment. Suggestive evidence for this assertion is provided by the fact that social isolation is associated with a heightened risk of disease and early mortality in both animals and humans (Cacioppo & Hawkley, 2003; House, Landis, & Umberson, 1988). Thus, the absence of social ties is toxic for health. Social relationships themselves can have dramatic and long-lasting effects on biological functioning and health as well. A harsh social environment characterized by cold, conflictual, or neglectful interactions is associated with a high risk of prolonged illness and early mortality, whereas warm and supportive relationships have long-term benefits for health and longevity. Social support, common to these latter relations, is the perception or experience that one is loved and cared for by others , esteemed and valued, and part of a social network of mutual assistance and obligations (Wills, 1991). The impact of social support on health equals or exceeds that of well-established predictors of health outcomes, including smoking and lipid levels.