|About the Book|
Social relationships are often cited as being beneficial for health. The answers to how and why social relationships generally improve health remain elusive however. Chapter 2 presents a study in rats that examines a structural dimension that mayMoreSocial relationships are often cited as being beneficial for health. The answers to how and why social relationships generally improve health remain elusive however. Chapter 2 presents a study in rats that examines a structural dimension that may bring about the health-promoting effects of social relationships: affiliative reciprocity during a mild stressor. Affiliative reciprocity during a stressor, a structural quality of social interactions, protected females from early mammary tumor development (the primary pathology in Sprague-Dawley rats) and from early all-cause mortality. Chapter 3 details a lifespan study that sought to determine whether individual differences in components of the glucocorticoid stress response measured at 450 days of age predict spontaneous mammary tumor outcomes. Female rats that would later develop malignant tumors exhibited higher peak corticosterone concentrations in response to a mild stressor than rats that developed benign or no tumors. Females attaining the highest peak corticosterone concentrations developed palpable mammary tumors earliest in life. Females least capable of recovering to baseline concentrations 2 h after a stressor developed the largest mammary tumor burden. Chapter 4 presents a study that examines mammary development after initial development of the mammary structure, and before pregnancy-associated terminal differentiation, as a risk factor for later mammary carcinogenesis. Compared to isolate-housed rats, group-housed females experienced both delayed involution of alveolar lobules during young adulthood and worse tumor outcomes in late adulthood. These results provide an example of how the social environment can modulate developmental processes, and heighten the predisposition for mammary carcinogenesis. The connection between mind and body is not unidirectional. Chapter 5 presents a set of studies that examines how health can influence sociality. In the first experiment, sick animals initiated and received less affiliation, but spent more time huddling with familiar adult cagemates. In the second study, when rats were given the opportunity to titrate their exposure to cagemates, sick rats moved as far from their cagemates as possible. Taken together, these findings illustrate specific ways in which sociality and health influence each other, and provide a blueprint for investigating if and how psychosocial factors interact with physiological systems to impact physical health.