Socioeconomic status (SES) during childhood and adolescence is an important predictor of adult health. Even so, there is little known about how childhood SES (chSES) influences long-term health trajectories. Here, the proposed project tests the hypothesis that chSES affects the development of key physiological systems (autonomic nervous system [AIMS], hypothalamic-pituitary adrenal cortical [HPA] axis, immune system) that in turn may influence risk for morbidity and mortality as an adult. The researchers place a special emphasis on identifying the environmental exposures and accompanying psychological mechanisms by which chSES may influence the developmental trajectory of these physiological systems. The researchers assess SES, social, physical and family environments during childhood, adolescence and adulthood by interview and then measure the stress-reactivity of the above mentioned physiological systems during adulthood. In regard to the specific aims, the researchers will first develop a uniform and comprehensive assessment of childhood SES and childhood environments. Within a stress-reactivity paradigm, the researchers hypothesize that adults who experienced lower chSES will possess more negative interpretations of ambiguous behavioral stressors and increased stress-evoked cardiovascular, neuroendocrine, and immune reactivity. This effect may be mediated by differential exposures to detrimental physical, social, and family environments during childhood. These environments may influence the development of psychological traits/states, behavioral health practices, and physiological systems with implications for adult health. Overall, the study and training supported by the F30 NRSA will attempt to identify the underlying physiological mechanisms through which chSES influences adult morbidity and mortality. A novel emphasis is placed on identifying characteristics of the childhood physical, social, and family environments that may mediate the hypothesized relation between chSES and stress related changes in the ANS, HPA axis, and immune system.