Physical and mental health disparities stemming from socioeconomic inequality and poverty are well documented (Evans, Wolf & Adler, 2012). There is clear evidence that (a) the groundwork for lifelong disease and premature death is laid during childhood (e.g., Chen & Miller, 2012), and (b) damage to and deregulation of the physiologic stress response is one of the most powerful mechanisms of the effects of poverty and economic inequality on illness and disease (e.g., Evans & Kim, 2012). To contribute solutions to health disparities, we need interventions that affect the physiologic systems that confer the risk. Since the stress response systems (hypothalamic-pituitary-adrenal axis/HPA and sympathetic-adrenomedullary/SAM) are a central mechanism for SES-based disparities, these are critical systems to target. Improving children's ability to cope with stress and regulate their reactivity has the potential to break the cycle of damage, but only if the coping strategies and regulatory processes that we target have effects at the physiologic level-we have preliminary findings suggesting that they do. The proposed project seeks to firmly establish this connection. Preadolescence is a crucial time during which children's ability to recognize stress and its causes matures, and repertoires for coping with stress grow in both size and complexity. Preadolescents are, therefore, at a ripe stage to both inform our basic science questions and benefit from future coping-based prevention. Our team has compiled a basic understanding of the efficacious and inefficacious forms of coping used by children and adolescents exposed to poverty-related stress (e.g., Santiago, Wadsworth et al., 2011; Wadsworth & Compas, 2002; Wadsworth & Santiago, 2008, 2009), and we have discovered that living with poverty-related stress constrains the development of and/or ability to utilize efficacious coping (Santiago, Etter et al., 2011; Wadsworth et al., 2011). We do not yet know whether coping that is efficacious at the behavioral level has concomitant effects on the underlying physiologic stress response systems in poor, rural preadolescents. The current project will use an experimental approach and data from multiple levels of analysis, including measures of both HPA and SAM activity, observational coding of in vivo coping, and experimental manipulation of coping to: (a) compare the physiologic downregulation of randomly assigned in vivo efficacious (secondary control) and ineffective (disengagement) coping in low-income preadolescents, (b) examine how preadolescents' typical strategies for coping moderate their ability to either make use of secondary control strategies or to regulate themselves despite being primed for avoidance, (c) identify subgroups of preadolescents with different reactivity and regulation profiles, and (d) examine the individual and family characteristics of the identified subgroups, including who is more and less successful in each condition-potentially identifying person-specific intervention targets. Discovery of ways to prevent and/or halt this progression of damage to a child's stress response system can offer new directions for combatting health disparities.