PROJECT SUMMARY Callous-unemotional behavior (CU behavior), characterized by atypically low empathy, prosociality and guilt, represents a serious impairment in moral development associated with severe and persistent conduct problems, violent crime, social rejection, and substance use disorders. Alarmingly, CU behaviors have been historically difficult to treat. By age 3, CU behaviors are reliably measurable, predict CU into late childhood, and are already associated with greater conduct and social problems. Despite this evidence, very few studies have examined precursors of CU behaviors (i.e., emerging CU) or identified risk and protective factors during infancy and toddlerhood, when morality develops rapidly and thus may be most malleable. This knowledge may identify more precise risk and protective processes underlying emerging CU that may be targeted to prevent a highly impairing psychosocial trajectory. Consistent with NIMH Strategic Objective 2 to “chart mental illness trajectories to determine when, where, and how to intervene,” this K23 application aims to identify neural correlates and environmental, child dispositional, and parenting risk and protective factors for emerging CU behavior across infancy and toddlerhood. To accomplish these aims, this proposal leverages an exceptional opportunity to add measures to an NIH-funded study following a large, high-risk cohort of mother-infant dyads annually from birth through age 3. The applicant will add critical measures to this parent study including observational and parent- report assessments of emerging CU, an event-related potential (ERP) task, and experimenter-child interactions to assess children's dispositions. This proposal will use ERPs to characterize neural markers of CU behavior and examine whether aspects of children's environments (early life adversity) and dispositions (low affiliation) measured in infancy predict maladaptive trajectories of emerging CU through age 3. Further, it will test whether low parenting warmth is implicated in these risk trajectories and could thus be a protective factor targeted in treatment. Findings will inform the developmental neurobiology of emerging CU behavior and elucidate promising early prevention and treatment targets. To execute this proposal, the training plan in this application addresses the applicant's need for training in 1) ERP assessment methods; 2) the developmental psychopathology of CU behavior; and 3) longitudinal design and analysis. A rich training environment and a multidisciplinary team of mentors in each of these areas is detailed. The described research and training activities will enable the candidate to become an independent scientist investigating neural and psychosocial risk for aberrant moral development and its role in the onset and maintenance of early childhood psychopathology.