Disrupted social engagement is a hallmark feature of autism spectrum disorders (ASD). Although developmental processes are implicated in the etiology of ASD, early detection and intervention strategies have been hindered by our limited understanding of genetic and environmental factors governing social brain development. Infants accomplish much of their learning within a social context, but it is unknown whether social cues modulate the efficacy of early learning. Newborns show a preference for social stimuli, suggesting that social cues may bias attention and information processing systems to learn more selectively and efficiently from social partners. In studies of human infants, the research team found enhanced learning when infants were trained with social compared to non-social cues. Most remarkably it was determined that the rate of infant learning predicts the quality of later social development. This study hypothesizes that social factors in a child's environment shape their learning and brain development, and that this important aspect of development is influenced by three neurochemical systems-the oxytocin (OXT), arginine-vasopressin (AVP) and mu opioid receptor systems-which are implicated in adult social behavior and motivation. The study will identify factors governing early learning and social development by employing parallel research strategies in mouse models and humans. The research team will examine if manipulating genes involved in adult social behavior affects social or non-social associative learning in mice. The research training team will also examine if allelic variants in the OXT and AVP receptor genes are associated with heterogeneity in learning or social development in children participating in human learning studies. These studies will provide insight into neurochemicals governing early learning and social development. The data will be paired with clinical observations of children undergoing assessment for ASD at Children's Hospital Los Angeles, analysis of autism-relevant phenotyping data collected in a clinical autism study, and observations of social-cognitive assessments in typically developing children. These mentored translational experiences add neurodevelopmental, mouse and human genetics, and clinical dimensions to the fellows prior training in adult social-emotional behavior, and provide an exciting opportunity to develop infant learning measures as an early and non-invasive biomarker for social development.