This is a mentored Research Career Development Award to support the career development of clinical investigators in patient-oriented research. This project will study the brain mechanisms involved in perceiving social information, thought to be impaired in people with autism. Brain activity and visual attention will be used to measure processing of social information in infants who are at increased risk for autism. The research will entail a longitudinal study of 60 infants at-risk for autism spectrum disorder (ASD) and 40 low-risk infants. Three experiments will be administered at 4 time points (6, 12, 18, and 24 months) to contrast social and non-social perception using static visual stimuli (mother/stranger face versus familiar/unfamiliar object), auditory stimuli (mother/stranger voice versus non-speech analogs), and dynamic audio-visual stimuli (naturalistic video clips of mother/stranger speaking versus non-biological motion and sounds). These experimental probes will map behavioral and brain specialization for social information in infancy in typical and atypical development. This research will elucidate early brain dysfunction in ASD for earlier detection and more effective intervention.