This is an NIH Career Enhancement Award to augment or redirect the research programs of established investigators through the acquisition of new research skills. The ability to reason about other's behavior is a pervasive aspect of mature and developing cognition. In past work, the researcher has demonstrated that infants possess a rich understanding of others' goals and intentions and identified some of the factors and experiences, such as infants' developing action abilities, that account for developmental change in this domain. The long-term goal is to provide a precise, mechanistic account of changes in infants' and children's understanding of others' behavior. However, progress toward this objective relies on the development of methods to assess the neurocognitive processes underlying action perception. This award will facilitate the systematic investigation of the neural basis of action perception using the event-related potential (ERP) technique. The research will include a pilot study to investigate the feasibility of using ERP methods to investigate the neurocognitive mechanisms underlying action perception in typically developing infants. The findings from this work will provide important information regarding the developmental mechanisms underlying early action perception and understanding. The proposed studies will create a novel method for assessing infants' action perception and other aspects of social cognition, and by translating concepts from developmental psychology to neuroscience and vice versa. In addition, the results may be particularly relevant to the diagnosis and remediation of autism, a developmental disorder that is characterized by deficits in reasoning about other people's behavior.