Humans are an intensely social species. We experience social interactions as rewarding from infancy, and the social cognitive skills that we develop in the context of our earliest interpersonal attachments are critical for our survival and personal well being. Lack of social connection is common in many psychiatric and neurodevelopmental disorders. In some disorders, like autism spectrum disorder, social cognition and social interaction impairments are the defining, core feature. Yet, despite the importance of social functioning in humans, our understanding of the neurobiological mechanisms that regulate social behavior is limited. This lecture will describe the roles of two neuropeptides, oxytocin and vasopressin, in the regulation of social behavior in animals, and how findings from this research are providing fundamental insights into human social disorders, with a particular focus on vasopressin and autism spectrum disorder. Recorded on 02/14/2025. (#40381)