Social impairment is a central, unifying feature of autism and autism spectrum disorders (ASD), and perhaps also the most debilitating, but there has been little headway in the development of pharmacological treatments for the social domain. The purpose of this research is to determine whether oxytocin-a peptide hormone that plays a role in affiliative behavior in animals-facilitates complex social cognition in adults with ASD and to elucidate the neurobiological mechanism involved in this process to clarify the viability of this potentially ground breaking treatment. Specifically, 35 adults with ASD will randomly receive a single dose of synthetic oxytocin, administered via nasal spray, or a matching placebo on two separate occasions. Researchers will then assess performance on a novel, complex social cognition task as well as brain activation using functional magnetic resonance imaging (fMRI). If positive, this research will point to a novel, potentially groundbreaking therapeutic candidate to target social dysfunction in ASD. Moreover, the focus on adults with ASD will be an important contribution to the field of autism because to date there is a paucity of effective interventions for adults with ASD.