While much effort has been directed at the deficits in social functioning and goal-directed behavior in individuals with autism, there has been little study of non-social forms of motivation that can cause profound problems in adaptive functioning. Research in other diseases has shown that the nucleus accumbens in the brain is underactivated in individuals with ASD, leading to disturbances in goal-directed behavior and learning. The goal of this study is to examine this brain area more carefully, and examine the utilization of this region during tasks which involve monetary, not social, rewards. The investigators will use the Monetary Incentive Delay Task, which has been used in other clinical populations such as schizophrenia. It is anticipated that an underactivity of the nucleus accumbens will be associated with impairments of this task. This experiment will also compare the activation of this brain area with measures of impairment in goal-directed behavior and with the severity of restricted and repetitive behavior symptoms. Significance: The proposed study will represent an important step forward in the way clinicians conceptualize the role of reinforcements when they deliver psychotherapeutic interventions.