This research project focuses on assessing the ability to control posture and movement in young children with autism and the relationship to restricted, repetitive and stereotyped patterns of behaviors (RRBs) in autism. Dr. Hass and his colleagues will use standardized clinical testing and biomechanical evaluation of performance on tasks with increasing challenge of motor skills to examine motor control abilities in children with autism. He will test the hypothesis that children with autism that display more RRBs will also show difficulties balancing and a greater degree of postural instability as compared to those who are not affected. This will include standard diagnostic and neuropsychological tests of autism together with assessments of postural control of children while they are standing, as well as moving. What this means for people with autism: Currently, little is known about the best way for a therapist to approach a young child with autism. Results from the proposed study will provide direct insight into postural control in children with ASD so that evidence-based and targeted physical and occupational therapy can be developed in better ways.