How do individuals with autism plan their movements?

Two experiments investigated how persons with and without autism plan manual aiming movements when advance information is direct and when strategic planning is required. In Experiment 1 advance information about hand, direction, and/or movement amplitude was manipulated. Reaction times suggested both groups adopted a hierarchical pattern of movement planning. In Experiment 2, participants performed aiming movements to one of two targets that were the same or different size. Participants without autism varied the starting location in anticipation of specific target stimuli whereas participants with autism consistently selected the midpoint. Overall, individuals with autism used advance information to plan their movements when this information was direct. However, their performance became stereotyped when strategies were self-generated.