When participants make judgments about the onset of self-initiated movements they typically report the movement occurred earlier than it had [Obhi, S. S., & Haggard, P. . Free will and free won’t. American Scientific, 92, 358–365.]. One interpretation is that feed-forward processes lead to awareness of the movement prior to execution. Because individuals with autism experience reduced preparatory activity prior to a voluntary movement, the present study sought to determine whether these anticipatory biases are exhibited by persons with autism. Participants (...) watched a dot move in a circle and pressed the spacebar any time after one revolution. A tone either followed the participants’ voluntary movement or was computer generated. Participants in both groups made anticipatory judgements regarding movement initiation . When the movement and tone occurred together this anticipatory bias was also present, regardless of which event participants focused on. Individuals with autism appear to have access to a similar representation of voluntary movements, however this representation may be more variable. (shrink)

Visual feedback regulation during movement is not fully captured in Plamondon's kinematic theory. However, numerous studies indicate that visual response-produced feedback is a powerful determinant of performance and kinematic characteristics of target-directed movement.

Several lines of evidence indicate that rapid target-aiming movements, involving both the eyes and hand, can be biased by the visual context in which the movements are performed. Some of these contextual influences carry-over from trial to trial. This research indicates that dissociation between the dorsal and ventral systems based on speed, conscious awareness, and frame of reference is far from clear.

Several lines of evidence indicate that the on-line control of rapid target-aiming movements can be influenced by the visual context in which the movements are performed. Although this may result in movement error when an illusory context is introduced, there are many situations in which the control system must know about context in order to get the limb to the target rapidly and safely.