A typical adaptation task: Participants are asked to move a cursor from home (center of a screen) to target positions (e.g., one of four corner displayed on a computer screen). Three phases include (A) baseline phase with normal visual feedback of the hand movements. In this phase, participants can move straight lines (illustrated in solid grey lines) from the home to one of the targets (arrows represent the moving direction); (B) adaptation/learning phase where the visual feedback of the hand movement is rotated for certain degrees (e.g., about 45 counter-clockwise in this illustration). During this phase, in order to produce a straight movement to the upright target, participant needs to make a straight left-to-right (horizontal) movement. The dotted lines represent the straight paths between the home and the targets. The solid grey lines represent the distorted moving trajectories at the early phase of the adaptation. The dash lines represent the slightly distorted trajectories at the late phase of the adaptation after participants learn the clockwise movements;
and (c) post-adaptation/learning phase where the visual feedback of the hand movement is returned to normal. Now, participants normally demonstrate errors in the opposite direction (i.e., aftereffect) because they have learned clockwise movements in the adaptation phase. Here, the solid grey lines represent to the distorted trajectories in the opposite direction.