Adaptation to gradual as compared with sudden visuo-motor distortions

If visual feedback is discordant with movement direction, the visuo-motor mapping is disrupted, but can be updated with practice. In this experiment subjects practiced discrete arm movements under conditions of visual feedback rotation. One group was exposed to 10°-step increments of visual feedback rotation up to a total of 90°, a second group to a 90°visual feedback rotation throughout the experiment. After the first group reached the 90°visual feedback rotation, its subjects performed faster, with less spatial error, and showed larger aftereffects than the subjects who practiced constantly under the 90°visual feedback rotation condition. Results suggest that gradually increasing feedback distortion allows more complete adaptation than a large, sudden distortion onset.