PHENOMENAL VERSUS PROCESS EXPLANATIONS OF PRISM AFTEREFFECTS

The phenomenal hypothesis that prism aftereffects depend upon sight of the Limb was tested in a ball-throwing task during prism exposure; th e participant's (N = 28) limb was either visible or not visible, but f eedback from the moving ball was available during the exposure. Aftere ffects were clearly demonstrated in both the visible-and nonvisible-li mb conditions, and total aftereffect was larger for participants in th e nonvisible-limb condition. Proprioceptive aftereffects were greater than visual aftereffects in the visible-limb group; however, the rever se was true for the nonvisible-limb group. Those results support a pro cessing hypothesis in which sensory feedback, not phenomenal experienc e, is necessary.