The kinesthetic spatial aftereffect as a function of the angular displacement of the joints of the arm

speed control hand plate TIle magnitude of the kinesthetic spatial aftereffect following different angular displacements from the vertical and horizontal planes during stimulation was examined in two experiments using 278 Ss. Both Gibson's direct and indirect effect were found when angular displacements were away from the vertical, however, a bimodal pattern was observed in both experiments when stimulation was away from the horizontal. An explanation for the interaxial difference cannot be provided by conventional theories and must be sought in a consideration of the structure of the joints which are involved with the production of the aftereffect.