The influence of visual illusions on grasp position

Visual size illusions have been shown to affect perceived object size but n ot the aperture of the hand when reaching to those same objects. Thus, visi on for perception is said to be dissociated from vision for action. The pre sent study examines the effect of visual-position and visual-shape illusion s on both the visually perceived center of an object and the position of a grasp on that object when a balanced lift is required. The results for both experiments show that although the illusions influence both the perceived and the grasped estimates of the center position, the grasp position is mor e veridical. This partial dissociation is discussed in terms of its implica tions for streams of visual processing.