Recognizing the motion of a graspable object is guided by handedness

Subjects viewing a rotating screwdriver presented in a motion picture were asked whether it was screwing or unscrewing. A difference emerged in the performance of right- and left-handers. In right-handers, stimulus orientations particularly awkward for a right-hand grip determined higher response times, compared with visually equivalent but more comfortable orientations. When they were also requested to imagine their right hand grasping the screwdriver, similar results were obtained. By imagining the left hand, response times increased and the differences between awkward and comfortable orientations disappeared. In contrast, consistent with their manual dominance, left-handers response times were similar to those obtained when imagining the left but distinct from those obtained when imagining the right hand. We conclude that handedness may guide the interpretation of visual events involving manipulable objects.