HAND, SPACE AND ATTENTIONAL ASYMMETRIES IN GOAL-DIRECTED MANUAL AIMING

Two experiments were conducted to explore the interaction of the two c erebral hemispheres in motor control, by examining hand, space and att entional asymmetries in goal-directed aiming. In Experiment 1, right-h anded subjects moved to targets more quickly with their right hand tha n their left hand. In addition, each hand was faster when moving in it s own hemispace. Although in a control condition, movements were initi ated more quickly with the left hand, visual distracters disrupted lef t hand performance more than right hand performance. For contralateral aiming, ipsilateral distracters caused the greatest interference. In Experiment 2, when targets and distracters were all presented at the m idline, a right hand advantage was found for movement time along with a left hand advantage for reaction time, independent of target and dis tracter location. Our findings are discussed in terms of a right hemis phere role in movement preparation and the allocation of attention in space, and greater left hemisphere involvement in movement execution.