SELECTIVE REACHING TO GRASP - EVIDENCE FOR DISTRACTOR INTERFERENCE EFFECTS

Transport and grasp kinematics were examined in a task in which subjec ts selectively reached to grasp a target object in the presence of non -target objects. In a variety of experiments significant interference effects were observed in temporal parameters, such as movement time, a nd spatial parameters, such as path. In general, the presence of non-t argets slowed down the reach. Furthermore, reach paths were affected s uch that the hand veered away from near non-taroets o in reaches for f ar targets, even though the non-targets were not physical obstacles to the reaching hand. In contrast, the hand veered towards far non-targe ts in near reaches. We conclude that non-targets evoke competing respo nses, and the inhibitory mechanisms that resolve this competition are revealed in the reach path.