Modifying one’s hand’s trajectory when a moving target’s orientation changes

The path that the hand takes to intercept an elongated moving target depends on the target’s orientation. How quickly do people respond to changes in the moving target’s orientation? In the present study, participants were asked to intercept moving targets that sometimes abruptly changed orientation shortly after they started moving. It took the participants slightly more than 150 ms to adjust their hands’ paths to a change in target orientation. This is about 50 ms longer than it took them to respond to a 5-mm jump in the moving target’s position. It is only slightly shorter than it took them to initiate the movement. We propose that responses to changes in visually perceived orientation are not exceptionally fast, because there is no relationship between target orientation and direction of hand movement that is sufficiently general in everyday life for one to risk making an inappropriate response in order to respond faster.