Pursuit eye movements enhance decision making and hitting accuracy in a go/no-go manual interception task

Abstract

It is well established that eye and hand movements are closely coupled in space and time—the eye saccades to and fixates on task-relevant object locations and leads the hand during reaching, grasping, or pointing movements. However, the relation between smooth pursuit and hand movements in response to dynamic visual targets is less well understood. Here, we investigate the relation between smooth pursuit and interception performance in a go/no-go manual interception task. We focus on two aspects of performance: the decision whether or not to move the hand, and the accuracy of the interception. Observers (n=10) viewed a small target moving along a linear path that either projected into a strike zone (hit) or went past it (miss); observers were instructed to intercept only in hit trials, and to not move their hand in miss trials. The target was shown for the full path to the strike zone, or for ¼, ½, or ¾ of the full trajectory. Eye movements were manipulated in separate blocks by instructing observers to maintain fixation on a stationary fixation cross, randomly positioned at three locations along the trajectory, or to move their eyes freely. Across conditions, better and faster pursuit (lower 2D position error, higher eye velocity) and more accurate fixation were linked to better decision and hitting accuracy. Importantly, engaging in smooth pursuit eye movements as compared to fixation resulted in a significant performance improvement across all observers. This pursuit benefit was of the same magnitude (8% average improvement in pursuit vs. fixation) with regard to decision making and hitting accuracy. These results underline the critical importance of smooth pursuit in guiding movement decisions and execution. They also imply that efference-copy signals, generated by the pursuit system, act early on the perceptual system to inform the decision whether or not to initiate a movement. Meeting abstract presented at VSS 2018