Abstract
When attempting to intercept a naturalistic target in flight (e.g. a thrown ball), humans initiate movements of the eyes and hand that are predictive of its future trajectory. However, it is unclear if the hands and eyes rely upon common or distinct predictive strategies. Studies suggest that online control strategies offer a sufficient account of hand positioning when the target moves in depth. In contrast, investigations of the oculomotor tracking of a target moving across a 2D plane suggest that visual pursuit utilizes a short-duration internal model of the target's future trajectory. Correlated error in the predictive movements would provide evidence for a common predictive strategy, yet few studies have investigated this for a target moving in depth. To investigate, we present a study in which subjects immersed in a virtual environment intercepted a target that disappeared during flight. Both the initial location and the location where it passed by the subject were randomized between trials. The duration of disappearance is a constant value of 500 ms on every trial. Three possible values of pre-disappearance duration (600, 800, and 1000 ms), and post-disappearance duration (200, 300, and 400ms) were randomly selected on a trial-by-trial basis. Because the target reappears very shortly before its arrival, one can improve the quality of post-disappearance visual feedback by predictively directing gaze towards the expected location of target reappearance. Similarly, placing the hand at a predicted passing location prior to reappearance can reduce the magnitude of movement required after reappearance. Analyses focus upon the error of these predictive movements and demonstrate a tight relationship between strategies for guidance of the eyes and hand.
Meeting abstract presented at VSS 2016