“Can I Reach It?” Perceptual Decisions for Reaching

Abstract Perceptual decisions are critical for goal-directed actions embedded in daily tasks. Reaching a good model system to examine perceptual decisions in neurotypical adults. We developed a paradigm that measures perceptual decisions about reachability and actual reaching performance with and without prehension and bilateral arms/hands use. We used it to examine how closely perceived action boundaries match actual action capabilities. Twenty-four (N=24) healthy adults (balanced for sex) view targets at easy, ambiguous, and difficult/impossible distances scaled to their arm reach. Participants judge whether each target is reachable from a seated position to accomplish the task. They then reach for the same targets. We repeat the process for participants to reach with prehension (reach and grasp objects) and also with bilateral arms/hands use. For each participant and each condition, we estimate a perceived reach boundary from the judgments and an actual reach boundary from performance. We also measure decision time and movement kinematics to capture movement strategies. The paradigm provides a basis (proof of concept) for future testing of how motor impairment could alter the calibration of perceived action capabilities. We plan to use this paradigm to test next individuals with cerebral palsy.