Motor learning mechanisms are not modified by feedback manipulations in a real-world task

Abstract

Error-based and reward-based mechanisms of motor learning co-occur in real-world scenarios but are traditionally isolated in laboratory tasks via feedback manipulations. We examined the distinctiveness of these mechanisms by applying lab-based feedback manipulations to a real-world task. Using Embodied Virtual Reality of pool billiards, we introduced visual perturbations while maintaining full proprioception. 32 participants underwent two sessions, learning visuomotor rotation with either error or reward feedback. The reward-dependent motor variability and inter-trial variability decay - indicators of reward-based learning - were higher in the error-condition. Moreover, post-movement beta rebound (PMBR), a neural marker of learning mechanisms, showed expected decrease under the reward-condition but no consistent trend under the error-condition. These suggest that participants could engage in reward-based learning even without reward feedback. This underscores the complexity of motor learning processes and highlights that visual feedback by itself cannot elucidate the interplay between error-based and reward-based mechanisms in real-world contexts.