How timely can our hand movements be?

Abstract

The temporal variability of our movements is reduced when we move fast. Here we study whether different sensory information (vision and proprioception) or prior knowledge of final position or travelled distance can affect the temporal precision of movements directed to static targets. We attempted to promote the use of either on-line feedback control (providing visual and proprioceptive information of the movement and maintaining the target position predictable trial-to-trial) or forward control (removing visual feedback and maintaining a predictable target position). In a first experiment, the variability of movement times indicates that temporal precision is affected by the predictability of the target's position and by different feedback conditions. In a second experiment we disentangled the question regarding whether it is the target's position estimate, the travelled distance or the velocity that enhanced the temporal performance. In accordance with previous studies, results indicate that velocity is the main factor in controlling temporal precision across different conditions.