A Visuomotor Model Enhances Human Position Sense

Integrating information from multiple sources reduces uncertainty. Besides sensory input, animals have access to another source of information about their body and the environment, i.e., their own motor commands, which alter the body and environment in a predictable way. Does this predictability reduce perceptual uncertainty, i.e., variance? Participants moved their unseen arm and reported movement endpoint locations. In two conditions, a predictive model of visuomotor contingencies could either be fully formed, and used for this estimation, or remained incomplete. This was achieved through context trials that provided visual endpoint feedback at a predictable vs. unpredictable latency, while carrying identical spatial information. In two experiments, we found that endpoint estimation was less variable when a full, spatiotemporal, model could be formed. Higher perceptual precision was paralleled by enhanced movement accuracy. We conclude that a visuomotor model provides a separate source of information, additional to sensory input, which enhances human position sense.