Visuomotor adaptation and savings to constant and varying visual feedback delays in a driving simulator

Perturbations to visual feedback disrupt one's ability to use vision to guide movement, leading to disrupted visuomotor control. The visuomotor adaptation mechanism recovers control by updating the visuomotor mapping to accommodate the visual perturbation during movement. A hallmark of adaptation is savings, where individuals demonstrate faster adaptation upon subsequent exposure to the same perturbation. Although faster adaptation to a previously experienced delay has been observed in response to constant visual feedback delays in two-dimensional tracking tasks, they have not been investigated in ecologically relevant contexts where individuals perform more complex visuomotor control tasks with varying delays. Previously, delay variability has been shown to significantly impair performance within these tasks, but it remains unclear how delay variability will impact adaptation and savings. Therefore, we investigated adaptation to constant and varying delays in a driving simulator over four sessions spaced 7 days apart. Across these sessions, participants exhibited savings, reflected in reduced average absolute spatial error, a shift in the average directional road position toward the middle of the road (instructed position), and flatter learning slopes, indicating a faster approach to asymptote. Crucially, there were no significant differences between the constant and varying delay conditions in any measure. Therefore, participants adapted to the delayed visual feedback with increased efficiency upon subsequent exposure to the same temporal perturbation. Additionally, delay variability did not disrupt adaptation or savings within the driving simulator task.