Recruitment of a novel cue for active control depends on control dynamics

We investigated how the visual-motor system recruits a novel visual feedback cue for a manual control task. We presented conditions in which an arbitrary cue (color) was coupled with task-relevant feedback (position or velocity), and measured the effect of the novel cue on performance. Participants used a joystick to keep a moving horizontal line centered on a display under velocity or acceleration control dynamics. Participants normally rely primarily on line position feedback for velocity control and line velocity feedback for acceleration control. The novel color cue was coupled with either line position (becoming red as it deviates from center) or line velocity (becoming red as it moves faster). For velocity control, performance error was smaller and response gain was larger when the novel color cue was coupled with line position than when it was coupled with line velocity. Conversely, for acceleration control, performance was better when color was coupled with line velocity than with line position. Our findings show that the visual-motor system can recruit a novel arbitrary cue to improve active control performance, but the effectiveness of the novel cue depends on its relationship to the feedback appropriate for control dynamics.