Cue recruitment in active control of a moving line

Abstract

The visual system can actively recruit new cues for perception (eg Haijiang et al, 2006 Proceedings of the National Academy of Sciences of the USA 103 483-488). To explore whether this cue recruitment occurs in visuomotor control, we examined observers' performance as they used a joy-stick to keep a horizontal line centered while its vertical position was randomly perturbed, either under velocity or acceleration controller dynamics. Observers needed position feedback for velocity control, and velocity feedback for acceleration control. An additional colour cue was introduced by making the line appear redder the more it deviated from the display center (position - colour cue) or the faster it moved (motion - colour cue). For velocity control, the overall rms position error was smaller in the position ^ colour condition than in the no-colour or motion ^ colour conditions (13:7 ± 8:4% and 8:9 ± 4:1% smaller, mean ± SE, N . 4); for acceleration control, the rms error was smaller in the motion - colour than in the no-colour or position - colour conditions (26:8 ± 15:1% and 9:8 ± 7:1% smaller). The visuomotor system can selectively recruit novel cues to enhance existing perceptual information for purposes of control.