Performance Limitations in Laterally Constrained Movements

A model of self-paced tracking performance developed earlier (Drury 1971) predicted a linear increase in spued of movement with increases in the width of a course between lateral barriers, except that for very wide courses the speed would be constant at some limiting speed. Three experiments were run to test this hypothesis using the task of drawing along straight courses with a pen-like stylus. It was found that the linear portion of the relationship continued up to widths six times those used in the previous study. The overall results showed a slow change from the linear portion of the relationship to the flat portion. The hypothesis that this was duo to the artifact of averaging across subjects was supported by data from the final experiment.