Effect of varying target height in a Fitts' movement task

Abstract Experiments are reported of the effect on movement times of varying target height in a Fitts' type of experiment. Data show that there are three well defined regions of control. The first of these, when the index of difficulty based on the target widdi in the direction of motion is larger than that based on the vertical height of the target, is dominated by the constraint in the direction of motion. The second is a transitional region where both vertical and horizontal constraints are effective. The third region is one where the vertical constraint dominates the times for the movement. Fitts' law is found to be applicable in the first and third regions. The same pattern of movement times, as a function of die two IDs, is obtained for discrete and reciprocal movements. As well, die time on target for die reciprocal movements demonstrates this same pattern. Keywords: Fitts' taskTarget heightMovement times