Extended Fitts' law in Three-Dimensional Pointing Tasks
Yeonjoo Cha, Rohae Myung · Proceedings of the Human Factors and Ergonomics Society Annual Meeting · 2010
This study explored an extended three-dimensional Fitts' law that is more suited for the pointing task than the conventional Fitts' law. The experiments were conducted under the manipulation of the distance to the target, size of the target, and direction of the target's location that can be described by two angles, θ 1 and θ 2. Considering the starting point as the center of coordinates, θ 1 is the angle between the positive z-axis and the target location and θ 2 is the angle between the positive y-axis and the projected target location on the x-y plane. From the experimental results, we confirmed that all four variables significantly affect the movement time. As we extended the index of difficulty of the conventional Fitts' model by incorporating θ 1 and θ 2, we established an extended Fitt's model that showed better accordance with the empirical data than the conventional Fitts' model, in terms of the r 2 and the standard error of the residual between the measured movement time and the predicted value.