Modelling of human's three-dimensional movement - Extending Fitts' model to three-dimensional pointing task

The purpose of this study is to construct a new model that predicts movement time as a function of the index of difficulty of a three-dimensional pointing task. Experimental factors were target size, target distance, and approach direction to the target. Pointing time and coordinate of pointer (right index finger) were measured. It was shown that the trajectory length and mean velocity were greatly affected by the approach direction. We obtained higher values of contribution for the model that introduced the effect of approach direction into the index of difficulty than for the conventional model without the effect.