Fitts' Law With An Average of Two or Less Submoves?

ABSTRACT

A number of researchers have noted that, with as few as 2 submovements (primary and corrective), the movement time versus index of difficulty (ID) data are described by Fitts' law, that is, there is a linear relationship between movement time (MT) and ID. A model is presented that shows that there may be an apparent relationship of this form between MT and ID with only 2 submovements. The model is based on the characteristics of ballistic movements and the required corrections to the endpoint of the primary submovement. The model shows the close relationship between the ballistic distance-covering phase of a movement and the consequent Fitts' law. The model is tested against several data sets and found to give a good description of the aiming process.

Keywords:

• Fitts' law
• submovements
• ballistic moves