Fitts Law Revealed

For those of you who don’t know what Fitts’ Law is, all I can say is that Fitts’ Law maintains that “movement time” can be mathematically expressed as a function of the distance travelled and the size of the target. More specifically,

MT = K log₂(A / W + 1),

where K is a constant of error, A is the “amplitude” or distance travelled between the two centers, and W is the width of the target.

Now the above equation isn’t Fitts’ original 1954 equation, but a modified equation by MacKenzie (1992)—which seems to be slightly more accurate.

So what’s this thing about MaxMenus, and what does it have to do with Fitts’ Law? Well, Fitts’ law has a huge impact on Human Computer Interaction, as UI designers use it to model mouse movement across the screen. MaxMenus pin the menus in the corners because they are infinitely deep, or rather, they have an infinite width.

In plain words, you can throw your mouse pointer in the direction of the corner, and eventually it will wind up on the menu. That is very clever.