The Stuff Dump

Mathematically, Fitts’s law is stated as follows:

MT = a + b log2(2A/W)

Basically, that means that the time to acquire a target is a function of the distance to and size of the target. It seems like a no brainer. The farther you are and the smaller the target, the longer it takes to move the cursor and point at said target. However, Tom Stafford said it best:

“Although the basic message is obvious (big things are easier to select) it is the precise mathematical characterization that is exciting, and that this characterization includes a logarithmic function - which means that the shape of the relationship between size and reaction time is curved so that small increases in size for small objects make it much easier to select them (whereas small increases in size for big objects don’t make that much difference). And the same applies for changes in target distance.”