Time to acquire a target is a function of distance to and size of the target.
Fitts's 1954 law is why screen corners and edges are valuable: they have effectively infinite size in one dimension, since the pointer cannot overshoot them.
In practice
- A "delete account" button placed beside "save changes" is pressed by accident far more often than one in a settings submenu.
- A shop that puts its impulse items at the till has put them where the hand already is.
- Further reading
- Wikipedia
- Subject
- Design & Systems
- Essay
- The limits every design runs into