When a target is large, you can stop the cursor across a wide region and still succeed. As the target shrinks, the final position must be controlled more precisely.
This increases the need for deceleration and small corrective movement near the endpoint.
Fitts’ law combines distance and target width into an index of pointing difficulty. For the same movement distance, decreasing effective width increases predicted movement time.
That relationship has been used for decades in human-computer interaction to study pointing devices and interface design.
A tiny target immediately beside the cursor and a tiny target across the screen are not equally difficult. Distance increases movement demand while size increases precision demand.
If you are comparing aim scores, record both or keep the layout constant.
A good training score should reward successful target acquisition, not merely fast cursor motion. If average time falls but accuracy collapses, the effective task performance may have worsened.
Try to reduce time while keeping hit rate stable.
Real interfaces and games rarely present every target at exactly the same size. A mixed-size drill forces you to change movement strategy from one target to the next: large targets tolerate a faster endpoint, while small targets require earlier deceleration and tighter control. That switching makes the session harder but can also make it more representative of practical pointing.
For clean progress tracking, keep one repeatable benchmark run as well. Use the same target settings for that benchmark, then use mixed-size or harder drills for practice. Separating the benchmark from the training variation prevents a harder session from looking like “lost progress” simply because the targets changed.
Their small hit area leaves less room for endpoint error, so stopping accuracy becomes more important.
No. Different sizes train different speed–accuracy demands. Progressive variation is more useful.
It can. Effective width along the movement direction and the visible/interactive hit area both influence acquisition.