The Most Commonly Misquoted Part of Fitts's Law
A candidate summarizes Fitts's Law in an interview as "bigger targets are always faster to hit."
What's missing from that statement, per the precise, citable form of the law?
The correct answer is "Distance to the target — acquisition time depends on both size and distance."
Fitts's Law states that acquisition time is a function of both the target's size and its distance from the starting point — closer and larger targets are faster to acquire, smaller and farther targets are slower and more error-prone. Stating only the size half is one of the most commonly misquoted versions of the law in interviews; the complete, citable form always includes distance, which is also why screen edges and corners (effectively zero extra "aim" distance needed) function as outsized targets regardless of their drawn size.
The distractors misstate the law: size alone doesn't fully determine acquisition time — that's precisely the incomplete version being corrected; Fitts's Law doesn't model color as a variable at all, it's a model of motor acquisition, not visual salience; and it isn't about the number of targets on screen either — that's the kind of decision- time cost Hick's Law describes, a related but distinct principle.
Share this question