UX Laws & Principles
Research-backed UX laws, principles, and methods connected to real insights
Accot-Zhai Steering Law
### Human physiology Moving a cursor along a long, straight line is physically difficult for humans due to the physiology of our elbows and wrists. As a result, the longer the motion, the greater the chance of error.
Doherty Threshold
Productivity soars when a computer and its users interact at a pace (<400ms) that ensures that neither has to wait on the other. ### System feedback Provide system feedback within 400 ms in order to keep users’ attention and increase productivity. ### Perceived performance Use perceived performance to improve response time and reduce the perception of waiting. ### Animation Animation is one way to visually engage people while loading or processing is happening in the background. ### Progress bars Progress bars make wait times tolerable, regardless of their accuracy. ### Purposeful delay Purposefully adding a delay to a process can actually increase its perceived value and instill a sense of trust, even when the process itself actually takes much less time.
Fitts' Law
The time to acquire a target is a function of the distance to and size of the target. ### Size Touch targets should be large enough for users to accurately select. ### Spacing Touch targets should have ample spacing between them. ### Placement Touch targets should be placed in areas of an interface that allow them to be easily accessed.
Simon Effect
People respond faster and more accurately when the location of a stimulus matches the location of the response, even when stimulus location is irrelevant to the task.
About UX Laws
UX Laws connect theoretical principles with real research insights. Each law is linked to supporting research findings from usability studies, helping you make evidence-based design decisions.