UX Laws
Behavioral patterns and cognitive constraints translated into practical interface decisions.
Aesthetic-Usability Effect
A polished interface often feels easier to use before anyone has tested how well it works.
Choice Overload
A large choice set can make decisions harder when the options are unfamiliar or difficult to compare.
Chunking
Group related information into meaningful units that are easier to scan, understand, and remember.
Cognitive Bias
Mental shortcuts help us judge quickly, but they can also produce predictable mistakes.
Cognitive Load
Every interface asks for mental effort. Good design spends that effort on the task, not on decoding the screen.
Doherty Threshold
Fast feedback helps people keep their train of thought while they work with a system.
Fitts’s Law
Targets are faster and easier to reach when they are larger and closer to the starting point.
Flow
Deep focus is more likely when goals are clear, feedback is immediate, and challenge fits the person's skill.
Goal-Gradient Effect
Effort can increase as a visible and meaningful goal feels closer.
Hick’s Law
Choosing a response usually takes longer as the number and uncertainty of possible responses increase.
Jakob’s Law
People bring expectations from the other products they already use.
Law of Common Region
Elements inside the same visible area tend to be perceived as a group.
Law of Proximity
Elements placed near one another tend to be perceived as related.
Law of Prägnanz
Ambiguous visual information tends to settle into a stable, regular, and economical interpretation.
Law of Similarity
Elements that share visible characteristics tend to be perceived as part of the same group.
Law of Uniform Connectedness
A continuous visual connection makes separate parts feel like one unit.
Mental Model
A mental model is the explanation a person builds for how a system works.
Miller’s Law
Working memory is limited, and meaningful grouping changes how much information people can handle.
Occam’s Razor
When two approaches solve the same problem equally well, prefer the one that requires fewer assumptions.
Paradox of the Active User
People often start doing the task before they invest time in learning the system.
Pareto Principle
A relatively small set of causes often accounts for a large share of the outcome.
Parkinson’s Law
Work can expand to fill the time and space made available for it.
Peak-End Rule
The most intense moment and the ending can weigh heavily in how an experience is remembered.
Postel’s Law
Accept harmless variation when intent is clear, then return consistent and well-defined output.
Selective Attention
Focused attention makes task-relevant information clearer while unexpected details can go unnoticed.
Serial Position Effect
Items near the beginning and end of a sequence can be easier to recall than those in the middle.
Tesler’s Law
Some complexity belongs to the task. Design decides who handles it and when.
Von Restorff Effect
An item that differs from its surroundings can receive more attention and be remembered better.
Working Memory
Working memory briefly holds and works with information needed for the task at hand.
Zeigarnik Effect
An interrupted goal can remain mentally active when a person still intends to return to it.