Interactive before/after demos for the 21 core Laws of UX.
See each law violated, then applied — with a ready-made stakeholder pitch for every design decision. A companion to lawsofux.com.
Aesthetic-Usability Effect
Users perceive beautiful design as easier to use — the same app, restyled, feels more trustworthy.
Doherty Threshold
Respond within 400 ms. A live search demo: same slow backend, radically different experience.
Fitts's Law
Bigger, closer targets are faster to hit. Try tapping the tiny checkout link vs. the thumb-sized one.
Goal-Gradient Effect
People speed up as they near a goal. Show progress — and give users a head start.
Hick's Law
More choices, slower decisions. A pricing page slimmed from six plans to three.
Jakob's Law
Users expect your site to work like every other site. A “creative” shop layout vs. conventions.
Law of Common Region
Elements inside a shared boundary read as a group. Ungrouped settings vs. clear card sections.
Law of Prägnanz
The eye simplifies complex images. A decorated dashboard vs. the simple form it was fighting.
Law of Proximity
Close together = belongs together. The same form, fixed purely with spacing.
Law of Similarity
Things that look alike seem related. Consistent link and button styling vs. visual chaos.
Law of Uniform Connectedness
Visually connected elements read as related. Wizard steps and paired controls, joined up.
Miller's Law
Working memory holds ~7 items. Chunk card numbers, codes, and content into digestible groups.
Occam's Razor
Prefer the simplest thing that works. A 12-field registration form cut down to three.
Pareto Principle
80% of users use 20% of features. Design for the vital few, tuck away the rest.
Parkinson's Law
Tasks expand to fill the time available. Set expectations and shorten the path.
Peak-End Rule
People judge an experience by its peak and its end. Don't let the last screen be the worst one.
Postel's Law
Be liberal in what you accept. A live phone-number field: strict rejection vs. graceful parsing.
Serial Position Effect
People remember the first and last items best. Put what matters at the ends of the nav.
Tesler's Law
Complexity can't be removed — only moved. Who does the hard work: the user or the system?
Von Restorff Effect
The one that differs gets remembered. Make the primary action unmistakable.
Zeigarnik Effect
Unfinished tasks stick in memory. Show what's incomplete and people come back to finish it.