Laws of UX: The Psychology Behind Good Interfaces, In One Place

Laws of UX is a reference for the psychological principles that quietly determine whether an interface feels obvious or infuriating. Fitts’s Law, Hick’s Law, the Von Restorff Effect, the Peak-End Rule, twenty-odd principles, each with its own page, a clear explanation, and a citation for where it came from.

It is also, appropriately for a site about design, extremely nice to look at. Which helps, because the alternative way to learn this material is a stack of cognitive psychology papers.

What is Laws of UX?

The site was built by Jon Yablonski, a designer who noticed that the useful principles behind interface design were scattered across textbooks, half-remembered blog posts and other designers’ heads. Nobody could point a junior designer at one place and say “read this.”

So he made that place. Each law gets a dedicated page with the same structure: a one-line statement, a short explanation, a set of takeaways, the origin story, and references. The consistency is what makes it work as a reference rather than an essay collection, you always know where the actual actionable part is.

The principles come from several different traditions. Some are genuine experimental results from human factors research: Fitts’s Law, formulated in 1954, predicts how long it takes to hit a target based on its size and distance, and it is why your operating system’s menu bar sits flush against the screen edge. Hick’s Law relates decision time to the number of options. Miller’s Law concerns the limits of working memory.

Others are observed patterns rather than measured laws. Jakob’s Law, “users spend most of their time on other sites, so they prefer your site to work the same way as all the other sites they already know”, is not a formula, but it is probably the single most useful sentence in the whole collection and it kills more clever-but-novel navigation ideas than any usability test.

The design of the site does real work too. Every law has a poster, downloadable, and the whole thing is presented with enough confidence that it functions as an argument for its own subject matter. There is a companion O’Reilly book that goes deeper, but the site is complete on its own terms.

What can you do with Laws of UX?

• Look up a specific principle. Each law has a permanent page. Bookmark the ones you cite often, they make good links in design reviews.
• Read the origin of each law. Knowing that Fitts’s Law came from 1950s human factors research, not a design blog, changes how much weight it carries in an argument.
• Download the posters. Every law has a poster you can print or drop into a slide. Useful for teaching and for wall space.
• Follow the references. Each page links to the underlying papers and books, so you can go from the summary to the source when you need to.
• Use it as an onboarding reading list. Sending a new designer through the full set is a genuinely efficient way to install shared vocabulary in a team.
• Skim the takeaways. Every page has a condensed list of practical implications, which is often all you need mid-project.

Tips to get the most out of it

Learn Jakob’s Law first and take it seriously. Most bad interface decisions are novelty for its own sake. If your checkout, search or navigation works differently from every other site your users visit, you need a very good reason and usually you do not have one.

Use the laws as vocabulary in reviews, not as trump cards. “This violates Hick’s Law” is a useful shorthand for “there are too many options here.” It is not a proof, and treating it as one is how design critique turns into scripture quoting.

Check which laws are measured and which are heuristics. The site tells you. Fitts’s Law has a formula; the aesthetic-usability effect is a research finding about perception; some principles are closer to rules of thumb. Knowing the difference keeps you honest.

Apply the Peak-End Rule to the boring parts. People remember the most intense moment and the ending of an experience, not the average. Fixing the worst step and the final confirmation screen buys more perceived quality than polishing the middle.

Read the Von Restorff Effect before designing any call to action. The thing that looks different is the thing that gets noticed, which means making six elements prominent is the same as making none of them prominent.

Pair it with actually watching someone use your product. These principles explain behavior; they do not substitute for observing it. The laws are best used to interpret what you saw in a test, not to skip the test.

If you like Laws of UX, also try…

• User Inyerface: a deliberately hostile interface that demonstrates every one of these principles by breaking it.
• Behance: full design case studies where you can see the reasoning play out on real projects.
• Bartosz Ciechanowski: the gold standard for explaining complex things through interactive design.
• BetterExplained: the same instinct applied to math, explanations built around intuition rather than notation.

More on how things get designed, and mis-designed, in Design & Creativity and Learning & Education.