A modern, psychology-based set of laws and effects that explain how people actually perceive, process, and decide — distilled from cognitive science into design-ready principles.
The Laws of UX, compiled and popularized by designer Jon Yablonski (lawsofux.com, O'Reilly book Laws of UX, 2nd edition 2024), are not original heuristics — they're well-established findings from cognitive psychology, behavioral economics, and Gestalt theory, reframed for working designers.
Where Nielsen tells you what a usable interface looks like, the Laws of UX tell you why — why users abandon a checkout with too many options (Hick's Law), why a flawed product feels good if it's beautiful (Aesthetic-Usability Effect), why progress bars motivate completion (Goal-Gradient Effect). They sit comfortably alongside any traditional heuristic set as a complementary lens.
Use these laws when you need to explain a UX decision to non-designers, when you're designing for high-stakes moments (sign-up, checkout, onboarding), or when an interface "feels off" but doesn't violate any classic heuristic.
Users often perceive aesthetically pleasing design as easier to use than less attractive design — even when the actual usability is identical. Beautiful interfaces buy goodwill that masks small frictions, but they don't excuse functional flaws.
The more options users are given, the longer they take to decide and the more likely they are to abandon the choice entirely. Limit visible options at decision points; surface defaults; group choices into categories rather than presenting a flat list.
Working memory holds individual items poorly, but it holds chunks well. Break long numbers, IDs, and lists into groups of 3–5 — phone numbers, credit-card fields, and step-by-step flows all rely on chunking to stay learnable.
A systematic error in thinking that shapes how users perceive options and make decisions — anchoring, framing, default-effect, loss aversion, and many more. Account for these biases when designing for accuracy, and resist exploiting them in ways that harm users (dark patterns trade short-term wins for long-term trust).
Cognitive load is the total mental effort required to use an interface. Reduce extraneous load by removing irrelevant elements, supporting recognition over recall, and offloading work onto the system whenever it's cheaper for the system to do.
Productivity soars when a computer and its user interact at a pace (under ~400ms) that ensures neither has to wait. Below this threshold, users stay in flow; above it, attention drifts and frustration builds.
The time to acquire a target is a function of the distance to and size of the target. Make important targets larger, place them closer to where the user already is, and exploit screen edges and corners — they have effectively infinite size for a cursor.
A mental state of complete immersion in a task, supported by clear goals, immediate feedback, and a balance of challenge and skill. To support flow, minimize interruptions, keep behavior predictable, and ramp complexity gradually as users build mastery.
The closer people get to a goal, the faster they move toward it. Show progress — checklists, multi-step indicators, gamified milestones — and consider giving users a head start, since perceived proximity accelerates completion.
The time it takes to make a decision increases logarithmically with the number and complexity of choices. Simplify menus, paginate large lists, and break complex tasks into smaller steps so each decision is easy.
Users spend most of their time on other sites, and they expect your site to work the same way. Lean into established patterns for navigation, search, forms, and shopping — novelty in conventions costs more than it earns.
Elements in a clearly defined region (a card, a panel, a bordered section) are perceived as belonging together. Use containers — backgrounds, borders, whitespace — to group related content even when proximity alone isn't enough.
Objects close to each other tend to be grouped together. Tighten spacing within a group; widen spacing between groups. Proximity is the cheapest, strongest grouping signal you have.
People perceive ambiguous or complex images as the simplest form possible, because it requires the least cognitive effort. Aim for clean, simple shapes and reduced visual noise — complexity that can be removed should be removed.
Elements that share visual properties (color, shape, size, orientation) are perceived as related. Use similarity to communicate function — every primary button looks the same; every error state looks the same — and break similarity to signal difference.
Elements that are visually connected — by lines, arrows, or a shared background — are perceived as more related than elements that are merely close. Connect related controls explicitly when proximity isn't enough.
A mental model is what the user believes the system is and how it behaves. Designs feel intuitive when they match an existing model and confusing when they don't. Borrow from familiar patterns to align with users' expectations, and surface the system's actual behavior whenever it diverges from those expectations.
The average person can hold about 7 (±2) items in working memory. The exact number is debated, but the practical lesson is solid: keep menus, lists, and decisions short, and chunk anything longer.
Among competing solutions, the one with the fewest assumptions is usually best. Strip an interface to the elements that earn their keep; every component should justify its presence.
Users never read the manual — they want to start using the product immediately and learn by doing, even when reading first would be faster. Design for productive engagement from the very first screen; embed help in context (tooltips, inline tips, empty states) instead of relying on documentation users will skip.
Roughly 80% of effects come from 20% of causes. In product terms: a small set of features drives most of the value. Identify the critical few and over-invest in them; everything else is a candidate for simplification.
Work expands to fill the time available. Set short, tight expectations — predictive autofill, auto-saved progress, instant search — and users will move faster than they would with longer, looser flows.
People judge an experience largely by how they felt at its peak (the most intense moment, good or bad) and at its end. Invest disproportionately in the highest-stakes moments and the final step — the empty state, the success screen, the receipt.
Be conservative in what you do, be liberal in what you accept from others. Accept user input forgivingly — extra spaces in emails, formatted phone numbers, currency symbols — and produce output rigorously, in the format the next system expects.
People focus their attention on a subset of stimuli — usually those related to their current goal — and filter the rest out, including things designers expect them to notice. Place critical information along the natural attention path (top, near the active region, in line with reading order) instead of in zones users routinely ignore (banner-blind areas, sidebars).
Users best remember items at the beginning and end of a list, and worst those in the middle. Place the most important navigation, options, or messages first or last; bury the least important content in the middle if it has to exist.
Also called the Law of Conservation of Complexity: every system has an irreducible amount of complexity. Either the design absorbs it (the engineering does the work) or the user does. Choose where it lives deliberately, and bias toward absorbing it.
When multiple similar items are present, the one that differs from the rest is most likely to be remembered. Use visual contrast — color, size, motion — to highlight what users need to notice, but use it sparingly so it keeps working.
Working memory is short-term storage for information the user is actively using. It's small and fragile — easily disrupted by interruption or new input. Don't force users to carry information across screens; show what they need at the moment they need it, and let them refer back without losing their place.
People remember unfinished tasks better than completed ones, and feel a pull to finish what they've started. Use this to motivate completion — visible progress bars, partially filled profiles, multi-step flows that show what's left — but don't weaponize it into nagging or guilt-driven engagement.
We use cookies to run this site and, with your permission, to understand how it's used and show relevant ads. Necessary cookies are always on. You can change your choice anytime from the footer. Learn more
