Aesthetic-Usability Effect
Users often perceive aesthetically pleasing design as more usable.
How to apply:
- Invest in spacing, typography, and motion before adding features.
- Use a restrained palette with one confident accent color.
Laws of UX
Psychology, card by card.
Pocket cards for all 30 UX laws. Open a card for the full guide, or share a direct link.
Choice Overload
People become overwhelmed when presented with too many options.
How to apply:
- Limit primary filters and plans to three or four visible options.
- Label a recommended option when multiple paths exist.
Chunking
Break information into meaningful groups to aid comprehension.
How to apply:
- Split long forms into titled steps or fieldsets.
- Group related settings under clear headings.
Cognitive Bias
Systematic thinking errors shape how users perceive and decide.
How to apply:
- Make consequences of irreversible actions explicit.
- Use defaults that benefit most users without trapping others.
Cognitive Load
Mental effort required to use an interface should be minimized.
How to apply:
- Reveal complexity only when users ask for it.
- Show previously entered information instead of making users remember it.
Doherty Threshold
Productivity peaks when system response stays under ~400ms.
How to apply:
- Optimistic UI can make actions feel immediate.
- Prefer skeleton loaders over generic spinners.
Fitts's Law
Time to reach a target depends on its size and distance.
How to apply:
- Use at least 44px touch targets for key actions.
- Keep primary buttons wide enough for confident tapping.
Flow
Immersive focus emerges when challenge matches skill without interruption.
How to apply:
- Avoid blocking dialogs for recoverable actions.
- Persist drafts automatically in editors and forms.
Goal-Gradient Effect
Motivation increases as users get closer to completing a goal.
How to apply:
- Add progress bars to onboarding and checkout flows.
- Show percentage complete for uploads and setup tasks.
Hick's Law
Decision time grows with the number and complexity of choices.
How to apply:
- Group menu items into scannable categories.
- Use steppers for complex configuration flows.
Jakob's Law
Users expect your site to work like others they already know.
How to apply:
- Place navigation, search, and account actions where users expect them.
- Reuse established form and table conventions.
Law of Common Region
Elements within a bounded area are perceived as a group.
How to apply:
- Wrap related settings in soft-bordered cards.
- Use section backgrounds to separate unrelated content.
Law of Proximity
Near elements are perceived as related.
How to apply:
- Keep helper text adjacent to the field it describes.
- Separate unrelated actions with clear vertical rhythm.
Law of Prägnanz
People interpret ambiguous visuals in the simplest form possible.
How to apply:
- Use clean iconography with consistent stroke weight.
- Reduce competing visual treatments on dense screens.
Law of Similarity
Similar elements are perceived as belonging together.
How to apply:
- Standardize status chips across the product.
- Keep card layouts consistent within a page type.
Law of Uniform Connectedness
Visually connected elements feel more related than disconnected ones.
How to apply:
- Add connectors in step indicators and onboarding.
- Link timeline events with a continuous vertical rail.
Mental Model
Users bring expectations from prior experience to your product.
How to apply:
- Name features using language your audience already uses.
- Mirror common object metaphors only when they still help.
Miller's Law
Working memory holds roughly 7±2 items at once.
How to apply:
- Limit top-level nav to five to seven items.
- Collapse secondary links into clear submenus.
Occam's Razor
Prefer the simplest solution that works.
How to apply:
- Audit screens for redundant controls and duplicate paths.
- Merge overlapping settings into one clear control.
Paradox of the Active User
Users skip manuals and learn by doing immediately.
How to apply:
- Use inline labels and empty states as guidance.
- Offer optional tours instead of forced walkthroughs.
Pareto Principle
Roughly 80% of outcomes come from 20% of causes.
How to apply:
- Make the top user journey frictionless before expanding scope.
- Highlight the metrics users can act on immediately.
Parkinson's Law
Work expands to fill available time.
How to apply:
- Use character counts for summaries and messages.
- Break large jobs into timed or numbered steps.
Peak-End Rule
Experiences are judged by their peak moments and the ending.
How to apply:
- Design celebratory but useful completion screens.
- Fix dead-end errors with recovery paths.
Postel's Law
Be liberal in what you accept; conservative in what you send.
How to apply:
- Support flexible date and phone formats.
- Use fuzzy search with helpful fallbacks.
Selective Attention
Users focus on stimuli relevant to their current goal.
How to apply:
- Emphasize one primary metric or action per view.
- Reduce decorative motion on task-focused screens.
Serial Position Effect
First and last items in a series are remembered best.
How to apply:
- Place key table columns on the left and actions on the right.
- Open menus with the highest-value category.
Tesler's Law
Every system has irreducible complexity — shift it from user to system.
How to apply:
- Offer recommended presets for complex configuration.
- Auto-detect sensible values from context.
Von Restorff Effect
Distinct items among similar ones are remembered best.
How to apply:
- Reserve the accent color mainly for primary CTAs.
- Use one strong visual treatment for critical warnings.
Working Memory
Temporary storage for information needed to complete a task.
How to apply:
- Show cart and selection summaries throughout checkout.
- Repeat key inputs on confirmation steps.
Zeigarnik Effect
Incomplete tasks stay in memory better than completed ones.
How to apply:
- Display “3 steps remaining” in setup flows.
- Preserve drafts with clear resume entry points.
