Stratpix
Psychology & Cognition

Laws of UX

Maintained by Jon Yablonski

A collection of psychology and cognitive-science principles that designers can apply directly to interface decisions.

Open Laws of UX

Why it matters

Turns "this feels wrong" into a defensible argument. When a stakeholder pushes back on removing a menu item, Hick’s Law gives you a named, citable reason rather than an opinion.

Key principles

  1. Hick’s Law - decision time grows with the number and complexity of choices. Reduce options at every decision point.
  2. Fitts’s Law - time to hit a target depends on its size and distance. Make primary actions big and close to the cursor or thumb.
  3. Jakob’s Law - users spend most of their time on other sites, so they expect yours to work the same way. Deviate only with justification.
  4. Miller’s Law - working memory holds roughly seven items. Chunk content instead of listing it flat.
  5. Doherty Threshold - keep system response under 400ms or attention drains and productivity drops.
  6. Tesler’s Law - every system has irreducible complexity. Decide whether the product or the user absorbs it.
  7. Peak-End Rule - people judge an experience by its most intense moment and its ending, not its average.
  8. Aesthetic-Usability Effect - attractive designs are perceived as more usable, which can mask real usability problems in testing.

Resources

Foundations, principles, tutorials, community Figma files, icon sets, and templates.