Index

All UX Laws

30 psychology-backed principles that explain how people perceive, decide, and remember when using interfaces.

Browse the full index below, open any law for takeaways and design applications, and use the related principles to explore connected ideas across the collection.

Visual Hierarchy & Perception

Aesthetic-Usability Effect

Users often perceive aesthetically pleasing design as more usable.

Cognitive Load & Decision Making

Choice Overload

People become overwhelmed when presented with too many options.

Cognitive Load & Decision Making

Chunking

Break information into meaningful groups to aid comprehension.

Attention & Focus

Cognitive Bias

Systematic thinking errors shape how users perceive and decide.

Cognitive Load & Decision Making

Cognitive Load

Mental effort required to use an interface should be minimized.

Interaction & Behavior

Doherty Threshold

Productivity peaks when system response stays under ~400ms.

Interaction & Behavior

Fitts's Law

Time to reach a target depends on its size and distance.

Interaction & Behavior

Flow

Immersive focus emerges when challenge matches skill without interruption.

Interaction & Behavior

Goal-Gradient Effect

Motivation increases as users get closer to completing a goal.

Cognitive Load & Decision Making

Hick's Law

Decision time grows with the number and complexity of choices.

System Design Principles

Jakob's Law

Users expect your site to work like others they already know.

Visual Hierarchy & Perception

Law of Common Region

Elements within a bounded area are perceived as a group.

Visual Hierarchy & Perception

Law of Proximity

Near elements are perceived as related.

Visual Hierarchy & Perception

Law of Prägnanz

People interpret ambiguous visuals in the simplest form possible.

Visual Hierarchy & Perception

Law of Similarity

Similar elements are perceived as belonging together.

Visual Hierarchy & Perception

Law of Uniform Connectedness

Visually connected elements feel more related than disconnected ones.

Attention & Focus

Mental Model

Users bring expectations from prior experience to your product.

Cognitive Load & Decision Making

Miller's Law

Working memory holds roughly 7±2 items at once.

System Design Principles

Occam's Razor

Prefer the simplest solution that works.

Attention & Focus

Paradox of the Active User

Users skip manuals and learn by doing immediately.

System Design Principles

Pareto Principle

Roughly 80% of outcomes come from 20% of causes.

Attention & Focus

Parkinson's Law

Work expands to fill available time.

Memory & Recall

Peak-End Rule

Experiences are judged by their peak moments and the ending.

System Design Principles

Postel's Law

Be liberal in what you accept; conservative in what you send.

Attention & Focus

Selective Attention

Users focus on stimuli relevant to their current goal.

Memory & Recall

Serial Position Effect

First and last items in a series are remembered best.

System Design Principles

Tesler's Law

Every system has irreducible complexity — shift it from user to system.

Visual Hierarchy & Perception

Von Restorff Effect

Distinct items among similar ones are remembered best.

Memory & Recall

Working Memory

Temporary storage for information needed to complete a task.

Memory & Recall

Zeigarnik Effect

Incomplete tasks stay in memory better than completed ones.