Cognitive load is the total amount of mental effort being used in working memory. In UX design, high cognitive load makes interfaces hard to use, while low cognitive load makes them intuitive.
Types of Cognitive Load
Intrinsic Load: Inherent complexity of the task
- Can't eliminate (task itself is complex)
- Example: Filing taxes is inherently complex
Extraneous Load: Unnecessary complexity from bad design
- CAN and SHOULD eliminate
- Example: Confusing navigation, jargon, poor layouts
Germane Load: Mental effort for learning and understanding
- Good cognitive load (helps users learn)
- Example: Tooltips that teach new features
Goal: Minimize extraneous load so users can focus on the task
Signs of High Cognitive Load
- Users forget what they were doing
- Frequent errors and mistakes
- Slow task completion
- Users give up mid-task
- Frustrated, overwhelmed users
- High bounce rates on complex pages
Reducing Cognitive Load
1. Simplify Navigation
✅ Clear categories via card sorting
✅ Limit menu items (5-7 per level)
✅ Use familiar patterns
✅ Progressive disclosure
2. Reduce Choices
- Hick's Law: More choices = slower decisions
- Group related options
- Highlight recommended option
- Hide advanced features initially
3. Use Recognition Over Recall
- Show options instead of asking users to remember
- Autocomplete, dropdowns, previews
- Visual aids and icons
- Persistent navigation
4. Minimize Visual Clutter
- White space reduces load
- Clear visual hierarchy
- One primary action per screen
- Remove unnecessary elements
5. Use Chunking
- Break info into smaller groups
- Phone numbers: 555-123-4567 (not 5551234567)
- Multi-step forms with progress indicators
- Related items grouped together
Cognitive Load + Navigation
High Load Navigation:
Categories: Home | Products | Solutions | Services | Resources
Users must process all options, figure out differences
Low Load Navigation:
Shop by:
- Product Type (phones, laptops, tablets)
- Use Case (work, gaming, creative)
Clear mental models, obvious paths
Card Sorting Reduces Load
How card sorting helps:
- User language = easier to understand
- Natural groupings = less mental processing
- Clear categories = obvious where to look
- Tested structure = validated with users
When navigation matches mental models, cognitive load drops dramatically.
Working Memory Limits
Miller's Law: People can hold 7±2 items in working memory
- Keep menus to 5-7 items
- Chunk information
- Don't overwhelm with choices
Design implication: Simple navigation with clear hierarchy reduces load
Load Types in Forms
High Cognitive Load Form:
- 50 fields on one page
- Unclear labels
- No hints or examples
- Errors shown after submission
Low Cognitive Load Form:
- Multi-step with 5-7 fields per step
- Clear labels with examples
- Inline validation
- Progress indicator
- Smart defaults
Real Examples
Amazon 1-Click Ordering
- Minimal cognitive load
- One decision: Buy now?
- Everything else is remembered
Google Search
- Simple: one box
- Autocomplete reduces typing
- Results grouped by type
- Progressive disclosure of details
Measuring Cognitive Load
Qualitative:
- User interviews: "Was this easy to understand?"
- Think-aloud studies: Listen for confusion
- Observe: Watch for hesitation
Quantitative:
- Time on task (high load = slower)
- Error rates (high load = more errors)
- Completion rates (high load = more abandonment)
Design Strategies
Progressive Disclosure
- Show essential info first
- Reveal advanced options on demand
- Reduces initial overwhelming feeling
Defaults and Smart Recommendations
- Pre-fill common choices
- Suggest likely options
- Reduce decisions needed
Clear Feedback
- Confirm actions
- Show system status
- Reduce uncertainty
Familiar Patterns
- Use standard UI elements
- Follow platform conventions
- Leverage existing mental models
Reduce cognitive load with better navigation. Use card sorting to discover natural mental models at freecardsort.com