# Cognitive design principles Cognitive design principles are guidelines for creating products and interfaces that align with how humans think, perceive, and act. The most influential set comes from [[Don Norman]]'s *The Design of Everyday Things* (1988, revised 2013), which established visibility, feedback, constraints, mapping, consistency, and affordance as core design concepts. These principles are grounded in [[Cognitive Psychology]] research on [[Perception]], [[Memory]], and [[Attention]]. These principles form the foundation of [[User Experience (UX)]], [[Interaction Design (IxD)]], and [[Human-Computer Interaction (HCI)]]. They explain why some designs feel intuitive while others frustrate users—good design works with human cognition, while poor design fights against it. The principles are complemented by [[Jakob Nielsen]]'s usability heuristics and [[Dieter Rams]]'s ten principles of good design. Together, they provide a comprehensive framework for evaluating and creating user-centered designs. ## Norman's Six Principles ``` ┌─────────────────────────────────────────────────────────────┐ │ NORMAN'S DESIGN PRINCIPLES │ ├─────────────────────────────────────────────────────────────┤ │ │ │ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │ │ │ VISIBILITY │ │ FEEDBACK │ │ CONSTRAINTS │ │ │ │ │ │ │ │ │ │ │ │ Make state │ │ Confirm │ │ Limit │ │ │ │ and options │ │ actions, │ │ possible │ │ │ │ visible │ │ show results │ │ actions │ │ │ └──────────────┘ └──────────────┘ └──────────────┘ │ │ │ │ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐ │ │ │ MAPPING │ │ CONSISTENCY │ │ AFFORDANCE │ │ │ │ │ │ │ │ │ │ │ │ Controls │ │ Same action │ │ Object │ │ │ │ relate to │ │ = same │ │ suggests │ │ │ │ effects │ │ result │ │ its use │ │ │ └──────────────┘ └──────────────┘ └──────────────┘ │ │ │ └─────────────────────────────────────────────────────────────┘ ``` ## Detailed Principles | Principle | Definition | Good Example | Bad Example | |-----------|------------|--------------|-------------| | **Visibility** | Relevant options and state are visible | File menu shows available actions | Hidden gestures with no cues | | **Feedback** | Actions produce clear response | Button depresses, sound plays | Form submits with no confirmation | | **Constraints** | Impossible actions are prevented | Date picker prevents invalid dates | Free text for date entry | | **Mapping** | Controls spatially/logically match effects | Stove knobs match burner layout | Random knob-to-burner mapping | | **Consistency** | Similar things work the same way | All dialogs have same button order | Save sometimes left, sometimes right | | **Affordance** | Form suggests function | Door handle shape indicates pull/push | Flat plate on pull door | ## Nielsen's Usability Heuristics | Heuristic | Description | |-----------|-------------| | **Visibility of system status** | Keep users informed | | **Match real world** | Use familiar concepts | | **User control and freedom** | Easy undo and exit | | **Consistency and standards** | Follow conventions | | **Error prevention** | Prevent problems | | **Recognition over recall** | Minimize memory load | | **Flexibility and efficiency** | Shortcuts for experts | | **Aesthetic and minimalist** | Remove irrelevant info | | **Help users with errors** | Clear error messages | | **Help and documentation** | Available when needed | ## Types of Constraints | Type | Description | Example | |------|-------------|---------| | **Physical** | Shape limits use | USB plug only fits one way | | **Semantic** | Meaning restricts use | Red = stop makes sense | | **Cultural** | Conventions guide use | Read left to right (in West) | | **Logical** | Reasoning limits options | Only one piece left = put there | ## Types of Mapping | Type | Quality | Example | |------|---------|---------| | **Natural** | Best | Steering wheel direction = car direction | | **Spatial** | Good | Controls laid out like the things they control | | **Arbitrary** | Poor | Keyboard F-keys (need memorization) | ## Applying Principles | Context | Key Principles | |---------|----------------| | **Forms** | Constraints, feedback, error prevention | | **Navigation** | Visibility, consistency, mapping | | **Onboarding** | Progressive disclosure, recognition | | **Error handling** | Feedback, recovery, prevention | | **Mobile** | Affordance, constraints (touch) | ## Principle Relationships | When violated... | Users experience... | |------------------|---------------------| | **No visibility** | Confusion, missed features | | **No feedback** | Uncertainty, repeated actions | | **No constraints** | Errors, invalid states | | **Poor mapping** | Wrong actions, frustration | | **Inconsistency** | Relearning, mistakes | | **Unclear affordance** | Hesitation, wrong interactions | ## Key Texts | Book | Author | Focus | |------|--------|-------| | *The Design of Everyday Things* | [[Don Norman]] | Core principles | | *Don't Make Me Think* | Steve Krug | Web usability | | *About Face* | Alan Cooper | Interaction design | | *Universal Principles of Design* | Lidwell et al. | Comprehensive reference | ## References - Norman, D. (2013). *The Design of Everyday Things* (revised edition) - Nielsen, J. "10 Usability Heuristics for User Interface Design" - https://www.nngroup.com/articles/ten-usability-heuristics/ ## Related - [[Cognitive design]] - [[Don Norman]] - [[Jakob Nielsen]] - [[User Experience (UX)]] - [[Interaction Design (IxD)]] - [[Affordance]] - [[Signifier]] - [[Usability]] - [[Heuristic Evaluation]]