Agent skill
nw-usability-engineering
Cognitive science principles applied to futuristic interface design -- Fitts, Hick, Miller, cognitive load theory, and Nielsen heuristics
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SKILL.md
Usability Engineering for Futuristic Interfaces
Core Cognitive Laws
Fitts's Law (Target Acquisition)
Formula: Time = a + b * log2(Distance/Width + 1)
Application: Important interactive targets must be large enough and close to likely cursor positions.
- Primary actions: minimum 44x44px touch target, 32x32px pointer target
- Screen edges and corners are infinite-width targets (use them for frequent actions)
- Group related actions to minimize cursor travel between sequential operations
- Radial menus (Warframe-style) minimize Fitts distance -- all options equidistant from center
Futuristic pitfall: Holographic/floating UI elements tempt designers to scatter controls in space. Every pixel of distance between sequential actions costs time. Cluster related controls even in expansive layouts.
Hick's Law (Decision Time)
Formula: Time = b * log2(n + 1) where n = number of choices
Application: Reduce simultaneous choices. Use progressive disclosure.
- Maximum 5-7 visible options at any decision point
- Group into categories first, then reveal details (two 5-option menus faster than one 25-option menu)
- Default/recommended option visually distinguished (larger, brighter, positioned first)
- Remove options rather than disabling them when context makes them irrelevant
Futuristic pitfall: Sci-fi interfaces love to display everything at once (NERV control room, Minority Report). Real users need progressive disclosure. Show the operational layer first, reveal engineering details on demand.
Miller's Law (Working Memory)
Principle: Working memory holds 7 +/- 2 chunks simultaneously.
Application: Never present more than 7 distinct information groups per view.
- Dashboard panels: 5-7 maximum per viewport
- Navigation items: 5-7 top-level categories
- Form fields per section: 5-7 visible at once (paginate/accordion beyond)
- Data table columns visible without scroll: 5-7 (allow horizontal scroll for detail)
- Chunk related items visually (proximity, shared background, border)
Futuristic pitfall: Dense utilitarian displays (Expanse-style) tempt exceeding 7 chunks. Solve with clear visual grouping -- proximity and shared containers turn 20 data points into 5 chunks of 4.
Cognitive Load Theory
Three types of cognitive load:
| Type | Definition | Design Goal |
|---|---|---|
| Intrinsic | Inherent complexity of the task | Cannot reduce -- task IS complex |
| Extraneous | Load from poor design | Eliminate -- this is YOUR fault |
| Germane | Load from learning/understanding | Facilitate -- support mental model building |
Reducing extraneous load:
- Consistent interaction patterns (same gesture/click always does same type of thing)
- Spatial stability (elements stay in predictable positions)
- Visual hierarchy via contrast, size, position (not decoration)
- Contextual help at point of need (not separate documentation)
- Reduce required memory by keeping state visible
Supporting germane load:
- Use metaphors that map to user's existing mental models
- Progressive complexity (basic first, advanced on demand)
- Visual feedback confirming correct mental model ("yes, that's how this works")
- Undo support everywhere (reduces fear of exploration)
Nielsen's 10 Usability Heuristics (Futuristic Lens)
1. Visibility of System Status
System communicates what is happening through appropriate feedback within reasonable time.
Futuristic application: Ambient indicators (color temperature, particle density, background pulse) for persistent state. Explicit notifications only for state changes requiring action. Dead Space's health-on-spine is ideal -- always visible, never intrusive.
2. Match Between System and Real World
System uses user's language, follows real-world conventions, information appears natural and logical.
Futuristic application: Sci-fi aesthetic must not override domain language. A medical dashboard should use medical terms, not sci-fi terms. The visual wrapper is futuristic; the content vocabulary is domain-native.
3. User Control and Freedom
Users need a clearly marked emergency exit to leave unwanted states without extended dialogue.
Futuristic application: Every modal has visible close. Every action has undo. Every navigation has back. Gestural interfaces (Minority Report-style) need an explicit "cancel" gesture. Never trap users in an animation sequence.
4. Consistency and Standards
Users should not have to wonder whether different words, situations, or actions mean the same thing.
Futuristic application: Once a visual pattern means something (glow = interactive, pulse = processing, red = critical), it means that EVERYWHERE. A single inconsistency destroys the entire visual language. Document the semantic mapping and enforce it.
5. Error Prevention
Eliminate error-prone conditions or present confirmation before commit.
Futuristic application: Destructive actions require two-step confirmation with distinct interactions (not two identical clicks). Preview results before committing. Constraint inputs to valid ranges rather than validating after entry.
6. Recognition Rather Than Recall
Minimize memory load by making objects, actions, and options visible.
Futuristic application: Keep recent actions, relevant options, and system state visible. Command-line-style interfaces need autocomplete and history. Never require users to remember codes, IDs, or sequences.
7. Flexibility and Efficiency of Use
Accelerators for experts that do not burden novices. Allow customization.
Futuristic application: Keyboard shortcuts, radial menus, command palettes for power users. Visual affordances for novices. Layer complexity: surface (visual), shortcuts (keyboard), command (direct input).
8. Aesthetic and Minimalist Design
Every extra unit of information competes with relevant information and diminishes visibility.
Futuristic application: The hardest heuristic for sci-fi design. Decorative elements (scan lines, particle effects, ambient data streams) must be VERY low opacity and never compete with functional content. Test: cover the decorative layer -- does the interface still work? Good. Now uncover -- does the decoration interfere with any functional element? If yes, reduce or remove.
9. Help Users Recognize, Diagnose, and Recover from Errors
Error messages in plain language, indicate the problem precisely, suggest a solution.
Futuristic application: Error states should feel recoverable, not catastrophic. Warm colors (amber) not aggressive (pure red) for recoverable errors. Show what went wrong, what the user can do, and offer a direct action button. Never just "Error occurred."
10. Help and Documentation
Best if system is usable without documentation, but provide help focused on user's task.
Futuristic application: Contextual tooltips, inline hints, progressive tutorials. Not a separate help section. Ghost-in-the-Shell-style data overlays on hover/focus that explain what an element does.
Accessibility as Design Constraint
Accessibility is not a bolt-on. Treat as a primary design constraint:
- Color: Never convey information by color alone. Pair with icons, labels, or patterns.
- Motion: All animations respect
prefers-reduced-motion. See interaction-choreography skill. - Contrast: WCAG AA minimum (4.5:1 text, 3:1 large text). Futuristic dark themes need careful testing.
- Focus indicators: Visible focus rings on all interactive elements. Glow effects serve double duty as focus indicators.
- Screen readers: Semantic HTML, ARIA labels where needed. Decorative elements are
aria-hidden. - Keyboard: Full keyboard navigation. Tab order follows visual flow. No keyboard traps.
Information Density Framework
Match information density to use context:
Level 1 — Glanceable (Destiny sofa-distance)
- 3-5 data points maximum
- Large type, high contrast, single-color accent hierarchy
- Use case: mobile dashboards, at-a-glance status, consumer apps
Level 2 — Operational (The Expanse cockpit)
- 8-12 data points, organized in spatial zones
- Secondary information accessible but not prominent, color-coded categories
- Use case: operational dashboards, driver/pilot interfaces, team monitors
Level 3 — Analytical (Iron Man holographic workspace)
- 15-25 data points across multiple panels
- Glassmorphism layering for depth, cross-referencing between panels
- Use case: data analysis, engineering dashboards, investigation tools
Level 4 — Immersive (NERV command center)
- 25+ data points with ambient data streams
- Requires trained users, utilitarian density with clear grid structure
- Use case: SRE war rooms, trading floors, mission control
Rule: Never design Level 4 density for Level 1 users. Match density to expertise and context. The Expanse's faction-specific simplification shows how: Belter interfaces show less by design, reflecting resource scarcity and practical need.
FUI Design Studios (Reference)
When seeking real-world inspiration for specific interface styles:
- Territory Studio: Ghost in the Shell, Blade Runner 2049, Avengers — masters of material experimentation
- Perception: Iron Man 2, Captain America, Batman v Superman — polished holographic systems
- Cantina Creative: Iron Man 2/3, Avengers, Blade Runner 2049 — Cinema 4D-heavy 3D workflows
- Jayse Hansen: Iron Man 3, Avengers 1&2, Star Wars TFA — created the "HUD Bible" for MCU consistency
- GMUNK: Tron Legacy, Oblivion — grid-based and minimalist functional design
- Ash Thorp: Ghost in the Shell, Ender's Game, Prometheus — high-concept visual design
- Rhys Yorke: The Expanse — utilitarian realism, faction differentiation, NASA-informed design
Evaluation Checklist
Before approving any design:
- Fitts: primary actions reachable without excessive cursor movement
- Hick: no decision point presents more than 7 options without grouping
- Miller: no view contains more than 7 distinct information groups
- Cognitive load: consistent patterns, spatial stability, visible state
- Nielsen heuristics: all 10 addressed (not all equally, but none ignored)
- WCAG AA: contrast ratios, focus indicators, screen reader support
- Reduced motion: all animations have non-motion alternative
- Error recovery: all error states show problem + solution + action
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