---
name: hci
description: Human-computer interaction design principles
license: MIT
metadata:
  audience: developers
  category: design
---

## What I do
- Design intuitive human-computer interfaces
- Apply cognitive load theory
- Implement gesture and voice interactions
- Create natural user interfaces
- Evaluate interaction paradigms
- Optimize user task efficiency

## When to use me
When designing interactive systems, selecting interaction modalities, or optimizing user efficiency.

## Key Concepts

### Interaction Paradigms
```
CLI: Command-line interfaces
GUI: Graphical user interfaces
WIMP: Windows, Icons, Menus, Pointers
NUI: Natural User Interfaces
TUI: Tangible User Interfaces
```

### Fitts's Law
```
Time = a + b * log2(D/W + 1)
D = distance to target
W = width of target
```
- Larger targets are faster to click
- Edges and corners are optimal positions
- Context menus reduce travel distance

### Hick's Law
```
RT = a + b * log2(n + 1)
n = number of choices
```
- Minimize options for speed
- Use progressive disclosure
- Chunk information

### Design Principles
1. Visibility of system status
2. Real-world mapping
3. User control
4. Error prevention and recovery
5. Consistency
6. Flexibility
7. Aesthetic design
8. Help and documentation

### Cognitive Models
- GOMS (Goals, Operators, Methods, Selection)
- Keystroke-Level Model (KLM)
- Cognitive Walkthrough
- Think-aloud protocol

### Input Modalities
- Mouse/keyboard
- Touch gestures
- Voice commands
- Eye tracking
- Brain-computer interfaces
- Motion sensors