design-everyday-things

# Design of Everyday Things Framework

Foundational design principles for creating products that are intuitive, discoverable, and understandable. The "bible of UX" — applicable to physical products, software, and any human-designed system.

## Core Principle

**Good design is actually a lot harder to notice than poor design, in part because good designs fit our needs so well that the design is invisible.** When something fails, users blame themselves — but the fault is almost always in the design. Great design bridges the gap between what people want to do and what the product allows: it is discoverable (you can figure out what to do) and understandable (you can figure out what happened).

## Scoring

**Goal: 10/10.** Score 2 points per satisfied row of the Quick Diagnostic (5 rows = discoverability, evaluation, error recovery, mapping, constraints). Bands: **9-10** = users act without instructions, understand every outcome, and recover from any error; **5-6** = one gulf or error path is broken; **<=3** = users must consult a manual or routinely blame themselves. Report the current score and the diagnostic rows failing it.

## The Two Gulfs

Every interaction with a product requires bridging two gulfs:

```
USER                                    PRODUCT
  │                                        │
  ├──── Gulf of Execution ────────────────→│
  │     "How do I do what I want?"         │
  │                                        │
  │←──── Gulf of Evaluation ──────────────┤
  │     "What happened? Did it work?"      │
```

### Gulf of Execution

**The gap between what users want to do and what the product lets them do.** Users ask: What can I do here? Which control do I use?

**Bridge with:** clear signifiers, natural mappings, constraints, familiar conceptual models.

### Gulf of Evaluation

**The gap between what the product did and what users understand happened.** Users ask: What happened? Did it work? What state is the system in?

**Bridge with:** immediate visible feedback, clear system-state indicators, meaningful error messages, progress indicators.

**Design goal:** Make both gulfs as narrow as possible — action and understanding should be immediate.

See: [references/two-gulfs.md](references/two-gulfs.md) for gulf analysis exercises.

## Seven Fundamental Design Principles

### 1. Discoverability

**Definition:** Can users figure out what actions are possible and how to perform them? Its five components — affordances, signifiers, constraints, mappings, feedback — are detailed below.

**Test:** Put a new user in front of your product. If they can't figure out what to do within 10 seconds, discoverability is broken.

**Anti-pattern:** "The user manual explains it." If users need a manual, the design failed.

### 2. Affordances

**Definition:** The relationship between an object's properties and a user's capabilities that determines how the object could be used.

**Key insight:** Affordances exist whether or not they are perceived — what matters for design is *perceived* affordance.

| Type | Definition | Example |
|------|------------|---------|
| **Real** | Physical capability exists | A button affords pressing |
| **Perceived** | User believes capability exists | A raised area looks clickable |
| **Hidden** | Exists but isn't obvious | Right-click context menu |
| **False** | Appears to afford action but doesn't | Decorative element that looks clickable |
| **Anti-affordance** | Prevents action | A barrier that blocks movement |

**Digital applications:**

| Element | Affordance | How to Signal |
|---------|------------|---------------|
| **Button** | Clicking/tapping | Raised, colored, shadow, hover state |
| **Text field** | Text input | Border, placeholder text, label |
| **Scroll area** | Scrolling | Scroll bar, fade at edge, partial content |

**Common failures:** flat design erasing perceived affordances (button or label?), too-small touch targets, interactive and decorative elements that look identical.

See: [references/affordances.md](references/affordances.md) for affordance design patterns.

### 3. Signifiers

**Definition:** Signals that communicate where the action should take place. **Affordances determine what you CAN do; signifiers show you WHERE and HOW.**

| Type | Definition | Example |
|------|------------|---------|
| **Deliberate** | Designed to communicate | "Push" label on door, placeholder text |
| **Accidental** | Unintentional but informative | Worn path in grass (people walk here) |
| **Social** | Other people's behavior | Line of people indicates entrance |

**Digital signifiers:**

| Signifier | What It Communicates | Example |
|-----------|---------------------|---------|
| **Cursor change + hover state** | This is interactive | Pointer → hand on links; button color change |
| **Icons + labels** | Function of the element | Magnifying glass = search; "Submit", "Cancel" |
| **Color + position** | Status, category, hierarchy | Red = error, green = success; close button top-right |

**Design rule:** When in doubt, add a signifier — better to over-communicate than leave users guessing.

See: [references/signifiers.md](references/signifiers.md) when deciding which signifier to add to an unclear control.

### 4. Mappings

**Definition:** The relationship between controls and their effects. **Natural mapping** means the spatial layout of controls matches the layout of what they control.

| Mapping Quality | Example | Why It Works/Fails |
|-----------------|---------|-------------------|
| **Natural** | Volume slider (up = louder) | Matches mental model |
| **Poor** | Light switch panel | No spatial correspondence to lights |
| **Poor** | Stovetop knobs in a row | Layout doesn't match burner positions |

**Digital principles:** controls near what they affect, layout mirroring content, direction matching expectation (scroll down = content moves up), related controls grouped.

| Technique | How It Works | Example |
|-----------|-------------|---------|
| **