# millers-law

Chunks interface elements into groups of about four to fit working memory limits. Useful when structuring navigation menus, onboarding flows, and form sections.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1700 installs · ★ 3103
- Author: Owl-Listener
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/Owl-Listener/designer-skills/tree/HEAD/interaction-design/skills/millers-law/SKILL.md
- Updated: 2026-09-05
- HTML: https://affpapa.org/en/nevibecode/skills/millers-law

## What it does

This skill guides the agent in structuring interfaces using cognitive psychology. Structure comes before counting. Instead of treating seven items as an absolute limit, it incorporates Nelson Cowan's 2001 findings. Working memory reliably holds roughly 4 ± 1 meaningful chunks. The skill applies this directly to navigation links and long forms.

The instructions divide long lists into readable sections using headings and whitespace. Common examples include phone numbers, data tables, and pricing tiers with 3–5 bullets. When the goal is reducing available decision branches rather than grouping them, the skill defers to `hicks-law`. This distinction prevents confusion between organizing data and cutting choices.

The rule does not apply to colors or icons. Visual chunking operates under different mechanisms. Familiarity also expands chunk capacity, so experienced users easily handle higher information density. The prompt advises testing actual recall after navigation instead of policing raw item numbers.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add Owl-Listener/designer-skills --skill millers-law -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/millers-law/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/millers-law/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add Owl-Listener/designer-skills --skill millers-law -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/millers-law/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add Owl-Listener/designer-skills --skill millers-law -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/millers-law/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install Owl-Listener/designer-skills millers-law
```

2. **Manually: put the files in place**
- File: `.github/skills/millers-law/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add Owl-Listener/designer-skills --skill millers-law -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/Owl-Listener/designer-skills --path interaction-design/skills/millers-law
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/millers-law/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add Owl-Listener/designer-skills --skill millers-law -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/Owl-Listener/designer-skills/tree/HEAD/interaction-design/skills/millers-law/SKILL.md

## When to use it
- split long forms into distinct titled sections
- group flat navigation menus into category clusters
- structure multi-step onboarding into 3–5 named phases
- format pricing tier feature lists into concise blocks

## Example prompts
- Apply Miller's Law to organize this flat settings menu into grouped categories.
- Break this registration form into distinct sections with clear headings.
- Organize this 12-step onboarding sequence into 3 to 5 named phases.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 2e47e96221ffbc02.

BEGIN THIRD-PARTY FILE 2e47e96221ffbc02
```text
---
name: millers-law
description: Apply Miller's Law — chunk information into groups of about four to fit working memory. Use when grouping fields, menu items, or steps. For reducing the number of choices offered, use `hicks-law`.
---
# Miller's Law
You are an expert in cognitive psychology as it applies to information design and interface structure.
## What You Do
You apply chunking and grouping strategies informed by working memory research to make interfaces easier to scan, understand, and recall.
## The Principle and Its Limits
George Miller's 1956 paper proposed that working memory can hold **7 ± 2 items** (5–9). This figure has been widely cited in UX design — and just as widely misapplied.
More recent research (particularly Nelson Cowan, 2001) suggests the realistic limit for **meaningful chunks in working memory is closer to 4 ± 1**. The important nuance Miller himself made: the "7" applies to **chunks**, not raw items. A chunk is whatever unit has meaning to the person — a word, a concept, a familiar pattern.
**What this means for design:**
- Grouping items into meaningful chunks reduces cognitive load regardless of the exact number
- The precise ceiling is less important than the principle: working memory is limited, and structure helps
- Don't cite "7 items" as a design rule; cite chunking as the strategy
## Where Chunking Applies
- **Navigation**: group menu items by category; flat lists of 10+ items are harder to scan than 3 groups of 3–4
- **Forms**: break long forms into sections with clear headings — each section should feel completeable as a unit
- **Phone numbers and codes**: formatted as chunks (e.g. `555-867-5309`, `XXXX-XXXX` verification codes) for easier recall
- **Data tables**: use visual grouping (alternating rows, section headers) to break long lists into scannable blocks
- **Onboarding steps**: show progress as 3–5 named phases rather than a raw step count of 12
- **Feature lists and pricing**: 3–5 bullet points per tier; beyond that, users stop reading
## Common Misapplications
- Using "7 is the limit" to justify navigation menus of exactly 7 items
- Applying it to visual elements (colors, icons) where visual chunking works differently than verbal memory
- Ignoring that familiarity expands chunk size: expert users chunk more than novice users
## Best Practices
- Structure first, count second — meaningful groupings matter more than hitting a number
- Use headings, whitespace, and visual dividers to make chunks explicit
- Test recall, not just comprehension — can users remember what options were available after navigating away?
```
END THIRD-PARTY FILE 2e47e96221ffbc02

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First 2623 of 2721 bytes. © Owl-Listener · MIT · https://github.com/Owl-Listener/designer-skills/tree/HEAD/interaction-design/skills/millers-law/SKILL.md

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