hooked-ux

# Hook Model Framework

Framework for building habit-forming products. Habits are not created — they are built through successive cycles through the Hook.

## Core Principle

**The Hook Model** = a four-phase loop that connects the user's problem to your solution frequently enough to form a habit, moving usage from deliberate to automatic.

```
Trigger → Action → Variable Reward → Investment
    ↑                                      │
    └──────────────────────────────────────┘
```

## Scoring

**Goal: 10/10.** When reviewing or creating product engagement mechanics, rate them 0-10 based on adherence to the principles below. A 10/10 means full alignment with all guidelines; lower scores indicate gaps to address. Always provide the current score and specific improvements needed to reach 10/10.

## The Four Phases

### 1. Trigger

**Core concept:** The actuator of behavior. Triggers are external (environment-driven: notifications, emails, ads) or internal (emotion-driven) — and the goal is to migrate users from external to internal triggers.

**Why it works:** Every habit starts with a cue. External triggers get users started, but internal triggers — boredom, loneliness, uncertainty, FOMO — drive unprompted usage; when your product becomes the automatic response to an emotion, you have a habit.

**Key insights:**
- Map your product to the specific negative emotion it resolves (boredom, loneliness, confusion, FOMO)
- Effective external triggers are well-timed, actionable, and lead to the simplest possible next action
- If users still need external prompts after ~30 days, no internal trigger has formed

**Product applications:**

| Context | Application | Example |
|---------|-------------|---------|
| **Onboarding** | External triggers establish the first loop | Welcome email with one clear action |
| **Retention** | Map product to internal emotional trigger | Instagram resolves boredom; Google resolves confusion |
| **Re-engagement** | External triggers bridge gaps until habit forms | Push: "Your friend just posted a photo" |

**Copy patterns:**
- "Don't miss what happened while you were away" (FOMO trigger)
- "Your friend just..." (social trigger bridging to internal)
- "Pick up where you left off" (routine trigger)

**Ethical boundary:** Never exploit vulnerable emotional states (depression, addiction, grief) — triggers should connect users to genuine value, not manufacture anxiety to drive opens.

See: [references/triggers.md](references/triggers.md) for trigger design, emotion mapping, and external-to-internal transition strategies.

### 2. Action

**Core concept:** The simplest behavior done in anticipation of a reward, guided by the Fogg Behavior Model: Behavior = Motivation + Ability + Trigger, all converging at the same moment.

**Why it works:** Increasing motivation is hard and unreliable; reducing friction (increasing ability) is easier and more effective. Every extra step, field, or decision is a drop-off point.

**Key insights:**
- Six elements of simplicity: time, money, physical effort, brain cycles, social deviance, non-routine
- The action is the simplest behavior in anticipation of reward — not the full task
- Hick's Law: more choices = slower decisions; reduce options to increase action rate

**Product applications:**

| Context | Application | Example |
|---------|-------------|---------|
| **Signup flow** | Minimize fields and steps | One-click Google/Apple sign-in |
| **Core action** | Completable in seconds | Twitter: type 280 characters and post |
| **Progressive disclosure** | Ask for more only after initial reward | Duolingo: play first, create account later |

**Copy patterns:**
- "Just one tap to..." (emphasizes simplicity)
- "No credit card required" (money/risk simplicity)
- Buttons should be verbs: "Post", "Save", "Share" — not "Submit" or "Continue"

**Ethical boundary:** Reduce friction on genuinely valuable actions only — dark patterns that hide costs or consequences behind simple actions are unethical.

See: [references/product-applications.md](references/product-applications.md) for action and investment design across product types.

### 3. Variable Reward

**Core concept:** The phase that keeps users coming back. Anticipation of reward — not the reward itself — creates dopamine, and rewards must be variable (unpredictable) to sustain engagement.

**Why it works:** The brain's dopamine system responds most strongly to anticipation of uncertain rewards — the slot machine effect. Three reward types — tribe (social), hunt (resources), self (mastery) — tap fundamental human drives.

**Key insights:**
- Tribe = social validation; Hunt = search for resources/information; Self = personal mastery
- Predictable rewards lose power; finite variability eventually becomes predictable — aim for infinite variability
- Autonomy is critical: users must feel in control; forced engagement backfires

**Product applications:**

| Context | Application | Example |
|---------|-------------|---------|
| **Social features (Tribe)** | Variable social validation | Instagram likes — you never know how many |
| **Content feeds (Hunt)** | Unpredictable resource stream | Infinite scroll with algorithmically varied content |
| **Gamification (Self)** | Accomplishment with variable difficulty | Duolingo streaks + surprise bonus challenges |

**Copy patterns:**
- "See what's new" (implies variability)
- "3 people responded to your post" (tribe reward, variable quantity)
- "You've unlocked a new achievement!" (self reward, unexpected)

**Ethical boundary:** If users consistently feel worse after engaging (regret, time loss, anxiety), the reward system is extractive — avoid infinite scroll without natural stopping points.

See: [references/rewards.md](references/rewards.md) for reward design patterns, reinforcement schedules, and reward timing.

### 4. Investment

**Core concept:** Users invest something — time, data, effort, social capital, money — that improves the product for next us