Three short team notes cover Nir Eyal's Hooked: How to Build Habit-Forming Products: the four phases of the Hook Model, a checklist of six hook elements, and a comparison with the AARRR funnel. Han curated them into this page. The wording is restated in short form, and the ideas belong to Eyal.
1The Hook Model in four phases
The Hook Model is a four-phase process that companies use to form a user's habit. The phases run in a loop: trigger, action, variable reward, investment.
1.1Trigger
A trigger starts the behavior. It prompts the user to act, and it comes in two types.
External triggers tell users what to do next:
- Paid. Advertising that acquires new users.
- Earned. Press mentions and features. These build over time.
- Relationship. Word of mouth, where the audience shares the benefit.
- Owned. Newsletters and notifications that users opt into. This is the most important type, because it comes from the user's own need and, repeated often enough, turns into a habit.
Internal triggers come from the user. The user feels the need without any outside prompt. Raw feelings in the user's mind or body create the urge to come back.
For a product to become a habit, it must couple tightly to a negative feeling. Products that ease boredom, loneliness, frustration, confusion or FOMO reach this stage. The product becomes the top-of-mind answer, and its name turns into a verb: Google, Facebook, Instagram, Spotify, YouTube. Once users cue their next behavior automatically, the new habit is part of their routine.
1.2Action
The action is what the user does in anticipation of a reward. Without it, the trigger is useless. Three factors drive it:
| Factor | Question it answers |
|---|---|
| Motivation | How much does the user want to do it? |
| Ability | Is anything in the way? |
| Simplicity | How many steps stand between the user and what they need? |
1.3Variable reward
The product must reinforce the user's motivation with rewards, the value users get each time they come back.
The point that separates the Hook Model from a plain feedback loop is craving. Feedback loops are everywhere, but predictable ones create no desire. The note's analogy is a different treat appearing in your fridge every time you open it. Not knowing what you will find makes you open the door again and again.
1.4Investment
In this phase the user puts something into the product: time, data, effort, social capital or money. Investment is not about opening a wallet and moving on. It means an action that makes the service better for the next pass. Inviting friends, stating preferences, building virtual assets and learning new features all count. Each commitment can make the next trigger more engaging, the action easier and the reward more exciting.
2Six checks before building a habit-forming product
The second note turns the model into six points an entrepreneur should weigh before building.
- Tie the product to users' pains. A trigger is an internal or external cue, and it is often a painful emotion such as fear, uncertainty, loneliness or boredom. Build the product around that pain, and find ways to link the app with relief from it.
- Make the action easy. Once users spot a trigger, they ignore it or act. People dislike pain, so they usually act. Make that action as easy as possible, like scrolling a Pinterest feed or pressing play on a YouTube video. The easier the action, the more likely users take it.
- Mix up the rewards. Users expect a reward for acting, such as less boredom, social acceptance or new information. Eyal says the reward must vary. People, and pigeons and mice, act more when the outcome is uncertain, which follows from how the brain's reward center works.
- Let users invest in the experience. Products become habit-forming when users find them irreplaceable. Physical goods such as furniture and clothing lose value over time, while great tech products gain value. The more followers you have on Twitter, and the more data you store, the more the product is worth to you. Each action also loads the next trigger: acting once makes the next use close to inevitable.
- Raise the frequency and build a community. A product with infrequent use should attach itself to actions that are already frequent and habit-forming, through content or community. Content could be a blog about things to do in the neighborhoods where you sell homes. Community could be events that engage your target audience. The more people discuss the product, the stronger its effect, and the discussion can produce ideas for a better version. A community talking about the product also moves it closer to being the top-of-mind solution.
- Engagement is not the only metric. For investing, look for "GEMs": companies with Growth, Engagement and Monetization.
3AARRR and the Hook Model compared
AARRR is a strategy for building the user journey. The Hook Model is a process for making a product habitual.
| AARRR | Hook Model | |
|---|---|---|
| Purpose | Strategy to build the user journey | Process to create a habitual product |
| Number of steps | 5 | 4 |
| Step 1 | Acquisition | Trigger |
| Step 2 | Activation | Action |
| Step 3 | Retention | Variable reward |
| Step 4 | Referral | Investment |
| Step 5 | Revenue | none |
AARRR focuses on bringing in new users. The Hook Model focuses on keeping current customers using the product. Both start by getting users to engage and steering them toward an intended action, so they look alike until the action step:
- AARRR treats the action as external, exposing the brand to potential new users.
- Hook treats the action as internal, building the habit and improving the product itself.
The two can coexist in product development. Their end goals differ, and both serve product growth. AARRR makes sure existing users help the product grow. The Hook Model makes sure the product becomes part of a consumer's daily habit. They meet at one stage: AARRR activation lines up with the Hook action.
The takeaway is to build on the synergy between the two. The product should offer:
- An easy, approachable action.
- A customizable experience.
- A variable reward.
The note ends with a personal view. It reads the pairing as a case of Agile in product strategy: nothing goes straight from point A to point B on a smooth, error-free plan. Requirements and market demand change, and the whole approach depends on users and how they interact with the product.
4References
- Nir Eyal, Hooked: How to Build Habit-Forming Products
- Nir Eyal's post on hooking users, Drive them crazy, on Nir and Far
- Video games can activate the brain's pleasure circuits on Psychology Today