Stop 09 · Growth & ExperimentationTopics · 7/10

The Hook Model

In short

Some apps you open without thinking. Nir Eyal's Hook Model explains the four-step cycle behind many habit-forming products, and it helps you ask whether a habit is good for users.

Nir Eyal's framework for habit-forming products — Trigger, Action, Variable Reward, Investment — a repeating loop that makes a product more likely to be revisited.

The purple blob in pyjamas reaches for a steaming cup of tea on the bedside table.

Think of it like this

The morning chai habit

You wake up groggy (trigger). You put the kettle on (action). Some mornings it's a chat with Papa, some mornings the news, always warm (variable reward). You've bought your favourite masala, so tomorrow's chai is even better (investment).

Watch it happen

One turn of the hook in a fitness app

Trigger

Action

Reward

Investment

1/5External trigger: a 7 am reminder. Over time, an internal trigger takes over, like feeling sluggish.

The big ideas

What you need to know

Triggers

External ones are notifications and emails. Internal ones are feelings like boredom or worry.

Easy action

The simpler the action, the more likely it happens. Remove taps and decisions.

Variable rewards

Unpredictable rewards hold attention more than identical ones. Use this with care.

Ethics matter

Ask: does this habit help the user? Build habits users would choose, not ones they regret.

Save yourself the pain

Common mistakes

Oops

Sending more notifications to force a habit.

Do this instead

Make the action easier and the reward real. Spammy triggers get muted.

Oops

Using hooks to keep people on something that harms them.

Do this instead

Apply the model to habits users want, like learning or saving money.

Your mission

Map a hook you're in

~20 min

Quick check

In the Hook Model, what is "investment"?

Go deeper

1Map a habit-forming app you use onto the 4 stages of the Hook Model.
2Identify the 'variable reward' in that product and why it keeps you coming back.
3Consider the ethical line between healthy engagement and manipulative dark patterns.