Hook Model
The Hook Model builds a habit loop into a product - a trigger prompts an action, the action earns a variable reward, and the user invests something back in, which sets up the next trigger - so use is built into the product's shape, not bolted on with marketing.
Arrows loop back on themselves: trigger leads to action, action to reward, reward to fresh investment, and round again.
Reach for this when…
- Users try your product once and don't come back.
- You are relying on ads to bring people back instead of the product itself.
- A feature gets used once then forgotten, and you don't know why.
How to run it
- Design the trigger: what internal need or external cue starts the loop.
- Make the action as low-friction as possible - one tap, not a form.
- Build in a variable reward - something not fully predictable, so it stays interesting.
- Ask the user to invest something small back in: data, content, effort, or a connection.
- That investment becomes the seed of the next trigger - check the loop actually closes.
A worked example
Situation. Mariana Solís built a language-learning app for commuters in San José, Costa Rica, that had strong downloads but a steep drop-off after day three.
Applied. She mapped the loop and found the reward stage was flat - every lesson gave the same fixed points, so there was nothing to look forward to. She rebuilt it around variable streak bonuses and randomised bonus questions.
Result. Daily return rate nearly doubled over six weeks, and users started inviting friends to compare streaks, an investment step that hadn't existed before.
The catch
The model is deliberately about engineering habit, and the line between a useful habit and a manipulative one is a judgement call, not something the model makes for you. It also assumes an internal trigger will eventually take over from external prompts, which doesn't happen for products people don't actually need. If the loop only survives on notifications, it isn't a habit yet.
If you'd be uncomfortable explaining the reward mechanic to the user directly, that's worth sitting with before you ship it.
Origin: Nir Eyal