Concept
Hook Model
The Hook Model is Nir Eyal's four-phase account of how products become habits: a trigger prompts an action, the action brings a variable reward, and the user makes an investment that improves the product and sets up the next trigger.
Eyal set out the model in Hooked (2014), written with Ryan Hoover, to explain why some products are used without advertising or reminders. Each pass through the loop makes the next more automatic, until an internal trigger, a feeling such as boredom or uncertainty, brings the user back without any external prompt. The model is descriptive: it explains why a product is or is not becoming a habit, and where the loop breaks. What people often get wrong is treating it as a growth trick. Eyal himself pairs it with an ethics test, the Manipulation Matrix, and the honest use of the model starts with naming which feeling the product relieves.
A real-life example
A product team in Eskişehir maps its fitness app on the four phases and finds the loop breaks at the investment: users finish a workout and leave nothing behind. The team adds one step after each session, choosing tomorrow's focus area, which personalises the next workout and sends a single morning prompt. Returning users rise, and the team removes two of its daily reminders.
How to use it
- 1Draw the four phases for one product and write what happens at each, from the user's side.
- 2Find the phase where the loop breaks, and fix that one before adding anything new.
- 3Test the result against the Manipulation Matrix before shipping it.