Product management glosary

Hook Model

What is the Hook Model?

The Hook Model is a product management concept that focuses on creating user habits to ensure the long-term success of a product. It is a four-step process that helps product managers and designers build products that engage users and keep them coming back for more. The model was developed by Nir Eyal, a renowned author, and expert in the field of behavioral design and habit-forming products.

Understanding the Hook Model is essential for product managers, as it provides a framework for creating products that users find valuable and engaging. By incorporating the Hook Model into the product development process, product managers can increase user retention, engagement, and ultimately, the success of their products.

The Four Steps of the Hook Model

The Hook Model consists of four main steps: Trigger, Action, Variable Reward, and Investment. Each step plays a crucial role in creating a habit-forming product.

1. Trigger

Triggers are cues that prompt users to take action. They can be either external or internal. External triggers are elements in the user's environment, such as notifications, emails, or advertisements, that prompt them to use the product. Internal triggers are user-generated cues, such as emotions, thoughts, or routines, that drive them to use the product. To create a habit-forming product, product managers must identify the triggers that will encourage users to engage with their product regularly.

2. Action

Action is the step where users perform a specific behavior in response to the trigger. The action should be simple and easy to perform, requiring minimal effort from the user. This increases the likelihood that users will take the desired action and continue to engage with the product. Examples of actions include clicking a button, swiping a screen, or typing a message.

3. Variable Reward

Variable rewards are the incentives that users receive after completing the action. These rewards should be unpredictable and vary each time the user engages with the product. This unpredictability creates a sense of excitement and anticipation, which keeps users coming back for more. Examples of variable rewards include receiving likes or comments on social media, discovering new content, or earning points or badges in a game.

4. Investment

Investment is the final step in the Hook Model, where users contribute time, effort, or resources to the product. This investment increases the likelihood that users will return to the product in the future, as they have a personal stake in its success. Examples of investments include creating a profile, adding friends, or uploading content. The investment also sets the stage for future triggers, as users are more likely to engage with the product when they have invested in it.

Applying the Hook Model in Product Management

Product managers can use the Hook Model as a guide when designing and developing products. By incorporating each of the four steps into the product's features and functionality, product managers can create a product that encourages user engagement and forms habits. This can lead to increased user retention, higher levels of user satisfaction, and ultimately, a more successful product.

It is important to note that the Hook Model should be used ethically and responsibly. Product managers should focus on creating products that genuinely add value to users' lives and avoid exploiting users' psychological vulnerabilities for short-term gains.


The Hook Model is a powerful tool for product managers looking to create habit-forming products that keep users engaged and coming back for more. By understanding and incorporating the four steps of the Hook Model - Trigger, Action, Variable Reward, and Investment - product managers can increase user retention and drive the long-term success of their products.