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The key points of 'Hooked: How to Build Habit-Forming Products' by Nir Eyal

In 'Hooked: How to Build Habit-Forming Products' by Nir Eyal, the author presents the Hook Model, a framework for creating habit-forming products. This model consists of four key elements: Triggering User Action, Action, Variable Reward, and Investment. Each element plays a crucial role in forming and sustaining user habits.

Key Takeaways

  • The Triggering User Action is the initial prompt that leads to user engagement.

  • The Action phase involves the user taking a simple and easy step to engage with the product.

  • Variable Reward refers to the unpredictable and satisfying outcomes that users receive from interacting with the product.

  • Investment encourages users to put effort into the product, making it more valuable over time.

  • Understanding the Hook Model can help product creators design products that form positive user habits and increase user engagement.

The Hook Model

Triggering User Action

The first step in the Hook Model is about triggering user action. This is where the product cues the user to take the initial action. The trigger can be external, such as a notification or an advertisement, or internal, stemming from habits or routines that cue the user subconsciously.

Triggers are designed to prompt the user to move from needing to wanting. The effectiveness of a trigger is determined by its ability to capture attention and motivate action. Here are some common types of triggers:

  • External Triggers: These include paid triggers, earned triggers, relationship triggers, and owned triggers.

  • Internal Triggers: These are associations stored in the user's memory, such as emotions or situations that instinctively prompt the user to engage with the product.


In the Hook Model, the Action phase is where the user performs the behavior that the product's design intends to provoke. Simplicity is key in this stage; the action must be as easy as possible to complete, reducing friction and encouraging user participation.

  • User's understanding of the task

  • Ease of completing the action

  • The user's motivation

Understanding the psychology behind what drives user action is essential for creating compelling products. By analyzing how users interact with the product and what barriers they face, designers can refine the user experience to promote habitual use.

Variable Reward

The concept of Variable Reward is a cornerstone in creating habit-forming products. It's the unpredictability of the reward that keeps users engaged and coming back for more. Rewards must satisfy users' needs, yet leave enough uncertainty to provoke their curiosity.

  • Tribe: Social rewards that create a sense of belonging.

  • Hunt: The search for material resources or information.

  • Self: Personal gratification and intrinsic rewards.

By mastering variable rewards, products can tap into the powerful human emotion of anticipation, which plays a crucial role in habit formation.


The final phase of the Hook Model is Investment. This step is crucial as it increases the likelihood of users returning to the product. Investment occurs when users put something into the product, such as time, data, effort, social capital, or money, which makes them value it more.

Users' investments lead to the 'IKEA Effect', which posits that labor enhances affection for its results. The more effort users put into something, the more they value it. This investment doesn't just create value; it sets the stage for the next trigger, creating a self-perpetuating loop that keeps users engaged.

Examples of user investments include:

  • Personalizing a profile

  • Learning new skills through the platform

  • Building a repository of content

  • Engaging with others, creating social ties

Each investment enhances the user's experience and binds them to the product, making the next trigger more effective and the action easier to initiate.


In conclusion, 'Hooked: How to Build Habit-Forming Products' by Nir Eyal provides valuable insights into the psychology of habit formation and how to create products that keep users engaged. The book's key points, including the Hook Model, variable rewards, and habit-forming loops, offer practical strategies for product designers and entrepreneurs. By understanding the principles outlined in the book, businesses can develop products that are more likely to form user habits, leading to increased user engagement and loyalty. 'Hooked' is a must-read for anyone involved in product development and user experience design.

Frequently Asked Questions

What is the Hook Model?

The Hook Model is a framework designed to create habit-forming products by understanding and leveraging the psychology of user behavior.

How does triggering user action fit into the Hook Model?

Triggering user action is the first step in the Hook Model, where external or internal triggers prompt users to take a specific action.

What role does 'action' play in the Hook Model?

The 'action' phase involves the simplest behavior in anticipation of a reward, forming the basis of a habit loop.

What is meant by 'variable reward' in the Hook Model?

Variable rewards are those that are unpredictable in nature, creating a sense of curiosity and driving continued engagement.

How does 'investment' contribute to habit-forming products?

The 'investment' phase requires users to put in effort, time, or data into a product, increasing the likelihood of returning to the product.

Can any product be designed using the Hook Model?

While the Hook Model can be applied to various products, it is important to consider ethical implications and user well-being when designing habit-forming products.

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