Hooked: How to Build Habit-Forming Products by Nir Eyal explores the psychology and strategies behind building products and services that are designed to create user habits. The book presents a framework called the "Hook Model" and delves into the ways companies can use it to build habit-forming products. Here are the key ideas from "Hooked":
The Hook Model
Eyal introduces the Hook Model, a four-step process that companies can use to create habit-forming products. The four components of the Hook Model are:

1. Trigger
Triggers are cues that prompt users to take action. There are two types of triggers: external triggers (e.g., notifications, advertisements) and internal triggers (e.g., emotions, thoughts).

2. Action
The action phase involves the user taking a specific behavior or action in response to a trigger. This can be clicking a link, scrolling a feed, or any other user action.

3. Variable Reward
Variable rewards are the unpredictable and satisfying outcomes that users receive after taking action. These rewards can be in the form of social validation, material gain, or something else.

4. Investment
In the investment phase, users put effort, time, or resources into the product or service. This creates a commitment and increases the likelihood of returning to the product in the future.
Habit Formation
Eyal explores the psychology of habit formation and how repeated use of a product or service can lead to habituation. He discusses the importance of creating a "hook" to keep users engaged and coming back for more.
Ethical Considerations
While discussing the Hook Model and habit-forming products, Eyal also addresses the ethical implications of designing products that encourage habituation. He emphasizes the responsibility of product designers to use these techniques for positive and ethical purposes.
Behavioral Psychology
Throughout the book, Eyal draws on insights from behavioral psychology and neuroscience to explain why people form habits and how products can leverage these psychological mechanisms.
Case Studies
Eyal provides numerous real-world examples and case studies from companies like Facebook, Instagram, and Twitter to illustrate how they have successfully applied the Hook Model to create habit-forming experiences.
Practical Advice
"Hooked" offers practical advice and strategies for product designers and entrepreneurs looking to build habit-forming products. Eyal provides guidance on how to identify triggers, optimize user actions, design variable rewards, and encourage user investment.
Breaking Habits
In addition to discussing how to build habit-forming products, Eyal also explores strategies for breaking undesirable habits and suggests that the same principles can be used to help individuals change their behaviors.

"Hooked" provides valuable insights into the psychology of habit formation and offers a framework that can be applied to product design and marketing. It's a useful resource for anyone interested in understanding the mechanics of habit-forming products and services.