Hooked: How to Build Habit-Forming Products


Nir Eyal wrote “Hooked: How to Build Habit-Forming Products” based off his years of practical experience in Silicon Valley. As he witnessed hundreds of products either flop or succeed, Eyal decided to embark on a research journey to understand why people seemed to get attached to some products over others. Ultimately, he wanted to discover how product engineers are able to alter user behavior in order to achieve unprompted user engagement.

Eyal uses examples of products that we rely on, which include many popular phone applications. Social media has been able to alter human behavior and maintain a permanent residence in our daily routines. Think about the number of times you open Snapchat, Instagram, or Facebook every day: waiting on lines, walking to class, and even while you’re having a conversation with a friend face-to-face. We are “hooked” on these products and engage with them out of sheer habit.

Through years of research, Eyal has developed a model to represent the cycles that must occur in order to captivate users. The Hook Model, as he calls it, is made up of 4 parts: Trigger, Action, Variable Reward, and Investment. Each step of this process is used in experiences such as apps, sports, games, movies or even our jobs to keep us engaged.

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The Hook Model

Overview of Hook Model

(1) Triggers occur in two forms: external and internal. These are calls to action that alert users to use the product. External triggers are external and can include an email, app icon, or link, which are mainly part of the company’s marketing strategy. As users continue using the product and cycling through hooks, they begin to form emotional connections with internal triggers. For example, when you are feeling bored or socially disconnected, a solution to solve this “emotional itch” is to check Facebook or Instagram. These social media companies do not have to spend any advertising money to get you to open their app repeatedly once you are hooked because the emotional internal trigger has been established.

(2) Actions do not necessarily occur if somebody sees a trigger. There are plenty of times that we see links to download apps, yet decide not to. Eyal introduces a formula that explains this behavior. There are 3 requirements for a person to take action: motivation, ability, and a present trigger. If a trigger is presented to a user at the moment they have motivation to move forward, and the ease-of-use that allows them to do so, they will take action and progress in the Hook Cycle. As increasing motivation for users to engage can be time-consuming and expensive, many companies venture to give people greater ability to use their product. For example, instead of registering and signing up for every new site and game we use, we often encounter easy-to-use Facebook logins that allow us to use credentials we have already established. This cuts down the process to use a product tremendously, and allows users to quickly sign up without time to rethink their decision.

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FitBit Badges

(3) Variable Rewards are one of the most fascinating aspects of the Hook Model. Eyal explains how products that do not interest the user with novel advancements and/or rewards will fail because they are not exciting. As Eyal writes, rewards must be variable and be one of these three types: Rewards of the Tribe, the Hunt, or Self. One of the best examples he used was “gamification.” Gamification is the use of gamelike elements in nongame environments. This practice can be seen in points, badges, and leaderboards that many apps are now using to entice users into a competitive and goal-oriented attitude. Many health apps are using these tactics to encourage users to walk a certain number of steps per day and compete with their friends. With badges awarded for reaching a certain goal, these apps keep users entertained with varying goals and rewards for accomplishments.

(4) Investment, the last stage of the Hook Model, is a phase in which users are engaged because of the anticipation of future rewards. When we pour time and effort into something, we tend to overvalue the outcome. Eyal explains that we value our work, so when we invest our work or money into a product, we justify that it must be worthwhile, giving even more value to the product. For example, when people spend real money on virtual video games such as FarmVille, they must logically justify that FarmVille is a fantastic app, otherwise they would not put their hard-earned money into a meaningless game. The Investment stage also serves to provide another internal trigger that cycle the Hook Model through once again, creating intrinsic habits.

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I would absolutely recommend this book to everybody, it is an interesting and thought-provoking read. It is written not only in an informative tone, but also serves as a step-by-step guide with “Do This Now” bullet points at the end of every chapter. Personally, I loved this book because I am interested in the intersection between technology and psychology. Eyal also dives into the reasons why some products are more appealing and habit-forming than others. This is important if you want to start your own company, develop a product, or simply become more aware of how companies are able to change our natural instincts and behaviors through their cleverly designed products.

9 thoughts on “Hooked: How to Build Habit-Forming Products

  1. As a marketing major, people often ask me what is the point of marketing. Is it to sell people things they don’t need? Or to help a good product get to the right people? This book sounds interesting as a guide to make a successful and enduring product, but could it be applied to a product we don’t really need? I’d be interested to hear if the book addressed this anywhere.


  2. It is interesting how certain social media apps take off and become ingrained in our daily life, while others do not. I definitely understand how apps with some type of reward could take off, like Pokemon Go, since people enjoy attaining goals, and being rewarded for them. At first I thought this only applied to games, however this ideology also applies to an app like Instagram, where people set goals for the amount of followers or likes they want to achieve, and then feel gratification when they reach their goals.


  3. Does this book mention anything about the ethical implication of creating habit-forming products? I’m always intrigued to read cases about how changing the color or wording of a button can double their engagement. It’s really valuable from the business’s perspective, but I’ve always felt that they can leave the consumer feeling manipulated if they ever find out.


  4. I’ve read a number of articles discussing whether popular applications like Instagram and Facebook are designed to maliciously manipulate users into “addiction,” or if it’s just dependent on the individual users. I like that the author chose 4 different topics that cause such habituation. Thanks for the summary!


  5. Seems like a very interesting read! I love the idea of the “Do this Now” section at the end of every chapter, as I feel like I would really try to implement some changes in my habits! I have been trying to limit my social media time lately so that I can be more productive, and at one point this summer I put my phone in black and white to reduce the vibrancy and interest in scrolling through instagram. Although this only temporarily lasted, it is cool to understand the psychology behind these habits and how the four components of the hook model come together. Great summary!


  6. This sounds like a very worthwhile read! It is incredible how hooked we have all become on the core social media apps; I often catch myself reaching for my phone several times a day to check Instagram even when I know I shouldn’t or know there won’t be any new content. Understanding what motivates these very real addictions seems really helpful for anyone trying to cut back their own usage. I especially liked the 3 requirements for a user to take action. It’s very true nowadays that if a new app doesn’t allow me to sign in with Facebook, I likely won’t continue with the signup process. Signup needs to be easy enough and quick enough that I don’t have the time to second guess the supposed benefits of the app.


  7. Great summary! It’s so interesting to read about a topic that applies to us on a daily basis. The psychology behind consumer products is so fascinating. I often find myself mindlessly scrolling through my social media feeds when I’m bored so that I can feel “connected”. Thanks for breaking down the summary by defining the 4 aspects of the Hook Model and giving great examples along with each.


  8. Interesting summary! The Hook Model offers thought-provoking insights into the psychology behind marketing and value creation. The “Do This Now” bullet points and step-by-step walkthrough are enticing me to read it ASAP! One question — is there a way to quantify the three requirements behind actions (motivation, ability, present trigger)?


  9. Nice post. I recently read a similar book (Storybrand) that made me completely rethink how to tell stories for engagement. This one has a very similar effect on how to design digital products. Good work!


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