Hooked: How to Build Habit-Forming Products by Nir Eyal and Ryan Hoover


  1. Through consecutive Hook cycles, successful products reach their ultimate goal of unprompted user engagement, bringing users back repeatedly, without depending on costly advertising or aggressive messaging. Trigger –> Action –> Habit (often, variable reward) –> Investment Phase

Key Takeaways

  1. Trigger
    1. A trigger is the actuator of behavior—the spark plug in the engine.
    2. Triggers come in two types: external and internal. Habit-forming products start by alerting users with external triggers like an e-mail, a Web site link, or the app icon on a phone.
    3. Internal triggers manifest automatically in your mind. Connecting internal triggers with a product is the brass ring of habit-forming technology.
  2. Action
    1. Following the trigger comes the action: the behavior done in anticipation of a reward. The simple action of clicking on the interesting picture in her news feed takes Barbra to a Web site called Pinterest, a “social bookmarking site with a virtual pinboard.”9 This phase of the Hook, as described in chapter 3, draws upon the art and science of usability design to reveal how products drive specific user actions. Companies leverage two basic pulleys of human behavior to increase the likelihood of an action occurring: the ease of performing an action and the psychological motivation to do it.
  3. Variable Reward
    1. What distinguishes the Hooked Model from a plain vanilla feedback loop is the Hook’s ability to create a craving. Feedback loops are all around us, but predictable ones don’t create desire. The unsurprising response of your fridge light turning on when you open the door doesn’t drive you to keep opening it again and again. However, add some variability to the mix—suppose a different treat magically appears in your fridge every time you open it—and voilà, intrigue is created. Variable rewards are one of the most powerful tools companies implement to hook users;
    2. For new behaviors to really take hold, they must occur often.
    3. My answer to the vitamin versus painkiller question: Habit-forming technologies are both. These services seem at first to be offering nice-to-have vitamins, but once the habit is established, they provide an ongoing pain remedy.
    4. Habits are not created, they are built upon
    5. Our brains are adapted to seek rewards that make us feel accepted, attractive, important, and included.
    6. With every post, tweet, or pin, users anticipate social validation. Rewards of the tribe keep users coming back, wanting more.
    7. Fogg states that all humans are motivated to seek pleasure and avoid pain; to seek hope and avoid fear; and finally, to seek social acceptance and avoid rejection.
    8. Consequently, any technology or product that significantly reduces the steps to complete a task will enjoy high adoption rates by the people it assists. But which should you invest in first, motivation or ability? Where is your time and money better spent? The answer is always to start with ability.
      1. The factors that influence a task’s difficulty. These are: Time—how long it takes to complete an action. Money—the fiscal cost of taking an action. Physical effort—the amount of labor involved in taking the action. Brain cycles—the level of mental effort and focus required to take an action. Social deviance—how accepted the behavior is by others. Non-routine—according to Fogg, “How much the action matches or disrupts existing routines.”
    9. the most habit-forming products and services utilize one or more of the three variable rewards types: the tribe, the hunt, and the self. In fact, many habit-forming products offer multiple variable rewards.
  4. Investment
    1. The last phase of the Hooked Model is where the user does a bit of work. The investment phase increases the odds that the user will make another pass through the cycle in the future. The investment occurs when the user puts something into the product of service such as time, data, effort, social capital, or money. However, the investment phase isn’t about users opening up their wallets and moving on with their day. Rather, the investment implies an action that improves the service for the next go-around. Inviting friends, stating preferences, building virtual assets, and learning to use new features are all investments users make to improve their experience. These commitments can be leveraged to make the trigger more engaging, the action easier, and the reward more exciting with every pass through the Hooked Model.
  5. Other               
    1. Dorsey believes a clear description of users—their desires, emotions, the context with which they use the product—is paramount to building the right solution.
    2. To combat the trolls, the game creators designed a reward system leveraging Bandura’s social learning theory, which they called Honor Points (figure 20). The system gave players the ability to award points for particularly sportsmanlike conduct worthy of recognition. These virtual kudos encouraged positive behavior and helped the best and most cooperative players to stand out in the community. The number of points earned was highly variable and could only be conferred by other players. Honor Points soon became a coveted marker of tribe-conferred status and helped weed out trolls by signaling to others which players should be avoided.
    3. The more users invest time and effort into a product or service, the more they value it. In fact, there is ample evidence to suggest that our labor leads to love. Together, the three tendencies just described influence our future actions: The more effort we put into something, the more likely we are to value it; we are more likely to be consistent with our past behaviors; and finally, we change our preferences to avoid cognitive dissonance. These tendencies of ours lead to a mental process known as rationalization, in which we change our attitudes and beliefs to adapt psychologically.
    4. Asking users to do a bit of work comes after users have received variable rewards, not before. The timing of asking for user investment is critically important. By asking for the investment after the reward, the company has an opportunity to leverage a central trait of human behavior.
    5. only because of the image itself, but because of her relationship with the pinner. Finally, Pinterest users invest in the site every time they pin an image of their own, repin someone else’s image, comment on, or like a piece of content on the site (figure 32). Each of these tiny investments gives Pinterest data it can use to tailor the site to each user’s individual taste; it also loads the next trigger. Each pin, repin, like, or comment gives Pinterest tacit permission to contact the user with a notification when someone else contributes to the thread, triggering the desire to visit the site again to learn more.
  6. Actionable steps / questions
    1. Walk through the path your users would take to use your product or service, beginning from the time they feel their internal trigger to the point where they receive their expected outcome. How many steps does it take before users obtain the reward they came for? How does this process compare with the simplicity of some of the examples described in this chapter? How does it compare with competing products and services?
    2. Social acceptance is something we all crave, and Fitocracy leverages the universal need for connection as an on-ramp to fitness, making new tools and features available to users as they develop new habits.
    3. The job of companies operating in conditions of inherent variability is to give users what they desperately crave in conditions of low control—a sense of agency.
    4. Speak with five of your customers in an open-ended interview to identify what they find enjoyable or encouraging about using your product. Are there any moments of delight or surprise? Is there anything they find particularly satisfying about using the product?
    5. Review the steps your customer takes to use your product or service habitually. What outcome (reward) alleviates the user’s pain? Is the reward fulfilling, yet leaves the user wanting more? Brainstorm three ways your product might heighten users’ search for variable rewards using: rewards of the tribe—gratification from others. rewards of the hunt—material goods, money, or information. rewards of the self—mastery, completion, competency, or consistency.
    6. You are now equipped to use the Hooked Model to ask yourself these fundamental questions for building effective hooks: What do users really want? What pain is your product relieving? (Internal trigger) What brings users to your service? (External trigger) What is the simplest action users take in anticipation of reward, and how can you simplify your product to make this action easier? (Action) Are users fulfilled by the reward yet left wanting more? (Variable reward) What “bit of work” do users invest in your product? Does it load the next trigger and store value to improve the product with use? (Investment)

What I got out of it

  1. A practical, actionable playbook on how to think about habit-forming products. Being thoughtful about each step provides a framework. What is the trigger (internal, external), what action does it induce, what is the variable reward and how often does it occur, how can you get customers to invest in the product (money, time, effort, brain cycles, etc…) to make it stickier