Hook Model

What is the Hook Model? How does it work?

The main dynamic in any growth process is the relationship you have with your users. If you have a long term connection with them and keep interacting with them, that paves the way for a sustainable growth process. If you constantly encounter problems in activating your users and prompting them to revisit you, then your growth process may be stunted. (Those who want a more detailed analysis on the positive contributions of retention to the growth process should definitely read my article titled “Introduction to Cohort Analysis for Internet Startups & What is LTV and CAC?”).In this article, I will be talking about the Hook Model, which is a global theory that intends to help us in regulating retention behaviour, as retention is the cornerstone of sustainable growth.  Nir Eyal, the author of Hooked, talks about the Hook Model that she developed to provide a better understanding of the products which have mechanisms that “hook” the users. By closely analyzing that model, I will be talking about possible methods to keep the users coming back to your product again and again.

When we consider the Hook Model, we see that it consists of 4 phases: trigger, action, variable reward and investment. Let’s take a closer look at these:


Triggers can be defined as initiators of action. The Hook Model divides these into two: internal and external triggers. We use the external triggers first to create repetitive action patterns in our users. These could be listed as e-mails, notifications, ads and basically every channel that gets us in contact with the user.

Internal triggers, on the other hand, are the motivations that occur within the users themselves, with no outer factor in play. Examples include checking Facebook or Twitter you feel lonely or bored. These two feelings, namely loneliness or boredom are internal triggers.

In order for internal triggers to form in a user, you need to be making efficient use of external triggers. You need to analyze all the connections that can be forged between the users and try to make the best of every opportunity you get. Let’s clarify this with a few examples.


Academia.edu makes use of these external triggers perfectly to reactivate their users. If someone lands on your profile page via a Google search, you get a notification. Academia.edu uses your sense of curiosity to their advantage to make you visit their site again.


Mobile applications are also quite creative when it comes to external triggers by using notifications. I will be talking in depth about how these notifications can be used as an opportunity for getting in touch with users in an upcoming article. Here, we have a screenshot from QuizUp. They capture the attention of the user by challenging them with the “Can you pass…” phrase and make them revisit  the application.


The users, now motivated by the triggers, take their first actions. In the Academia.edu example, clicking on the “View Country” button constitutes the “action” for the Hook Model, whereas for the QuizUp example, taking the test is as such.
There are two things that need to be considered at this point. In using the triggers, you need to do so with maximum motivation impact, and the actions should be as smooth and easy as possible.

Variable Reward

To form a habit in your users with your product and make revisiting a natural behaviour, you need to be able to present certain variable rewards for the user for each time they visit. Let’s continue with another example. We all log on to Twitter when we are bored. If Twitter was unable to present us with new content each time we did so, forming a habit would have been impossible. In order to form a habit in your users, you need to have rewards that pertain to the main value you are offering. Pinterest is a platform where you are able to find visual content depending on your area of interest and each time you check the site, you come across new content. In planning your product and the actions that go along with it, you need to be certain that the rewards you put forward are satisfactory and interesting.


The investment phase is the final phase in the Hook Model. You have triggered your users into taking action and managed to satisfy them with rewards. Now is the time for the users to contribute to you with the investment phase. In continuing with the Twitter example, let’s say a bored user logged in to Twitter and was greeted with a reward, such as interesting content. When the user chooses to engage with the content (such as retweeting, replying or favouriting) they have made an investment in the product. Therefore, the contributions they make to the product during the investment phase turn into triggers or rewards for other users.

To sum up, the Hook Model helps us understand how a product managed to become a habit for users. The model consists of four phases. In the first phase, you need a trigger to attract the users to the product. These may be external triggers such as e-mails or notifications, or user generated triggers for products that have become habits for them. After triggering the users, the second step is actions. The action phase needs to be simple, smooth and quick. After the users take action, you need to greet them with rewards. If they are bored, they need to be presented with new content. Upon satisfying your users you can now ask them to take certain actions, therefore making them revisit your product. For those who want to learn more, I highly recommend taking a look at Nir Eyal’s presentation on the matter.

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