The Hook Model: Retain Users by Creating Habit-Forming Products

Originally published on November 9, 2023

The hook model—or ‘hooked’ model—is a concept introduced by Nir Eyal to describe how digital products can retain customers by getting them to form habits. Customers repeatedly pass through the four stages of the “hook”: trigger, action, variable reward, and investment. The hook process gets people to acquire an emotional association with the product, prompting them to use it even when there are no external triggers.

What is the hook model?

The hook model describes how apps and platforms become part of customers' unconscious behavior. When customers use products that follow the hook model, they transition from requiring an external trigger to cue their product use, like an advertisement, to using it because of an internal, unconscious trigger, like an emotion. The hook model is a four-phase process.

Trigger

An external trigger initially sets off the hook cycle. An external trigger can be any stimuli that prompts a customer to start using a product, including different types of marketing. For example, we might begin using a product after seeing a paid ad, reading a blog post outlining its benefits, or getting a link from a friend.

Once a customer is triggered, they pass on to the next stage of the hook model. The most successful products have customers pass through the different stages several times until the triggers become internal.

Let’s say you start using a social media app after a friend sends you a link—that’s the first trigger. Once you download the app, you receive more triggers in the form of notifications, prompting you to catch up on people you follow.

After using the app for a while, you develop an emotional association with it. The app relieves boredom, provides information, and helps you feel connected. Your emotions—like boredom or loneliness—are now internal triggers that prompt you to open the app, even when there are no notifications or other external triggers.

Action

The action is what customers do in response to the trigger and anticipation of a reward.

For example, if the trigger is the link to a funny reel your friend sends you, the action is clicking that link and watching the video. Another trigger could be a notification that X of your friends have new posts on a social media app, with the intended action being opening the app and scrolling through the stories.

Variable reward

A product gives a customer a variable reward for completing the intended action. Rewards can vary from information or a solution to a problem to pain relief, entertainment, or social gratification through likes or comments.

The variability of the reward is crucial to the hook model. Novelty activates the dopamine system, which causes us to feel pleasure when we experience something new.

Eyal uses the analogy of the light in the refrigerator to explain how novelty impacts the hook model. The light coming on when you open the fridge is a linear reward. Every time you open it, the same thing happens. But if your fridge played a different song or told a new joke every time you opened it, you’d be enticed to open it more.

The “reward” for scrolling through images on social media apps is variable because we never know what will come up next. Our brains want to keep scrolling to chase a dopamine hit from new images, messages, or follow requests.

Investment

In the hook model, when customers experience pleasure from the reward, they’re prompted to make an investment. The investment involves some effort on the part of the customer, such as:

• Sharing data by signing up for the platform.
• Sharing preferences by liking images or following people.
• Uploading content.
• Paying for the service.

The investment serves two purposes. First, it gets the customer to engage with the product. According to Eyal, when we put some work into something, we’re more likely to return to it.

If we put in time or effort, we want to come back to see a return on our investment. If you learn to use a new app or upload your files to a platform, you’re more likely to return to it than go to a new one.

The investment phase of the hook model also helps companies create more successful products. In the case of a financial investment, the effect is apparent—when someone pays to subscribe, your product makes more money.

Less obvious, though, is when a customer invests by sharing their data or preferences. However, this investment enables you to optimize your product by tailoring it to their characteristics and interests.

When you upload photos, comment on or like pictures, and follow people on social media, you’re investing social capital that motivates you to open the app again later. Your actions also let app makers learn more about you to optimize the platform.

How habits fit into the hook model

The hook model gets customers to develop a habit associated with a product or service so they return without needing continuous advertising or external triggers. Customers will reach for the app whenever they experience an internal trigger.

A habit is something you do regularly with little or no thought. You develop a habit after passing through a product’s hook cycle several times.

For example:

• You follow your favorite celebrities on Instagram. You feel stressed out after work and subconsciously reach for the app. Scrolling through the aspirational pictures on the train home soothes your stress and distracts you from work.
• Your brain associates Twitter with world and entertainment news, so now you scroll through Twitter while eating breakfast. It stops your boredom and helps you feel connected to the rest of the world.
• You started to organize your work in a productivity platform like Asana. Now, whenever you feel overwhelmed on Monday morning, you log in to prioritize your work and get a sense of accomplishment as you check off tasks.

Hook model benefits

Using the hook methodology in product development enables you to retain users without continuous effort. With higher retention, you can spend less on new customer acquisition and now have a wealth of user data to optimize your product.

When your product isn’t yet part of a customer’s habit, getting them to use it requires persuasion. You spend effort and money on marketing to promote your product and trigger them to log in.

Once customers are “hooked,” they essentially trigger themselves and are less likely to churn. If you’ve developed a social media habit, it takes significant effort to stop using the app, and you won’t churn easily.

Once customers habitually use your product, you also get access to data to improve your product and further increase retention. For example, you can collect shared user information and track user behavior, like what they hover and click on. With that data, you can personalize your platform by showing the features or content most relevant to them.

Getting information from habitual users also means you can adjust the platform to make it easier to use. Optimize your app or site based on the paths users naturally follow to make using it as frictionless as possible.

For instance, remove unused features and streamline the path to the most-used features. If you notice customers use your product for a particular task, create new features for that use case to make their lives easier.

How to manufacture desire by implementing the hook model

Eyal says the hook model simulates desire by prompting people to develop internal triggers that make them want to use your product. A product should push people to acquire those internal triggers, make the “action” parts of the hook easy to perform, and provide a novel and satisfying reward.

Develop a product that satisfies a customer's need or desire

To develop a customer habit, your product should reward them by fulfilling a need or desire. Eyal explains that these rewards fall into three categories:

• Rewards of the tribe: Give people a sense of connection or belonging, like connecting with family or a group with similar interests.
• Rewards of the hunt: Provide a more tangible reward, like a material item or a piece of information, like instructions for completing a task.
• Rewards of the self: Make people feel good about themselves, like the opportunity to check items off a list in a satisfying way.

Provide external triggers

External triggers that direct people to use your product initiate the hook model. The triggers should promise a reward and prompt people to take action.

For example, Instagram sends notifications that your friends have added new posts, prompting you to open the app to see what they uploaded.

Provide triggers in different ways, for instance:

• Paid ads.
• Content marketing, like blog posts or videos, that direct people to your product.
• Owned channels. For example, once a customer initially downloads or subscribes to your product, trigger them with emails or notifications.

Make the actions easy and appealing

The most successful habit-forming products make the “action” process seamless. If the action is too complicated or takes too long, people will get frustrated and leave. Create a great user experience with functionality like single sign-on, auto-filled forms, and simple navigation.

Provide a variable reward

Your reward should satisfy your user’s needs or wants, have an element of novelty, and entice users to stay with your product.

For example, at the end of a YouTube video, you feel satisfied with what you watched, and you also see links to other videos that keep you on the platform.

Get customers to make an investment

Organize your product to prompt customers to “invest” as soon as they receive their reward. Remember, their investment should require some effort, so they’ll be motivated to come back and help you optimize the product further.

Understand which hooks work with Amplitude

Implementing the hook model can help you implement a habit-forming product that keeps customers coming back for more. A digital analytics platform like Amplitude can help you throughout all stages of applying the hook model. Amplitude Analytics can help you understand how often your customers return today and what triggers or actions drive them back at the best rates.

Then, using Amplitude Experiment, you can test different variations of variable rewards to see which drive the most engagement or investment. With those learnings, you can also use Amplitude CDP to personalize your external triggers or variable reward experiences to help customers establish an emotional association with your product, driving a lift in investment.