Hook Model

Updated: March 21st, 2025

Product management glossary / Hook Model

What is the Hook Model?

The Hook Model is a powerful framework many Product Managers and Product Designers follow when designing habit-forming products. These are the types of products that your users keep coming back to time and time again, often due to behavioral design elements that create an engaging feedback loop that has users craving for more.

When building digital products, the aim of the game is to create and launch something that’s sticky. If you can keep users around, your product is more likely to scale and grow. The Hook Model is a tool to help you turn your product into a regular habit for your users. It offers a framework to transform your product into the go-to option whenever a customer is faced with a problem or pain point your tool is designed to solve.

“How much better off would your user’s lives be if you could find a way to get them to use your product or service out of habit?”

Nir Eyal, Creator of the Hook Model

And as a Product Manager, think how much easier your life would be. Using the Hook Model to reduce customer churn and keep engagement rates high means you’ve got a product built to last. That’s immensely desirable for PMs.

At its core, the Hook Model is a four-phase process:

Triggers ⚡– Prompts that encourage users to take action and do something
Action 🎯- A behavior that the user has to do to get hooked
Variable rewards 🏆- A response a user gets from the action
Investment ⏳- Something the user puts into the product – like time or effort – that encourages them to come back

Some of the most successful digital products have utilized the Hook Model. Think how Duolingo encourages daily language practice or how Instagram entices users to scroll endlessly through a visually captivating feed.

As Product Managers and Designers aiming to create successful products that users can’t resist, the Hook Model is something you need to know.

The Hook Model diagram, showing how it flows from trigger, action, variable reward, and investment

Who created the Hook Model?

The Hook Model was created by behavioral design expert Nir Eyal. It emerged after more than a decade of research into what makes the world’s most captivating and addictive products. Eyal’s findings are distilled in his influential book, Hooked: How to Build Habit-Forming Products, a must-read for Product Managers aiming to create a product experience that users can’t put down.

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Eyal identified a repeating pattern in the product design of highly engaging tools and apps – one that connects user behavior to a product with enough frequency to form habitual behaviors.

By tracking customer behavior and pinpointing psychological triggers, he crafted a Product Management framework that all these products follow that taps into natural human tendencies like craving novelty and seeking rewards.

“What I discovered in over 10 years of research was that there is a pattern to these habit-forming products that are designed into the UX of the world’s stickiest products and services. We call that the Hook Model.

This is an experience designed to connect your user’s problems to your product with enough frequency to form a habit.”

Nir Eyal, Creator of the Hook Model

From: Tech In Asia Virtual Product Development Conference

The Hook Model draws parallels to the allure of slot machines: simple mechanics paired with variable rewards that make them irresistibly engaging. The same principles guide the design of apps, transforming them into indispensable parts of users’ daily routines.

Today, this framework has shaped products across industries, from social media and gaming to health and education. For Product Managers, designers, and development teams, the Hook Model is the blueprint for creating habit-forming experiences that resonate deeply with users – and keep them coming back for more.

How does the Hook Model work?

The Hook Model describes four distinct phases for a user’s interaction with your product. Each phase plays a crucial role in building an experience that becomes part of a user’s routine. Let’s go through them again:

1. Trigger
2. Action
3. Variable reward
4. Investment

These four phases flow one into the other, creating a never-ending cycle – a vortex – that users can’t get out of, cementing the usage of your product as a long-term daily habit, just like brushing your teeth.

Here’s a look at each phase in a bit more detail, and how they work:

Trigger

All product hooks start with a trigger. The trigger is a prompt. A call to action. It’s the thing that first encourages a user to check out and try your product. They’re the initial motivation that drives a user to sign up, complete an action, and experience the value proposition of the product firsthand.

To start the Hook Model cycle, you need to get your triggers in front of your target users, as much as possible.

What are the different types of Hook Model triggers?

There are so many different types of triggers you can try out to get users started with your product or service. They can be split up into two groups: external triggers and internal triggers.

External triggers

These are the most common types of triggers that a new user will experience and are the external factors that encourage a user to check out your product. Most of these triggers are going to be marketing-based, be it social posts, paid ads, emails, and more.

That said, some external triggers can also include things like word of mouth or online popularity. If you’ve got social capital where everyone is using your product, that’s going to entice others to try out this , cool sounding tool.

External triggers can be:

Paid Triggers: These require financial investment, like paid ads or sponsored post to prompt users to engage with or re-engage with the product.
Earned Triggers: These rely on time investment rather than money, such as media mentions or SEO content that organically attracts attention to the product.
Relationship Triggers: These depend on word-of-mouth and social proof, like user-generated content or referral codes, where happy users share their experiences to influence others.
Owned Triggers: These are the most effective because users have voluntarily opted in, such as newsletter subscriptions or push notifications, and engage with them regularly due to familiarity.

Internal triggers

Internal triggers come from inside the user. In other words, they are less tangible things like emotions and feelings.

Internal triggers often only come into play once a user has tried your product and grown an attachment to it. You can only really build this attachment if you’ve demonstrated your product’s wow moment and have matched the wants and needs of your customers.

An internal trigger can be something like boredom, which leads to users turning to your app without the need for external prompts.

As you can imagine, internal triggers are really powerful automatic behaviors. They’re the little impulses and voices in the back of a user’s head that tell them to start using your product.

Action

An action is what a user does with your product. It’s the minimum they need to do to trigger user activation and experience the reward that keeps them coming back. You need to keep this minimum action easy to do, which influences the usability design of your product.

When thinking about the intended action you want your user to perform, you need to make it as easy as possible. You need to remove as many friction points to minimize the time and effort needed to get the reward.

If the action is going to be a bit tricky or time-consuming, then you need to make sure that the motivation levels of the user are high so that they can actually be bothered to complete it.

Remember phone-in radio competitions? Say you’re driving along in your car and your local radio station starts a competition offering $10 for everyone who simply phones in within the next 30 minutes.

That’s a pretty easy thing to do, and the reward is pretty sweet. That should compel people to do it.

Okay, but how about instead of just phoning in, you need to phone in, pay a 50c charge, and then answer 10 questions correctly only to get put into a raffle draw? All for only $10. That action is harder, and will likely put loads of people off. The reward doesn’t match what listeners need to do.

But what happens if the prize changes to $100,000? Yeah, the required actions are still pretty convoluted, but the reward is more compelling, meaning that more will phone up and take the gamble.

So, why is that? Well, that can all be explained by the Fogg behavioral model, created by Dr BJ Fogg.

The Fogg Behavioral Model, used to explain how to create a good action in the Hook Model

This model shows the essential components you need when crafting an action, and how they all need to come together for the action to work. For you to spark a human behavior and get users hooked, you need to maintain motivation, make that action easy to do, and keep prompting users to perform the action.

“If you get rid of motivation or reduce it, the behavior will diminish. If you make the behavior harder to do or impossible, you stop the behavior. And if you remove the prompt, you stop the behavior”

Dr BJ Fogg, Creator of the Fogg Model

From: How to think clearly about behavior change | Nudgestock 2020

This action-to-reward ratio is something you’re going to have to figure out when building your product with the Hook Model.

Variable Reward

A variable reward is the goal your users are striving for when they engage with your product. In other, more PMy words, it’s the value proposition they’ll see and feel after taking action.

When a user completes an action, they receive a reward. These rewards play a huge role in motivating customers to keep coming back. Think Pavlov’s dog: every time he heard that bell, he was excited for his treat.

But here’s the twist: some rewards are more powerful than others, and many lose their effectiveness over time. Let’s go back to that dog. Every time the bell rang, he knew he’d get food, but imagine if he didn’t know if it would be beef, chicken, or pork. The unpredictability would keep him more engaged, right?

The same goes for us. If the reward becomes predictable, we lose interest. That’s why social media platforms are masters of the Hook Model. Every time you log in, there’s a variable reward of new, unpredictable content. We never know what will pop up next in our feed.

In fact, social media is a lot like the random slot machines that inspired the Hook Model.

Types of variable rewards

As Nir Eyal outlines here, there are three main types of variable rewards that target different aspects of human desire: self-fulfillment, material benefits, and social validation. Each type can be strategically used to create a more compelling and habit-forming user experience.

Rewards of the Self: These rewards come from personal satisfaction or self-fulfillment, like achieving mastery, which helps build lasting customer habits.
Rewards of the Hunt: These are tangible, material rewards, such as unlocking new features or securing a good deal, driving ongoing engagement.
Rewards of the Tribe: These rewards come from social validation and interaction, like receiving likes or comments, which encourage connection and engagement.

Investment

In the Hook Model, the investment phase is all about the user’s commitment to a product – of both time and effort. As users interact with your product, they put in effort that, over time, deepens their relationship with it.

For example, the more time a user spends within your tool, the better they get at it. As they become more proficient, tasks that once took time now happen with ease, making it even more likely they’ll return. In SaaS, this translates into product stickiness and user retention: the more your customers use your product, the more value they derive from it, which makes them less likely to switch to a competitor.

Additionally, when users invest in your product, they’re not just investing time. Whether it’s by adding data, customizing their settings, or uploading content, they’re also creating a sense of ownership. This makes them more likely to come back to reap the benefits of their work. Think of it as putting effort into building something you want to see grow.

The more users invest, whether financially, emotionally, or with their data, the harder it becomes for them to leave. In fact, higher investment leads to higher switching costs: migrating data, changing preferences, or learning a new tool becomes a costly and time-consuming endeavor.

This principle is crucial for Product Managers because it helps make your product indispensable. When users have invested in learning and customizing their experience, they have more reasons to keep engaging and fewer reasons to leave.

And now that you have invested users, you can start the loop again with another trigger, and create consecutive hook cycles that become more compelling each time you use them.

Why is the Hook Model important for Product Managers?

Integrating the Hook Model into product development is essential for Product Managers who want to create products that users love, keep coming back to, and integrate into their daily lives. This behavioral design framework helps PMs tap into psychological triggers that drive user habits, fostering engagement and loyalty.

When used correctly, the Hook Model helps companies go beyond simply providing a functional product to creating an irresistible user experience.

As users become more accustomed to interacting with your product, they start to expect certain rewards, which drives them to return again and again. It’s no longer about creating a one-time interaction, but about cultivating a long-term relationship with your users. This process involves understanding their needs, emotions, and behaviors and crafting a product experience that aligns with those desires.

For PMs, understanding the intricacies of the Hook Model allows them to design products that are not just useful, but habit-forming. From product onboarding to personalized rewards, each interaction can be optimized to boost engagement and increase user retention.

The beauty of the Hook Model lies in its cyclical nature: the more users interact with the product, the stronger their connection to it becomes, similar to growth loops.

Here are some of the key benefits of implementing the Hook Model in product development:

Enhanced user engagement: By creating products that users are motivated to return to, PMs can boost user engagement and retention.
Improved product stickiness: Products designed with the Hook Model become integral to users’ routines, making them less likely to switch to competitors.
Increased Customer Lifetime Value: Habit-forming products encourage users to invest more time and resources, leading to higher customer lifetime value.
Competitive advantage: By understanding and leveraging user behavior, PMs can create products that stand out in the market, offering unique value propositions.
Data-driven insights: Implementing the Hook Model encourages continuous customer feedback loops and data collection, enabling PMs to refine and optimize the product based on real user behavior.

By embracing the Hook Model, Product Managers can craft products that not only meet user needs but also become an indispensable part of their lives, ensuring long-term success and competitive growth.

Example of the Hook Model in action

The best way to fully understand something is to see it in action, in live, living color. To get a complete understanding of how the Hook Model works, so that you can do it yourself, let’s break down the model for one of the most addicting products of the last few years. One that I’m sure you’ve used – maybe on your lunch break – regularly.

Of course, I’m talking about: WORDLE