Table of contents
Who Is Nir Eyal?
Nir Eyal is an author, lecturer and investor known for his expertise in behavioural design and habit formation. His book, Hooked: How to Build Habit-Forming Products, is widely used by growth marketers and product teams to create products users return to regularly.
Eyal developed the Hooked Model, a practical framework that helps marketers understand user psychology and design products that encourage habitual use ethically.
What Is the Hooked Model?
Nir Eyal’s Hooked Model is a four-stage framework — Trigger, Action, Variable Reward, and Investment — that explains how successful products build habits, encouraging users to return regularly without relying heavily on external marketing. It leverages psychological principles to help marketers build sustainable growth loops that keep users engaged. Aha moments also play a vital role in this process, helping new users realise core product value early in their journey. If you’re interested in the behavioural economics behind why users return—or don’t—consider reading about loss aversion in marketing and growth as well. For another influential behavioural model, see our guide to the BJ Fogg Behavior Model and how it explains the drivers behind user actions.
The Hooked Model has four key stages:
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Trigger
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Action
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Variable Reward
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Investment
Trigger
A trigger is the prompt that encourages users to take action. Triggers can be external (notifications, emails, ads) or internal (boredom, curiosity, social connection). Effective triggers clearly communicate the desired action and occur at the right moment.
Action
The action is the simplest behaviour a user performs in anticipation of a reward. Examples include opening an app, clicking a link or scrolling through a feed. To maximise engagement, actions should be easy, intuitive and frictionless.
Variable Reward
Variable rewards are unpredictable incentives that keep users returning. The uncertainty creates anticipation and releases dopamine, reinforcing the habit loop. Examples include discovering new content, receiving social validation or achieving unexpected milestones.
Investment
Investment refers to the effort, time or data users put into a product, increasing the likelihood they’ll return. Investments create a sense of ownership and personalisation, making the product more valuable over time. Examples include following other users, customising preferences or building a personal profile.
Applying the Hooked Model to Growth Method
Here’s how the Hooked Model applies practically to Growth Method, the only work management platform built specifically for growth marketers:
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Trigger: Growth Method sends timely notifications and reminders when experiments move between stages or when team members provide feedback. These external triggers prompt users to log in and engage.
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Action: Users respond to triggers by logging into Growth Method to review experiment progress, submit new ideas or check analytics. The intuitive interface ensures these actions are effortless.
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Variable Reward: Growth Method provides variable rewards through real-time analytics, experiment results and team feedback. Users experience excitement from discovering successful experiments, uncovering insights or receiving positive feedback.
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Investment: Users invest in Growth Method by submitting ideas, categorising experiments and customising reports. This investment creates a personalised experience, making the platform increasingly valuable and encouraging regular use.
Key Takeaways for Growth Marketers
The Hooked Model offers valuable insights for growth marketers aiming to build products that drive sustainable user engagement. Here are practical takeaways:
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Identify clear triggers (external and internal) that prompt user action.
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Ensure user actions are simple, intuitive and frictionless.
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Incorporate variable rewards to maintain user interest and encourage repeated interactions.
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Encourage user investment through personalisation, customisation and data input to increase product value over time.
By applying these principles, growth marketers can create habit-forming products that drive long-term user retention and sustainable growth.
How the Hooked Model Compares to Other Growth Frameworks
Growth marketers often use the Hooked Model alongside other frameworks that answer different questions. Here’s how they fit together:
| Framework | Core question it answers | Best used for | Learn more |
|---|---|---|---|
| Hooked Model | Why do users come back on their own? | Designing habit-forming product experiences | This article |
| AARRR (Pirate Metrics) | Where do users drop off across the funnel? | Measuring Acquisition, Activation, Retention, Referral, Revenue | AARRR Framework |
| Growth Loops | How does growth compound without new spend? | Structuring self-reinforcing acquisition and retention systems | Growth Loops |
The Hooked Model works well underneath both: it explains the psychological mechanics that make a growth loop or a funnel stage actually stick.
We are on-track to deliver a 43% increase in inbound leads this year. There is no doubt the adoption of Growth Method is the primary driver behind these results.
Laura Perrott, Colt Technology Services
About Growth Method
Growth Method is the agentic marketing platform for B2B teams — built so people and agents can plan strategy, ship campaigns, and learn what works, all in one place. The Hooked Model is a good reminder that growth isn’t just about driving more traffic into a habit loop; it’s about running the hypothesise → launch → measure → iterate cycle fast enough to learn which trigger, action or reward actually moves your numbers. That’s the workflow Growth Method is built around: campaigns move through clear stages, ideas are automatically scored against your goals, and results are analysed and reported without extra manual work.
Book a call to see how Growth Method can help your team apply frameworks like this one, or apply for early access to start running your first experiment this week.
Frequently asked questions
What is Nir Eyal’s Hooked Model?
Nir Eyal’s Hooked Model is a four-stage framework — Trigger, Action, Variable Reward, and Investment — that explains how successful products build habits that bring users back without relying on paid marketing.
What are the four stages of the Hook Model?
The four stages are Trigger (the prompt that starts the cycle), Action (the simplest behaviour taken in anticipation of a reward), Variable Reward (an unpredictable payoff that creates anticipation), and Investment (effort or data a user puts in that increases the odds they’ll return).
Is the Hooked Model the same as the Hook Model?
Yes. “Hooked Model” and “Hook Model” refer to the same framework from Nir Eyal’s book Hooked: How to Build Habit-Forming Products.
How is the Hooked Model different from AARRR or Growth Loops?
AARRR measures where users drop off across acquisition, activation, retention, referral and revenue, and Growth Loops describe self-reinforcing systems that compound growth. The Hooked Model sits underneath both, explaining the psychological mechanics that make any funnel stage or loop actually stick.