How to Build Habit-Forming Products

by Nir Eyal

Hooked shows you how to build “sticky” consumer products that people use out of habit. It details a four-step “Hooked Model” for doing this: a trigger leads users to your product, they take some action and get a random reward, and they invest something into the product that makes them come back again. It blends psychology theory, case studies, and tactical advice for PMs looking to build habit-forming products.

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Key Insights

Insight #1

You acquire users using “external triggers” that bring them into your product, such as ads, press, and social media. To retain users, you need to create “internal triggers” that make users return to your app unprompted; for instance, people instinctively open Facebook when they’re bored or Instagram whenever they order a good-looking dish at a restaurant.

Insight #2

People are attracted to novelty, so your product must offer “variable rewards,” such as the random stream of new content users find on Pinterest or Twitter.

Insight #3

Getting users to invest time and effort in your product (e.g. following people, uploading pictures, or personalizing settings) makes them more likely to stick with your product. When people put work into things, they start believing those things are worthwhile to avoid cognitive dissonance — nobody wants to believe they invested in something worthless.

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Key Quotes

“For many products, forming habits is an imperative for survival. As infinite distractions compete for our attention, companies are learning to master novel tactics to stay relevant in users’ minds.”

“Imagine if Facebook or Twitter needed to buy an ad to prompt users to revisit their sites — these companies would soon go broke.”

“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.”

“To initiate action, doing must be easier than thinking.”

Relevance Section


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The four-step Hooked Model works very well for a subset of consumer apps, and there are several frameworks and concepts that are useful for newer PMs, but the rest of the book falls flat.

If you’re building a social network, media consumption, or other consumer app that seeks to command a lot of users’ attention, the Hooked Model is a great framework. The “Do This Now” section at the end of each chapter — which gives tactical tips for PMs building these products — are powerful and actionable. And the examples of how products have successfully used this framework, while dated (they’re painfully 2014), do a good job of putting theory into practice.

But it’s important not to overstate the power of the framework. If you’re building an enterprise app, you definitely do not want to use it: people want their payroll software to get the job done with zero gimmicks and take less, not more, of their attention. The model works OK for utility-focused consumer products, but the “variable rewards” part (the core insight of the model) falls flat: nobody wants Uber to give them random prices or Google to show you random results. Even for its core use case (attention-seeking apps), the model has started showing its age — people these days tend to value digital well-being and can notice poorly-disguised growth hacks. Overall, though, the model is powerful if you acknowledge its limitations.

Besides the model, the book is a mixed bag. Several must-know PM concepts — the importance of user testing, the difference between acquisition and retention strategies, and the vitamin-versus-painkiller debate, to name a few — are scattered throughout. But the case study, which shows how a Bible app used the Hooked Model, is strange, since most PMs aren’t going to build anything at all like that app. The final chapter, which explains how to test if you’re implementing the model right, is vague and hand-wavy. And Eyal’s ethical defenses of his teachings fall flat; he fails to seriously consider the ethical questions of building addictive products.

All PMs should read Hooked, if only to understand how attention-grabbing consumer products are built. Acknowledge its flaws and you’ll learn some useful skills, frameworks, and concepts.

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What You Will Learn

Of course, the main thing you’ll learn about is the four-step Hooked Model: trigger, action, variable reward, investment. You’ll see what these mean, keys to doing them right, and examples of how apps have done them well in the past.

The Hooked Model comes with a lot of useful sub-frameworks: the four types of external triggers (paid, earned, relationship, and owned), the three ingredients for making users take actions (motivation, ability, and trigger), the six factors that influence a task’s difficulty (time, money, physical effort, brain cycles, social deviance, and non-routineness), to name a few.

Hooked also explores several psychological concepts, such as how habits work, the drive for novelty, anchoring, and the need for autonomy. And you’ll also read about several core PM concepts, such as user testing, user-generated content, gamification, monetization, switching costs, and so on.

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Who Should Read This

Hooked is a great guide if you’re working on any consumer product — it may not be directly applicable if your product is a utility or productivity tool, but it’s good to know how the rest of the consumer space operates. The tactical “Do This Now” sections will be directly applicable to your day-to-day work, a refreshing change from the usual PM books that only give generic, high-level advice.

If you’re new to PMing, the broad PM concepts are crucial to know, and having the Hooked Model in your back pocket will help if you’re walking into an interview and need to evaluate consumer products. Industry veterans will likely have seen all these PM concepts before, though the applied psychology bits will probably be new. In short, there’s something different in the book for everyone.