Hooked: How to Build Habit-Forming Products

by Nir Eyal

Some products have a very high CLTV. For example, credit card customers tend to stay loyal for a very long time and are worth a bundle. Hence, credit card companies are willing to spend a considerable amount of money acquiring new customers. This explains why you receive so many promotional offers, ranging from free gifts to airline bonus miles, to entice you to add another card or upgrade your current one. Your potential CLTV justifies a credit card company’s marketing investment.

For example, in the free-to-play video game business, it is standard practice for game developers to delay asking users to pay money until they have played consistently and habitually. Once the compulsion to play is in place and the desire to progress in the game increases, converting users into paying customers is much easier. The real money lies in selling virtual items, extra lives, and special powers. As of December 2013, more than 500 million people have downloaded Candy Crush Saga, a game played mostly on mobile devices. The game’s “freemium” model converts some of those users into paying customers, netting the game’s maker nearly $1 million per day.6

A classic paper by John Gourville, a professor of marketing at Harvard Business School, stipulates that “many innovations fail because consumers irrationally overvalue the old while companies irrationally overvalue the new.”8 Gourville claims that for new entrants to stand a chance, they can’t just be better, they must be nine times better. Why such a high bar? Because old habits die hard and new products or services need to offer dramatic improvements to shake users out of old routines. Gourville writes that products that require a high degree of behavior change are doomed to fail even if the benefits of using the new product are clear and substantial.

The enemy of forming new habits is past behaviors, and research suggests that old habits die hard. Even when we change our routines, neural pathways remain etched in our brains, ready to be reactivated when we lose focus.13 This presents an especially difficult challenge for product designers trying to create new lines or businesses based on forming new habits. For new behaviors to really take hold, they must occur often. In a recent study at the University College London, researchers followed participants as they attempted to form a habit of flossing their teeth.14 As one of its findings, the study concluded that the more frequently the new behavior occurred, the stronger the habit became. Like flossing, frequent engagement with a product—especially over a short period of time—increases the likelihood of forming new routines. Google Search provides an example of a service built upon a frequent behavior that helped create users’ habits. If you’re skeptical that Google is habit forming (and you are a frequent Google user), just try using Bing. In a head-to-head comparison of the efficacy of an incognito search, the products are nearly identical.15 Even if the geniuses at Google have in fact perfected a faster algorithm, the time saved is imperceptible. So why haven’t more Google users switched to Bing? Habits keep users loyal. If a user is familiar with the Google interface, switching to Bing requires cognitive effort. Although many aspects of Bing are similar to Google, ev...

A company can begin to determine its product’s habit-forming potential by plotting two factors: frequency (how often the behavior occurs) and perceived utility (how useful and rewarding the behavior is in the user’s mind over alternative solutions). Googling occurs multiple times per day, but any particular search is negligibly better than rival services like Bing. Conversely, using Amazon may be a less frequent occurrence, but users receive great value knowing they’ll find whatever they need at the one and only “everything store.”

Remember, the Hooked Model does not get people to do things they don’t want to do. Your product must ultimately be useful. The Habit Zone is meant to be a guiding theory, and the scale of the illustration is intentionally left blank. Unfortunately for companies, research thus far has not found a universal timescale for turning all behaviors into habits. A 2010 study found that some habits can be formed in a matter of weeks while others can take more than five months.21 The researchers also found that the complexity of the behavior and how important the habit was to the person greatly affected how quickly the routine was formed.

Gatekeepers such as investors and managers want to invest in solving real problems or meeting immediate needs by backing painkillers. Painkillers solve an obvious need, relieving a specific pain, and often have quantifiable markets. Think Tylenol, the brand-name version of acetaminophen, and the product’s promise of reliable relief. It’s the kind of ready-made solution for which people are happy to pay. Vitamins, by contrast, do not necessarily solve an obvious pain point. Instead they appeal to users’ emotional rather than functional needs. When we take our multivitamin each morning, we don’t really know if it is actually making us healthier. In fact, recent evidence shows taking multivitamins may actually be doing more harm than good.22

Let’s consider a few of today’s hottest consumer technology companies: Facebook, Twitter, Instagram, and Pinterest. What are they selling—vitamins or painkillers? Most people would guess vitamins, thinking users aren’t doing much of anything important other than perhaps seeking a quick boost of social validation. After all, think back to before you first started using these services. No one ever woke up in the middle of the night screaming, “I need something to help me update my status!” But like so many innovations, we did not know we needed them until they became part of our everyday lives. Before making up your mind on the vitamin versus painkiller debate for some of the world’s most successful tech companies, consider this idea: A habit is when not doing an action causes a bit of discomfort. The sensation is similar to an itch, a feeling that manifests within the mind until it is satisfied. The habit-forming products we use are simply there to provide some sort of relief. Using a technology or product to scratch the itch provides faster satisfaction than ignoring it. Once we come to depend on a tool, switching to something else takes work. My answer to the vitamin versus painkiller question: Habit-forming technologies are both. These services seem at first to be offering nice-to-have vitamins, but once the habit is established, they provide an ongoing pain remedy.

More choices require the user to evaluate multiple options. Too many choices or irrelevant options can cause hesitation, confusion, or worse—abandonment.4 Reducing the thinking required to take the next action increases the likelihood of the desired behavior occurring with little thought.

The ultimate goal of all external triggers is to propel users into and through the Hooked Model so that, after successive cycles, they do not need further prompting from external triggers. When users form habits, they are cued by a different kind of trigger: internal ones.

To ameliorate the sensation of uncertainty, Google is just a click away. E-mail, perhaps the mother of all habit-forming technology, is a go-to solution for many of our daily agitations, from validating our importance (or even our existence) by checking to see if someone needs us, to providing an escape from life’s more mundane moments. Once we’re hooked, using these products does not always require an explicit call to action. Instead, they rely upon our automatic responses to feelings that precipitate the desired behavior. Products that attach to these internal triggers provide users with quick relief. Once a technology has created an association in users’ minds that the product is the solution of choice, they return on their own, no longer needing prompts from external triggers. In the case of internal triggers, the information about what to do next is encoded as a learned association in the user’s memory. The association between an internal trigger and your product, however, is not formed overnight. It can take weeks or months of frequent usage for internal triggers to latch onto cues. New habits are sparked by external triggers, but associations with internal triggers are what keeps users hooked. As Yin said, “I just use it whenever I see something cool.” By thoughtfully moving users from external to internal triggers, Instagram designed a persistent routine in people’s lives.

The ultimate goal of a habit-forming product is to solve the user’s pain by creating an association so that the user identifies the company’s product or service as the source of relief.

Dorsey believes a clear description of users—their desires, emotions, the context with which they use the product—is paramount to building the right solution. In addition to Dorsey’s user narratives, tools like customer development,11 usability studies, and empathy maps12 are examples of methods for learning about potential users.

External triggers tell the user what to do next by placing information within the user’s environment. Internal triggers tell the user what to do next through associations stored in the user’s memory. Negative emotions frequently serve as internal triggers. To build a habit-forming product, makers need to attach the use of their solution to a frequently felt internal trigger and know how to leverage external triggers to drive the user to action.

Fogg posits that there are three ingredients required to initiate any and all behaviors: (1) the user must have sufficient motivation; (2) the user must have the ability to complete the desired action; and (3) a trigger must be present to activate the behavior. The Fogg Behavior Model is represented in the formula B = MAT, which represents that a given behavior will occur when motivation, ability, and a trigger are present at the same time and in sufficient degrees.1 If any component of this formula is missing or inadequate, the user will not cross the “Action Line” and the behavior will not occur.

Fogg states that all humans are motivated to seek pleasure and avoid pain; to seek hope and avoid fear; and finally, to seek social acceptance and avoid rejection. The two sides of the three Core Motivators can be thought of as levers to increase or decrease the likelihood of someone’s taking a particular action by increasing or decreasing that person’s motivation.

While internal triggers are the frequent, everyday itch experienced by users, the right motivators create action by offering the promise of desirable outcomes (i.e., a satisfying scratch).

Consequently, any technology or product that significantly reduces the steps to complete a task will enjoy high adoption rates by the people it assists.

“Take a human desire, preferably one that has been around for a really long time . . . Identify that desire and use modern technology to take out steps.”

To increase the likelihood that a behavior will occur, Fogg instructs designers to focus on simplicity as a function of the user’s scarcest resource at that moment. In other words: Identify what the user is missing. What is making it difficult for the user to accomplish the desired action? Is the user short on time? Is the behavior too expensive? Is the user exhausted after a long day of work? Is the product too difficult to understand? Is the user in a social context where the behavior could be perceived as inappropriate? Is the behavior simply so far removed from the user’s normal routine that its strangeness is off-putting? These factors will differ by person and context; therefore, designers should ask, “What is the thing that is missing that would allow my users to proceed to the next step?” Designing with an eye toward simplifying the overall user experience reduces friction, removes obstacles, and helps push the user across Fogg’s action line.

Simply put, Google reduced the amount of time and the cognitive effort required to find what the user was looking for. The company continues to relentlessly improve its search engine by finding new ways to remove whatever might be in the user’s way—no matter how seemingly trivial. While its home page remains remarkably pristine, Google now offers myriad tools to make searching easier and faster—including automatic spelling correction, predictive results based on partial queries, and search results that load even as the user is typing. Google’s efforts are intended to make searching easier to keep users coming back.

How can a Web site make browsing easier? One solution, popularized by digital pin-board site Pinterest, is the infinite scroll. In the past getting from one web page to the next required clicking and waiting. However, on sites such as Pinterest, whenever the user nears the bottom of a page, more results automatically load. Users never have to pause as they continue scrolling through pins or posts without end

Influencing behavior by reducing the effort required to perform an action is more effective than increasing someone’s desire to do it. Make your product so simple that users already know how to use it, and you’ve got a winner.

The company made the desired action as simple as possible, knowing that getting users to experience the service would yield better results than trying to persuade them to use it while still on the home page.

In 2009 the Twitter home page attempted to boost motivation; by 2012 Twitter had discovered that no matter how much users knew about the service, driving them to open an account and start following people resulted in much higher engagement.

The study showed that a product can decrease in perceived value if it starts off as scarce and becomes abundant.

The mind takes shortcuts informed by our surroundings to make quick and sometimes erroneous judgments.

The study demonstrates the endowed progress effect, a phenomenon that increases motivation as people believe they are nearing a goal. Sites such as LinkedIn and Facebook utilize this heuristic to encourage people to divulge more information about themselves when completing their online profiles. On LinkedIn every user starts with some semblance of progress (figure 18). The next step is to “Improve Your Profile Strength” by supplying additional information. As users complete each step, the meter incrementally shows the user is advancing. Cleverly, LinkedIn’s completion bar jump-starts the perception of progress and does not include a numeric scale. For the new user, a proper LinkedIn profile does not seem so far away. Yet even the “advanced” user still has additional steps she can take to inch toward the final goal.

The study revealed that what draws us to act is not the sensation we receive from the reward itself, but the need to alleviate the craving for that reward.

Novelty sparks our interest, makes us pay attention, and—like a baby encountering a friendly dog for the first time—we seem to love it.

Stack Overflow devotees write responses in anticipation of rewards of the tribe. Each time a user submits an answer, other members have the opportunity to vote the response up or down. The best responses percolate upward, accumulating points for their authors (figure 19). When they reach certain point levels, members earn badges, which confer special status and privileges. Naturally, the process of accumulating upvotes is highly variable—no one knows how many will be received from the community when responding to a question.

The need to acquire physical objects, such as food and other supplies that aid our survival, is part of our brain’s operating system. Where we once hunted for food, today we hunt for other things. In modern society, food can be bought with cash, and more recently by extension, information translates into money.

Rewards of the self are a defining component in video games, as players seek to master the skills needed to pursue their quest. Leveling up, unlocking special powers, and other game mechanics fulfill a player’s desire for competency by showing progression and completion.

Have you ever caught yourself checking your e-mail for no particular reason? Perhaps you unconsciously decided to open it to see what messages might be waiting for you. For many, the number of unread messages represents a sort of goal to be completed. Yet to feel rewarded, the user must have a sense of accomplishment. What happens when in-boxes become flooded with too many messages? Users can give up when they sense the struggle to get their in-boxes under control is hopeless. To combat the problem and give users a sense of progress, Google created “Priority Inbox.”20 Using this feature, Gmail cleverly segments e-mails into sorted folders to increase the frequency of users achieving “in-box zero”—a near-mystical state of having no unread e-mails.

Ultimately, the company found that people did not want to use a Q&A site to make money. If the trigger was a desire for monetary rewards, users were better off spending their time earning an hourly wage. And if the payouts were meant to take the form of a game, like a slot machine, then the rewards came far too infrequently and were too small to matter. However, Quora demonstrated that social rewards and the variable reinforcement of recognition from peers proved to be much more frequent and salient motivators. Quora instituted an upvoting system that reports user satisfaction with answers and provides a steady stream of social feedback. Quora’s social rewards have proven more attractive than Mahalo’s monetary rewards. Only by understanding what truly matters to users can a company correctly match the right variable reward to their intended behavior.

Variable rewards are not magic fairy dust that a product designer can sprinkle onto a product to make it instantly more attractive. Rewards must fit into the narrative of why the product is used and align with the user’s internal triggers and motivations. They must ultimately improve the user’s life.

Unfortunately, too many companies build their products betting users will do what they make them do instead of letting them do what they want to do. Companies fail to change user behaviors because they do not make their services enjoyable for its own sake, often asking users to learn new, unfamiliar actions instead of making old routines easier. Companies that successfully change behaviors present users with an implicit choice between their old way of doing things and a new, more convenient way to fulfill existing needs. By maintaining the users’ freedom to choose, products can facilitate the adoption of new habits and change behavior for good.

Experiences with finite variability become less engaging because they eventually become predictable. Businesses with finite variability are not inferior per se; they just operate under different constraints. They must constantly churn out new content and experiences to cater to their consumers’ insatiable desire for novelty. It is no coincidence that both Hollywood and the video gaming industry operate under what is called the studio model, whereby a deep-pocketed company provides backing and distribution to a portfolio of movies or games, uncertain which one will become the next megahit. This is in contrast with companies making products exhibiting infinite variability—experiences that maintain user interest by sustaining variability with use. For example, games played to completion offer finite variability, while those played with other people have higher degrees of infinite variability because the players themselves alter the gameplay throughout. World of Warcraft, the world’s most popular massively multiplayer online role-playing game, still captures the attention of more than 10 million active users eight years after its release.31 FarmVille is played mostly in solitude, but World of Warcraft is frequently played with teams; it is the hard-to-predict behavior of other people that keeps the game interesting. While content consumption, like watching a TV show, is an example of finite variability, content creation is infinitely variable. Sites like Dribbble, a platform f...

While some products, like the ones we’ve just discussed, add variability to the user experience, others operate in conditions that are already variable. For example, Google wouldn’t want to add variability to its search results page because searching on the web is inherently variable. Uber wouldn’t want to add variability to your ride because the experience of getting to where you’re going is already plagued with uncertainty—“Will I get to where I’m going on time?” For companies like Google and Uber, adding more variability to an inherently variable user experience makes no sense. Can you imagine what would happen if your Uber driver decided to take you for a spin around the block just for fun?

Whether the product is an enterprise-focused service helping customers get a grip on the effectiveness of their marketing spend, a financial information portal, a health tracking app, or a corporate dashboard, all sorts of products operate in conditions of inherent variability. Companies building these sorts of products and services need not necessarily add more uncertainty, but rather give the user a greater sense of agency and control over inherently variable circumstances.

E-mail, for example, utilizes all three variable reward types. What subconsciously compels us to check our e-mail? First, there is uncertainty concerning who might be sending us a message. We have a social obligation to respond to e-mails and a desire to be seen as agreeable (rewards of the tribe). We may also be curious about what information is in the e-mail: Perhaps something related to our career or business awaits us? Checking e-mail informs us of opportunities or threats to our material possessions and livelihood (rewards of the hunt). Lastly, e-mail is in itself a task—challenging us to sort, categorize, and act to eliminate unread messages. We are motivated by the uncertain nature of our fluctuating e-mail count and feel compelled to gain control of our in-box (rewards of the self).

Variable reward is the third phase of the Hooked Model, and there are three types of variable rewards: the tribe, the hunt, and the self. Rewards of the tribe is the search for social rewards fueled by connectedness with other people. Rewards of the hunt is the search for material resources and information. Rewards of the self is the search for intrinsic rewards of mastery, competence, and completion. When our autonomy is threatened, we feel constrained by our lack of choices and often rebel against doing a behavior. Psychologists refer to this as reactance. Maintaining a sense of user autonomy and trust is a requirement for sustained engagement. Experiences with finite variability become increasingly predictable with use and lose their appeal over time. Experiences that maintain user interest by sustaining variability with use exhibit infinite variability. Variable rewards must satisfy users’ needs while leaving them wanting to reengage with the product.

The more users invest time and effort into a product or service, the more they value it. In fact, there is ample evidence to suggest that our labor leads to love.

The homeowners’ greater willingness to place the large, obtrusive sign on their lawns after agreeing to the smaller one demonstrates the impact of our predilection for consistency with our past behaviors. Little investments, such as placing a tiny sign in a window, can lead to big changes in future behaviors.

The Hooked Model is not just a framework for changing one-time behaviors; it is a design pattern to create unprompted engagement in order to connect the user’s problem to the designer’s product. To form the associations needed to create unprompted user engagement, something more than the three-step feedback loop is required. The last step of the Hooked Model is the investment phase, the point at which users are asked to do a bit of work. Here, users are prompted to put something of value into the system, which increases the likelihood of their using the product and of successive passes through the cycle.

Also in contrast to the action phase, the investment phase increases friction. This certainly breaks conventional thinking in the product design community that all user experiences should be as easy and effortless as possible. This approach still generally holds true, as does my advice in the action phase to make the intended actions as simple as possible. In the investment phase, however, asking users to do a bit of work comes after users have received variable rewards, not before. The timing of asking for user investment is critically important. By asking for the investment after the reward, the company has an opportunity to leverage a central trait of human behavior.

The big idea behind the investment phase is to leverage the user’s understanding that the service will get better with use (and personal investment). Like a good friendship, the more effort people put in, the more both parties benefit.

The stored value users put into the product increases the likelihood they will use it again in the future and comes in a variety of forms.

The collection of memories and experiences, in aggregate, becomes more valuable over time and the service becomes harder to leave as users’ personal investment in the site grows.

Reputation makes users, both buyers and sellers, more likely to stick with whichever service they have invested their efforts in to maintain a high-quality score (figure 29).