Building habit-forming products

Cheatsheet, notes, book summary and key points on Hooked by Nir Eyal.



3 years ago | 7 min read

Why do most smartphone owners check their phone within 15 minutes of waking up and check up-to 80 times a day? Why do we find ourselves mindlessly scrolling Instagram or automatically Google when we have a question?

Hooked: How to make habit-forming products by Nil Eyer explains a four-step process that makes using an app become a habit. It answers why some apps are incredibly popular while others aren’t. What makes us engage with certain products out of sheer habit and is there a pattern underlying how technologies hook us?

Here are my notes from the book, Hooked.

What is a Habit?

My physical notes on the topic
My physical notes on the topic

An automatic behaviour like opening Instagram many times throughout the day, done with little or no conscious effort, is called a habit.

For many companies, turning their products into habits drives a lot of value. Once a product has become a habit, it is linked to emotions and routines to a product, prompting them to return to it time after time, without having to resort to expensive advertising.

How are they formed?

  • Habits form when the brain takes a shortcut and stops actively deliberating on what to do next. We base most of our daily decisions on the way we have found resolution in the past. Habits gave us the ability to focus our attention on other things and storing automotive responses in Basal Ganglia.
  • As customers forms routines around the product, they come to depend on it and become less price-sensitive. This gives companies pricing flexibility. For example, companies of free to play video games start charging for a thing like extra lives, special powers and selling virtual items. Evernote and medium have upgraded features of premium.

How do we get hooked?

  • Hooks are a series of experiences that can together modify user behaviour and encourage the formation of new habits. The author has created a four-phase process to explain how companies use to forms habits through the services we use daily. The 4 phases of this model are Trigger, Action, Variable Reward, Investment.


My physical Notes on the topic
My physical Notes on the topic

This is the first step of the Hook Model. Triggers move the user to take action. They are cues that prompt certain behaviour. They come in two types: external & internal.

External triggers

They tell the user what to do next by placing information within the user’s environment. There are four types of external triggers:

  • Paid Triggers (advertising through various channels, mainly used to acquire new users)
  • Earned Triggers (press mentions and features, usually acquired through media relations built over time)
  • Relationship Triggers (the audience sharing the benefit of the product with others — virality, in one word)
  • Owned Triggers (newsletters and notifications that the user has opted in to receive)

Owned triggers are the most important ones because they occur more often and prompt repeat engagement until a habit is formed.

Internal Triggers

  • For a product to truly become a habit, its triggers need to move from the external forms to the internal. They tell the user what to do next through users emotions and associations stored in the memory
  • Products coupled with negative feelings (boredom, loneliness, frustration, confusion, indecisiveness), thoughts, or pre-existing routines, usually leverage internal triggers. As a product relieves these negative emotions repeatedly, our mind subconsciously begins to associate it with this relief.
  • To scratch the nagging itch that negative emotion brings, we resort mindlessly to the top-of-mind solution: googling is a click away every time we feel unsure or logging on Facebook promises validation every time we feel alone.
  • To build better habit-forming products, companies need to deeply understand their users’ behaviours, needs, fears, and desires.


Action is the second step of the Hook Model. Action is the use of the product, based on ease of use and motivation. Behaviour done in anticipation of reward. If the user doesn’t take action, the trigger is useless.






B= The action is doing something with little or no barriers, in anticipation of a reward.

Motivation= the level of desire to take that action.

Ability= the number of obstacles that stand in the user’s way.

What motivates people?


There are three. Core motivators.

Fogg states that all humans are motivated to seek

  • Pleasure and avoid pain;
  • to seek hope and avoid fear; and
  • finally, to find social acceptance and avoid rejection.


To increase the ability of the user, consider the six factors of simplicity:

  • Time: Is the user short on time?
  • Money: Is behaviour too expensive?
  • Physical Effort: Is the action too labour-intensive?
  • Brain Cycles: Is the product too difficult to understand?
  • Social Deviance: Is the action perceived as socially inappropriate?
  • Non-Routineness: Is the action outside of the user’s regular routine?

We should start with increasing ability first. The highest return on investment generally comes from increasing a product’s ease of use. Increasing motivation is expensive and time-consuming.

How to increase motivation and ability?

Both motivation and ability can also be increased using counter-intuitive methods called heuristics. These are mental shortcuts that all of us employ to make quick decisions. Examples include:

  • The scarcity effect — the scarcer a product is, the higher is its perceived value, e.g. the ‘limited stock’ tag on Amazon products ends up increasing sales for those products.
  • The framing effect — context can alter the desirability of a product, e.g. the same wine is reported to be tastier if the price is increased.
  • The anchoring effect — one aspect of a product is given undue importance over other features, e.g. people end up buying more products of a brand that has a discount sticker on it, even if its quality and the effective cost might be no different than other competing products in the vicinity.
  • The endowed progress effect — in case of reward programs, the closer users feel they are to the goal the more motivated they become, e.g. the ‘Improve Your Profile Strength’ step in LinkedIn has a completion bar that starts off all users with part of the bar already filled, strengthening their belief that a full profile is not far away.

Variable rewards

This is the third phase of the Hook Model. You reward the users for taking action by solving their problem or — many times — by merely satisfying the craving for that reward.

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. There are three types of variable rewards:

Rewards of the tribe

Our brains are adapted to seek rewards that make us feel accepted, attractive, relevant, and included. Tweets, likes, upvotes, re-pins, comments, emails, they all fuel our needs for social validation.

Rewards of the hunt

Satisfying our basic survival instincts by helping us acquire things we consider important, like cash and information. Working hard for a bonus at work or scrolling through our endless Twitter feed for valuable information are included in this category.

Rewards of the self

The intrinsic rewards of self can make people continue taking action, even on tasks they don’t appear to enjoy for a more personal form of gratification. Such rewards address our desire for mastery, competence, and completion.

Infinite Variability

Without infinite variability or novelty in the rewards, we tend to lose interest and excitement quickly. Finite variability makes rewards increasingly predictable after use, and their appeal is lost over time.

Product designers need to understand what triggers and motivates the user and what doesn’t, e.g. Mahalo, a Q&A forum gave monetary rewards to answerers but bombed, while Quora, a similar service, only provides upvotes, and is very successful.


  • Last step of Hook Model.
  • Frequency of new behaviour is a leading factor in forming a new habit.
  • The power of commitment makes some people play video games until they keel over and die. It is used to influence people to give more to charity, and it has even been used to coerce prisoners of war into switching allegiances.
  • This happens because of 3 human tendencies: The more we invest time & effort into a product, the more we value it, We seek to be consistent with our past behaviours, and we tend to change our preferences to avoid cognitive dissonance.
  • These tendencies of ours lead to a mental process known as rationalization, in which we change our attitudes and beliefs to adapt psychologically. Rationalization helps us give reasons for our behaviours, even when those reasons might have been designed by others.
  • We, humans, evolved the tendency to reciprocate kindness because it improved our species’ ability to survive. As it turns out, we invest in products and services for the same reasons we put effort into our relationships.

Actionable take ways:

  • Who is your product’s user? Come up with 3 internal triggers that could cue your user to action (emotions, thoughts, or routines). Finish this brief narrative: “Every time the user (internal trigger), he/she (first action of intended habit).”
  • Use the five why’s method. Try asking the question “why” as many times it takes to get an emotion.
  • Walkthrough the path your users would take to use your product or service, beginning from the time they feel their internal trigger to the point where they receive their expected outcome.
  • What do users really want? What pain is your product relieving? (Internal trigger) What brings users to your service? (External trigger) What is the simplest action users take in anticipation of reward, and how can you simplify your product to make this action easier? (Action) Are users fulfilled by the reward yet left wanting more? (Variable reward) What “bit of work” do users invest in your product? Does it load the next trigger and store value to improve the product with use? (Investment)
  • Creating habits can be a force for good, but it can also be used for nefarious purposes. What responsibility do product makers have when creating user habits?
  • Am I using these products as intended? How might these products improve their on-boarding funnels, reengage users through additional external triggers, or encourage users to invest in their services?
  • Speak with three people outside your social circle to discover which apps occupy the first screen on their mobile devices. Ask them to use these apps as they normally would and see if you uncover any unnecessary or nascent behaviours.


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