Hooked in 10 Minutes


I enjoyed Nir Eyal’s book. However, I needed to apply it to an application I was designing so created the following summary intended to summarize the book’s principles as applies to defining new features. Read the book. But use this summary to save time applying it.

Starting with the End in Mind – An App Design Model Based on Nir Eyal’s Hooked

Hooked provides a model for creating application experiences that both gain and keep users. The following summarizes the Hooked model and maps it to potential new product features

The Value of User Attention and Focus

Applications built to support positive behaviors get user attention and focus that translate directly into:

  • A willingness to pay for features
  • Referrals

The Value of Long Term Engagement

Keeping users engaged is a function of creating positive user habits and is a source of direct competitive advantage.

The ultimate goal is to increase customer lifetime value (CLTV). However, designing for habitual adoption requires patience.

Overcoming Existing Habits – 9X better for 5 months

Research shows that replacing an old habit requires the new habit to be 9x better. Otherwise, people migrate back to the old habit. Habits take between a few weeks to about 5 months to form. So a new approach has to both engage users frequently and deliver value.

Two factors turn behaviors into habits:

  • Frequency
  • Perceived utility.

Creating a New Habit

When we think about offering a “pain killer” we should recognize that in today’s attention-deficit world, “scratching an itch” is like relieving pain. Think “checking email.”

Habit forming products often start as “nice to have itch scratching” that turn into “must have” solutions providing continuous pain relief. Again, think of email. The Hooked Model defines four phases in which this takes place:

  • Triggers – prompt the user to do something
  • Actions – allow the user to act quickly and easily
  • Variable Rewards – compel users to return: “what happens next?”
  • Investments – retain users via their own time/effort spent.

Addressing each phase in application design leads to habit-forming solutions that benefit users and the provider. Rather than copying features, we must focus on understanding the inherent drivers behind successful habit forming triggers, actions, variable rewards and investments for our target users.

Simply put, by design the app must increase in value to users the more they use it.


There are two types of triggers:

  • External – manifests via prompt, e.g., a relationship trigger that sends a notification request to users to:
    • Rate something
    • Report on something
    • Many other possibilities.
  • Internal – manifests via “auto emotions” or “scratching the itch”
    • Negative (most powerful): boredom, loneliness, frustrated, confused, indecisive, feeling left out; discomfort (e.g., checking email or social media sites, or seeing what’s new for inspiration)
    • Positive (also effective): desire to share, feeling connected, in the loop, appreciated, valued (e.g., report on a win! Let everyone know there’s something new! Let everyone know where those marketing $s go!)


To initiate action, the “doing” must be easier than “thinking.” The formula for inducing action is: B = MAT, where:

Behavior occurs when:

  1. The user has sufficient motivation
  2. The user is able to complete the action
  3. A trigger is present

Motivation: all humans

Seek Avoid
Pleasure Pain
Hope Fear
Acceptance Rejection

Ability is capacity to do something. Factors influencing:

  • Time
  • Money
  • Physical Effort
  • Brain Cycles
  • Non-Routine

What is it preventing the user from achieving the desired outcome? How can this be overcome? Answering these questions is key to successful design.

Variable Rewards

Users seek novelty and an element of mystery or unpredictability in the outcome. Without it, lower usage rates occur (i.e., preview to next TV episode). Functions contributing to variable rewards include:

  • Tribal Activity – participating with others helps create unpredictability
  • Hunter Activity – searching for available content and updates
  • Self Improvement Activity – getting better at something useful or meaningful.


The more users invest in a solution, the more they value it. We irrationally value our own efforts. Users prompted to put something of value into a system increase the likelihood they’ll continue using it. Twitter “following” is a good example of a simple investment that leads to increase likelihood that a new user will check Twitter later.

This phase increases friction – unlike the Action Phase. This should come after the user has experienced variable rewards ideally. Timing is critical. Key is to instill in the user an understanding that the service will get better with both continued use and personal investment.

Classic Examples of the Model in Action

Aside from the most classic example: email, other apps show the model in action.

Toyota Prius: Users quickly get addicted to MPG performance with the dashboard displaying how they’re doing as they drive. Direct economic incentive plus the gaming aspect has changed the driving experience.

iTunes/Radio: Illustrates the power of personal investment and personalized triggers. Adding content is a major driver for user stickiness for iTunes / Radio users. Once users have created a library, personalized suggestions provide triggers leading to additional user investment. Personalization also provides variable reward experience by showing how the technology adapts and improves based on user investment.

Linkedin: Shows how easy investment leads to commitment. Users experience various external triggers prompting them to complete their profiles. Once they’re complete, users tend to use the service a lot more than if they don’t according to Linkedin. It has added variable reward via content streaming from groups and individuals and other means.

Twitter: Twitter’s technology could be built in a day. So it’s not the technology but rather the investment by users in building hundreds of followed and follower people that creates the stickiness. It provides variable rewards primarily via continuous UGC streaming variety to everyone. It provides Self Improvement motivation via the 140 character limit; and Tribal and Hunter activities by definition.

Any.do: less well known, this app illustrates how effectively notifications can be worked into the user experience. Pleasant, thoughtful notifications suggest users: plan their day at 9am; or complete next steps following a scheduled meeting and many other great ideas.


User Motivation to Try – First Use

The starting place for design success is with a solid narrative as to why a busy user would choose this app over the existing solutions in place today.

The Why Tool – asks the question “why?” 5 times to drill to the “heart” of the user’s motives:

  • Why does Mary use this app?
    • So she can optimize her time
  • Why?
    • So she can have more time to focus on closing
  • Why?
    • So she can be relevant to her colleagues and CEO
  • Why?
    • So she can be a direct part of the organization’s success
  • Why?
    • Because the alternative is hellish: unappreciated effort and chaotic execution.

Mary will consider using the app over alternative tools to avoid pain (chaos, frustration, inefficiencies) and to experience pleasure (connection with others, recognition for contributions, relevant to her colleagues).

Who Are App’s Habitual Users?

User                        Frequency            Triggers

Sales                        Daily                        ?

Executives            Weekly                    ?

Trigger and Actions Functionality

TAF: Feature 1…

TAF: Feature 2…

TAF: Feature 3

Variable Reward Functionality

VAR: Feature 1…

VAR: Feature 2…

VAR: Feature 3…