Summary of Hooked by Nir Eyal and Ryan Hoover

books psychology growth

Key Ideas

Habit forming products can be created using the Hooked model: Trigger, Action, Variable Rewards, and Investment. Hooked Model



Habits are defined as automatic behaviors triggered by situational cues.

Habits give us the ability to focus our attention on other things by storing automatic responses. Our brain takes a shortcut and stops actively deliberating over what to do next. The brain then codifies behaviors that provide a solution to whatever situation it encounters.

New habits are hard to form and easy to lose. To convert a behavior into a habit, it needs to happen frequently and deliver high utility.

Habit forming products are both Painkillers (solve an obvious need, relieving a specific pain, have quantifiable markets) and Vitamins (appeal to users emotional, rather than functional needs.)

The Hooked Model

The hooked model is a 4 step process to building habit forming products. Hooked Model

1. Trigger

A trigger actuates the behavior by providing the spark. There are two types of triggers:

  1. External triggers
    • Paid triggers: Ads
    • Earned triggers: Favorable press mentions, app store feature placements, viral videos.
    • Relationship triggers: One person telling another about the product, Social media shares, word of mouth.
    • Owned triggers. Email newsletter, app icon, notifications.
  2. Internal triggers
    • When a product becomes associated with an emotion, thought, pre-existing routine, these become internal triggers to use the product. For example, people take a photo with the intent of posting it to Instagram.

2. Action

The author’s rely on BJ Fogg’s Fogg Behavioral Model to illustrate the MAP method for when people will take an action.

Fogg Behavior Model

Some hearistics to increase motivation:

3. Variable Reward

The variable part is important. Without that, we have a vanilla feedback loop.

Types of rewards

Finite vs Infinite Variability

4. Investment

Getting users to do a bit of work increases the odds that they will make another pass through the entire cycle. Strategies include:

Escalation of commitment: the more users invest time and effort into a product or service, the more they value it. Heuristics to understand why this happens:

Storing value: getting users to store value in your product increases the chances they will use it again and reduces their propensity to churn. Ways to create stored value: