Hooked… how to build habit-forming products… by Nir Eyal, an entrepreneur on a mission to discover what makes certain startups an integral part of pop culture.

Years of studying successful startups led to insights about influencing consumer behavior.  And then, these insights were codified in the Hook model: a cycle of events, engineered to keep users coming back.

The Hook cycle consists of 4 stages: trigger, action, variable reward, and investment.

1. Trigger

In order to engage a consumer for the first time, you need a trigger.  Something to prompt the consumer to take action.  This can take the form of paid advertising, PR, and email invites.

This type of trigger is an external one, as opposed to an internal trigger that comes from the consumers themselves.  An example of an internal trigger is “feeling bored”.  In response, you instinctively fire up facebook and connect with friends.

The idea is to employ external triggers that eventually form habits, so that future consumer engagement is prompted by internal triggers and the consumer doesn’t even have to think about it.

2. Action

The goal of the trigger is to promise a reward and demonstrate how to get it: click the link – the action… check out friends having fun – get the reward.

The action has to be as streamlined, delightful, and simple as possible.  The most important thing for a startup is to eliminate as many steps as possible from its process.

Remembers, doing something out of habit means doing it without even thinking!  So the action here needs to be easier than thinking in order to form a habit.

3. Variable reward

After taking action, now the consumer needs to receive a reward.  This can be a relief from boredom with a funny photo, something entertaining, or something useful.

But how is this different than the well-known feedback loop?  User takes action, receives reward, and the cycle repeats.  Been there, done that.

The operative word here is: variable.  Rewards need to be variable in order to hook a consumer into a cycle and form a habit.  Otherwise, the consumer starts anticipating the reward and eventually loses interest and doesn’t come back.

4. Investment

Finally, following the reward, it’s time to ask for a small investment in the form of a personal contribution: make your consumers work a little and store value in your product.  This will make them stickier consumers!

It’s actually been shown that we value our own work much more than it’s actually worth.  So a consumer’s investment in a product increases its value disproportionately.

This is sometimes called “the IKEA effect.”  Besides saving a ton of money by having us do all the assembly, IKEA also benefits because we like the furniture much more than it deserves, simply because we’ve poured our very own sweat and tears.


Every investor wants to invest in the next painkiller idea – one that solves a big pain point.  Yet some of the most successful startups are hardly painkillers: Facebook, Pinterest, Twitter, Instagram.

These companies are masters of the Hook model.  A compelling trigger prompts a super-simple action that delights us with a variable reward, and then we’re all too happy to make our own small contribution – or investment – which itself creates future triggers.

For example, when you swipe right on Tinder and there’s a match, the other party receives a notification that pulls them back onto the platform.

The Hook model is all too powerful.

The question is: how will YOU harness its power?


"Hooked" storyboard page 1

"Hooked" storyboard page 2

"Hooked" storyboard page 3