Brief Intro to the Hook Model

Recently I’ve just finished reading Hooked by Nir Eyal and I found it to be a brilliant formalisation of building truly habitual products. The real power of it comes when applying it within the context of startups, and reminds us that we have a great deal of responsibility building next-generation products and services. In this blog post I want to give you a brief introduction to the Hook model and why each step is crucial to building a habit.

If you haven’t heard of it before and like what you’re hearing, I highly suggest you drop by Amazon to get a copy. If you’re based in Federation House drop by our pod to borrow ours!

What is the Hook model?

In short – it’s a conceptual model made up of four steps to explain how habits are first formed, and how that habit keeps you coming back for more. Let’s give you an example use case, and use the hook model to explain how it works.

Take a slot machine – most people know about them, those gambling machines wide spread within casinos. One of them catches your eye and it’s only 10p per spin so you sit down, insert a coin and pull the lever down watching the reels spin. Two of the symbols match and you think “Dang, so close!” and can’t help but feel one more spin wouldn’t hurt, perhaps you could even win a few pennies?

The Trigger

By trigger we mean the thing that brings to our attention to the task that could be performed, in our example spinning the reels. The first time we encounter slot machines we need an external trigger, something that prompts us to spin the wheel such as big flashy lights, the promise of winning funds or even a free spin.

Once a habit is formed, the trigger usually becomes internal and is one of the key factors to making a habit stick. For a lot of gamblers there is an internal “itch to scratch” to try their luck and maybe win some money back, or perhaps they have a deal where every 10th spin is free. Physiologically the body releases endorphines every time we win and we want to replicate that feeling. Not to mention we’ve already invested time and effort into it – more on this under “Investment”.

The Action

Here we mean the things that we must do in order to fulfill the task. The most important thing to make a task a habit is to ensure the action or actions you take are as simple as possible. Sticking with the gambling example inserting a coin and pulling a lever is as simple as it gets. Imagine if you had to solve a mathematical puzzle, but the odds of winning increased. The number of people who would begin gambling drops, simply because the barrier to entry is raised.

Once you’ve been presented with a trigger, whether internal or external, the action should follow and needs to be as easy as possible to do in order to increase the likelihood of a habit being formed. Another great example is ordering take-out; compared to ordering over the phone, apps like Just Eat or Hungry House have the ability to re-order a past order. With a few taps you can order your favourite meal, pay for it and have it delivered when you’re internally triggered to have a lazy dinner.

Variable Reward

This is the magical step that makes you want to do the task again and again. With slot machines the variable reward is quite obvious, you could win or you could lose. Sometimes you get a small reward and once in a blue moon you could hit the jackpot. It’s the anticipation that some reward could be given that makes tasks addictive.

Another great example are the lightning deals on Amazon – I’m guitly of having a habit of checking it in the morning to see if anything I wanted to purchase is on offer, or if there’s something I didn’t think I wanted was on sale. Some days there would be nothing but there are days when I find the perfect product on sale and saving a few pennies felt great.


This is the final step; you must have some sort of investment in order to make a habit a long term one. Without a person investing something, whether time, money or effort, then the habit will be in danger of dying. In our slot machine example a person invests their time and money in the hopes that they will win the jackpot eventually. The longer they keep spinning the more they’ve invested into it, and they “can’t quit now” since it should pay off eventually.

This phenomenon can be seen in many different forms and is known as the Gamblers Falacy. Another great example is Runescape and online games in general – the more time you spend on them the higher your level, wealth and social circle. You become bought into it and if you leave now, all of that investment goes “down the drain” – a hard decision for many in cases of addiction.


Without a trigger you have no reminders to perform the task; with a difficult action you increase the value a person must place on the outcome compared to the cost of performing the action; with a predictable reward the novelty wares off and we lose interest; and finally without investing something we find it easier to not form a habit since we didn’t give time, effort or money.

I could go in deeper but I wouldn’t be doing the book justice. Definitely give it a read, understand what it means to make a product with a hook and use it responsibly.

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