The Hook Model as an interactive UI
Self-conducted research project: Emerging Practices in Interaction Design
Weekly progress blog posts​​​​​​​
About the project
Emerging Practices in Interaction Design was a self-conducted research project that literally took me on a journey across the world—From Sydney to San Francisco!
The open brief required us to develop a research based project of our choice that followed two simple rules:
Behaviour design has always been a favourite topic of mine, especially after coming across a book called "Hooked—How to build habit-forming products".
This research was mainly to dissect the book and create an interactive prototype to illustrate the insights on this book, whilst learning a new prototyping tool.
In summary, Nir Eyal explained in his book a model he calls the Hook Model, used by pretty much every successful product we interact with these days from Spotify to social media to your e-mail app. The "hook" consists of four phases: trigger > action > reward > investment; and successfully looping users through the four phases is guaranteed to form a habit, according to the author.
As I dug into my research I also listened to some very interesting podcasts, TED and YouTube talks on behaviour, like this talk by BJ Fogg's at SXSW 2013, and read chapters of the following books:
- Nudge: Improving Decisions About Health, Wealth, and Happiness – by Richard H Thaler;
- The power of habit—Why do we do the things we do, and how to change it – by Charles Duhigg;
- Mental models—Aligning design strategy with human behaviour – by Indi Young.
Now it was time to sketch some interactions.
Design & Prototype
Pen and paper are always the best tools to organise my thoughts, so I sketched some interactions within each phase of the hook model. 
Once I move to the computer, Sketch is my tool of choice. It talks to the tool I wanted to learn (Principle App) seamlessly to create delightful animations by default—the secret is in great housekeeping with your layers.
Using excerpts from each chapter and inspired by familiar products we interact with everyday, I take the user through each phase of the "hook" in a linear journey, incrementally inserting interactions and design elements as the ideas in the book sink into our mind phase by phase. For example, as I discuss triggers at first the user only has one choice per interaction as she/he moves forward—one trigger is all it takes to start the loop.
When I talk about "Action" as the simplest behaviour in anticipation of a reward, I touch on BJ Fogg's formula—B=TAM [called B=MAP by him nowadays]—to explain what must be in place for a behaviour to occur. From the second phase forward the user slowly sees more interaction per screen.
In phase three I exemplify how the hunt for information and the satisfaction we get from completing tasks reward us. The anticipation for these rewards, particularly if presented in a variable format, increases dopamine in our brains.
Finally, in the last phase I introduce little "nuggets of delight" in the design to stimulate the user's reward-seeking system, while illustration how brands ask the user to "do some work" after receiving their reward. This can change how much the user values their product or service. These investments can be, for example: loading the next triggers; or increasing the user's sense of belonging by inviting friends to use the service; or increasing ease of use for future interactions by creating collections.
You can read my weekly progress through the project in my blog. A partial walk through the phases of the prototype can be seen in this video.
If you have the Principle App on your device you can also download the prototype here and try it out. And e-mail me to let me know your thoughts!
[Update: May 2018]
Once I finalised this project I tweeted about it, attaching videos and tagging the author in my tweets. This caught his attention and he asked to know more about it via email. After a few back and forth emails about the project he helped me visit hometown, San Francisco, to meet him and attend his annual Habit Summit.
What a fantastic experience! I came back to Sydney refreshed and inspired to gain more knowledge about behaviour design. Overall the entire project was incredible!
Would you like to discuss this project?
Thank you! I'll be in touch soon.

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