The big picture
Hook Model
A product model where cycling through trigger, action, variable reward, and investment turns use into habit.
Practitioner frameworkA thinking tool for design. Direct tests of its effect are limited.
Example
You see a notification, open the app, sometimes find something new, then post yourself. Your post brings the next notification.
Why it works
The more time and data users invest, the more triggers they create, until they return without being reminded. Habit formation varies widely: a study of everyday health behaviors found a median of 66 days, ranging from 18 to 254.
On the web
Design return visits as a pair: a reason to come back and a small discovery when people do. Use what users invested, such as saved filters or drafts, as the next entry point.
When it backfires
Building habits that do not serve users invites criticism for fostering compulsion. The author himself limits the model to products the maker would use and that improve users’ lives.
Sources
Describes habit-forming products as a loop of trigger, action, variable reward, and investment.
Eyal, N. (2014). Hooked: How to Build Habit-Forming Products. Portfolio. Open source
Tracked 96 people adopting a daily health behavior. Among participants whose data fit the model, automaticity took a median of 66 days, ranging from 18 to 254.
Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998-1009. Open source
Connect with the classics
These links are editorial readings, not research findings. Check the original meaning on each classics page.
苟日新，日日新，又日新。If you can renew yourself one day, renew yourself daily, and again. A small new thing on each visit is a reason to return.
The Great Learning Commentary 2: renewing practice →