How apps are designed for habit formation

I recently read an interesting post about how platforms, in this case UberEats, use certain frameworks to form habits around their apps. The author, Max Matsinger, references the Hook Model by Nir Eyal. According to this model, habits are formed through four phases: Trigger, Action, Variable Reward, and Investment. I've highlighted the main points presented:

Trigger:

"Uber Eats relies heavily on external triggers in the form of app notifications, promotional offers, and reminders. These cues are strategically timed to coincide with moments when users are most susceptible to ordering food. Imagine it’s 7 PM, and you’ve just finished a long day at work. You’re tired, and the last thing you want to do is cook. Suddenly, your phone buzzes with a notification from Uber Eats — 15% off your favorite restaurant. Do you resist, or do you hit “order” without thinking twice?"

Action:

"According to the Fogg Behavior Model from Dr. Fogg, action occurs when motivation, ability, and a trigger converge. If Uber Eats wants us to order food, they need to make the desired action — placing an order — as effortless as possible.

Reducing friction and simplifying the ordering process is key.

The app’s design prioritizes ease of use. With saved payment details, preset delivery addresses, and user-friendly navigation, the process of ordering food is streamlined.

Research shows that minimizing cognitive load — the mental effort an action costs is critical in driving repeated behavior. By making it incredibly simple for users to order food in just a few taps, Uber Eats eliminates any barriers that might prevent users from completing their orders.

Another common challenge in apps like Uber Eats is decision fatigue — the mental exhaustion that comes from being presented with too many choices.

Instead of getting lost in endless scrolling, users are presented with personalized suggestions based on their previous orders, dietary habits, location, and time of day. Ultimately, making the decision to decide what to eat feel intuitive and easy."

Variable Reward:

"The concept of variable rewards taps into one of the most powerful principles in behavioral psychology: the unpredictability of outcomes.

In the context of Uber Eats, variable rewards come in the form of fluctuating promotions and discounts. Users are often presented with time-sensitive offers, ranging from percentage discounts on their favorite foods to free delivery.

When users experience unexpected rewards, their brains release dopamine, a neurotransmitter tied to craving and reinforcement. This surge of dopamine creates a positive association with the action that led to the reward, such as ordering food through Uber Eats.

Over time, this reinforces the behavior, making users more likely to engage again. The unpredictability of these rewards adds an extra layer of anticipation and excitement, keeping users curious about what they might receive next."

Investment:

"Users contribute something valuable — time, effort, or personal data — that strengthens their commitment to the product.

Behavioral research suggests that when users invest in a product, they are more likely to return to it, as personal investment creates a sense of psychological ownership.

Uber Eats encourages users to invest by offering features that allow for personalization.

Users can save their favorite restaurants and customize their preferences. Each time a user adds a restaurant to their favorites list or they are investing in the app, which increases the likelihood of future engagement.

Writing a review is not just a personal investment — it enhances the overall value of the product and user experience. Each time someone leaves a review, it benefits other users by providing valuable insights, making the app more useful and trustworthy for everyone."