When I need to design an interactive software, the Gestalt principles and Fitts’s Law are very useful tools to help guide my design. They can be used to check whether my design is user-friendly.
At first, I felt confused about why we even need to study these rules. They have such a long history and have already become embedded in people’s subconscious. When we use a good design, it feels comfortable, even delightful. As interaction designers, when we design software, we usually replicate the most successful existing designs for the sake of safety and efficiency. Those successful designs have already formed a habit in the subconscious of users. For example, people unconsciously expect buttons with similar shapes and colors to have similar functions. Interaction designers also follow these established design conventions.
My question eventually got answered. We learn and understand these laws so that we can use them properly to make good designs. Just like we cannot break the rules without first knowing them. Imagine if we tried to replicate an excellent design without knowing why it was excellent—we could never truly apply it. More importantly, once we understand how these designs work according to principles and laws, we know how to break traditions. For example, Apple kept the home button on the iPhone for a long time. The home button was a very successful design because it was convenient and easy to reach with the thumb. It clearly fit Fitts’s Law. Later, Apple removed this function. That was a huge leap, but also a very successful one, because they found another way to return to the home screen that felt just as natural—and even better.
This may not be the best example, but what I want to say is that knowing the rules is about finding more possibilities. When you know that some good designs follow certain principles, you can achieve the same success while also opening up new possibilities.