What is the key principle of Gestalt psychology that is relevant to user interface design?

The key principle of Gestalt psychology that is highly relevant to user interface design is the law of Prägnanz, also known as the law of good Gestalt or the law of simplicity. This principle states that people tend to perceive visual information in the simplest, clearest, and most organized way possible. In UI design, this means that users will naturally group elements that are close together, similar in appearance, or share a common fate (e.g., movement). Designers can leverage this principle to create interfaces that are easy to understand and navigate. For example, grouping related form fields together using visual boundaries makes it clear that they belong to the same section. Using consistent colors and fonts across similar elements helps users quickly recognize their function. By adhering to the law of Prägnanz, designers can reduce cognitive load and improve the user experience by making the interface intuitive and visually appealing. In essence, users prefer designs that are simple, orderly, and coherent, and Gestalt principles provide a framework for achieving this.