Which principle relates to grouping elements within the same area?

The principle that relates to grouping elements within the same area is known as "Common region." This principle suggests that elements that are enclosed within the same visual boundary or region are perceived as being related or part of a group. For example, items placed within a box or a defined space are seen as belonging together, which helps users to understand the structure and organization of information more intuitively.

In contrast, the principles of proximity, continuity, and symmetry address different aspects of visual perception. Proximity refers to the closeness of elements, indicating that objects near each other are often perceived as associated. Continuity deals with the visual paths that lead the eye along a line or curve, while symmetry involves the balance of elements in a design. While these principles support organization in design, "Common region" specifically focuses on the idea of spatial boundaries that create groupings within the design layout.