Law of Common Region describes a principle of visual perception: elements are perceived as belonging together when they are enclosed within the same clearly defined area or boundary.
Rooted in Gestalt psychology and widely applied in UX design, this law reminds us that borders, backgrounds, and containers strongly signal relationships between elements. Even when items are not close to one another, sharing a common region can override other grouping cues like proximity or similarity. Effective interfaces use regions intentionally to create structure, clarify hierarchy, and help users quickly understand how content is organized.
This poster presents the Law of Common Region as part of a broader collection exploring cognitive laws and UX fundamentals — created for designers, product teams, and anyone interested in how visual boundaries shape perception and understanding in digital interfaces.
