Law of Common Region
Elements tend to be perceived into groups if they are sharing an area with a clearly defined boundary.
Key Takeaways
Common region creates a clear structure and helps users quickly understand the relationship between elements and sections.
Adding a border around a group of elements creates an effective common region that signals they are related.
A clearly defined background behind a group of elements also establishes common region and perceived grouping.
Origin
The Law of Common Region is one of several Gestalt principles of grouping, first proposed by Gestalt psychologists to explain how humans naturally perceive visual elements as organized patterns. These principles — which include Proximity, Similarity, Continuity, Closure, and Connectedness — describe the mind's innate disposition to perceive patterns in stimuli based on certain rules. The concept of Prägnanz, or the tendency toward the simplest possible interpretation, underlies all of these principles.