Law of Similarity
The human eye tends to perceive similar elements as a complete picture, shape, or group, even if those elements are separated.
Key Takeaways
Elements that are visually similar are naturally perceived as related by users.
Color, shape, size, orientation, and movement can all indicate that elements belong together and share meaning or functionality.
Links and navigation systems should be visually differentiated from normal text elements to ensure they are consistently recognizable.
Origin
Like other Gestalt grouping principles, the Law of Similarity was proposed by Gestalt psychologists who studied how humans naturally perceive organized patterns. The principle of Prägnanz — the mind's tendency toward perceiving the simplest coherent patterns — underlies this law. The five Gestalt grouping principles (Proximity, Similarity, Continuity, Closure, and Connectedness) work together to explain how we visually organize and make sense of complex interfaces.