Elements connected by uniform visual properties—whether through lines, enclosures, or shared backgrounds—are perceived as a single unified group more strongly than elements grouped by any other Gestalt principle. Palmer and Rock's pivotal research (1994) demonstrated that connectedness overrides proximity, similarity, and common region effects, establishing physical or visual connection as the most powerful grouping force in human perception, operating through pre-attentive processing within 60-100 milliseconds of viewing. Research by Palmer (1992) found that common region grouping increased perceptual organization accuracy by 34% compared to proximity-only layouts, demonstrating that bounded regions create stronger perceptual effects than spatial relationships alone.
Palmer and Rock's groundbreaking 1994 study challenged traditional Gestalt hierarchy by demonstrating that uniform connectedness—elements sharing continuous visual connections—creates stronger perceptual grouping than previously-identified principles. Their experiments showed that when elements connect through lines, shared backgrounds, or enclosing borders, observers perceive unified groups even when proximity or similarity suggest different organizations. This connection dominance reflects fundamental visual system priorities evolved for tracking relationships and understanding structural connections in environments.
The researchers distinguished uniform connectedness from other grouping principles by its reliance on actual visual continuity rather than similarity or spatial inference. Connected elements share contiguous regions or continuous boundaries creating physical rather than conceptual relationships. This tangible connection triggers specialized visual processing recognizing unified objects—explaining why connected elements feel inseparably grouped while merely similar or proximate elements maintain perceptual independence despite grouping tendencies.
Palmer's comprehensive Vision Science treatise (1999) positioned uniform connectedness within broader perceptual organization theory. His work explained that visual system processes connected regions as single entities before analyzing individual components—connected elements constitute perceptual units rather than separate objects grouped secondarily. This processing priority makes connectedness exceptionally powerful for interface design requiring unambiguous relationship communication.