Uniform connectedness is the principle that elements that are connected by uniform visual properties, the most common being colour, are seen as more related than other elements that do not share a visual property. This is a recent addition to the Gestalt principles of psychology, based on the perception of elements with uniform visual properties as a single group or chunk of information. A single matrix composed of dots is seen as columns where common regions, lines or colours connect the dots vertically, whereas it is send as rows when the common regions, lines or colours connect them horizontally.
In design, uniform connectedness is mostly commonly applied in two ways: common regions or connecting lines. Common regions can be formed when edges come together visually, a common trick in designing software or remote control interfaces. Connecting lines are more explicit in the way that they connect elements, and is more commonly used for elements that are less obviously grouped (i.e. when they are not close in space) or when a designer wants to imply a sequence of elements.
The principle of uniform connectedness usually prevails over other Gestalt principles, so that even where there is proximity or similarity, elements with uniform connectedness are more likely to be grouped together and seen as a single item. This can be an important advantage for interfaces that are otherwise poorly designed or difficult to structure, helping a designer to bring order to an otherwise chaotic visual impression.
They is a great approach to provide a visual connection between elements in any design or visualisation, helping users or viewers group text or controls together and to see any sequences that are important to understand. It’s also a great principle to keep in mind in designing visual charts and data displays.
Universal Principles of Design by Lidwell, Holden and Butler