Uniform Connectedness is a Gestalt principle of perception that states that elements connected by lines or grouped by regions are perceived as more related than elements not connected by lines or grouped. One strategy of Uniform connectedness is to connect 2 or more elements directly by a line. The other strategy of Uniform connectedness is to group 2 or more elements by an enclosing region or a shaded area. This is the strongest Gestalt grouping principle, and overrides proximity and similarity. So for example 2 similar elements that are next to each other can appear related however this relation can be easily broken by simply drawing a line connecting each of these elements to foreign entities.
William Lidwell, Kritina Holden and Jill Butler, Universal Principles of Design (USA: Rockport publishers, 2003), 246.
Uniform connectedness can by applied in design by organizing control panels with many switches, buttons or functions. Connecting lines can be used to imply a sequences of steps. Region shading can be used to associate text with corresponding controls, or to group together common functions.
Original source image
William Lidwell, Kritina Holden and Jill Butler, Universal Principles of Design (USA: Rockport publishers, 2003), 247.
Online image
Dialog in comics is matched to the corresponding character by drawing the dialog bubble around the text and having the line connect to the character.
http://www.wikiwand.com/en/Comics
Real world image
Whirlpool Microwave button panel, Tustin
It’s a great strategy, and clear explanations and good examples are excellent.
I think it is a traditional and fundamental way of perceiving the elements of the same attribute to the user by using the connected line or grouped regions.
A few years ago, since the mobile design concept became material design, I’ve been necessary to tie the same experience together. In other words, it is essential to distinguish between elements of the same attribute and elements of another attribute. I think that the strategy you choose becomes more and more critical.
Apple HIG, Peek and Pop:
https://developer.apple.com/ios/human-interface-guidelines/user-interaction/3d-touch/
Apple HIG, Settings:
https://developer.apple.com/ios/human-interface-guidelines/app-architecture/settings/