Final answer:
The principle according to which a region with the same visual properties is perceived as a single unit is a concept from Gestalt psychology. It includes methods of grouping such as proximity, similarity, and the laws of good continuation and closure.
Step-by-step explanation:
According to the principle of Gestalt psychology, a connected region of the same visual properties, such as lightness, color, texture, or motion, is perceived as a single unit. This principle is one of several that explain how we organize sensory information to make coherent sense of our environment. Gestalt theorists have identified several ways in which we group elements in our visual field such as by proximity, similarity, the law of good continuation (smooth, continuous lines), and closure (perceiving complete figures even when parts are missing).
For instance, the principle of similarity leads us to group things that are alike, which is why in a football game, players are grouped by the color of their uniforms. Likewise, the principle of proximity would have us see objects that are close to one another as part of the same group. Understanding these principles helps us realize that our perception is not just a straightforward representation of sensory input, but is also subject to the ways in which our brains organize and interpret this information.