The german psychologist Gestalt, is known for the perceptual studies of how the eye and brain conceive, the theory of visual psychology. His theories all center around the brains visual process of analysis, and the multiple methods in which we organize information.
According to Design Basics by David Lauer, unity is the presentation of an integrated image. In other words, a congruity or agreement exists among elements in design, there is a harmonious collaboration. According to Gestalt, there are multiple forms of organization the human mind seeks towards simplicity. For example, by grouping objects close in proximity together, it enables our mind to remember and identify the multiple images within the image. Our brain in addition tends to relate/group objects of similarity together. Thirdly, our brain adapts to missing pieces of information by closing the gaps between patterns to see the larger picture. This process is known as closure. In another form of organization, something repeats in various parts of the design to relate parts to each other, known as repetition. Continuation usually involves a line, an edge, or direction from one form to another. All of these mentioned forms of composition create unity in design.
A key concept of Gestalt theory is that variety adds visual interest, this interest or focal point may be achieved through position. If unity is achieved without variety, then overbearing monotony can lead to evocation of ill feelings towards the design, imitating assembly lines and institutions. This leads us to Lauer's theory of chaos and control, "without some aspect of unity, an image or design becomes chaotic and unreadable." Thus design without any aspects of unity is visually unappealing, and reveals a sloppy unorganized design.
Gestalt claimed that perception was a subjective and multi sensory process. Ultimately perception is the "the spontaneous drive towards simplicity." The minds constant struggle to separate unity from chaos.
Kampis, George. "Active Perception." JAIST: Japan Advanced Institute of Science and Technology. Web. 27 Oct. 2009. .
Lauer, David A., and Stephen Pentak. Design Basics (with ArtExperience Online Printed Access Card). Belmont: Wadsworth, 2007. Print.