The German word for "shape" or "figure" is Gestalt: An explaination of how human visual perception works

The marriage between our vision and the shapes we see…………

Early in the twentieth century, a group of German psychologists sought to explain how human visual perception works. They observed and cataloged many important visual phenomena. One of their basic findings was that human vision is holistic: Our visual system automatically imposes structure on visual input and is wired to perceive whole shapes, figures, and objects rather than disconnected edges, lines, and areas. The German word for "shape" or "figure" is Gestalt, so these theories became known as the Gestalt principles of visual perception.

Today's perceptual and cognitive psychologists regard the Gestalt theory of perception as more of a descriptive framework than an explanatory and predictive theory. Today's theories of visual perception tend to be based heavily on the neurophysiology of the eyes, optic nerve, and brain Not surprisingly, the findings of neurophysiology researchers support the observations of the Gestalt psychologists. We really are—along with other animals—"wired" to perceive our surroundings in terms of whole objects. Consequently, the Gestalt principles are still valid—if not as a fundamental explanation of visual perception, at least as a framework for describing it. They also provide a useful basis for guidelines for graphic and user interface design.

For present purposes, the most important Gestalt principles are: Proximity, Similarity, Continuity, Closure, Symmetry, Figure/Ground, and Common Fate. In the following sections, I describe each principle and provide examples from both static graphic design and user interface design.

GESTALT PRINCIPLE: PROXIMITY
The principle of Proximity is that the relative distance between objects in a display affects our perception of whether and how the objects are organized into subgroups. Objects that are near each other (relative to other objects) appear grouped, while those that are farther apart do not.
However, according to the Proximity principle, items on a display can be visually grouped simply by spacing them closer together to each other than to other controls, without group boxes or visible borders. Many graphic design experts recommend this approach in order to reduce visual clutter and code size in a user interface.

GESTALT PRINCIPLE: SIMILARITY
Another factor that affects our perception of grouping is expressed in the Gestalt principle of Similarity: Objects that look similar appear grouped, all other things being equal.

GESTALT PRINCIPLE: CONTINUITY
In addition to the two Gestalt principles concerning our tendency to organize objects into groups, several Gestalt principles describe our visual system's tendency to resolve ambiguity or fill in missing data in such a way as to perceive whole objects. The first such principle, the principle of Continuity, states that our visual perception is biased to perceive continuous forms rather than disconnected segments.


GESTALT PRINCIPLE: CLOSURE
Related to Continuity is the Gestalt principle of Closure, which states that our visual system automatically tries to close open figures so that they are perceived as whole objects rather than separate pieces. Our visual system is so strongly biased to see objects that it can even interpret a totally blank area as an object. Just showing one whole object and the edges of others "behind" it is enough to make users perceive a stack of objects, all whole. The Closure principle is often applied in graphical user interfaces (GUIs). For example, GUIs often represent collections of objects—e.g., documents or messages-as stacks

GESTALT PRINCIPLE: SYMMETRY
A third fact about our tendency to see objects is captured in the Gestalt principle of Symmetry. It states that we tend to parse complex scenes in a way that reduces the complexity. The data in our visual field usually has more than one possible interpretation, but our vision automatically organizes and interprets the data so as to simplify it and give it symmetry. In printed graphics and on computer screens, our visual system's reliance on the symmetry principle can be exploited to represent three dimensional objects on a two dimensional display.

GESTALT PRINCIPLE: FIGURE/GROUND
The next Gestalt principle that describes how our visual system structures the data it receives is Figure/Ground. This principle states that our mind separates the visual field into the figure (the foreground) and ground (the background). The foreground consists of those elements of a scene that are the object of our primary attention, and the background is everything else. The Figure/Ground principle also specifies that the visual system's parsing of scenes into figure and ground is influenced by characteristics of the scene. However, our perception of figure vs. ground is not completely determined by scene characteristics. It also depends on the viewer's focus of attention.
In user interface and Web design, the Figure/Ground principle is often used to place an impression-inducing background "behind" the primary displayed content. The background can convey information—e.g., the user's current location—or it can suggest a theme, brand, or mood for interpretation of the content.

GESTALT PRINCIPLES: COMMON FATE
The previous six Gestalt principles concerned perception of static (un-moving) figures and objects. One final Gestalt principle—Common Fate—concerns moving objects. The Common Fate principle is related to the Proximity and Similarity principles: Like them it affects whether we perceive objects as grouped. The Common Fate principle states that objects that move together are perceived as grouped or related.

GESTALT PRINCIPLES: COMBINED
Of course, in real-world visual scenes, the Gestalt principles work in concert, not in isolation. For example, a typical Mac OS desktop usually exemplifies six of the seven principles described above (excluding Common Fate): Proximity, Similarity, Continuity, Closure, Symmetry, and Figure/Ground. On a typical desktop, Common Fate is used (along with similarity) when a user selects several files or folders and drags them as a group to a new location With all these Gestalt principles operating at once, unintended visual relationships can be implied by a design. A recommended practice, after designing a display, is to view it with each of the Gestalt principles in mind—Proximity, Similarity, Continuity, Closure, Symmetry, Figure/Ground, and Common Fate—to see if the design suggests any relationships between elements that you do not intend.