Grouping & Hierarchy We group objects visually by similarity. The orderly or logically pairing (joining) of objects with one another which leads to recognition, comprehension, and perhaps sequential order.
All indicators of hierarchy require a comparison between the objects, images or words that are perceived to be a part of a common system of some sort—an overall group. This context implies the visual “rules: or “clues” that we, the viewer, need to be able to make sense of what we are looking at. This context might be thematic, topical, cultural, technical or any other means of organizing or grouping.
Hierarchy is the order of importance within a group (such as the regiments of an army) or in a body of text (such as the sections and subsections of a book). Hierarchical order exists in nearly everything we know, including the family unit, the workplace, politics, and religion. Indeed, the ranking of order defines who we are as a culture.
Hierarchy is expressed through naming systems: general, colonel, corporal, private, and so on. Hierarchy is also conveyed visually, through variations in scale, value, color, spacing, placement, and other signals.
Like fashion, graphic design cycles through periods of structure and chaos, ornament and austerity. A designer’s approach to visual hierarchy reflects his or her personal style, methodology, and training as well as the zeitgeist of the period. Hierarchy can be simple
or complex, rigorous or loose, flat or highly articulated. Regardless of approach, hierarchy employs clear marks of separation to signal a change from one level to another. As in music, the ability to articulate variation in tone, pitch, and melody in design requires careful delineation.
In interaction design, menus, texts, and images can be given visual order through placement and consistent styling, but the user often controls the order in which information is accessed. Unlike a linear book, interactive spaces feature multiple links and navigation options. Cascading Style Sheets (CSS) articulate the structure of a document separately from its presentation so that information can be automatically reconfigured for different output devices, from desktop computer screens to mobile phones, PDAs, kiosks, and more. A different visual hierarchy might be used in each instance. The average computer desktop supports a complex hierarchy of icons, applications, folders, menus, images, and palettes—empowering users, as never before, to arrange, access, edit, and order vast amounts of information—all managed through a flexible hierarchy controlled and customized by the user. As technology allows ever greater access to information, the ability of the designer to distill and make sense of the data glut gains increasing value.
Generally speaking, Visual Grouping and Hierarchy is controlled by the manipulation of objects/images by factors from these main categories:
- Principles of Gestalt
- Principles/Elements of Design
The principles of Gestalt are all grouping principles, they are:
- Figure and Ground
The word above is clearly perceived as figure with the surrounding white space ground.
In this image, the figure and ground relationships changeas the eye perceives the the form of a shade or the silhouette of a face.
This image uses complex figure/ground relationshipswhich change upon perceiving leaves, water and tree trunk.
Similarity occurs when objects look similar to one another. People often perceive them as a group or pattern.
The example above (containing 11 distinct objects) appears as as single unit because all of the shapes have similarity.
Unity occurs because the triangular shapes at the bottom of the eagle symbol look similar to the shapes that form the sunburst.
When similarity occurs, an object can be emphasised if it isdissimilar to the others. This is called anomally.
The figure on the far right becomes a focal point because it is dissimilar to the other shapes.
- ContinuationContinuation occurs when the eye is compelled to move through one object and continue to another object.
Continuation occurs in the example above, because the viewer’s eye will naturally follow a line or curve. The smooth flowing crossbar of the “H” leads the eye directly to the maple leaf.
- ProximityProximity occurs when elements are placed close together. They tend to be perceived as a group.
The nine squares above are placed without proximity. They are perceived as separate shapes.
When the squares are given close proximity, unity occurs. While they continue to be separate shapes, they are now perceived as one group.
The fifteen figures above form a unified whole (the shape of a tree) because of their proximity.
- ClosureClosure occurs when an object is incomplete or a space is not completely enclosed. If enough of the shape is indicated, people percieve the whole by filling in the missing infomation.
Although the panda above is not complete, enough is present for the eye to complete the shape. When the viewer’s perception completes a shape, closure occurs.
- Figure and Ground
- Isomorphic Correspondence
We respond to some images very strongly, based on our experiences in the physical world. Sharp, pointed shapes communicate danger or pain because we’ve felt the pain of thorns, broken glass, etc. A picture of a Thanksgiving turkey may stir memories of warm, happy family dinners. We’re responding to the meaning of the image, associating it with memories we have. (see interactive demo for examples)
Interactive demo of Gestalt Principles (Shockwave plug-in needed)
Visual Perception by Daniel Chandler, has good visual examples.
The Visual Representation of Information covers many of the principles discussed above, with examples.
Gestalt and Typography looks at proximity and similarity, then applies these ideas to typography. (Shockwave plug-in needed)
Gestalt by Betty Seabolt is a good verbal explanation with, unfortunately, no visuals.
Art, Design and Gestalt Theory by Roy R. Behrens is a detailed academic explanation.
We also use the basic Elements of Design and Principles of Design to control image similarity (grouping) or contrast.
Other Principles of Design or variables are employed to further manipulate or enhance the perception of group or wholeness/unity: