Beyond HTML!

Information Outlook, Nov, 1998 by Charles J. Greenberg

Have you noticed that the library within the walls is deceptively quiet these days? As the World Wide Web (WWW) becomes the library without walls on users' desktops, information itself has become the representation of services and resources. An increasing amount of library outreach to its parent community is done though amateur or professional graphic design skills with Hypertext Markup Language (HTML). Information professionals have by necessity become graphic designers, creating and adapting print and electronic documents, whether you use a hired hand to do the actual HTML coding or possess the determination to do it yourself. Your design decisions and handiwork will end up in electronic:

* Newsletters and service announcements

* Resource guides and bibliographies Educational and use resources

* Public relations materials & virtual "tours" of facilities

* Administrative and business documents

* Databases and catalogs

We know we are designing many electronic documents and interfaces that may never be intended for printing or paper distribution. Yet our own previous training and experiences with creating and using print may effect our perspective on the possibilities for interface design.

Are information professionals constrained by traditional print paradigms? More than likely, information professionals are victimized by those paradigms: expensive dissemination, easy vandalism, infrequent revision, sequential presentation, etc. Although HTML and the WWW offer solutions to most of these problems and the possibility of a rich visual design palate, most information professionals have no formal training in graphic or interface design. Don't be too discouraged, however. Most graphic designers have no formal understanding of human perception, memory, or recall!

This article starts from the premise that knowledge of cognition, memory, and graphic design principles can and should improve design outcomes for the computer interface. Understanding the basis for visual perception and cognition begins with acknowledging the biological basis of our visual senses.

OUR VISUAL SENSES

Visual scientists generally agree that the brain performs rapid "parallel processing" of color, shape, and motion. Two types of receptor cells dominate the visual structure of our eyes: rods and cones. Rod cells function in dim light and are sensitive only to contrast, not to color. When you search for the right key in a dark hall, you are relying on the perception provided by rod cells. Cone cells are the sensory mechanism for color. Most cone receptor cells are differentiated into three sub-types by their sensitivity to a particular section of the color spectrum, either red, green, or blue. Besides color, cones are also sensitive to and produce the sensations of shape and motion.

Understanding the biological basis of the human visual system can guide the usage of interface attributes, particularly the use of color. Blue-sensitive cones are the least numerous of the color-sensitive cones. In the fovea, or center of the eye's retina, there is also the smallest distribution of blue-sensitive cones. In considering color design, it would make sense to use blue as a background or peripheral color and not use blue for detailed features in the center of an interface. Using the color red to draw attention makes biological sense as well. Of course, most persons have experienced the uncomfortable sensation of vibrancy or after-images when color opposites are placed next to one another, so care must be taken to create a comfortable experience with the color palette.

Ever hear of the color consultant Roy G. Biv? This renowned figure is actually the key to remembering the spectral order of colors visible to the human eye: red, orange, yellow, green, blue, indigo, and violet. If your design style calls for a rainbow, don't forget that spectral order appears natural. Positioning colors from opposite ends of the spectrum together will tend to create the sensations of vibration and after-images.

COGNITIVE PROCESSING FOR MEMORY

Whether or not we believe that our cognitive processes are deliberate or automatic, there is little doubt that the computational era has also brought a systematic model to the forefront of theories of human cognitive processing. A typical example of systematic human information processing has been presented in John R. Anderson's work Cognitive Psychology and Its Implications (4th ed., W.H. Feeman, 1995). In Anderson's model, sensory stimuli based on visual processing must go through a systematic process of attention and rehearsal if they are to have any chance of conversion to long-term memory. The difficulty of turning sensation into memory derives from the impermanence that characterizes sensory memory. This short-term memory is visual in nature and particularly prone to rapid degrading when not given a repetitive processing boost and eventual long-term storage.

Anderson's identifies attention as a limited resource that can be allocated only for a small number of simultaneous processes. Well-rehearsed processes require less and less attention, and those well-rehearsed processes become automatic, freeing mental processing resources up for rehearsing new sensory memories. For instance, a bicycle rider pays more attention to the horizon and immediate navigation decisions than moving the pedals. Thinking about abundant graphics and multimedia on most commercial WWW pages, it is no wonder that a searcher may forget their purpose when several simultaneous animations beckon.