In developing student--computer dialogs such as the Scientific Reasoning Series, we are concerned with the visual and temporal structure of this material on the computer screen. The computer is a new learning medium, different from books, lectures, films, and human tutorial aid. A full realization of the potential of the computer demands careful attention to characteristics important in learning with the new medium. I attempt no full discussion of these issues, amply discussed in literature available from the Educational Technology Center, but will mention the principal factors. The design standards aim to enhance the learning process.
The screen is a new ``tablet'' where information can be placed, in space and in time, by the user or the computer. This electronic tablet is not a printed page, a blackboard, or a TV screen. It has its own properties.
Screen structure can do much to aid reading. We can use blank space extensively, since it is ``free'' on the computer screen. We can use short lines. We can avoid hyphenation. We can keep natural phrases together on a line. We can remove information no longer relevant. We can interweave text and graphics. We can build up graphics as needed. We can use special effects -- blinking text, flashing boxes, oscillating letters, color, big letters -- to emphasize words or phrases.
Timing serves to improve comprehension. We can pause before or after an important word or phrase. We can pause at natural, grammatical breaks, such as the ends of sentences or at other punctuation. Students can control the rate of text output. These strategies are employed in the Scientific Reasoning Series.
While our use of these factors at the Educational Technology Center is based largely on informal observation, we have conducted more formal studies about some of these features.