Students performed a variety of tasks using a statistics text presented either in conventional printed form or via the text browser “SuperBook” (Remde, Gomez and Landauer [18]). Students using SuperBook answered more search questions correctly, wrote higher quality “open-book” essays, and recalled certain incidental information better than students using the conventional text. Subjective ratings overwhelmingly favored SuperBook. The advantage of SuperBook appears to be particularly strong for questions that are not anticipated by the author's organization of a text.

SuperBook is a hypertext browsing system designed to improve the usability of conventional documents. Successive versions of SuperBook were evaluated in a series of behavioral studies. Students searched for information in a statistics text. presented either in conventional printed form or in SuperBook form. The best version of SuperBook enabled students to answer search questions more quickly and accurately than they could with the conventional text. Students wrote higher quality “open-book” essays using SuperBook than they did with the conventional text, and their subjective ratings of the documentation strongly favored SuperBook. This work is a case study of formative design-evaluation. Behavioral evaluation of the first version of SuperBook showed how design factors and user strategies affected search and established baseline performance measures with printed text. The second version of SuperBook was implemented with the goal of improving search accuracy and speed. User strategies that had proved effective in the first study were made very easy and attractive to use. System response time for common operations was greatly improved. Behavioral evaluation of the new SuperBook demonstrated its superiority to printed text and suggested additional improvements that were incorporated into “MiteyBook,” a SuperBook implementation for PC-size screens. Search with MiteyBook proved to be approximately 25 percent faster and 25 percent more accurate than that obtained with a conventional printed book.

Why do some people have much more difficulty than others in learning a computer-based skill? To answer this question, we observed first-time users of computers as they learned to use a computer text editor. In two experiments, older people had more trouble than younger people and those who scored low on a standard test of spatial memory had greater difficulty than high scorers. These correlations were stable over several hours of practice and did not vary as a function of the type of terminal used or specific editing problems attempted. Correlations involving age and spatial memory could not be explained by other characteristics such as amount of education, reasoning ability, or associative memory ability. Results like these that relate learning difficulty to specific characteristics of people ultimately may suggest ways to change computer interface design or training to accommodate a wider range of users.

In previous studies two background characteristics of computer novices were consistently correlated with their success in learning to use a line-based computer text editor. Older people and those who scored low on a standard test of Spatial Memory had more difficulty than younger people and those with higher Spatial Memory test scores. In the present study, we observed computer novices as they learned to use a screen-based editor, which presumably reduced spatial memory load. Contrary to expectations, performance using a screen-based editor was again strongly correlated with Spatial Memory test scores. However, the correlation between performance and subjects' age was significantly reduced. Overall, subjects were able to perform the same text editing exercises almost twice as fast using the screen editor compared to subjects in previous experiments using the line editor. These results are discussed in terms of the different cognitive demands placed on users by line and screen text editors.

Today, it is not unusual for secretaries to use computer-based word-processing systems to deal with manuscripts, correspondence, and memos. In the future, such functions as updating personal calendars, filing, and leaving messages undoubtedly will be handled by computers. For all these functions, people without a technical background are required to interact effectively with a computer system.