Psychology as a mother of invention

Important progress has been made in the methodology for making computer systems easier to use. Highlights are the "Wizard-of-Oz" technique and rapid iterative developmental testing. It is argued that more fundamental advances, inventions of truly new and useful computer-based cognitive tools, will result from deeper behavioral analysis of the capabilities and limitations of human performance. Three such analysis methods are described; failure analysis, individual difference analysis, and time profile analysis. A few dramatic success stories are recounted. Promising targets for "synthesis by analysis" are proposed. The reason for this meeting is a shared desire to make computers better tools for people to use in the pursuit of their goals. I 'm going to talk about how to go about doing that. First I'll review what I believe to be highlights of what's been learned so far about how to do our business. Then I'll propose some ways in which I think we can make our future efforts have even broader and more profound effects. As a group, the members of the sponsoring organizations and the audience combine psychology, the study of behavior, with computer science and design, disciplines of invention and construction. It's clear enough why both interests are engaged by the task of building computer tools for human use. But it has not always been obvious how to produce an effective merger of the two. Memory is only too fresh of the days in which programmers programmed only for other programmers, and psychologists only carped. Not long enough gone is the time when human factors specialists were called in to bless a system shortly before it was marketed, and if allowed to do an evaluation at all, took so long and learned so little as to be classified as an expense. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish, requires a fee and/or specific permission. ©1987 ACM-0-89791-213-6/87/0004/0333 $00.75 In the last 5 years we have come a long way. There has been a sea change in attitudes. Designers and programmers have inscribed the words "user friendly" on their doorposts, while whole divisions of Fortune 500 companies have focused their efforts on usability. Tools "such as user interface management systems have been developed to make it easier to focus on the issue, and a number of user-oriented inventions like windows, mice and icons have actually found their way into wide use. Methods for informing the design and development process have also improved dramatically. The most effective improvements have come from the introduction of techniques by which new ideas can be tried and tested for usability quickly, cheaply, and very early in the development cycle. In one, the "Wizard-of-Oz" method pioneered by John Gould (Gould, Conti and Hovanyecz, 1983), new system functions or features are evaluated before anything at all is built by having a hidden human play the role of the would-be computer. Another extremely effective methodology that is being applied with increasing frequency and benefit is rapid iterative user testing during development. Feedback from tests of small numbers of representative users suggests modifications of an early prototype which are quickly made, similarly tested, loop. An exemplary application is described by Good, Whiteside and Wixon (1984), who obtained a manyfold reduction in user difficulties by iteratively redesigning an interface on the basis of experience with a prototype installed in a shopping center test facility. Still another promising technique has been the development of approximate computational models of users that allow "ballpark" evaluations of certain aspects of interfaces during the design phase itself (Card, Moran and Newell, 1983; Kieras and Polson, 1985) Also, of course, there has been a considerable accumulation of art and wisdom on the part of both human factors people and designers who have been paying attention to these matters, and much of it has been capttlred in compendia of design guidelines (e.g. Smith and Mosier, 1984), and is even beginning to be frozen into requirements and standards. What's next? I believe there are important opportunities for a deeper synergy between behavioral analysis and the powerful techniques of computer science for realizing systems that help with intellectual tasks, I believe that we should broaden the conception of our role as workers