Abstract: An exploratory three-phase study examined the ability of adults diagnosed as moderately developmentally disabled to successfully use a personal computer, input devices preferred, and user interface design factors to be considered when designing or selecting applications for this population. Phase I observed the reaction of the participants, none of whom had ever used a computer, to a graphical user interface. In Phase II usability tests compared the mouse, the trackball, and the touchscreen to gather heuristic data on input device preference and develop user interface design guidelines for applications for the target population. Phase III tested the guidelines by developing two prototype games: "Shopping," designed to teach money-handling skills, and "Getting Dressed," to teach a basic life skill. Phase I showed that participants liked and understood the graphical user interface. All could use the touchscreen, and most could use the mouse. Phase II usability testing found that the mouse was preferred over the touchscreen and the trackball, although its drag-drop times were longer. Reasons given were less fatigue and greater control. Phase III found participants preferred screens that allowed them to control the action, that quick or unexpected screen responses were upsetting, and that strong, realistic visual feedback was important. The study is seen as a first step in developing guidelines to make the computer accessible to those with moderate developmental disability.

Keywords: Case studies; Design; Disability, mental; Empirical studies; Guidelines; Hardware development; Mentally retarded adults; Pointing device input; Prototyping; Screen output; Special populations

Originally published: Proceedings of the Human Factors and Ergonomics Society 38th Annual Meeting, 1994, pp. 300-304

Republished: G. Perlman, G. K. Green, & M. S. Wogalter (Eds.) Human Factors Perspectives on Human-Computer Interaction: Selections from Proceedings of Human Factors and Ergonomics Society Annual Meetings, 1983-1994, Santa Monica, CA: HFES, 1995, pp. 349-353.