The Design of Technological Displays (Tutorial Paper)

A technological display is the interface between the human and technological systems. This tutorial is concerned with computer-based systems and displays that enable humans to interact with computers, and most of the examples are taken from real-time systems. It is with these systems that display design becomes most critical, since the human must respond accurately under speed stress. The displays must help the human comprehend complex and rapidly changing system events. Due to limitations in display size, the data are often highly coded and difficult to interpret. The learn- ability and memorability of displays are therefore important aspects of display design. The field of technological displays can be described in terms of certain broad categories. From a presentation point of view, displays can be classified as either alphanumeric or graphic. Within the field of alphanumeric CRT displays, a further distinction occurs between the conversational mode, where input is limited to a specific CRT location, and the formatted display that allows entry at pre-specified locations anywhere on a fixed mask. These types of displays are illustrated with examples from real-time telephone traffic management systems. The fundamental display design process consists of eight major steps that carry the designer from the initial analysis of the operating system to the detailed formatting of each display. At each stage the designer makes decisions based on adequate knowledge of human needs and limitations. Specific areas for additional psychological research are pointed out. In its broadest sense, the technological display is any presentation of data associated with an engineering or scientific discipline. To narrow things somewhat, it is necessary to distinguish between real-time displays and non-real-time displays. The distinction has more to do with the intended mode of use by the human than with the data or their method of generation. A display is an aid to the performance of some task. The user of the real-time display is involved in tasks that force him to decode and encode information within a rapidly changing environment. The speedometer in a car is an example. It is updated frequently and the driver needs to obtain information in a brief glance. If the display lags behind the speed of the auto or if it is difficult to determine quickly the current reading, the display is poorly designed. Thus, in general, real-time displays have the advantage that they can be objectively evaluated by the criteria of speed and accuracy of use.