HUMAN–COMPUTER INTERACTION

OVERVIEW

The utilities of information technology are spreading into all walks of life, from the use of self- standing personal computers and networking to Internet and intranet. This technology has allowed for tremendous growth in Web-based collaboration and commerce and has expanded into information appliances (e.g., pagers, cellular phones, two-way radios) and other consumer products. It is important that these interactive systems be designed so that they are easy to learn and easy to operate, with minimal errors and health consequences and maximal speed and satisfaction. Yet it can be challenging to achieve an effective design that meets these criteria.

The design of interactive systems has evolved through several paradigm shifts. Initially, designers focused on functionality. The more a system could do, the better the system was deemed to be. This resulted in system designs whose functionality often could not be readily accessed or utilized, or tended to physically stress users (Norman 1988). For example, how many homes have you walked into where the VCR is flashing 12:00? This example shows that even devices that should be simple to configure can be designed in such a manner that users cannot readily comprehend their use. Further, the occurrence of repetitive strain injuries rose as users interacted with systems that engendered significant physical stress. The development of such systems led to a shift in design focus from functionality to usability. Usability engineering (Nielsen 1993) focuses on developing interactive systems that are ergonomically suitable for the users they support (Grandjean 1979; Smith 1984), as well as cognitively appropriate (Vicente 1999). This approach aims to ensure the ease of learning, ease of use, subjective satisfaction, and physical comfort of interactive systems. While these design goals are appropriate and have the potential to engender systems that are effective and efficient to use, system designers have found that this focus on usability does not always lead to the most user- acceptable system designs. In recent years, environmental concerns (i.e., social, organizational, and management factors) have led to design practices that incorporate a greater emphasis on studying and understanding the semantics of work environments (Vicente 1999), often through ethnographic approaches (Nardi 1997; Takahashi 1998). Through participant-observation practices, efforts are made to understand more completely the tasks, work practices, artifacts, and environment that the system will become a part of (Stanney et al. 1997). This is often achieved by designers immersing themselves in the target work environment, thereby becoming accustomed to and familiar with the various factors of interactive system design. These factors include users’ capabilities and limitations (both cognitive and physical), organizational factors (e.g., management and social issues), task requirements, and environmental conditions that the work environment supports (see Figure 1). Through the familiarity gained by this involvement, designers can develop systems that are more uniquely suited to target users and the organizations for which they work.

This chapter provides guidelines and data on how to achieve these objectives through the effective design of human–computer interaction, which takes into account the human’s physical, cognitive, and social abilities and limitations in reference to interacting with computers and / or computer based appliances. In doing so, it relies on the available standards, practices, and research findings. Much of it is guided by currently available technology but may also be applicable as technology changes and new applications evolve.

The overall thrust of the chapter is that good physical design of the workplace will minimize the probabilities of the occurrence of health consequences; good cognitive design will maximize the utility of interactive systems; and good social and organizational design will effectively integrate these systems into existing work domains. In general, it is suggested that human–computer interaction will be optimized when the following are observed:

• The system design is ergonomically suited to the user.

• Interactive design matches the mental models of users.

• Only information needed for decision making is presented.

• Information of a similar nature is chunked together.

• The interface is adaptive to individual differences due to innate, acquired, or circumstantial reasons.

• The system design supports existing work practices and related artifacts.

Interactive system design is thus about many interfaces; it considers how users relate to each other, how they physically and cognitively interact with systems, how they inhabit their organizations, and how these interfaces can best be supported by mediating technologies. Focusing on each of these areas highlights the need for a multidisciplinary interactive system design team. As Duffy and Sal- vendy (1999) have documented, in teams that consist of design and manufacturing engineers, mar- keting specialists, and a team leader, even when they have common goals, each member retrieves and uses different information and has a different mental model that focuses on unique aspects in achieving the same design objectives.

The following sections will focus on different aspects of interactive system design, including ergonomics, cognitive design, and social, organizational, and management factors.