Human Factors in Man-Machine Systems

T h e field of hwnan factors is analyzed in an effort to discover its scope and organizdtion. Three orthogonal partitions of the field serve to define eight mutually exclusive, jointly exhaustive, and interdependent sectors. These m e considefed separately. Never far from the minds of human factors specialists are such questions as “What is the scope of the human factors profession? ” “Just what are the human factors in a man-machine system? ” and “What relations exist among them? ” The following analysis has proved of value in organizing bibliographic materials, and it is offered here in the hope that it may assist in defining the compass and structure of our new profession. Whatever the human factors in a man-ma-chine system may be, let us represent them by points in the circular field of the figure. We can immediately divide this field between those factors which affect the job behavior of the men who have been incorporated into the system as human components (hereafter referred to as the crew) and those other factors which affect the condition of crew and passengers,. This is ac-complished by the vertical line (Fig. 1). Next, we can partition the field into three zones, orthogonal to the first two, and contain-ing the systemic, functional, and general factors, respectively. The systemic human factors are the human utility and cost to the system in its operation. They are thus the concern of high-level system planners, men who are concerned not merely with human factors but with the “big picture.” The general human factors, in contrast, are the province of men who are not primarily con-cerned with man-machine systems at all, but with men- or more generally, organisms. These factors consist of the behavioral and eco-logical characteristics of men in general- i.e., I This analysis quite frankly follows the paradigm of a vehicular system, but its application is not re-stricted to systems of that kind. Thus “passengers” may be interpreted as personnel other than crew who are affected by the system’s operation