Where is the System in the Man-Machine System?

Abstract

Implications of the man-machine concept for Human Factors as a discipline are derived. Two fundamental research questions stem from this assumption: Are psychological principles describing individual and group behavior sufficient to explain operator and multiman-machine system operations; and, what is the relationship between individual responses and system outputs? Review of the Human Factors literature indicates that most studies ignore the system and fail to answer these questions. explored.One of the fundamental premises of Human Factors (HF), which in the author's use of the term includes analysis, equipment design, evaluation, training, manpower determination, etc., is that it is a "system" discipline, dealing with behavioral factors in the context of something called the man-machine system (MMS) or simply the "system" (Christensen, 1964, DeGreene, 1970, Meister, 1971. References aside, this premise is so well accepted by the discipline that it is considered somewhat trite to mention it.Everyone presumably knows what the MMS is and what it means for HF. In consequence, rarely does anyone ask what this assumption means. The purpose of this paper is to examine the implications of the MMS assumption.2. On a somewhat more complex level, the individual can extend himself by interacting with other individuals. This interaction is direct and almost always verbal, although without mechanical/electronic interfaces. This is the group or what some have termed the man-man system.Since both the individual and the man-man system lack an equipment interface to transform energy and manipulate their environment, their study properly belongs to the psychologist or in the case of the man-man system, the sociologist. 3. At still another level whose complexity cannot really be compared with the individual and the man-man system, one finds the operator system, whose distinguishing characteristic is that the individual interacts with his environment through some sort of interface, which means that there is a transformation of energy or matter across that interface.Once the individual is given a mechanism to manipulate his environment, he becomes the operator. The mechanism can be as simple as a stick with which he can draw in the sand, or as complex as a space ship he can pilot to the moon. With very simple mechanisms it is sometimes difficult to tell whether one is dealing with an operator or an individual. The basic criterion, however, is clear; it is whether or not the individual can exercise an effect on his environment through some tool other than his body. 4. At the most complex level there is the multiman-machine system (MMMS), more simply termed the multiman system, which consists of two or more operators interacting with each other and with their environment through some mechanical/electronic interface. Again, the multiman system varies in complexity from the minimal two-man operation to something as extensive as the space launch complex at NASA Houston.

The Indeterminate Man-Machine System

“…Although psychological principles are important, therefore, for system development, these have not unfortunately been studied in a system (i.e., input-output transformation) context (Meister, 1974). Consequently the task of applying psychological principles to reduce indeterminacy is very difficult.…”

“…If it is anything, Human Factors (HF) is a system discipline, by which is meant that it is--or should be--concerned with the output of the total man-machine system as that output is affected by personnel variables and as personnel operations are influenced by system characteristics (Meister, 1974). It is therefore necessary to study the characteristics of systems as well as the behavior of operators within these systems.…”