The General Systems Theory (BERTALANFFY, 1975) studies the abstract organization of phenomena, regardless their form and configuration. It investigates all the principles of complex entities, and models that can be used for their description. Moreover, every system is sociotechnical, since they always comprise people and their devices, although it is necessary to distinguish between systems where the technology has the central role, and systems in which people are responsible for determining what is done and how work occurs (HOLLNAGEL e WOODS, 2005).
According to Bertalanffy, a system is an organized entity consisting of a set of elements and interactions. Bertalanffy also states that there are models, principles and laws that can be applied to systems in general, regardless of their type, nature of the elements that compose them, or their relations.
Thus, according to the general systems theory, systems organize in two categories:
Open Systems: self-regulatory systems that perform permanent interactions with the environment, generating positive and negative feedbacks. Their self-regulatory mechanisms make them keep their internal organization, thus evolving in an increasingly complex way;
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Closed systems: systems that work isolated from their environment, in increasing entropy, i.e., those systems which elements lack of interaction and synergy, generating disorder.
Regulatory actions occur in order to make the system operational at a given time interval. Therefore, even with the intrinsic or extrinsic interference of external or internal agents the system is able to keep its purposes (VIDAL and CARVALHO, 2008).
Thus, the self-regulation of systems is a spiral process in which a portion of the system outputs is fed back, serving as input for the same system. While the positive self- regulation increases fluctuations in system operation promoting changes that affect its stability, negative self-regulation outweigh the variations observed in order to stabilize the operation of the system.
Furthermore, no work activity occurs solely. Activities take place in sociotechnical system through the interactions between people, the technology, and the organization.
Therefore, the operation of systems depends essentially on their socio-technical features.
Thus, systems are, most of all, characterized by their purpose, structure, or function.
Purpose is defined by the organization of systems’ components in order to achieve a goal, forming an organized structure by linking functions.
Regardless of whether the application is autonomous, a technological system is always embedded in a sociotechnical context. Every system has been designed, constructed, and used by people. Every system produces something with an intended use, therefore with an intended user (HOLLNAGEL e WOODS, 2005). This is what makes it possible for a system to be represented and supported by a device, a machine or a set of rules.
Figure 2-1 presents the layers of a complex sociotechnical system, showing that, in order to achieve the desired level of performance, not only the capabilities and limitations of the individual must be understood, but also the interactions with the technical system must considered. Moreover, social-organizational factors also play a crucial role in system performance (VICENTE, 1999).
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Figure 2-1: Layers of a complex sociotechnical system (adapted from Moray and Huey (1988))
To what concerns complexity, every system tackles big or small levels of complexity, depending on the conditions to which the system in exposed. However, as higher the complexity the more difficult it is to represent its essential parameters without losing its functional properties. Thereby, four properties are described for complex sociotechnical systems as follows:
Non-determinism: it is impossible to anticipate the behavior of systems precisely, even when their features are fully known;
Limited functional decomposability: it is difficult, if not impossible, to study the system properties for its decomposition in stable parts;
Distributed nature of information and representation: some functions of complex systems cannot be positioned. The information is located in different places and usually in possession of different agents. A system is distributed when its resources are physically or virtually spread out across multiple locations. This distribution can be made by redundancy, contingency, or as a result of work organization;
Emergence and self-organisation: when situations are unpredictable, new information arises also unpredictably. In order to flow information, agents reorganize the system’s structure, usually changing its cooperation
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mechanisms. The transmission of information between agents depends on environmental factors and on the cognition of each individual agent. On the other hand, emergence does not occur due to incomplete information about the system components, but due to the non-linear and distributed aspect of interactions. Moreover, if a system is able to reorganize itself, its functions have a greater response time, and thus it cannot be described as functionally stable
The essential properties listed above make it possible to identify relevant issues concerning the functioning of sociotechnical systems. Also, the identification of distributed nature of systems shows how their capacity to cope with unpredictability is related to control of locally situated information.
The possibilities of unexpected events, as well as the difficulties in describing their operation, are associated to variability and workers’ improvisations, performed in order to fulfill specification gaps and accomplishing expected results. Moreover, if it is hard to specify the system, it is obviously harder to design support devices for it.
Therefore, complexity increases the possibility of emergence of new types of failures in systems, as it allows for more process variation, which can be combined in unexpected ways. Critical systems, like the ones that comprise risks to the physical integrity of its members – like health care systems – demand support devices designed taking into account relevant elements of how work takes place.