In the last century, there was a growth of new technological sectors. These included rapid changes in areas such as nuclear, oil & gas, aviation, and chemicals, among others. All of these sectors involved not only the growth of the individual products but an interconnected systems of technologies along with people involved in the operation and maintenance of these integrated technologies. These systems are often complex in nature an involve a lot of uncertainty in their operation.
As these systems slowly developed, there was a rapid recognition that appropriate care has to be taken to ensure that these systems do not malfunction. Specifically, in safety-critical systems, malfunctions result in incidents, accidents, disasters and catastrophes. The hazards that these technologies, specifically nuclear and chemical, pose are not only limited to the limited to the immediate but lasts over subsequent generations. One can only think about places such as Chernobyl in erstwhile USSR or Bhopal in India where health implications of systemic disasters have been appalling. Therefore, a major challenge in these systems has been the need to ensure reliable operations. In order to ensure systemic operations, a crucial aspect of these technological systems has been the inclusion of the human as part of the overall system.
HMI design in technological systems has been studied extensively in cognitive systems engineering, a sub-discipline of Human Factors intersecting with Systems Engineering. For ease of understanding we will divide the involvement of the humans in technological systems in two categories. The first category deals with humans in-relation to other humans (groups, teams and organization, including health and occupational safety).
The second category deals with humans in relations with the immediate technologies — human machine interaction. This second category is the key idea that will be explored in this tutorial. Our main challenge is to design the human machine interface (HMI). It should be noted that the these complex technological sectors involve a heavy emphasis on the engineered dimension. This heavy technological focus imposes certain constraints on the activities of the users. In other words, the HMI design challenge is to design in such as manner so as to balance both the technology and the human together. This will ensure through the process of design that the operator is efficacious in any given situation while ensuring overall systems safety. Human factors researchers have, therefore, emphasized the harmony between the humans and technologies by ensuring a “joint-optimization” of the two.
Human and technology taken together in a unified whole: “joint optimization” of humans and technologies.
Role of human technology interaction in complex technological systems. Adapted from Kyriakidis, Kant, Amir and Dang, 2018.
In addition to the above, the design of HMI in technological systems should be human-centred; i.e. it should support the mental models of the operators involved in the operating the system while taking the technology into account. Towards this end, User-Centred Design (UCD), has been quite successful in promoting the need for involving the users right from the beginning of the planning and design process as well as throughout the systems life-cycle. While the need to ask users and get their feedback at all stages has been highly efficacious for design, there are certain limitations that UCD faces in highly complex technological systems.
First, focussing on “users” as a category in not enough to design the HMI. This is because users and operators are different roles that humans take up in complex systems (Kant, 2017). Operation of systems will require mental models and activities of operators because it is differentiated from what users do in terms of interaction with the system. In other words, operators and users have different goals and in our case mindsets in the manner in which they interact with the system and the design process should be such so as to cater to the needs and requirements of the operators. Second, the operator’s mental models of the complex technologies need to be addressed more holistically such that both novice as well as expert operators are able to deal with unanticipated situations such as abnormal plant functioning. In moments of acute unanticipated disturbance, operators, being human, may not have all the vantage insights that need to be addressed for operation.
In order to deal with unanticipated situations as well as having a holistic understanding of mental models for novices and experts alike, we have to understand the underlying constraints of technology and represent it in ways that becomes efficacious for the operators. By identifying the constraints imposed by the technology, we will be able to identify human activities that fit in within those constraints without violating them. Stated in design terms, the technological basis has to be represented in terms of an experiential basis. In terms of HMI design, if we are able to represent the technological constraints in the HMI such that the operators are aware of it, then during abnormal conditions, they will be able to act such that the constraints are restored and the system returns back to its normal functioning.
Therefore, our design challenges involves developing better representations, preferably, simple forms to depict the inherent complexity of the work domain, so that the operator’s mental models are supported. Based on a number of studies done in a variety of technological sectors, researchers from human factors have found this approach of representing constraints to be quite beneficial for HMI design. In the discipline of human factors, a number of conceptual and design theories, frameworks and methodologies have been developed. In this primer, we will focus on one approach called Ecological Interface Design (EID) that has been significantly successful in addressing the challenges of HMI design in complex technological systems.
Note: It should be noted that the exposition of EID in this primer is at a broader level and is presented in an overview format. A more detailed treatment of EID can be found in books listed in Bibliography and Further reading section. In addition, the insights presented here about EID should be taken together with other principles and strategies used by designers for developing interfaces.