INTRODUCTION TO COGNITIVE TASKS

INTRODUCTION

In any purposeful human activity there is a blend of physical components or manipulations and cognitive components, such as information processing, situation assessment, decision making, and planning. In many tasks, however, the cognitive components are more demanding and crucial for the task performance than the physical components. We call these tasks cognitive. Design, managerial and production planning, computer programming, medical diagnosis, process control, air traffic con- trol, and fault diagnosis in technological systems are typical examples of cognitive tasks.

Traditionally, cognitive tasks have been carried out by white-collar workers, middle and upper cadres of enterprises, as well as several freelance professionals. With the advent of information technology and automation in modern industrial settings, however, the role of blue-collar workers has changed from manual controllers to supervisors and diagnosticians. In other words, developments in technology are likely to affect the requirements about knowledge and skills and the way operators interact with systems. Consequently, cognitive tasks abound in modern industries.

In view of these changes in cognitive and collaborative demands, ergonomics must play a crucial role in matching technological options and user requirements. Cognitive ergonomics or cognitive engineering is an emerging branch of ergonomics that places particular emphasis on the analysis of cognitive processes—for example, diagnosis, decision making, and planning—required of operators in modern industries. Cognitive ergonomics aims to enhance performance of cognitive tasks by means of several interventions, including:

• User-centered design of human–machine interaction

• Design of information technology systems that support cognitive tasks (e.g., cognitive aids)

• Development of training programs

• Work redesign to manage cognitive workload and increase human reliability

Successful ergonomic interventions in the area of cognitive tasks require a thorough understanding not only of the demands of the work situation, but also of user strategies in performing cognitive tasks and of limitations in human cognition. In some cases, the artifacts or tools used to carried out a task may impose their own constraints and limitations (e.g., navigating through a large number of VDU pages), which add up to the total work demands. In this sense, the analysis of cognitive tasks should examine the interaction of users both with their work environment and with artifacts or tools; the latter is very important as modern artifacts (e.g., control panels, electronic procedures, expert systems) become increasingly sophisticated.

As a result, this chapter puts particular emphasis on how to design man–machine interfaces and cognitive aids so that human performance is sustained in work environments where information may be unreliable, events be difficult to predict, goals have conflicting effects, and performance be time constrained. Other types of situations are also considered, as they entail performance of cognitive tasks. Variations from everyday situations are often associated with an increase in human errors as operators are required to perform several cognitive tasks, such as detecting variations, tailoring old methods or devising new ones, and monitoring performance for errors. Sections 2 and 3 introduce human performance models that provide the basic framework for a cognitive analysis of the work environment, artifact constraints, and user strategies. Design principles and guidelines derived from these models are also presented in these sections. Section 4 describes the methodology of cognitive task analysis. Finally, Section 5 discusses two case studies presenting the cognitive analysis carried out for the design of cognitive aids for complex tasks.