Cognitive Workload Analysis

The amount of information processing and decision-making required in task performance impacts the workload experienced by the performer. Workload is defined as the physiological and mental demands that occur while performing a task or a combination of tasks. Hart & Staveland add to this definition that "Workload is not an inherent property, but rather it emerges from the interaction between the requirements of a task, the circumstances under which it is performed, and the skills, behaviors, and perceptions of the operator." *

A goal of Human Factors is to design tasks, jobs, and system interfaces so that the worker is not so undertasked as to become bored leading to vigilance errors, nor so overtasked and stressed as to miss cues or make decision errors. To assess tasks for underload or overload, there are four generally accepted categories of assessment methods:

• Subjective Ratings
• Performance Data
• Physiological Measures
• Analytical Techniques.

Selection of the most appropriate workload assessment category and method depends upon the nature of the task under study.

* Hart, S.G. & Staveland, L.E. (1988). "Development of NASA-TLX (Task Load Index): Results of empirical and theoretical research," in Human Mental Workload, P.A. Handcock & N. Meshkati (Eds.), Elesvier.