An Investigation of the Relationship Between Subjective Mental Workload and Objective Indicators of User Activity

Whilst the concept of physical workload is intuitively understood and readily applicable in system design, the same cannot be said of mental workload (MWL), despite its importance in our increasingly technological society. Despite its origin in the mid 20th century, the very concept of ”mental workload” is still a topic of debate in the literature, although it can be loosely defined as “the amount of mental work necessary for a person to complete a task” (Miller, 1956; Longo, 2014). Several methods have been utilized to measure of MWL, including physiological methods such as neuro-imagery, performance-based metrics, and subjective measures via questionnaires, such as the NASA-TLX method (NASA, 2022). In this work, the relationship between subjective measures of MWL and objective indicators of activity is examined. Herein, a series of web-based tasks have been developed with mouse-activity monitoring implemented in JavaScript in order to study this relationship. The experimental results indicate that user mouse activity does not correlate with subjective indicators of MWL