On the measurement of pilot perceptual workload: a comparison of assessment techniques addressing sensitivity and intrusion issues

Abstract

A flight stimulator-based study was conducted to examine 14 distinct mental workload estimation measures, including opinion, secondary task, physiological, and primary task measures. Both the relative sensitivity of the measures to changes in mental workload and the differential intrusion of the changes on primary task performance were assessed. The flight task was varied in difficulty by manipulation of the presentation rate and complexity of a hazard-perception task that required each of 48 licensed pilots to rely heavily on their perceptual abilities. Three rating scales (Modified Cooper Harper, Multi-descriptor and Workload Compensation Interference/Technical Effectiveness), 2 secondary task measures (time estimation and tapping regularity), 1 physiological measure (respiration frequency) and 1 primary task measure (danger-condition response time) were reliable indicants of workload changes. Recommendations for applying the workload measures are presented.