An Objective Measure for Detecting Workload and Errors in Monotone, Repetitive or Fatigue-Causing Environments Using Pupil Variation

Abstract

The measurement of workload in real working situations is a challenging issue. Subjective measures like questionnaires are often too intrusive because they disrupt the worker from the task and its workload, which then changes the assessment. Also, they are subjective measures always bringing up the argument whether it is a real impact or just a subjective opinion. Both issues diminish the validity of the questionnaire approach. Objective psychophysiological measures, on the other hand, are difficult to apply, as they are often confounded with physical load. As an example, heart rate variability is only a ‘half-way valid’ psychophysiological measure as physical load interplays with this measure; hence heart rate variability cannot be used in physically demanding situations. This deficiency excludes this parameter for almost all real working environments. The paper suggests using pupil-variation as a valid indicator for monotone or fatigue-causing work in real working conditions. The indicator was developed in different studies such as long-haul flights, manufacturing and computer-based training. This paper will outline the methodology and key results of the studies.