Context Effects in the Measurement of Subjective Workload: Prolonged Exposure to the Same or Different Contexts

Abstract

The present study investigated the effect of context on the subjective measurement of workload using the continuous memory task. Twelve levels of task difficulty were manipulated either between-subjects or within-subjects. Participants performed the continuous memory task for 48 trials under either a single difficulty level (between-subjects context) or under all 12 difficulty levels (within-subjects context). Workload was measured using ModSWAT— a technique that uses the sum of the SWAT dimensions to form the workload composite rather than the standard conjoint measurement procedure. Results indicated no difference in performance as a function of context but that context affected ratings of subjective workload. Under the single context condition, participants rated the workload of the easiest conditions higher than if the same conditions occurred within context of other more difficult conditions. Results are discussed in terms of their implication for practical assessment of subjective workload.