Cognitive Workload Assessment in Procedural Tasks

Objective To examine how task anomalies and time pressure influence cognitive workload in procedural tasks and to identify whether workload effects are transient or sustained. Background Procedural tasks often involve sequential actions for which disruptions, such as operational anomalies or time pressure, may exceed operator capacity. Understanding the temporal dynamics of workload under these conditions is essential for designing adaptive systems to effectively support human performance. Method Thirty participants performed three cooking tasks under nominal and off-nominal conditions (trials with induced operational errors and time pressure). Workload was continuously assessed using subjective ratings and physiological measures including skin conductance level (SCL), percent change in pupil size (PCPS), and blink rate (BR). Results Subjective workload was consistently greater in off-nominal conditions. Physiological measures varied in sensitivity to the task condition and type of task: BR reliably indicated elevated task demands, PCPS was sensitive only under multiple operational anomalies, and SCL showed limited responsiveness to all factors. Two distinct workload patterns were observed: isolated operational anomalies led to transient workload spikes, while multiple accumulating anomalies produced sustained high-workload states, reflecting a “workload history” effect. Conclusion Cognitive workload responses depend on both the type and accumulation of task disruptions. BR provides a robust real-time marker, while subjective ratings capture perceived effort. Application Findings inform the design of adaptive support systems capable of distinguishing between momentary operational challenges and cumulative strain, enabling tailored operator assistance in procedural and safety-critical domains.