Gaze behaviours, situation awareness and cognitive workload of air traffic controllers in radar screen monitoring tasks with varying task complexity.

Objectives. Air traffic controllers should maintain high situational awareness (SA) and low cognitive workload to ensure aviation safety. However, increased task complexity may influence air traffic controllers' SA and cognitive workload. Meanwhile, eye-tracking provides insights into the gaze patterns that might signify SA. This article investigates the gaze behaviours, SA and cognitive workload of different radar screen monitoring tasks with varying task complexity. Methods. Twenty-eight participants performed three radar screen monitoring tasks, including call-sign association, position identification and heading projection. Cognitive workload and SA were evaluated for each task using the National Aeronautics and Space Administration task load index (NASA-TLX) and situational awareness global assessment technique (SAGAT), respectively. The Gaussian mixture model was used to cluster the SA into high/low. Eye-tracking reveals the gaze behaviours that may contribute to the SA formation. Results. Cognitive workload and SA significantly differ between different levels of task complexity. While task complexity has a significant main effect on the fixations of human operators, it does not significantly influence the pupil diameter. Conclusions. Fixation-related metrics may signify the changes in SA under varying task complexity, while the side effects of cognitive workload should be mitigated.