Physiological investigation of cognitive load in real-life train travelers during information processing.

Management of travelers' cognitive load is crucial for efficient information processing for optimal railway operations. We investigated variations in travelers' cognitive load with different expertise levels, in a field study. We aimed to assess the use of three eye metrics: pupil diameter, saccade amplitude and gaze of fixation duration for cognitive load analysis between expert and novice travelers in a Mass Transit train station: Saint-Michel Notre Dame. Physiological measures of emotional activity through skin conductance responses were also investigated, together with subjective measures of mental load using NASA-Task Load Index. Our results followed our expectations, where novice travelers expressed higher cognitive load than expert travelers, characterized by wider pupil diameter, larger amplitude of saccade and longer gaze duration, as well as higher electrodermal activity and NASA-TLX. Additional observations showed that experts used hierarchical and symmetrical scan paths, with more intense exposure on relevant information, characterized by brighter heat maps. This difference in behavior showed a clear difference in strategies for information retrieval at different expertise levels. Metrics of eye tracking device, together with electrodermal activity, proved to be potent in cognitive load analysis of train travelers, and helped to provide insights for real-life information processing.