Frequency-Specific Sensory Warning Design for Multitasking Human–Computer Interfaces

In this study, the MATB tracking task served as the primary task, and the system monitoring task served as the secondary task. Within this dual-task setting, we examined how visual flicker frequency and auditory tone frequency affect task performance and cognitive workload. To complement subjective workload assessment, eye-tracking measures were used to characterize workload-related ocular responses and attentional allocation. The experiment adopted a within-subject block design, in which the same group of participants completed all visual flicker, auditory tone, and baseline conditions. 30 participants (19–30 years; M = 23.9; 12 female, 18 male). All participants reported good health, normal or corrected-to-normal vision, and normal hearing, and none had prior experience with similar experiments. Using the Multi-Attribute Task Battery (MATB) paradigm, we systematically examined three visual flicker frequencies (1, 3, and 5 Hz) and three auditory tone frequencies (1, 2, and 4 kHz). Thirty-six participants completed dual-task experiments, and behavioral performance, NASA-TLX workload ratings, and eye-tracking measures were integrated to evaluate frequency-specific effects. The results revealed modality-dependent effects of warning frequency.