課題難易度が瞳孔径変動に及ぼす影響について [in Japanese] Effects of the Task Workload on Pupil Diameter Variability [in Japanese]
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We carried out experiments to measure the effect of the task workload on pupil diameter variability and psychological state using two kinds of task. One was time-based task in Experimentl, and the other was cognitive-based task in Experiment2. Pupil diameter (PD) was monitored and recorded by means of infrared video camera, while observers performed time-based task using auditory stimuli which was presented at different time intervals and cognitive-based task using auditory stimuli which was presented at different levels of the cognitive difficulties. After each trial, observers responded their subjective psychological state during the trial. In both experiments, the results showed that subjective responses of "activity", "time pressure" and "anxiety" increased according to increasing the level of the task workload. Moreover, using the same frequency band as that of heart rate variability (LF/HF), in both experiments, significant correlations were observed between the ratio of lower frequency components to higher components (LF/HF) of PD fluctuations and the subjective psychological state. These results indicate that LF/HF of PD fluctuations will be effective evaluation indices for mental stress, and the optimum bands for LF/HF of PD fluctuations change by the kind of task and the bands for cognitive-based task will shift to higher frequency than that for time-based task.
- IEICE technical report
IEICE technical report 108(27), 125-130, 2008-05-12
The Institute of Electronics, Information and Communication Engineers