2023 年 25 巻 2 号 p. 65-82
In this basic study related to the use of fragrances in offices and car cabins, the physiological effects of fragrances (odors) on cognitive performance were analyzed in association with their psychological effects. A visual search task simulating the acquisition of visual information while driving was used, and behavioral, physiological, and subjectively reported indices were analyzed to estimate the effects of odors while performing the task. To analyze physiological effects, an electrocardiogram (ECG) and an electroencephalogram (EEG) were recorded, and heart rate variability and EEG power (theta, alpha, beta) at Fpz were calculated. Analysis of covariance using the data before odor delivery as covariates was used to compare the changes in each index across the odor conditions. Linear mixed-effects models were used to analyze the relationships between the behavioral and physiological indices in association with the results of the subjective reports. The mental strain induced by the task appeared to be attenuated by the effect of odors modulating the autonomic nervous system, and prefrontal cortical activation and mental relaxation were achieved without a deterioration in performance. The results further indicated that the physiological effects of odors might be associated with psychological effects such as improving motivation and increasing general activation. In the context of cognitive task performance, the odor effects were not always sedative; rather, they modulated activity to a level appropriate to perform the task.
