Study of olfactory effect on individual driver under driving

Long term monotonous driving has been often found to decrease the driver´s arousal level and effect his/hers property of perception, cognition and judgment. It is preferable to apply arousal assist for the driver instead of huge stimulus such as warning sound and vibration to the driver while driving. On the other hand, the effect of the scent is also reported as an environmental stimulus for driver. In this study, the seven kinds of scent were used as olfactory stimulation and the influence of scent on the driver´s psychosomatic state was examined using a fixed-based driving simulator by measuring biological measurements including electrocardiogram and finger plethysmograph. As for brain activity of olfactory cortex, the multi-channel near-infrared spectroscopy (MNIRS) has been shown to enable the evaluation of changes in hemodynamic. The MNIRS was also used to monitor the activity of the frontal cortex as mirrored by hemodynamic responses subjected to olfactory stimulation. As a result, it is verified that not only characteristics of the scent but also the driver´s preference and subjective judgment of scent changes affect on the each driving performance. The brain change by olfactory stimulation and the brain change by other stimulation were also investigated. The effects of the functional brain imaging of olfactory activity were measured and the comfortable scent was effective for maintaining the arousal level.