Abstract
We previously showed that urban environmental sounds lacked for inaudible high-frequency component (HFC) and could result in various modern diseases through decrease in the deep brain activity. These findings suggest a strategy to improve the urban information environment by complementing urban environmental sounds with HFC and the deep brain activity. We examined the physiological and psychological effects of the complement of the urban environmental sound with HFC originated from natural environmental sounds of tropical rain forests. We found positive physiological effects including enhancement of the power of the alpha frequency range of the electroencephalogram, which serves as the index of stress-free status and highly correlates with DBA, and increase of the activities of NK cell and immunoglobulin as well as decrease of adrenaline. In addition, we found a psychological effect that the amenity of the environment improved.
