Investigation of temporal change in heartbeat in transition of sound and music stimuli

Abstract

Music is widely believed as one of the most effective media forms that effect on human psycho-physiologically. Many people expect the effects of music and uses music pieces in various situations. For example, relaxation effect of music is used in change in personal mind in daily life, creation of sedative atmosphere in a home, and therapeutic purposes. Oppositely, parts of music pieces excite people in disco and party. These various effects of music have been investigated in many previous studies. Especially, relaxation effects of music were investigated from various view points with psycho-physiological experiments. Although many previous studies investigated the effects, the effects have not been clarified at all. One of the reasons of that is existence of many music factors; melody, tempo, harmony, rhythm, etc. Anyway, investigations of music and its effects will contribute to theoretical use of music for therapy and so on. This chapter aims to investigate the temporal change in heartbeat intervals in a transition between different sound stimuli. Heartbeat is one of the most important physiological indices and is often used as physiological index to investigate the effect of music and sound stimuli, because the heartbeat reflects autonomic nervous activity [Pappano, 2008] of a listener and is easy to measure. Furthermore, a device measuring electrocardiogram is generally cheaper than devices measuring other physiological indices such as electroencephalogram. Although many previous studies have investigated the effect of music and sound with heartbeat interval as physiological index, very few previous studies have investigated the change in heartbeat in the transition of different stimulus; most of the previous studies have observed average of heartbeat intervals a certain range in preand post-listening sound stimulus. Observing temporal change in heartbeat is important and contributes to improvement of exposure method of music and sound to the listeners. For example, time intervals eliciting effect of music and sound and decreasing the effect are important information to determine the time length to exposure them to the listeners. The experimental method in the present study is set by referring to our previous study [Fukumoto et al., 2009]. As further investigations, we newly add No-sound stimulus to relaxation music piece (Air by Bach), white noise, which are music and sound stimuli employed as sound stimuli in the previous study. In the listening experiment of our previous study, two min relaxing music piece and white noise were employed as the different sound stimuli, and these sound stimuli were played twice alternately after five min rest. The alternate exposure of different sound stimuli is also employed in the present study.