Abstract
We proposed a methodology for estimating the psychosomatic state transition of a human. We named it “The changing four term state hypothesis”. This changing state hypothesis consists of two orthogonal axes. The vertical axis of the changing state hypothesis can be quantified based on the activity level of the autonomic nerve system. The horizontal axis of the changing state hypothesis can be quantified based on the activity level of the homeostatic function. From these two axes, the psychosomatic state is classified into four states. This state of human body is always going back and forth among these four states. This psychosomatic state will be various based on the individual characteristics such as the preference of each operator. For example, while an operator uses a support system, the activation level of sympathetic nerve becomes predominant. Therefore, it is important to estimate the psychosomatic state in consideration of individual characteristics because each operator has own state transition of “the changing four team state hypothesis”. On the other hands, the psychosomatic state changes under the external stimuli like olfactory stimulus or acoustic stimulus. These external stimuli can be utilized for the human machine interface of support system. For example, it was reported that the sonic system mounted on a car or a train enables to minimize the drowsiness of operator and the super-sonic system can minimize the mental stress. We think that if it becomes possible to estimate the psychosomatic state of human, we can provide the suitable human support system that corresponds to the change of psychosomatic state. In this research, we investigated the transition of psychosomatic state under presenting olfactory stimulus, auditory stimulus and mental workload. Finally, we analyzed the relation between the psychosomatic state transition and individual characteristics.
