Public Interest Immersed in the Field of Information Environment: How has Japanese Interest in Energy and Environmental Problems Varied?

We studied the relevance of the secular variation of Japanese interest in energy and environmental problems to the information primarily released by the news media. From the investigation of the extent of public interest in three matters, the global warming, the energy saving and nature, all indicated by opinion surveys, the number of newspaper articles and the frequency of Internet retrieval search, we proposed a model such that the public interest along with the acquired public knowledge were given as a function of public memory of the information primarily provided by the news media. The society was assumed here to be immersed in a virtual field of information environment, which induced the collective interest of the public and was proportional in strength to the extent of the public memory with oblivion. Introducing two types of oblivion function, we found the model to well reproduce the real time-variation of the Japanese interest, except for the case of nature, almost irrespective to the form of the function. Some comments were made on the attenuation of the public interest that occurred when the field became weakened.