A CELLULAR AUTOMATON MODEL FOR THE CHANGE OF PUBLIC ATTITUDE REGARDING NUCLEAR-ENERGY

A model was constructed to investigate how the public opinion on nuclear energy varies depending upon information environment and personal communication between people. Here the nuclear risk informed of by the newsmedia and the frequency of anti-nuclear movements are treated as exogenous variables. The information environment is assumed to be represented in terms of public opinion as well as those exogenous variables, and the public are assumed to vary, randomly but homogeneously in a global sense, their attitude regarding nuclear energy in accordance with the strength of information environment. Personal communication begins round some opinion leaders who were excited by the information environment, and the attitude of the public who are affected by the opinion leaders are secondarily changed to anti-nuclear or pro-nuclear states. Moreover the public attitude is also changed naturally in an exponential way with time. Public opinion is supposed to appear as a superposed result of these three modes of attitudinal change. Such public opinion is fed back to the information environment. All the treatments are discretized and the process of personal communication is modeled by the cellular automaton method. Each cell in this approach is assumed to take one discrete state of six possible states which represent the status of public opinion. Model constants are determined by fitting calculations to the actual fraction of opinion in Japan. From simulation with this model, the following become clear: (i) The society is a highly non-linear system with a self-organizing potential: (ii) In the society composed of one type of constituent members with a homogeneous characteristic, the trend of public opinion is catastrophically turned over only when the effort for ameliorating the public acceptance extended over a long period of time, such as education, persuasion and advertisement, exceeds a certain threshold, and (iii) in the case when the amount of information on nuclear risk released from the newsmedia is reduced continuously from now on, the acceptability of nuclear energy is remarkably improved so far as the extent of the reduction exceeds a certain threshold.