① The concept of "spiral of silence" was first seen in a paper published in the Journal of Communication by Neumann 1974. This hypothesis consists of three propositions: A The expression of personal opinions is a social and psychological process. The expression of views and the spread of "silence" are a spiral social communication process. That is to say. The silence of one side leads to the increase of the other side's opinions, which makes the dominant opinion stronger, and then forces more dissidents to turn to silence. Mass communication influences and restricts public opinion by creating a "public opinion environment". (2) Theoretical Viewpoint A The formation of public opinion is the result of the interaction of mass communication, interpersonal communication and people's cognitive psychology of "public opinion environment". B The opinions emphasized by mass media are easily identified as "majority" or "dominant" opinions because of their openness and wide dissemination. C the pressure or sense of security brought by this environmental awareness will lead to the spiral expansion process of "silence of inferior opinions" and "loud voice of superior opinions" in interpersonal communication, and lead to the birth of overwhelming "majority opinions"-public opinion. (3) Explain the understanding of it according to the actual situation.