We have covered enormous ground in this text because public opinion is such an interesting and complex phenomenon. This complexity makes the field of public opinion research very broad and multidisciplinary. Since there is so much varied research in the area, it is difficult to wrap things up, to come to a clean and decisive halt in our analysis of public opinion. Early on in this book, we argued that the meaning of "public opinion" is always shifting: How we think about the concept depends upon historical circumstance as well as upon our research hypotheses and the technologies we have on hand to assess public opinion. At this point in American politics, it seems as though our techniques for opinion expression and measurement are very sophisticated, but there will always be new developments because candidates for office, elected officials, interest group spokesmen, journalists, party leaders, and citizens will always have an interest in the effective evaluation of the popular mood. We must remember, too, that market researchers have contributed greatly to the development of public opinion measurement techniques and that political actors will continue to look to the commercial world for ideas about persuasion and assessment of public opinion.
From a scholarly perspective, one thing about public opinion is clear: It must be studied from an interdisciplinary viewpoint. As you saw in this book, public opinion is a psychological, sociological, and political phenomenon all at the same time. Public opinion formation takes place constantly as people react to the world around them. We are bombarded with persuasive communications daily, from the mass media, from local political leaders, from our friends and our families. This flood of incoming information—often symbolic in nature—has a tremendous effect on the way we think about particular political events, actors, and policy. We have studied the way individuals' opinions are shaped, but we have also looked at those who do the shaping, the mass media in particular. And we have spent some time on the relationship between public opinion and the nature of American government and social policy. All of these linkages—between people