The Evolution of Agenda-Setting Research: Twenty-Five Years in the Marketplace of Ideas

Communication scholars frequently invoke the concept of a marketplace of ideas during discussions about speechmaking, the diversity of media content and voices, and related First Amendment issues. They invoke it less often during intramural discussions of how specific concepts and perspectives, or our research agendas as a whole, have evolved over the years. Yet communication research does operate in a marketplace of ideas that is the quintessential laissez-faire market. The role of our journals is to create a market for the ideas advanced by members of the field. Individual scholars pick and choose topics at will-idiosyncratically and whimsically, some critics say-and publish at irregular intervals. Research teams, to the extent that they exist in communication research, usually arise spontaneously and have short life spans. Institutionalized focused research programs are rare. The communication research marketplace is a volatile arena, a situation fostered by the rapidly changing nature of communication itself during the past 50 years. Under these circumstances the continuing and growing vitality of agenda-setting research is remarkable. As a theoretical perspective, it has had a rich 25-year history since McCombs and Shaw’s (1972) opening gambit during the 1968 presidential elect ion. Philosopher of science James Conant (1951) noted that the hallmark o f a successful theory is its fruitfulness in continually generating new questions and identifying new avenues of scholarly inquiry. The fruitfulness of the agenda-setting metaphor is documented by three features: (a) the steady historical growth of its literature, (b> its ability to integrate a number of communication research subfields under a single theoretical um-