Personal Influence

Conceptualized by Elihu Katz and directed by mentor Paul F. Lazarsfeld at Columbia University, the 1955 book Personal Influence revolutionized understandings of how people interact with media institutions by reviewing and critiquing the substantial media theories that primarily dominated social thought at the time. Highlighting their principal argument, the duo subtitled the volume The Part People Play in the Flow of Mass Communication, thus demonstrating their key implication: mass media influence is not always one that is direct but is instead frequently mediated interpersonally through key figures who position social issues they have extricated from mass media sources.

Prior to the book's publication, social scientists studying mass communication largely believed that people assigned weight and relevance to information learned through media sources by their own means and of their own accord. That is, media theorists largely believed that the connection between mass media messages and the public was a direct one. Katz and Lazarsfeld challenge this notion in Part One of the volume by exploring how select groups of people are key to the circulation of messages within social groups, particularly messages they have extracted from mass media sources. Their theory argues, then, that instead of the largely held “one-step” system of influence that positions people as direct receivers of media messages, a “two-step” system of message dissemination is instead in play, through which key public figures identify media concepts, introduce them to people in their social networks, and explain how they are relevant to their social community. To support their assertions, the authors employ the rest of the volume exploring Katz's groundbreaking Decatur, Illinois, study examining mass communication's impact on social interaction. Not only does this study offer remarkable empirical evidence for the authors' theories, it also expands upon the assertions presented in Part One of the text—including data that suggest the media issues circulated through social systems in everyday talk were not limited to politics and public affairs, but also included recreation, fashion, discussion of popular culture, and consumer action.

The book is still frequently cited as one of the leading influences toward bringing mass communication into the exploration of how information flows interpersonally through the public sphere. After being out of print for a short period, the text was reissued in honor of its 50th anniversary in 2005 with a new essay from Katz, who revisits the research design and methodology of the Decatur study; examines the influence the study had on his career; and offers an overview of related work completed by mentor and coauthor [Page 546]Lazarsfeld, who passed away in 1976. Also included is an introduction from the late Elmo Roper, who founded the Roper Center for Public Opinion Research.