1. University of Wisconsin
2. This paper is based on part of Dr. Greenberg's Ph.D. dissertation and on research conducted as a project of the Mass Communications Research Center at the University of Wisconsin, where Dr. Tannenbaum is the director. The research was supported in part by the Research Committee of the Graduate School from funds supplied by the Wisconsin Alumni Research Foundation. Dr. Greenberg is currently a research associate, Institute for Communication Research, Stanford University.