Gurus, Opinion Polls and Social Learning

Abstract

This paper analyzes cheap talk in an investment model with information externalities. In contrast to Gossner and Melissas (2006), I allow for (i) competition effects, (ii) positive network externalities and (iii) more than one interviewed player. In the presence of competition effects, a player will never truthfully reveal her information about the realized state of the world. In the presence of positive network externalities, however, there exists a parameter range where, under mild additional conditions, the unique equilibrium is the separating one. Finally, using numerical computations, I show that for a sufficiently large number of interviewed players there exists a separating equilibrium in my entire parameter range.Cheap Talk,Information Externality, Social Learning, Herd Behaviour