In this paper we study the eﬀects of adding unmediated communication to static, ﬁnite games of complete and incomplete information. We characterize S U ( G ), the set of outcomes of a game G , that are induced by sequential equilibria of cheap talk extensions. A cheap talk extension of G is an extensive-form game in which players communicate before playing G . A reliable mediator is not available and players exchange private or public messages that do not aﬀect directly their payoﬀs. We ﬁrst show that if G is a game of complete information with ﬁve or more players and rational parameters, then S U ( G ) coincides with the set of correlated equilibria of G . Next, we demonstrate that if G is a game of incomplete information with at least ﬁve players, rational parameters and full support (i.e. all proﬁles of types have positive probability), then S U ( G ) is equal to the set of communication equilibria of G .
Gerardi, Dino, "Unmediated Communication in Games with Complete and Incomplete Information" (2002). Cowles Foundation Discussion Papers. 1635.