The (Non-)Robustness of Influential Cheap Talk Equilibria When the Sender's Preferences Are State Independent
34 Pages Posted: 18 Feb 2015
Date Written: December 17, 2014
Chakraborty and Harbaugh (2010) prove the existence of influential cheap talk equilibria in one sender one receiver games when the state is multidimensional and the preferences of the sender are state independent. We perform two robustness checks of this result. First, we show that only the babbling equilibrium survives the introduction of any small degree of Harsanyi-Uncertainty, i.e. uncertainty about the sender's preferences in the spirit of Harsanyi (1973). Second, we show that adding a small degree of state dependence in the sender's preferences removes all influential hyperplane equilibria provided the state dependence satisfies a generic property (of essentially not being of a linear or quadratic form) and removes all influential equilibria in many games. If such a game has an influential equilibrium it is likely robust to at least some kind of Harsanyi-Uncertainty.
Keywords: cheap talk, communication, information transmission, robustness
JEL Classification: C72, D82, D83
Suggested Citation: Suggested Citation