Cheap talk and spiteful preferences in ultimatum games: Experiments and evolutionary rationale

Does the possibility to talk to people we interact with change the outcomes of our interactions? Communication as a coordination device is the topic of the first part of this thesis. We study the effect of "cheap talk", where sending a particular message does not affect the material outcomes of the game per se. We consider the onset of communication in an experimental repeated game. The players share one language, and they send strategy proposals that might help them to coordinate on the efficient equilibria. We also present an evolutionary model of communication in coordination games where the meaning of the messages is not fixed exogenously. Under which conditions does communication prevail? In the second part of the thesis we study social preferences in ultimatum games. Recent theories in behavioral game theory are built on the assumption that individual's preferences in games have to be specified with respect to the material outcomes of all players, and not just the player's own material outcome like in the paradigm of modern economics. We extend the literature by an experimental study on three-person ultimatum games, going beyond the games which these theories have been based upon, and suggest an evolutionary foundation of the behavior we observe.