Supplementary Appendix to Coevolution of Deception and Preferences: Darwin and Nash Meet Machiavelli

Abstract

Abstract In Heller and Mohlin (2017) we develop a framework in which individuals' preferences coevolve with their abilities to deceive others about their preferences and intentions. Specifically, individuals are characterised by (i) a level of cognitive sophistication and (ii) a subjective utility function. Increased cognition is costly, but higher-level individuals have the advantage of being able to deceive lower-level opponents about their preferences and intentions in some of the matches. In the remaining matches, the individuals perfectly observe each other's preferences. Our main result shows that, essentially, only efficient outcomes can be stable. Moreover, under additional mild assumptions, we show that an efficient outcome is stable if and only if the gain from unilateral deviation is smaller than the effective cost of deception in the environment. In this supplementary analysis we relax the assumption of perfect observability in matches without deception, and study the robustness of our main results to the introduction of partial observability.