Cooperation,Conflict and the Evolution of Communication

Abstract

This paper presents a general model that covers signaling with and without conflicts of interest between signalers and receivers. Krebs and Dawkins (1984) argued that a conflict of interests will lead to an evolutionary arms race between manipulative signalers and sceptical receivers, resulting in ever more costly signals; whereas common interests will lead to cheap signals or "conspiratorial whispers." Previous simulation models of the evolution of communication have usually assumed either cooperative or competitive contexts. Simple game-theoretic and evolutionary simulation models are presented; they suggest that signaling will evolve only if it is in the interests of both parties. In a model where signalers may inform receivers as to the value of a binary random vari able, if signaling is favored at all, then signalers will always use the cheapest and the second cheap est signal available. Costly signaling arms races do not get started. A more complex evolutionary simulation is described, featuring continuously variable signal strengths and reception thresholds. As the congruence of interests between the parties becomes more clear-cut, successively cheaper signals are observed. The findings support a modified version of Krebs and Dawkins's argument. Several variations on the continuous-signaling model are explored.