Cooperation, conflict and the evolution of communication

This paper presents a general model that covers signaling with and without conflicts of interest between signalers and receivers. Krebs and Dawkins (1 984) argued that a conflict of interests will lead to an evolutionary arms race between manipulative signalers and sceptical receivers, resulting in e ver more costly signals; whereas common interests will lead to cheap signal s or "conspiratorial whispers." Previous simulation models of the evolution of communication have usually assumed either cooperative or competitive co ntexts. Simple game-theoretic and evolutionary simulation models are presen ted; 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 ro the value of a binary random variable, if signaling is favored at all, then si gnalers will always use the cheapest and the second cheapest signal availab le. Costly signaling arms races do not get started. A more complex evolutio nary simulation is described, featuring continuously variable signal streng ths and reception thresholds. As the congruence of interests between the pa rties becomes more clear-cut, successively cheaper signals are observed. Th e findings support a modified version of Krebs and Dawkins's argument. Seve ral variations on the continuous-signaling model are explored.