The Prisoner's Dilemma Game and Cooperation in the Rat

Cooperation in pairs of rats playing the prisoner's dilemma game was investigated. Six pairs of animals were taught to make either cooperative or uncooperative responses by running to one or the other end of a T-maze. Two T-mazes were joined together such that animals could respond simultaneously. Animals were run under conditions in which visual communication was present and absent. Mutually uncooperative responses were the most common and mutually cooperative behaviors the least preferred. Introduction of a barrier between the mazes, which removed visual communication between pairs, sharply accentuated uncooperative behavior. Similarities of the present findings to results with human subjects and the implications of using game theory for studying cooperative behavior in animals are discussed.