VERBAL INTERACTION PROMOTES COOPERATION IN AN ITERATED PRISONER’S DILEMMA GAME: A MULTIPLE BASELINE METACONTINGENCY EXPERIMENT

Abstract

Some metacontingency experiments were based on cooperation procedures such as the iterated prisoner’s dilemma game (IPDG), but dismissed earlier results on cooperation as pertaining only to operant (not cultural) selection and did not control verbal interactions among participants. The present study evaluated the effects of verbal interactions on participants’ choices in an IPDG. Three sets of four university students played in four networked computers (screened by panels) and were exposed to conditions with or without permission to use a virtual chat room in a multiple baseline design. Without verbal interaction, choices varied, but tended to be all-defect. Once verbal interaction was allowed, choices quickly shifted and stabilized in all-cooperate on almost all trials. An IPDG can be interpreted as programming a metacontingency in which the higher payoff for the group (a cultural consequence) selects participants’ choices of the cooperative alternative (a culturant). As the cooperation literature had similarly found, verbal interactions among participants even through virtual chat room promotes the selection by the higher payoff. Metacontingency and cooperation procedures such as the IPDG are indistinguishable and their results must be evaluated together.