Payoff Control in the Iterated Prisoner's Dilemma

TL;DR

This paper introduces a new framework for controlling payoff regions in the iterated prisoner's dilemma, enabling a player to unilaterally influence outcomes and categorize strategies, with promising results against various opponents.

Contribution

It develops a general framework for payoff control in the iterated prisoner's dilemma, allowing unilateral confinement of payoff pairs and categorization of strategies.

Findings

Control strategies effectively confine payoff pairs within desired regions.

Many existing strategies are categorizable within the new framework.

Control strategies perform well in tournaments and against human-like opponents.

Abstract

Repeated game has long been the touchstone model for agents' long-run relationships. Previous results suggest that it is particularly difficult for a repeated game player to exert an autocratic control on the payoffs since they are jointly determined by all participants. This work discovers that the scale of a player's capability to unilaterally influence the payoffs may have been much underestimated. Under the conventional iterated prisoner's dilemma, we develop a general framework for controlling the feasible region where the players' payoff pairs lie. A control strategy player is able to confine the payoff pairs in her objective region, as long as this region has feasible linear boundaries. With this framework, many well-known existing strategies can be categorized and various new strategies with nice properties can be further identified. We show that the control strategies perform well either in a tournament or against a human-like opponent.