A Psychologically-Inspired Agent for Iterative Prisoner's Dilemma

In this paper, a psychologically-inspired model for an Iterative Prisoner’s dilemma (IPD) agent is proposed. This model is inspired by the “psychic apparatus” theory that was developed by Sigmund Freud in 1940. The model captures an agent with a true “character” by concurrently supporting the three constructs of personality: the Super-Ego, which represents the ideal part of the agent that always tries to elicit cooperation from opponents, the Id, which is characterized by its willingness to defect all the time to achieve instant gratification, and the Ego, which is the intelligent, realistic, part of the agent that relies on opponent-modeling techniques to decide on the best next move. These three constructs compete against each other in order to take control of the agent. This model was successfully prototyped and participated in a simulated IPD tournament along with other benchmark strategies. “FREUD”, as the agent is called, achieved outstanding results in this mini-tournament by winning with a good margin. Our model represents a novel abstraction for IPD agent architecture that is potentially applicable to any decision-making task that requires evaluating the benefit of competitive vs. cooperative behavior.