Self-deception as a mediator of cooperation and defection in varying social contexts described in the iterated prisoner's dilemma

Deception and self-deception may be two related psychological capacities serving to enhance an individual's inclusive fitness. Self-deception has been defined as any psychological act in which one thought or belief is held at the expense of another. This study was designed to test the notion that we may deceive ourselves about our own intentions or the intentions of others in order to facilitate cooperation, if the cooperative behavior has the potential to improve fitness. We may also deceive ourselves in situations where we may need to compete with others, if not competing might represent a loss of fitness. The Self-Deceptio Questionnaire was administered to 80 women and 70 men to determine their levels of self-deception. A series of vignettes, conforming to the Prisoner's Dilemma game format, were administered in questionnaire material to measure participant's predispositions to cooperate or defect in three different contexts (family, mating, and neutral). Men predicted they would be less cooperative than women over all conditions, and participants anticipated cooperating more with kin than with non-kin. Moreover, participants who were high self-deceivers chose more cooperative responses in both family and mating contexts than those with low self-deception scores. Finally, the three-way interaction among sex, context, and level of self-deception suggested that the role of selfdeception in cooperation may vary according to the sex of the individual and the context.