Examining Spillovers between Long and Short Repeated Prisoner's Dilemma Games Played in the Laboratory

We have participants play two sets of repeated Prisoner's Dilemma (RPD) games, one with a large continuation probability and the other with a small continuation probability (stage game payoffs and continuation probabilities are common knowledge). We find that, regardless of which is played first, participants typically cooperate when the continuation probability is large and defect when the continuation probability is small. However, there is an asymmetry in behavior when transitioning from one continuation probability to the other. When switching from large to small, transient higher levels of cooperation are observed in the early games of the small continuation set. Conversely, when switching from small to large, cooperation is immediately high in the first game of the large continuation set. This asymmetry suggests a bias in favor of cooperation. We also examine the link between altruism and RPD play. We find that small continuation probability RPD play is correlated with giving in Dictator Games (DGs) played before and after the RPDs, whereas high continuation probability RPD play is not. Finally, we find less giving in the post-RPD DG than the pre-RPD DG, regardless of continuation probability order