Conditional Cooperation: Disentangling Strategic from Non-Strategic Motivations

We use a novel experimental design to distinguish strategic from non-strategic motives for cooperation in social dilemmas. By using the strategy method in a repeated sequential prisoners' dilemma with a known probabilistic end, we can differentiate between end-game and non-end-game behavior. Individuals that cooperate non-strategically do not change their behavior depending on whether the game continues or not. In contrast, strategically-motivated individuals cooperate only if the game continues and otherwise defect. Our design allows us to control for learning effects and beliefs concerning the cooperativeness of others. Results with two different subject pools indicate that the most common motive for cooperation is indeed strategic. Moreover, strategic motivations also explain most of the commonly-observed pattern of conditional cooperation.