In the Blink of an I: On Delayed but Identical Subjective Reactions and Their Effect on Self-Interested Behavior

People believe that they have shared an identical subjective experience--that they have I-shared--when they react identically and simultaneously to the same stimulus. Despite growing evidence for I-sharing, researchers have yet to ask whether simultaneity really makes a difference. We test the importance of simultaneity for I-sharing effects. Participants played prisoner's dilemma with someone who shared their subjective self, their objective self, or neither. Some participants learned this information immediately; others, after a short delay. Time delay decreased cooperation in the subjective similarity condition, but not in the objective similarity or neither conditions. These findings underscore the importance of simultaneity for I-sharing effects and highlight the implications of I-sharing for cooperation and self-interested behavior.