Voluntary participation with outside individual options facilitates group collaboration via improved optimism

Abstract Whether in business ventures or research projects, voluntary participation is at the heart of collaboration. Previous studies concerning collaboration have primarily focused on the free-riding problem, largely overlooking this mundane but critical aspect. We address this gap by modeling collaborative situations as people’s voluntary choices between joining an uncertain public goods provisioning in groups and pursuing a certain but less profitable individual option. Theoretically and experimentally, we show that this voluntariness increases the likelihood of group success by filtering out otherwise pessimistic defectors or encouraging them toward cooperation. We further discuss how our findings can be synthesized with the larger body of literature about collective versus individual options: We show that whether individual options aid or hinder collaboration hinges on the degree of the “externality” of loners (who pursue the individual option) to the group. As long as the externality is small, the existence of individual options robustly aids collaborative success by fostering cooperation through improved optimism within groups.