Cooperation versus social welfare

Understanding and promoting cooperative behaviour among self-interested individuals is a critical concern in physical, biological, and social sciences. Numerous foundational mechanisms for the evolution of cooperation have been identified, and these mechanisms have served as the basis for developing tools and interventions designed to sustain and enhance cooperative behaviour. However, since both foundational mechanisms and the derived tools and interventions often involve costs affecting individuals or institutions, striving for maximum cooperation can sometimes harm social welfare, defined as the total population payoff. Herein, we review existing evolutionary mechanisms for the evolution of cooperation as well as tools and interventions based on these mechanisms, emphasising the often-overlooked hidden costs that may lead to a misalignment between cooperation and social welfare. By explicitly incorporating these hidden factors into the models, we analyse the conditions under which they reduce social welfare, across a broad range of social dilemma games and evolutionary forces. Additionally, we review experimental studies that support and inform mathematical models and agent-based simulations. We highlight when considering social welfare is crucial, as misalignment is most likely to occur. Ultimately, we argue that social welfare, not just cooperation, should be the primary optimisation objective when designing interventions for social good. We also suggest several key directions to further explore this often-overlooked issue in the literature. Overall, we reveal that hidden costs often influence the alignment between cooperation and social welfare, challenging the common prioritisation of cooperation alone.