An international research team led by Researcher Yosuke Murase from RIKEN has introduced a new theory on “indirect reciprocity,” a mechanism that underpins cooperation in society. This study highlights the critical role of opinion synchronization in maintaining cooperative behavior, offering insights for evolutionary biology and social design applications.
Opinion Synchronization as the Basis of Cooperation
Cooperative behavior, a hallmark of human societies, extends even to non-relatives. Indirect reciprocity, which maintains cooperation through reputation, has been a focal point of research. However, previous studies varied significantly in approach and lacked a unified framework.
This new study presents an integrative model centered on the concept of “opinion synchronization.” In societies where opinions align, reputations are consistently shared, fostering stable cooperation. Conversely, in societies with divergent opinions, cooperation becomes evolutionarily unstable, as demonstrated through mathematical analysis.
The research also reconciles disparate theoretical models. For instance, public assessment models assume universal agreement on reputations, facilitating stable cooperation. In contrast, private assessment models allow for differing opinions, altering the conditions under which cooperation persists. The newly proposed framework elucidates these differences through the lens of “opinion correlation.”
This groundbreaking work not only advances understanding of the evolutionary foundations of cooperation but also provides valuable insights for designing social norms and policies.