Do bonobos and chimpanzees experience “unfairness”? A replication of two cornerstone studies.

This award notice, issued by the Regieorgaan Open Science under the Nederlandse Organisatie voor Wetenschappelijk Onderzoek, concerns a research project titled Do bonobos and chimpanzees experience unfairness? A replication of two cornerstone studies. The project focuses on inequity aversion in non-human primates to better understand the evolutionary origins of fairness and cooperation. By examining the behaviors of capuchins, chimpanzees, and bonobos, the study aims to resolve conflicting findings regarding whether these species reject unfair rewards or act to prevent inequity. The research emphasizes the need for larger sample sizes and more controlled conditions to eliminate alternative explanations, such as food expectation, which have complicated previous results. Through the replication of foundational studies, the project seeks to clarify the role of inequity aversion in primate sociality and its connection to human social cooperation. The notice was posted on September 1, 2026, under solicitation number 080.25071.