This interdisciplinary research project will examine how large-scale cooperation is maintained de-spite the negative impacts that inequitable outcomes have on cooperation. This project will bring together researchers with experience in behavioral and experimental economics and psychology, biological anthropology, collective animal behavior, and evolutionary biology and ecology to enhance understanding of the interplay between inequity and cooperation in large-scale cooperation in human and closely related societies. The project will bridge the traditional boundaries of these disciplines by bringing a stronger focus on behavioral mechanisms to questions traditionally asked by biological anthropologists and by calling the attention of behavioral economists to the importance of ecological and evolutionary context in studies of decision making. The project will provide an exciting education and training opportunity for a post-doctoral researcher and for a number of undergraduate students. The investigators also will work with Untamed Science, a scientist-run company that makes online media content for teachers and students, to develop materials that can share information about the project with a broad range of K-12 students.
Humans routinely participate in interactions in which one individual receives more than another, such as when one individual is paid more than another for completing the same job. People tend to react negatively in such situations, with detrimental consequences for their relationship with their partner. How are high levels of cooperation maintained in human societies, given that our aversion to "unfair" outcomes can impede joint action? On the one hand, responding negatively to inequity likely provides an individual advantage. Over the long term, people who respond to such disparities by finding new cooperation partners do relatively better than those that do not. But being too sensitive to such disparities may impede large-scale cooperation at the group level. Given the foundational role of cooperation in human society, understanding how responses to inequity shape decision-making in the context of cooperation is particularly important. Prior research on this topic usually has focused on the interactions between two individuals divorced from their larger social context, so it has not been possible to investigate how these pair-wise interactions shape patterns of group-level behavior. Ethical considerations, privacy concerns, and logistical limitations also have made it difficult to envision conducting the necessary experiments in human social groups. To overcome these obstacles, this project will consist of experiments that study capuchin monkeys (Cebus paella) as a model system for investigating how social context shapes the expression of inequity aversion and the achievement of collective goals in both captive and naturally occurring social groups. Capuchin monkeys provide valuable and appropriate insights because they have extraordinarily large brain-to-body and neocortex-to-body ratios, they are highly cooperative in a variety of different contexts, and they share humans' aversion to inequitable outcomes. The experiments conducted as part of this project investigate how social context shapes the expression of inequity aversion in both socially and ecologically relevant contexts, and they will test how a predisposition to respond negatively to "unfair" outcomes impacts collective behavior. The experiments will employ novel experimental feeders that remove any influence from human experimenters in order to study individual and group behavior in the complex environment of intact social groups. This project is supported through the NSF Interdisciplinary Behavioral and Social Sciences Research (IBSS) competition.
