Despite much research regarding how animals and humans solve social problems, few studies have utilized comparable procedures, outcomes, or measures, thus little is known about the evolution of decision-making behavior. In this project, the Principal Investigators will investigate how primates, including humans, deal with problems that arise in interactions with other group members. Understanding what outcomes are achieved, and how they vary across species, has implications for theories of the evolution of sociality and our understanding of social decision-making. The research will examine strategic decisions involving costly conflict and trust, varying the cooperativeness or competitiveness of the frame. The results will provide shed light on the evolution of human decision-making behavior.

This research will help to clarify the similarities and differences between nonhuman primates and humans with respect to social decision-making and will more properly place nonhuman behavior in context with human behavior and to understand the roots from which human economic decision making emerged. In addition to the theoretical merits, this interdisciplinary research will be integrated into summer workshops for graduate, undergraduate, and high school students at the Economic Science Institute at Chapman University and disseminated to the general public through partnerships with schools and Zoo Atlanta. It will also provide training for multiple postdoctoral fellows, graduate and undergraduate students.

Project Report

Every day, people must decide whether, and how, to interact with others. If people cooperate, the gains can be substantial, but on the flip side, there are enormous costs to both individuals and to society for failures to cooperate or for cheating. How do people decide when and with whom to cooperate, and how do people respond to others who do not cooperate? Our research program investigates a series of decision-making situations called social dilemmas. Specifically, we focus on social dilemmas that are set up such that pairs of individuals each decide between two response options and the subsequent payoffs to each individual depend upon both their own choice and the choice made by their partner. We are particularly interested in how people coordinate their responses in order to achieve the best outcomes for everyone involved. In some situations, this may be straightforward, as the incentives to coordinate are the same for both partners, but in others, the incentives may differ such that one or both individuals might be motivated to cheat. This cheating may lead to temporarily higher payoffs for the cheater, but it harms the partner, and if the cooperative relationship breaks down, may ultimately result in far lower payoffs for both individuals. This type of outcome is beneficial for neither the individual nor for society. While many factors influence such decision-making, it is important to understand how humans’ responses in these social dilemmas compare to those of other primates. This is important for two reasons. First, such explorations represent a model system in which we can methodically vary features in order to test possible strategies for increasing coordinated outcomes among humans. Second, in order to better understand how humans make these decisions, we need to identify 1) the features of such comparisons that have been selected for across species and 2) those features which are due to humans’ unique selective environment. For instance, while many primate species are able to find the coordinated (cooperative) outcome on social dilemmas (even when they are set up in such a way that there is incentive to cheat), in some situations, humans seem to find the coordinated outcome using different cognitive mechanisms than the other primates. Understanding which mechanisms are unique to humans and how they allow humans to make better decisions that more often reach the cooperative outcome, will provide an understanding of how decisions to cooperate (or not) are made. These findings can then be used to address a variety of societal issues related to the breakdown of cooperation at many levels of human societies.

National Science Foundation (NSF)
Division of Social and Economic Sciences (SES)
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Donald Hantula
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University of Texas, M.D. Anderson Cancer Center
United States
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