Evolution of Cooperation

The Evolution of Cooperation (Sarah Brosnan, PI): Humans routinely confront situations that require coordination between individuals, from mundane activities such as planning where to go for dinner to incredibly complicated activities, such as international agreements or trans-national ventures, such as the International Space Station. Moreover, despite some failure, we frequently succeed in these situations. How did this ability arise, and what prevents success in those situations in which it breaks down? To understand how this capability has evolved, Dr. Brosnan’s CEBUS lab utilizes an explicitly comparative approach at both the species and individual levels.
 
At the species level, we explore how individuals in many different species make these decisions, how these decisions differ across species, and what are the underlying mechanisms that support successful cooperation. By determining how these species’ responses correlate with different aspects of each species’ socio-ecology, we can begin to make informed guesses about the function of behavior, or why it evolved. For instance, in one line of research we have discovered a correlation between species that respond negatively to inequity and the tendency to cooperate with non-kin outside of family groups. We also find that primates coordinate on economic games, but that Old World primates find better outcomes than do New World primates, indicating a split within the primate taxon.
 
At the individual level, we use a similar approach to explore how differences in decision-making outcomes within a species correlate with aspects of individual’s demographic characteristics, such as age, rank, sex, or personality, as well as social variables, such as individuals’ relationships. Very recently we have begun to explore how responses vary (or not) depending on the social environment. In particular, we are utilizing group level cooperation paradigms and, with Meg Crofoot at UC Davis, are expanding this work to the field.
 
Finally, in partnership with the GSU Center for Behavioral Neuroscience, a team of LRC scientists (including Drs. Brosnan, Hopkins & Beran) are exploring how hormones such as oxytocin affect decision-making in primates. Our recent evidence indicates that oxytocin actually decreases food sharing in capuchin monkeys, so our main interest is in understanding what effect these hormones are really having on behavior, and how this varies across species. Such studies help us to better understanding the evolution of cooperation in primates, and hence provide insight in to how cooperation works in humans.
Funding: NSF SES 1331418; The John Templeton Foundation; The National Academies Keck Futures Initiative