Generosity without Reciprocity: Computation Models of Risk-Pooling & Sharing Norms in Human Societies

Thur Feb 23

Human Evolution and Social Change
College of LIberal Arts and Sciences
CASI
ISTB-1 Room 401
Campus: Tempe
Cost: Free

As part of its Challenges of Complexity speaker series, ASU's Complex Adaptive Systems Initiative (CASI) presents Athena Aktipis at 3:30 p.m., February 23, 2012.

Human societies face uncertainty and ecological volatility due to drought, disease, theft and other unavoidable risks. The management of these risks poses a central problem, and one that may be mitigated though cultural norms and social networks that effectively pool risk. The osotua sharing system used by the Maasai appears to be such a system. In collaboration with Lee Cronk, Aktipis modeled the basic characteristics of Maasai ecology and the osotua sharing system. Their first model showed that the osotua system promotes herd survival through a limited pooling of risk. In a related model, they found that more connected and heterogeneous social networks lead to greater herd viability.They are now comparing the performance of risk-pooling (osotua) rules to reciprocity rules in ecologically realistic conditions. Results suggest that reciprocity does not fare as well as risk-pooling under a variety of parameters. They have also developed a novel economic game to study the effects of cultural framing on risk-pooling. One of their preliminary findings is that players who read about the osotua sharing norms engaged in more risk-pooling behaviors and fewer behaviors characteristic of tit-for-tat reciprocity than players who did not read about such norms. Their review of the ethnographic literature also suggests that humans commonly use risk-pooling to manage the risks associated with living in variable or marginal environments. That risk-pooling appears wide-spread and to be so easily triggered suggests it may be a basic part of the human behavioral repertoire.

Aktipis is the director of Human and Social Evolution at the Center for Evolution and Cancer at UCSF and a research professor in the Department of Psychology at Arizona State University. She applies cooperation theory and evolutionary modeling to diverse phenomena, from human altruism to the behavior of cancer cells. She also works in several applied domains, including resource management institutional design, medical decision making and cancer biology.