Evolution of cooperation Gilberto Câmara, Earth System Science Center, INPE Licence: Creative Commons ̶̶̶̶ By Attribution ̶̶̶̶ Non Commercial ̶̶̶̶ Share Alike http://creativecommons.org/licenses/by-nc-sa/2.5/
Acknowledgments for using previous material Martin Nowak (Harvard University, USA) Francisco C. Santos (Université Libre de Bruxelles, Belgium) Craig Callender (Philosophy, Univ California San Diego, USA) Ana Aguiar (INPE, Brazil) Tiago Carneiro (Federal University of Ouro Preto, Brazil) Guy Brasseur (NCAR, USA)
What cooperation can achieve... Those were the days… http://www.youtube.com/watch?v=0HrjevD2vhk&feature=related
Collective spatial action: volunteered GI Are Brazilians less cooperative? Less tech-savvy? Does google solve their problems? Are they happy with their public data?
Collective spatial action: pedestrian modelling Notting Hill Carnival (London) Batty, “Agent-Based Pedestrian Modelling”, in: Advanced Spatial Analysis, ESRI Press, 2003.
Collective spatial action: deforestation
Collective spatial action: global change Fossil fuel Land use change 10 8 6 4 2 1960 2010 1970 1990 2000 1980 CO2 emissions (PgC y-1) 8.7 1.2 9.9 PgC 12% of total Le Quéré et al. 2009, Nature-geoscience, 2009
An explicit spatial problem in global change: land change “Land-change science has emerged as a foundational element of global environment change and sustainability science” (Rindfuss et al, “Developing a science of land change”, PNAS, 2004).
source: Global Land Project Science Plan (IGBP)
Impacts of global land change More vulnerable communities are those most at risk
Nature: Physical equations Society: Decisions on how to We need spatially explicit models to understand human-environment interactions Nature: Physical equations Describe processes Society: Decisions on how to Use Earth´s resources
Modelling collective spatial actions: the complex systems approach photo: Chico Albuquerque Situated individuals (persons, groups, agents) Interaction rules - communication Decision rules - actions Properties of space
Our spatially explicit models need good social theories to guide them Nature: Physical equations Describe processes Society: Decisions on how to Use Earth´s resources
We need social theories to understand human-environment interactions Survey Moran, “Environmental Social Science: Human-Environment Interactions and Sustainability” (2010) Social simulation Schelling, “Micromotives and macrobehavior” (1978). Batty, “Cities and complexity” (2005). Game theory von Neumann and Morgenstern, “Theory of games and economic behavior” (1944) Nash, "Equilibrium points in n-person games“ (1950). Evolutionary dynamics Maynard Smith, ”Evolution and the theory of games” (1982) Axelrod, “Evolution of cooperation” (1988). Novak, “Evolutionary dynamics: exploring the equations of life” (2005). Institutional analysis Ostrom, “Governing the commons” (1990).
Tragedy of the Commons (Hardin, 1968) Assume a common-property resource (exclusion is difficult and joint use involves subtractability) with no property rights. (Pasture open to all) Each herdsman tries to keep as many sheep as possible on the commons. Each tries to maximize gain.
Add those sheep! The rational herdsman concludes that he should add another sheep. And another…And another…And so does each herdsman “Ruin is the destination toward which all men rush, each pursuing his own best interest…”
Prisoners’ Dilemma Two suspects are caught and put in different rooms (no communication). They are offered the following deal: If both of you confess, you will both get 3 years in prison If you confesses whereas the other does not, you will get 1 year and the other gets 5 years in prison . If neither of you confess, you both will get 2 years in prison.
Prisioner´s Dillema as a Model for the Tragedy of the Commons Suppose the commons can support 2 sheep at no cost and that each additional sheep put in the commons has a cost of 1/3 of its price due to overgrazing. Assume two herdsman with one sheep on the commons each. If a herdsman puts another sheep in the commons, he receives all the proceeds from the sale of each additional animal. His temptation is 4/3 and the sucker´s payoff for the other herdsman is -1/3.
Prisioner´s Dillema as a Model for the Tragedy of the Commons You are the herdsman. What are your options? Do you cooperate or defect? D C 1 -1/3 1/3 4/3 To efficiently study several social tension we can start from the benefit cost dilemma presented in the beginning. If we consider that each player plays simulataneously as a donor and receptor we reach to the following payoff matrix. We have 4 parameters for each situation. The reward for mutual cooperation, the punishment for mutual defection, the sucker’s payoff (when an individual is cheated and finally, the payoff received by a defector interacting with a cooperator. you Payoff matrix other
Everybody’s property is nobody’s property (Hardin) Tragedy of the Commons? Everybody’s property is nobody’s property (Hardin)
Preconditions for the tragedy of the commons Lack of restraint on pursuits of self-interest Consequences are externalities (I don’t have to pay)
Externalities in the global commons Activity of one person has an impact on the well-being of another. Positive externalities (or external benefits): Benefits realized by those who didn’t pay for them. Negative externalities (or external costs): Costs borne by those who didn’t generate them. Byproducts that harm others. SUVs in USA Climate Change in Africa
Is the tragedy of the commons inevitable? Experiments show that cooperation emerges if virtuous interactions exist source: Novak, May and Sigmund (Scientific American, 1995)
Repeated prisioner´s dillema Four different strategies for repeated prisioner´s dillema source: Novak, May and Sigmund (Scientific American, 1995)
Repeated prisioner´s dillema Evolution of prisioner´s dillema comparing different strategies source: Novak, May and Sigmund (Scientific American, 1995)
How can cooperation happen? Nowak MA (2006). “Five rules for the evolution of cooperation” Science 314:1560-1563 (most highly cited multidisciplinary paper – ISI, 1st quarter 2010) "I would lay down my life for two brothers or eight cousins“ (J.B.S. Haldane)
Five rules for evolution of cooperation b = benefit for the recepient c= cost for the donor
Common pool resources (Elinor Ostrom)
The ultimate common pool resource
Governing the commons [Ostrom, Science, 2005] 7
Governing the commons: Ostrom´s conditions Clearly defined boundaries. Congruence between appropriation and provision rules and local conditions. Collective-choice arrangements. Monitoring and graduated sanctions. Conflict-resolution mechanisms. Minimal recognition of rights to organize. Organized governance activities. 7
Ostrom on governing the commons “The challenge is how best to limit the use of natural resources so as to ensure their long-term economic viability.” “Neither the state nor the market is uniformly successful in enabling individuals to sustain long-term, productive use of natural resource systems.” “Optimal equilibrium with centralized control is based on assumptions concerning accuracy of information, monitoring capabilities, sanctioning reliability, and zero costs of administration.”
Conclusion Spatial models of human-environment interactions can support the study of common pool resources