Evolutionary Biology

Structure of Cooperation in Heterogeneous Networks

Cooperation is present in all life forms, but it is precisely in human society, where it reaches the maximum expression. Since the origins of civilization, humans realized the impossibility of surviving in isolation and without the others help. Step by step, specialization of labor generated new ideas and concepts and contributed to the improvement of manual skills, which benefits were subsequently reverted to group level. This dynamic together with the development of language enabled to reach higher forms of collective organization. Throughout history, humans have created rules, doctrines and laws to regulate the functioning of society. Gradually (after many, many years of evolution), this process led to our complex society basically based on sophisticated models of nations and supranational institutions. Nowadays, high technological specialization and advances in science would not have been possible without human cooperation. In a world increasingly developed in all areas, and in which the interaction networks between individuals are becoming more complex and evident, different hypotheses emerge to explain the foundations of human cooperation on a large scale and the true motivations that underlie this mechanism. From a social perspective, the behavior of individuals in certain circumstances is a mystery yet to reveal.

Thus, it is not surprising that the understanding of cooperative phenomena in natural and social systems has been the subject of intense research during decades. This is because the observed survival of cooperation among unrelated individuals in social communities is not expected when selfish actions provide a higher benefit. The problem can be addressed from many different perspectives and is far from being solved. In our group, we use Evolutionary Game Theory to study how cooperation survives. We have addressed this problem taking into account the complex topological patterns of the networks of contacts that define the interactions of the gamers. Our results have shown that the paths towards cooperation (or defection) strongly depend on the underlying structure and explained why cooperation in SF networks is favored. Although the latter results explain how cooperation survives in heterogeneous structures, they don’t provide insights into a more fundamental problem: if SF networks are better suited for cooperation, where did they come from? To answer this question, we have been working on the development of models for growing networks where the grow process is fed back with the results of the game being played while the network is growing. Current interests of our group in this line of research include the study of new evolutionary graph problems, the introduction of theoretical techniques that allow to study the problem as a phase transition, the coevolution of evolutionary dynamics and network topology and the emergence of cooperation when different dilemmas are at work.

Selected Publications (for a full list of papers and pdf’s, please visit the individual profiles of group’s members)

  1. M. Starnini, A. Sánchez, J. Poncela, and Y. Moreno, “Coordination and Growth: The Stag Hunt Game on Evolutionary Networks”. Journal of Statistical Mechanics: Theory and Experiment, P050008 (2011).
  2. J. Poncela, J. Gomez-Gardenes, and Y. Moreno, “Cooperation in Scale-Free Networks with Limited Associative Capacities”. Physical Review E, 83, 057101 (2011).
  3. C.P. Roca, S. Lozano, A. Arenas and A. Sánchez, “Topological Traps Control Flow on Real Networks: The Case of Coordination Failures”, PLoS ONE 5(12): e15210 (2010).
  4. Jelena Grujic, Constanza Fosco, Lourdes Araujo, José A. Cuesta y Angel Sánchez, “Social Experiments in the Mesoscale: Humans Playing a Spatial Prisoner’s Dilemma”,PLoS ONE 5 (11), e13749 (2010).
  5. J. Poncela, J. Gomez-Gardenes, L.M. Floría, Y. Moreno and A. Sánchez, “Cooperative Scale-Free Networks despite the Presence of Defector Hubs”, Europhysics Letters, 88, 38003 (2009).
  6. J. Poncela, J. Gomez-Gardenes, A. Traulsen, and Y. Moreno, “Evolutionary Game Dynamics in a Growing Structured Population”, New Journal of Physics, 11, 083031 (2009).
  7. Carlos P. Roca, José A. Cuesta y Angel Sánchez, “Evolutionary Game Theory: Temporal and Spatial Effects beyond Replicator Dynamics”, Physics of Life Reviews 6, 208-249 (2009).
  8. Carlos P. Roca, José A. Cuesta y Angel Sánchez, “On the Effect of Spatial Structure on the Emergence of Cooperation”, Physical Review E, 80, 046106 (2009).
  9. S. Meloni, A. Buscarino, L. Fortuna, M. Frasca, J. Gomez-Gardenes, V. Latora and Y. Moreno, “Effects of Mobility in a Population of Prisoner’s Dilemma Players”, Physical Review E, 79, 067101 (2009).
  10. J. Gomez-Gardenes, J. Poncela, L. M. Floria, and Y. Moreno, “Natural Selection of Cooperation and Degree Hierarchy in Heterogeneous Populations”, Journal of Theoretical Biology, 253, 296 (2008).
  11. J. Poncela, J. Gomez-Gardenes, L.M. Floría, A. Sánchez and Y. Moreno, “Complex Cooperative Networks from Evolutionary Preferential Attachment”, PLoS ONE, 3, e2449 (2008).
  12. J. Poncela, J. Gomez-Gardenes, L. M. Floria, and Y. Moreno, “Robustness of Cooperation in the Evolutionary Prisoner’s Dilemma on Complex Networks “, New Journal of Physics, 9, 184 (2007).
  13. J. Gomez-Gardenes, M. Campillo, L. M. Floria, and Y. Moreno, “Dynamical Organization of Cooperation in Complex Topologies”, Physical Review Letters, 98, 108103 (2007).