Human behavior in prisoner's dilemma experiments suppresses network reciprocity

During the last few years, much research has been devoted to strategic interactions on complex networks. In this context, the Prisoner's Dilemma has become a paradigmatic model, and it has been established that imitative evolutionary dynamics lead to very different outcomes depending on the details of the network. We here report that when one takes into account the real behavior of people observed in the experiments, both at the mean-field level and on utterly different networks, the observed level of cooperation is the same. We thus show that when human subjects interact in a heterogeneous mix including cooperators, defectors and moody conditional cooperators, the structure of the population does not promote or inhibit cooperation with respect to a well mixed population.J. A. C. and A. S. acknowledge grants MOSAICO, PRODIEVO and Complexity-NET RESINEE (Ministerio de Ciencia e Innovación, Spain) and MODELICO-CM (Comunidad de Madrid, Spain). Y. M. was partially supported by Spanish MICINN (Ministerio de Ciencia e Innovación) projects FIS2008-01240 and FIS2009-13364-C02-01, by the FET-Open project DYNANETS (grant no. 233847) funded by the European Commission and by Comunidad de Aragón (Spain) through the project FMI22/10.Publicad