Cooperation, clustering, and assortative mixing in dynamic networks

Abstract

Humans' propensity to cooperate is driven by our embeddedness in social networks. A key mechanism through which networks promote cooperation is clustering. Within clusters, conditional cooperators are insulated from exploitation by noncooperators, allowing them to reap the benefits of cooperation. Dynamic networks, where ties can be shed and new ties formed, allow for the endogenous emergence of clusters of cooperators. Although past work suggests that either reputation processes or network dynamics can increase clustering and cooperation, existing work on network dynamics conflates reputations and dynamics. Here we report results from a large-scale experiment (total = 2,675) that embedded participants in clustered or random networks that were static or dynamic, with varying levels of reputational information. Results show that initial network clustering predicts cooperation in static networks, but not in dynamic ones. Further, our experiment shows that while reputations are important for partner choice, cooperation levels are driven purely by dynamics. Supplemental conditions confirmed this lack of a reputation effect. Importantly, we find that when participants make individual choices to cooperate or defect with each partner, as opposed to a single decision that applies to all partners (as is standard in the literature on cooperation in networks), cooperation rates in static networks are as high as cooperation rates in dynamic networks. This finding highlights the importance of structured relations for sustained cooperation, and shows how giving experimental participants more realistic choices has important consequences for whether dynamic networks promote higher levels of cooperation than static networks.

Self-regulation versus social influence for promoting cooperation on networks

“…In this regard, the continuous prisoner's dilemma has been proposed as a representative model able to account for different levels of cooperation 3,32,33 .Moreover, the presence of graphs of connections among players is typical for real populations, where asymmetric relationships are frequently observed. The evolution of strategies on graphs has been investigated in several studies [34][35][36][37][38][39][40][41][42] . Among them, the replicator equation on regular infinite graphs, embedding network reciprocity, has been developed and analyzed in 15,43,44 .…”

Direct Reciprocity and Model-Predictive Strategy Update Explain the Network Reciprocity Observed in Socioeconomic Networks

“…First, before even testing an experimental dataset against a candidate process of strategy update, we must be able to distinguish the cooperative from the defective mood of the subjects, if any mood really does exist. This distinction is not completely clear from the available experiments, in which C and D were the only options and, except the experiment described in [62] about evolving networks, subjects had to chose whether to play C or D with all neighbors at each game round. Consequently, risk-avoiding defections can be easily confused for a defective mood.…”

“…It is therefore important, in our opinion, to allow the subjects to act independently with their neighbors and to abstain from playing with selected ones. For example, allowing independent actions for each neighbor has been recently shown to favor cooperation [62], although it is definitely experimentally challenging. Subjects playing C or abstaining with most neighbors could be classified in the cooperative mood; subjects mainly playing D in a defective mood; and a mix of C and D would indicate the absence of a mood.…”

“…Finally, although static and sparse networks are the ideal setting for direct reciprocity, as agents repeatedly interact with the same limited number of neighbors, mechanisms to evolve the social ties in feedback with the game outcomes are known to enhance the evolution of cooperation [62][63][64]. It would then be interesting to study our setting on suitable dynamical networks.…”

Práticas Relacionais, Mecanismos De Governança E Confiança Em Uma Rede De Cooperação

“…As redes podem promover a cooperação quando sua topologia existente ou emergente permite que cooperadores condicionais na rede se isolem da exploração por nãocooperadores. As redes dinâmicas geram taxas muito altas de cooperação, mesmo sem conhecimento de reputação (MELAMED et al, 2018).…”