Emotional Strategies as Catalysts for Cooperation in Signed Networks

Abstract

The evolution of unconditional cooperation is one of the fundamental problems in science. A new solution is proposed to solve this puzzle. We treat this issue with an evolutionary model in which agents play the Prisoner's Dilemma on signed networks. The topology is allowed to co-evolve with relational signs as well as with agent strategies. We introduce a strategy that is conditional on the emotional content embedded in network signs. We show that this strategy acts as a catalyst and creates favorable conditions for the spread of unconditional cooperation. In line with the literature, we found evidence that the evolution of cooperation most likely occurs in networks with relatively high chances of rewiring and with low likelihood of strategy adoption. While a low likelihood of rewiring enhances cooperation, a very high likelihood seems to limit its diffusion. Furthermore, unlike in non-signed networks, cooperation becomes more prevalent in denser topologies.

Degree Variance And Emotional Strategies Catalyze Cooperation In Dynamic Signed Networks

“…One can observe several similarities in the results from the two kinds of starting configurations. As noted in our previous contributions ( [15,16]), and coherently to what observed by [19], the relative speed (i.e. the probability) of the network which cooperation survives and those where it disappears completely.…”

“…As noted in our previous work ( [15]), the introduction of the COND strategy relaxes the parametric conditions for cooperation to survive. In the context of this paper, we note that this happens both for the regular lattice initialization, where the approximate condition for the survival of cooperation becomes P rew > 20/13P adopt (∼ 1.53P adopt ), and for the random network where it becomes P rew > 4/3P adopt (∼ 1.3P adopt ).…”

“…Extending the analysis of [15] to regular lattices, we studied the effects of the introduction of a conditional strategy that considers the relational signs to the partner to decide whether to cooperate or defect. The conditional strategy enlarged the parametric space in which cooperation evolved.…”

“…A recent series of our ( [15,16]) and other authors' papers ( [21]), extended the analysis of the emergence of cooperation to signed networks. We introduced the possibility of network ties to turn positive or negative, or to be deleted and relinked as a consequence of previous interactions.…”

“…We run a sensitivity analysis of this parameter in[15] 4The assumption of existence of transitive closure makes the model more realistic and increase cooperation. As shown in[15] however, our results are qualitatively robust when we relax this assumption and consider totally random rewiring 5. This parameter is assumed to be small but positive.…”