Injecting complexity in simulation models: Do selection and social influence jointly promote cooperation?

Abstract This paper employs a simulation model to investigate the effectiveness of cooperation selection (“selecting similar others”) and social influence (“do as others do”), since both mechanisms promote cooperation in theoretical analyses and experimental studies. However, it is unclear how effective cooperation selection and social influence are in simulation models where both mechanisms operate simultaneously alongside additional social dynamics, such as reciprocity and transitivity. This paper relies on a model loosely based on an empirical case in which students selected others based on how cooperative they perceive the other. Using existing theoretical cooperation models as a benchmark, we insert relational, behavioral, and contextual assumptions into our model and build on data from 95 students when we vary the strength of cooperation selection and social influence relative to empirically observed levels. We take co-evolution stochastic actor-oriented models as basis because the model inherently accounts for the interdependence of behavior and network selection. Our simulations reveal that cooperation benefits most when cooperation selection and social influence are strongly positive. Through the combination of cooperation selection and social influence, the simulations show that cooperators form dense local clusters, influencing their peers to keep cooperating while insulating themselves from social influence from defectors. Robustness checks confirm the stability of these findings across diverse parameter configurations.