Before revision:  When the correlation is not perfect however, defectors placed within clusters of cooperators can act as Trojan horses, allowing defection to invade. The results are relevant both to computer simulations of cooperation in networks and in particular to real-world cooperation experiments, where the number of replications is typically low and stochastic initial correlations between cooperativeness and network position may be present .
After revision:  When the correlation is not perfect however, defectors placed within clusters of cooperators . Interestingly, the largest enhancement is observed in Poisson networks with increased degree assortativity, where cooperation does better than under scale-free degree distribution. The study provides new knowledge about the conditions under which cooperation may evolve and persist. The results are furthermore important to consider in regard to cooperation experiments, where the number of replications is typically low and stochastic initial correlations between cooperativeness and network position may be present .