Before revision:  The effect depends nontrivially on the combination of the social network structure (degree distribution and assortativity), the type of social dilemma, and the presence of Trojan horses , i.e. defectors placed within clusters of cooperators.
After revision:  The effect depends nontrivially on the combination of the social network structure (degree distribution and assortativity), the type of social dilemma, and the presence of Trojan horses ( defectors placed within clusters of cooperators.