Numerical and analytical study of evolution of indirect reciprocity

The evolution of indirect reciprocity by images scoring proposed by Nowak and Sigmund is systematically studied with numerical simulations and theoretical analysis. Two different types of evolutionary stable societies, cooperative and defective, can be found in that model. Our study reveals important influences of the information on the society. First, the information exchange rate can determine the type of the society. A society with high information exchange rate prefers a cooperative state, while society with low information exchange rate remains in a defective state. Second, it affects the ability of a society to resist the mutation. An analytical approach using information theory is presented, which catches certain features observed in the numerical simulation.