Double Attitude Spatial Evolutionary Game And Emergence Of Cooperation

Evolutionary game theory studies how individuals with different strategies react with each other in repeated games, based on game theory and biological populations.This theory provides a good mathematical way to study biological system and even human society.An important problem in this area is:how cooperation generates and survives in nature selection. As in recently studies, cooperation becomes the third main role in evolution, besides variation and nature selection.There are many evolutionary models in the area of emergence of cooperation and direct reciprocity is one of them.In the third part of the paper, we establish a model based on interact prisoner's dilemma. The background of the model is that nowadays in the rural areas of China, peasants can make their own choices to go to the city for a new job or stay in the rural area. A decision is made based on working ability and the information a peasant gets.A multivariate evolutionary model of this problem is established and the numerical simulation shows that going to the city brings about a rise in the peasants'income, and also that such a rise,as well as the number of peasants going to the city,is influenced by the capacity of the cities and income gap between agricultural and non-agricultural industries.In the forth part of the paper, we establish a multi-agent model with double attitude individuals, also based on spatial evolutionary game theory,and then cooperation and conflict phenomenon are discussed. Different from classical definition of altruism which requires a cost of oneself in order to help others;we separate attitudes towards oneself and his opponent into two independent parts.Furthermore, each part can be positive or negative.Then we get four kinds of individuals in the population:cooperator, defeater, selfisher and altruist. The spatial simulation results show that, in a broad rang of parameters;these four kinds of individuals have complex dependent or repellent relations.And some interesting phenomenon appears e.g. selfishers protect cooperators and restrain defeaters,altruists fend defeaters and a high cooperation of altruism can form in some situation.