Cooperative Behavior And Outcome Evaluation Of Chicken Games In Different Contexts

Cooperation promotes individual development and social prosperity.The research on cooperation in the laboratory usually use social game tasks.Goal/expectation theory suggested that cooperative behavior usually depend on the goal of achieving mutual cooperation and an expectation that the other will cooperate.In order to maximize profit,individuals will quickly and timely evaluate the outcome,and accordingly decide whether to cooperate or not in the subsequent games.At present,Event related potential(ERPs)was used to investigate the time course of outcome evaluation.Present studies have investigated the influence of factors other than cooperation,such as gender and personality,on cooperative behavior.However,to reveal the internal mechanism of cooperation,it is still necessary to explore the factors that can directly affect cooperation,such as the cooperative tendency of opponent and cooperative or competitive relationship between the two parties on cooperation.Based on this aim,present thesis will use the iterated Chicken Game,with the help of ERPs technology,to explore how individuals cooperate and evaluate the outcomes.In study 1,participants were randomly matched with the opponents with different cooperative rates(80%vs.20%),so as to investigate how the cooperative tendencies of the opponent affected participant’s cooperation and outcome evaluation.The results showed that the cooperative rate of participants in the competitive opponent group was significantly higher than that in the cooperative opponent group.And in 1-40 trials,the proportion of the cooperative participants in the competitive opponent group was significantly lower than the cooperative opponent group.There was no significant difference between the two groups in 41-100 trials.While in 101-120 trials,the ratio of cooperative participants in the competitive opponent group was significantly higher than that in the cooperative opponent group,and this situation remained until the end of the task.For EEG results,the dFRN induced by the outcome of participant’s aggression was more negative than cooperation.The average amplitude of P300 caused by the opponent’s aggression in the cooperative opponent group was significantly higher than that in the competitive opponent group.The regression analysis showed that only in the competitive opponent group,the P300 caused by CA outcome can significantly negatively predict the cooperative rate of the next game.In study 2,using iterated Chicken Game,participants’ cooperation and outcome evaluation in different relationship between participant and opponent were investigated by setting "non-zero-sum game" and "zero-sum game" through instructions.The results showed that the cooperative rate of the "non-zero-sum" group was significantly higher than that of the "zero-sum" group.The total score of the "non-zero-sum" group was significantly higher than that of the "zero-sum" group.The difference of scores in "zero-sum" group was significantly greater than that of the "non-zero-sum" group.For EEG results,the dFRN induced by participant’s cooperation was significantly lower than that caused by aggression.Theta-ERS and P300 are significantly higher after opponent cooperated than aggressed;P300 and Theta-ERS were greater when participant aggressed than cooperated in the "non-zero-sum" group.While in the"zero-sum" group,the outcome of participant’s cooperation caused more positive P300 than aggression.The regression analysis found that only in the "zero-sum game" group,the larger the P300 induced by AA,the higher the cooperative rate in the next game.