Altruistic Punishment, Feeling Of Defection, And The Prediction Between Them In Trust Game: An ERP Study

Although a few studies have found that subjects feel quite bad when faced with the trustee’s betrayal, the psychological and neural mechanism of this feeling of being defected calls for more research. Induced by defection, one tend to do altruistic punishment to the defector in the trust game. Altruistic punishment means that one would punish violator of social norms even if this will bring loss for himself. The psychological mechanism of altruistic punishment remains controversial. Some research suggested that it is the perceived negative feeling caused by violation of social norms that drive someone to punish; while concerning the cost incurred by punishment, the cognitive control mechanism might work to restrain one from implement punishment impulsively. However, some other studies believed that, those who did punishment had a better ability of cognitive control over self-interest, as for concerning of fairness and social norm; while for those with worse cognitive control ability, triumph of self-interest over moral concerns would lead to not-to-punish. So the debate is, to suppress the negative emotional tend or to conquer self-interest, which is the function of cognitive control? We would also try to answer that whether the ERPs of being defected could predict subjcts’ following punishment decision in each trial, through comparing the ERPs when being defected in trials of punishment with that in trials of non-punishment.To answer the above questions, we directed an anoymous repeated trust game, and recorded subjects’ event-related potentials(ERPs) in time courses such as being defected and deciding whether to punish defectors costly. In the formal experiment, the subject acted as investor and receive both a fixed amount of money as fundamental money and an variable amount of money for investing in each trial. He should decide whether to give the investing money to the trustee for earnings. If invested, that money would grow tenfold; and the trustee whether returned a half, i.e. five times the investing money, to the subject or returned nothing to him. If received nothing back, that subject have the opportunity to decide whether to punish the trustee on his own cost.Outcome:(1). More negative feedback-related negativity(FRN) and more positive late positive component(LPC) is recorded when subjects faced with defection compared with return.(2). Greater LPC when subjects deciding not to punish than deciding to punish.(3). Both recording the ERPs when faced with defection, trials finally decided to punish had greater LPC activation than trials finally decided not to punish.Conclusions:(1). In the returning stage, subjects faced with defection regard other’s defection as a negative outcome and feel more negative feeling than faced with return, which is presented by FRN and LPC respectively.(2). The greater LPC when deciding not to punish means that more cognitive effort is spent on suppression of negative feeling.(3) The LPC activation when being defected could predict the final decision in punishment decision, that is, the more negative the subjects feels in a trial, the greater LPC amplitude and the more chance to implement punishment.