An ERPs Study On Feedback Coding In Risky Decision Making

There always exists a debate about the relationship between the coding of the valence and magnitude of feedback in risky decision making and two ERPs components – FRN and P3.And,the function of P2 in coding the feedback of risky decision is unclear.Based on previous researches,the study aims to explore the coding of feedback valence and magnitude in the outcome phase of risky decision making by using gambling task.Experiment 1 repeats the classical gambling task in order to certificate whether the code of feedback is same as Independent coding theory which suggests that FRN is sensitive to valence and P3 is sensitive to magnitude and explore the function of P2 in coding the feedback;Based on the classical gambling task,Experiment 2 means to dissociate the coding process of FRN and P3 by manipulating the level of SOA of feedback so as to clarify the relationship between the coding of the valence and magnitude of feedback in risky decision making and FRN and P3.The ERPs data of classical gambling task shows that the main effect of magnitude on P2 component is significant,with the amplitude of P2 is larger when the feedback is large magnitude than small magnitude.The main effect of valence and magnitude on FRN component is significant,with the amplitude of FRN is larger when compares the loss feedback with the gain feedback and the amplitude of FRN is larger when compares small magnitude feedback with large magnitude feedback.However,there is no significant effect on P3 component.The behavioral data of gambling task with different levels of SOA shows that the main effect of SOA is significant,with the reaction time is longer when SOA is 200 ms than SOA is 300ms;The main effect of valence and magnitude are significant and the reaction time of loss feedback and large magnitdue feedback are longer when compared with gain feedback and small magnitude feedback;The interaction between valence and magnitude is significant and the reaction time of large magnitude feedback is longer than small magnitude feedback when the feedback is loss while the reaction time of small magnitude feedback is longer than large magnitude feedback when the feedback is gain.The interaction among SOA,valence and magnitude is significant.When the SOA is 200 ms,the reaction time of loss feedback is longer than gain feedback when the feedback is large magnitude and when the SOA is 300 ms,the recation time of loss feedback is longer than gain feedback when the feedback is large magnitude.The ERPs data of gambling task with different levels of SOA shows that the main effect of magnitude on P2 component is significant,with the amplitude of P2 is larger when the feedback is large magnitude than small magnitude.The main effect of SOA on FRN component is significant,with the amplitude of FRN is larger when SOA is 200 ms than SOA is 300 ms.The main effect of valence on FRN is marginal significant.And the main effect of SOA on P3 component is significant,with the amplitude of P3 is larger when SOA is 200 ms than SOA is 300 ms.Base on the result of the study,two conclusions could be concluded:Firstly,P2 component is sensitive to the magnitude of feedback in risky decision making,with the amplitude of P2 is larger when the feedback is large magnitude than small magnitude,which reflects the code of the magnitude of feedback.Secondly,When the process time is adequate,FRN is sensitive to the valence and magnitude of feedback in risky decision making,with the amplitude of is larger when the feedback is loss than gain and feedback is small magnitude than large magnitude;When the process time is limited,FRN tends to be sensitive to the valence of feedback,which may reflect the prior code of the valence of feedback in the time course of FRN.