Abstract: Counterfactual thinking occurs when an individual experiences thoughts that ignore what has happened in the past, and generates a hypothesis which comparing “what is” with “what might have been”. It is the pop problem in the field of decision-making. Most previous studies focused on topics like which factors influenced the production of counterfactual thinking or different types of counterfactual thinking of different people. Few of them studied different degree of counterfactual thinking generated by different people. Until 2008, Pierro et al. used scenario approach and found that people with different regulatory mode had different degrees in counterfactual thinking and regret experience. Comparing with locomotion, assessment usually produced greater counterfactual thinking and experienced greater regret. Although behavioral studies on counterfactual thinking have accumulated some valuable results, its neural mechanism remains to be deep explored. In 2010, FRN (Feedback Related Negativity) and P300 were found to be sensitive components of counterfactual thinking. On the basis of studies forgoing, we deemed to investigate the differences of assessment and locomotion on counterfactual thinking and the evidence on neurophysiological activity. It is hoped that there would be some of the difference between the two groups, which would be reflected in the amplitude of FRN and P300.
In the present study, scales of Regulatory Mode were used to test 375 students and finally 32 participants were picked and divided into two groups (Assessment and Locomotion). The ERP technique was applied in a simple gambling task to test the neurophysiological activity. Participants were told to earn the money as more as possible, whereas the feedback of each trail was randomly presented.
The results were analyzed by Repeated Measure ANOVA. Behavioral results showed that: higher assessment significantly produced greater counterfactual thinking than higher locomotion; EEG results indicated that: the main effect of group was significant in both FRN and P300, namely the amplitude of assessment was greater than locomotion.
In short, different regulatory modes did produce different counterfactual thinking, which were reflected in FRN and P300. Comparing with locomotion, assessment tended to produce greater counterfactual thinking and have more intense emotional experience. After understanding the differences between assessment and locomotion, the two groups of people can use the merits while avoid the defects of themselves, so as to make the right decision and have a happier mood comparatively.

Key words: Counterfactual Thinking, Regulatory Mode, ERP, FRN, P300