Modulating the Activity of the Left OFC and VMPFC With tDCS Alters Regret in the Stock Repurchase Effect

Humans regret their choices when they miss out on a good opportunity, especially in individual investment. Regret is an emotion prone to appear in human decision-making in some stock trading operations, as in the repurchase effect—the phenomenon in which people prefer to repurchase stocks that experience a price decrease after they sell them over those that experience a price increase after they sell them. Neuroscientific studies show that ventromedial prefrontal cortex (vmPFC) and orbitofrontal cortex (OFC) activation is correlated with experiencing regret. However, the part of the cerebral cortex associated with regret is unknown, as is the part of the cerebral cortex associated with the repurchase effect. As a result, transcranial direct current stimulation (tDCS) technology is used to stimulate the left OFC/vmPFC to determine which is associated with regret in the repurchase effect. After stimulation, in our experimental design, we let the subjects trade stocks in the experiment and rate how regretful they felt regarding each trade. We found that stimulating the left OFC led to a difference in regret in the repurchase effect, which is a significant finding of our trading experiment. However, stimulating the vmPFC had no significant effect. In addition, from post hoc analyses (Bonferroni), the subjects who received anodal stimulation felt more regret than the subjects who received sham stimulation. In summary, the results of our experiment suggest that regret in the stock repurchase effect is modulated by the activity of the left OFC