Counterfactual thinking and reward processing: an fMRI study of responses to gamble outcomes

The process of comparing obtained outcomes to alternative possible outcomes, known as counterfactual thinking, is inescapable in daily life; however, the neurocognitive mechanisms underlying counterfactual thinking and how they influence emotional responses to better and worse outcomes is not well understood. We conducted an event-related functional magnetic resonance imaging (fMRI) gambling study in which participants were informed of two equally possible outcomes of a card gamble before they selected a card. Participants reported experiencing mixed emotions (i.e., both positive and negative affect) for disappointing wins (winning the lesser of two amounts) and relieving losses (losing the lesser of two amounts). Neuroimaging results supported the hypothesis that these mixed emotions were associated with activation of a fronto-parietal network, which subsequently influenced processing in reward and punishment regions (dorsal and ventral striatum, right anterior insula). The fronto-parietal network was sensitive to outcomes that resulted in mixed emotions, whereas reward and punishment regions were sensitive to comparisons between obtained and unobtained outcomes. These findings provide insight into the neurocognitive mechanisms underlying the mixed emotional experiences that result from counterfactual comparisons, and inform our understanding of how the brain is optimized to use the wealth of environmental information to inform current and future behavior.