Neurobiological regret and rejoice functions for aversive outcomes.

A decision maker may experience regret when a choice he makes results in a more adverse outcome than a different choice would have yielded. Analogously, he may experience rejoice when his choice resulted in better outcomes. We used fMRI to investigate the neural correlates of regret and rejoice where payoffs are in terms of a non-monetary medium. Incentives were created using painful outcomes in the form of mild electrical shocks to the foot and the possibility of avoiding them. We hypothesized that the neural response to a painful outcome resulting from an individual's choice would also reflect the degree of regret as measured by the likelihood that alternative choices would have yielded the same adverse outcome. Similarly, when an individual avoids a potential shock, he would experience a degree of rejoice that correlates with the probability he had of receiving the shock. For example, winning a bet when winning was unlikely, even if the outcome is the same, evokes more rejoice than winning when it was highly probable. Our results suggest that activation of a cortical network, consisting of the medial orbitofrontal cortex, left superior frontal cortex, right angular gyrus, and left thalamus, correlates with the degree of regret. A different network, including the rostral anterior cingulate, left hippocampus, left ventral striatum, and brain stem/midbrain correlated with rejoice. The right inferior orbitofrontal cortex, pre-supplementary motor area, anterior cingulate, and posterior cingulate showed similar patterns of activation with both regret and rejoice, suggesting that these regions may be associated with surprise from the realization of relatively unlikely events. Our results suggest that distinct, but overlapping networks are involved in the experiences of regret and rejoice.