Serotonin modulates behavioral reactions to unfairness

One of the first social rules we learn aschildren is the golden one: Treat othersas you wish to be treated. Unfortunately, our peers do not always deserve gold stars for their behavior, which tempts us to retaliate. Resisting aggressive impulses may be difficult, but success-fully navigating social life sometimes requires self-regulation in the face of perceived injustice. Serotonin (5-HT) has long been implicated in social behavior, including impulsive aggression, but its precise involvement in impulse control is controversial (1). Because social interactions can evoke strong emotions, it is plausible that 5-HT modulates impulsivity via emotion regulationmech-anisms. Emotion regulation during social interac-tions has been studied with the ultimatum game (UG), in which one player (the proposer) pro