Social decisions play a crucial role in the success of individuals and the groups they compose. Group members respond vicariously to benefits obtained by others, and impairments in this capacity contribute to neuropsychiatric disorders like autism and sociopathy. We studied how neurons in three frontal cortical areas encode the outcomes of social decisions as monkeys performed a reward-allocation task. Neurons in the orbitofrontal cortex (OFC) predominantly encoded rewards delivered to oneself. Neurons in the anterior cingulate gyrus (ACCg) encoded reward allocations to the other monkey, reward allocations to oneself, or both. Neurons in the anterior cingulate sulcus (ACCs) signaled reward allocations to the other monkey or no one. Within this network of received (OFC) and foregone (ACCs) reward signaling, ACCg emerges as a key nexus for the computation of shared experience and social reward. Individual and species-specific variations in social decision-making might result from the relative activation and influence of these areas.

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