Steve Chang et. al. studied encoding of the outcomes of social decisions in three frontal cortical areas as monkeys performed a social reward allocation task. Orbitofrontal cortex neurons signaled received rewards, anterior cingulate (ACC) sulcus neurons signaled foregone rewards, and the ACC gyrus was involved in the computation of shared experience and social reward.
Nature Neuroscience (2012) doi:10.1038/nn.3287