What motivates repayment? Neural correlates of reciprocity in the Trust Game.

Reciprocity of trust is important for social interaction and depends on individual differences in social value orientation (SVO). Here, we examined the neural correlates of reciprocity by manipulating two factors that influence reciprocal behavior: (1) the risk that the trustor took when trusting and (2) the benefit for the trustee when being trusted. FMRI results showed that anterior Medial Prefrontal Frontal Cortex (aMPFC) was more active when participants defected relative to when participants reciprocated, but was not sensitive to manipulations of risk and benefit or individual differences in SVO. However, activation in the temporal-parietal-junction (rTPJ), bilateral anterior insula and anterior cingulate cortex (ACC) was modulated by individual differences in SVO. In addition, these regions were differentially sensitive to manipulations of risk for the trustor when reciprocating. In contrast, the ACC and the right dorsolateral prefrontal cortex were sensitive to the benefit for the trustee when reciprocating. Together, the results of this study provide more insight in how several brain regions work together when individuals reciprocate trust, by showing how these regions are differentially sensitive to reciprocity motives and perspective-taking.