Arbitration between insula and temporoparietal junction subserves framing-induced boosts in generosity during social discounting

•Generosity toward others declines across the perceived social distance to them.•Framing a generous choice as preventing other-loss reduces social discounting.•Temporoparietal junction (TPJ) subserves generous choice yielding other-gain.•The insular cortex is recruited during generous choice that prevent other-loss.•TPJ and insula differentially modulate activity in ventromedial prefrontal cortex. Generosity toward others declines across the perceived social distance to them. Here, participants chose between selfish and costly generous options in two conditions: in the gain frame, a generous choice yielded a gain to the other; in the loss frame, it entailed preventing the loss of a previous endowment to the other. Social discounting was reduced in the loss compared to the gain frame, implying increased generosity toward strangers. Using neuroimaging tools, we found that while activity in the temporoparietal junction (TPJ) and the ventromedial prefrontal cortex (VMPFC) was associated with generosity in the gain frame, the insular cortex was selectively recruited during generous choices in the loss frame. We provide support for a network-model according to which TPJ and insula differentially subserve generosity by modulating value signals in the VMPFC in a frame-dependent fashion. These results extend our understanding of the insula role in nudging prosocial behavior in humans.