Abstract
Research on social influence has mainly focused on the target of influence (e.g. consumer, voter), while the cognitive and neurobiological underpinnings of the source of the influence (e.g. marketer, politician) remain unexplored. Here we show that advisers managed their influence over their client strategically, by modulating the confidence of their advice, depending on the interaction between adviser’s level of influence on the client (i.e., being ignored or chosen by the client), and relative merit (i.e., their accuracy in comparison with a rival). Functional magnetic resonance imaging showed that these sources of social information were tracked in distinct regions of the brain’s social and valuation systems: relative merit in the medial-prefrontal cortex, and selection by client in the temporo-parietal junction. In addition, increased functional connectivity between these two regions during positive merit trials predicted their effect on behaviour. Both sources of social information modulated the activity in the ventral striatum. These results further our understanding of human interactions and provide a framework for investigating the neurobiology of how we try to influence others.