Belief in a just world is associated with activity in insula and somatosensory cortices as a response to the perception of norm violations

Previous studies identified a network of brain regions involved in the perception of norm violations, including insula, anterior cingulate cortex (ACC), and right temporoparietal junction area (RTPJ). Activations in these regions are suggested to reflect the perception of norm violations and unfairness. The current study aimed to test this hypothesis by exploring whether a personal disposition to perceive the world as being just is related to neural responses to moral evaluations. The just-world-hypothesis describes a cognitive bias to believe in a just world in which everyone gets what he or she deserves and deserves what he or she gets. Since it has been demonstrated that ACC, RTPJ, and insula are involved in the perception of unfairness, we hypothesized that individual differences in the belief in a just world are reflected by different activations of these brain areas. Participants were confronted with scenarios describing norm-violating or -confirming behavior. FMRI results revealed an activation of dorsal ACC, RTPJ, and insula when perceiving norm violations, but only activity in insula/somatosensory cortex correlated with the belief in a just world. Thus, our results suggest a role for insula/somatosensory cortex for the belief in a just world.