Brain responses to social norms: Meta-analyses of fMRI studies
Social norms have a critical role in everyday decision-making, as frequent interaction with others regulates our behavior. Neuroimaging studies show that social-based and fairness-related decision-making activates an inconsistent set of areas, which sometimes includes the anterior insula, anterior cingulate cortex, and others lateral prefrontal cortices. Social-based decision-making is complex and variability in findings may be driven by socio-cognitive activities related to social norms. To distinguish among social-cognitive activities related to social norms we identified thirty six eligible articles in the functional magnetic resonance imaging (fMRI) literature, which we separate into two categories (a) social norm representation, and (b) norm violations. The majority of original articles (> 60%) used tasks related with fairness norms and decision-making, such as ultimatum game, dictator game or prisoner’s dilemma; the rest used tasks related to violation of moral norms, such as scenarios and sentences of moral depravity ratings etc. Using quantitative meta-analyses we report brain common and distinct brain areas that show concordance as a function of category. Specifically, concordance in ventromedial prefrontal regions is distinct to social norm representation processing, whereas concordance in right insula, dorsolateral prefrontal and dorsal cingulate cortices is distinct to norm violation processing. We propose a neurocognitive model of social norms for healthy adults, which could help guide future research in social norm compliance and mechanisms of its enforcement.