Emotional mechanisms of social biases and social norms

It is well-known that human decisions are strongly guided by social norms and that we are influenced by the behaviour and recommendations of relevant others (such as one’s peer group). The Erasmus Centre for Neuroeconomics was one of the first to study the neural mechanisms underlying social influence and social conformity. We hypothesized that one possibility for such a mechanism was that social norms are simply processed as rewards or punishments.

By means of fMRI we indeed found that a deviation from the social norm triggers a neuronal response in dopaminergic areas (rostral cingulate zone/pMFC and ventral striatum) similar to the ‘prediction error’ learning signal suggested by neuroscientific models of reinforcement learning. Furthermore, the amplitude of this neural error signal predicts the individual’s tendency to conform to the opinion of the group.

A follow-up study using transcranial magnetic stimulation (TMS) confirmed the critical role of the pMFC in social conformity. Disrupting the pMFC by means of TMS indeed reduced an individual’s tendency to conform to the group’s opinion. These findings provide evidence that social norms evoke conformity via a basic and automatic learning mechanism reflected in the activity of the dopaminergic regions.

In general, people tend to conform more strongly to the behavior of the people with whom they identify (in-group members) than to the behavior of less relevant others (out-group members). We found that conformity to the in-group is mediated by both positive affect as well as the cognitive capacity of perspective taking (Stallen et al. , 2013), and that the hormone oxytocin, implicated in a variety of social behaviors, enhances conformity especially to one’s in-group (Stallen et al., 2012). 



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