Social deviance activates the brain’s error-monitoring system

Social psychologists have long noted the tendency for human behavior to conform to social group norms. This study examined
whether feedback indicating that participants had deviated from group norms would elicit a neural signal previously shown
to be elicited by errors and monetary losses. While electroencephalograms were recorded, participants (N = 30) rated the attractiveness of 120 faces and received feedback giving the purported average rating made by a group of
peers. The feedback was manipulated so that group ratings either were the same as a participant’s rating or deviated by 1,
2, or 3 points. Feedback indicating deviance from the group norm elicited a feedback-related negativity, a brainwave signal
known to be elicited by objective performance errors and losses. The results imply that the brain treats deviance from social
norms as an error.