Brain activation upon ideal-body media exposure followed by peer feedback in late adolescents

Media content matters in social contexts, especially for adolescents who socialize largely with their peers in media(ted) environments. This is well-exemplified by body image development being influenced by media's thin body-ideal and peer influences. This study investigated peer feedback and media imagery interactions through analyzing brain activity using fMRI. Such neural measures complement self-report measures and reveal mechanisms that are unapparent otherwise. Girls (18–19 years-old, N = 24) were exposed to 30 thin and 30 average-sized media models while in an MRI-scanner. They rated each model as 'too thin' or 'normal', followed by congruent or incongruent peer feedback. Results showed increased activity in the ACC and insula in incongruent situations (e.g., participant: 'normal-weight'; feedback: 'too thin'), especially for those with lower self-esteem. This increased activity occurred in brain centers that become active in uncertain situations (e.g., when social norms are exceeded), indicating that media-based feedback directly influenced brain responses to deviating norms.