Emotional processing is influenced by top-down processes such as reappraisal of emotion-inducing events. Besides one’s own stimulus appraisal, information from the social environment can be used to modify the stimulus’ meaning. This study investigated whether perspective taking changes participants’ brain potentials to unpleasant pictures. Event-related potentials (ERPs) were measured while twenty-nine participants evaluated arousal of neutral or negative pictures. Subsequently, they received bogus feedback about another person’s picture evaluation. Then, the same picture was presented again and participants were instructed to view the picture from the other person’s perspective. Higher bogus- versus self-ratings of picture arousal increased P300 and late positive potential (LPP) amplitudes to unpleasant stimuli, whereas lower bogus- versus self-ratings did not influence ERPs. Thus, perspective taking only modulated ERPs when bogus ratings signaled potential underestimation of arousal. Resulting increases in responsiveness might constitute an adaptive mechanism preparing the organism against harm.