Neural responses to shared positive and negative experiences: unveiling the social feedback processing dynamics.

This study examined the impacts of shared experience valence on the dynamic processing of social feedback. Electroencephalography (EEG) was recorded when participants performed an adapted social judgment paradigm with three stages: social feedback expectation, social feedback evaluation, and expectation updating. Behavioral analysis revealed higher acceptance expectation and lower rejection expectation in the shared positive experience (SPE) condition than in the shared negative experience (SNE) condition; receiving acceptance feedback increased acceptance expectation in the subsequent trial. EEG results revealed that at the social feedback expectation stage, rejection evoked a larger stimulus-preceding negativity magnitude than acceptance in the SNE but not SPE condition. At the social feedback evaluation stage, rejection feedback evoked a smaller early frontal theta than acceptance feedback in the SNE but not SPE condition; unexpected acceptance evoked a larger P300 than unexpected rejection in the SPE but not SNE condition. At the expectation updating stage, unexpected acceptance elicited larger late posterior theta than expected acceptance in the SNE but not SPE condition. These results suggest that shared positive experiences reduce vigilance toward impending rejection and increase sensitivity to pleasantness, whereas shared negative experiences blunt reactivity to rejection feedback and foster social learning from unexpected acceptance to enhance positive expectation.