Physical Pain Sensitivity Effects On Social Judgement Feedback Processing And Its Cognitive Neural Mechanism

Physical pain is a distressing experience associated with actual or potential tissue damage such as having a finger cut with a kitchen knife.Social pain is an unpleasant experience caused by the breakdown of social relations or the loss of social value such as social exclusion or rejection.While both experiences are unpleasant affective experiences,physical pain and social pain,serving as a warning of threat,function to protect individuals from a present or potential injury or hurt.Social pain can partly activate brain regions related to physical pain(such as the anterior insula and the anterior cingulate cortex),evokes increase in theta oscillations(θ,4-8 Hz)in anterior cingulate cortex,which are typically implicated in detecting,monitoring,and reacting to threat related events.Based on the similarity in subjective experience and neural representations between physical pain and social pain,the present study investigated the individual variations in sensitivity to physical pain and social pain,and tested the hypothesis that healthy individuals who were more sensitive to physical pain were also more sensitive to social pain.In Study 1,a modified social-judgment task was adopted,in which the emotional arousal and neural response to expected and unexpected social acceptance / rejection conditions were assessed.Participants with low or high pain-sensitivity(LPS and HPS)were screened by scores on a pain-sensitivity questionnaire,and confirmed by experimental pain-sensitivity assessment.In the social judgement task,participants first provided expectations about being liked/disliked by “peers”,and then received “peers” feedback indicating acceptance or rejection.Behavioral results showed that while both groups rated rejection as more unpleasant than acceptance,this difference was greater in the HPS group than LPS group.EEG results showed that only participants in the HPS group exhibited greater early theta(θ)oscillations to rejection than to acceptance,regardless of whether the feedback was expected or unexpected.However,both groups consistently exhibited greater late θ oscillations to rejection than to acceptance only when the feedback was unexpected.These results suggest that participants in the HPS group have higher emotional arousal and θ oscillations response to social pain.Thus,it showed that participants in the HPS group had greater sensitivity in detecting social cues signaling acceptance or rejection at an early stage of information processing.In order to examine whether the relationship between the two is only applicable to social evaluation feedback,the second experiment was set up as a control experiment.In Study 2,the neural responses to non-social feedback were evaluated and compared between the LPS and HPS groups.All participants participated in a time estimation task to estimate the duration of 1 second and received feedback(correct or incorrect timeestimation).The results showed that neither early nor late θ oscillations induced by nonsocial feedback differed between groups.It suggested that sensitivity of physical pain fail to influence the information processing of non-social feedback.In Experiment 1,we found that HPS group was more sensitive to social judgement feedback valence than LPS group in emotional response and early θ oscillation.Only participants in the HPS group exhibited greater early θ oscillations in response to rejection than to acceptance,regardless of whether the feedback was expected or unexpected.These results suggest that participants in the HPS group were more sensitive to social cues signaling acceptance or rejection at early stages of information processing.The Experiment 2 showed that neither ERP responses nor θ oscillations following non-social feedback(correct or incorrect time-estimation)differed between groups.The results showed that the high sensitivity of HPS group to the feedback valence of social judgement was specific.Altogether,the results support the idea that the two share a common "neural alarm system" : the overlapped sensitivity to physical pain and social evaluation among healthy individuals,could be governed by a common system for detecting and monitoring potentially threatening environmental events,regardless of whether the origin is sensory or sociocultural.