Oxytocin Modulation Of Experienced And Perceived Social Exclusion

Social exclusion is a common phenomenon during which individuals are excluded or rejected by another person or group leading to impaired needs of belonging and connection.Social exclusion normally includes different forms such as exclusion,rejection,insolation,and igore.Social exclusion is an aversive social experience not only when being excluded personally but also when observing that others suffering from being excluded.Long-term social isolation leads to detrimental effects on both mental health and cognitive functions.The hypothalamic neuropeptide oxytocin plays an important role in social cognitive processes.An increasing number of studies have demonstrated that intranasal oxytocin reaches the brain and numerous previous studies have reported effects of intranasal oxytocin on social cognitive behavior including empathy,interpersonal interaction,and social bonding in human.Together this suggests that the administration of intranasal oxytocin represents an attractive experimental strategy to study the modulatory role of oxytocin on human behavior.The current project aimed to investigate the effects of intranasal oxytocin on social exclusion,both when being excluded personally(study 1)and when observing others being excluded(study 2).Study 1 employed a modified version of a virtual ball tossing game(Cyberball)which incorporated one player that excluded the participant,one that included the participant,and one treated others equally.The aim was to examine oxytocin effects on personally experienced social exclusion by in-group members and long-term effect on memory,affection,and social preference related to previous exclusion.Results from study 1 indicated that subjects in both placebo and oxytocin group exhibited increasing ball-throws to excluders during the Cyberball game,thus no effect of oxytocin on social interaction during the Cyberball game was found.However,after one week,male,but not female,subjects in the oxytocin group exhibited an increased preference for playing again with players who had previously excluded them.In addition,this oxytocin effect was positively associated with independent traits.Study 2 also employed a modified version of the Cyberball game during which participants initially observed that another player(victim)was excluded during the game(OBSERVE session)and subsequently participated themselves in the game with the victim,the excluder and another new neutral player(PLAY session).The game additionally incorporated monetary rewards for the participants for excluding the victim thus increasing personal financial interest for the exclusion of the victim.The aim of study 2 was to examine oxytocin effect on observing others being excluded for the purpose of maximize self-interest and whether oxytocin influences social pain empathy and altruistic behaviors or self-interest behaviors when these are competing.Study 2 employed functional MRI to additionally investigate the underlying neural effects of oxytocin on the brain and included identical assessemens of long-term effect of oxytocin in a one week follow-up as study 1.Results from study 2 indicated that observing others being excluded compared to being included was associated with increased activity in the posterior cingulate cortex(PCC),left midcingulate cortex(l MCC),precuneus,left inferior parietal lobule(l IPL),and right posterior superior temporal sulcus(rp STS)which are core regions of the mentalizing network.Oxytocin had no effect during this phase.However,when subjects subsequently played with the excluder in the PLAY session,the victim who was excluded,and a new player simultaneously,those who received oxytocin treatment chose to throw more balls to the excluder who could be expected to be reciprocate and therefore maximizing the financial reward and self-interest.On the neural level,this behavioral effect of oxytocin was associated with greater medial orbitofrontal cortex activation when playing with the excluders and this was negatively correlated with trait-altruism scores.This study demonstrated that in the context of competing motivations for exhibiting altruistic or self-interest behavior in social interactions,oxytocin enhanced self-interest behaviors rather than altruistic behaviors.Again,the follow up assessments revealed that in comparison to the placebo group,the oxytocin group preferred to reconnect with excluders.In conclusion,oxytocin has no effect when being excluded by one member from the in-group,however,it increases subjects' willingness to reconnect with excluders.Oxytocin did not influence empathy when observing others being excluded but it promotes subjects to exhibit stronger self-interest when altruistic and self-serving behaviors compete in the same paradigm.This effect was still observable after one week when subjects in the oxytocin group showed higher preference to reconnect with excluders to restore social affiliation.Thus,the current project demonstrated that oxytocin increased subjects' preference for excluders who socially excluded them or excluded others to restore social bonding.The findings from this project provide further support for the important role of oxytocin in human social behavior and suggesting that under some circumstances it may promote self-serving rather than prosocial behavior.