In-Group Favoritism

"Oxytocin may strengthen existing social bonds (for example, between relatives/friends), but it does not help create new bonds between strangers, implying that it is less of a “love”, “empathy” or “moral” molecule and maybe more of an “us-versus-them” molecule [29].

Indeed, oxytocin may actually promote antisocial behaviors toward unfamiliar individuals [29].

Oxytocin can increase positive attitudes toward individuals with similar characteristics, who then become classified as “in-group” members, whereas individuals who are dissimilar become classified as “out-group” members [30].

Oxytocin promotes ethnocentric behavior, incorporating the trust and empathy of in-groups with their suspicion and rejection of outsiders. It promoted dishonesty when the outcome of lying benefited the group to which an individual belonged (the in-group) [31].

When given oxytocin, individuals alter their subjective preferences in order to align with in-group ideas over out-group ideals [32].

The in-group bias is evident in smaller groups; however, it can also be extended to groups as large as one’s entire country leading toward a tendency of strong national zeal. A study done in the Netherlands showed that oxytocin increased in-group favoritism of their nation while decreasing acceptance of members of other ethnicities and foreigners [33].

It has thus been hypothesized that this hormone may be a factor in “xenophobic” tendencies. Furthermore, oxytocin was correlated with participant desire to protect vulnerable in-group members [34]''.