Effects of Oxytocin on Social Comparisons in Intergroup Situations.

Oxytocin (OXT) is known to affect various social processes, including social comparisons and intergroup competition. In this study, we examined whether social comparisons in intergroup situations can be modulated by OXT and, if so, how this modulation manifests. Using a double-blind placebo-controlled design, we randomly assigned male participants to either OXT or placebo treatment and then asked them to play a card game with either an in-group or an out-group member. The OXT-treated participants showed a greater social comparison effect in the games with an out-group member than in games with an in-group member. Specifically, the participants in the OXT treatment condition showed a greater acceptance rate for relative gain (downward comparison) and a lower acceptance rate for relative loss (upward comparison) while playing with an out-group member rather than an in-group member. In contrast, no such effect was observed among placebo-treated participants. These findings demonstrate that OXT facilitates intergroup social comparisons with out-group versus in-group members.