Dose-response effects of exogenous oxytocin on social cognition: A systematic review

Oxytocin, a neuropeptide known for its role in social bonding, has garnered considerable attention for its potential to enhance social cognition in humans. Intranasal administration of oxytocin is the standard method in exogenous oxytocin research. This systematic review critically examines the effects of exogenously administered oxytocin on three core components of social cognition: emotion recognition, empathy, and interpersonal trust. By comparing findings across studies using intranasal oxytocin doses ranging from 1 IU to 48 IU in healthy adult humans, we evaluate evidence for a potential dose-response relationship. The majority of studies administered a standard dose of 24 IU and generally reported significant improvements in emotion recognition, empathy, and trust. However, divergent findings at this dose have also been observed. Evidence for both lower and higher doses remains mixed. Much of the support for the Inverted-U Curve hypothesis - suggesting that oxytocin's effects follow a nonlinear trajectory with optimal outcomes at moderate doses - comes from studies lacking direct dose comparisons. Furthermore, the effects of oxytocin on social cognition appear to be strongly moderated by individual and contextual factors, raising questions about the generalizability of the Inverted-U model. Additional research is necessary to clarify the conditions under which dose-dependent effects occur.