Intranasal oxytocin decreases self-oriented learning.

Abstract

Oxytocin has been found to play an important role in human social cognition and social interaction. Over the last two decades, surge studies have been conducted to investigate how oxytocin impacts other-oriented processes, such as trust and generosity (Zak et al. in PLoS ONE 2(11):e1128, 2007); however, the examination of the effect of oxytocin on self-related processes was relatively inadequate. Appropriate and efficient social interactions require both self- and other-related information processing. Recent studies have found that intranasal oxytocin (IN-OT) influences the self-related process, although the results have been mixed. The computational process underlying the effects of IN-OT on self-processing remains unknown. We aim to investigate the effect of IN-OT on self-oriented learning across different contexts (self-other independent vs. self-other dependent) and uncover the process by which IN-OT affects dynamic behavior changes. We performed two double-blind, placebo-controlled studies and used reinforcement learning theory to integrate action and related feedback for participants' behaviors. In study 1, IN-OT decreased self-oriented reward learning when self-oriented learning and prosocial (other-oriented) learning were assessed separately. These effects were partially due to the OT-related increase in choice variability during self-oriented learning. In study 2, IN-OT also decreased learning performance during self-oriented reward learning when self-related and other-related rewards were present together. These effects occurred at an early stage of the learning process and could be moderated by the participants' social value orientation. Our findings show that OT attenuates the process of self-oriented learning and provides an underlying computational process. Our findings shed new light on the dynamics of IN-OT's effects on human self-oriented learning processes. For future studies on OT effects on self-oriented learning, individual factors such as social value orientation should be taken into consideration in research development and analysis.