Oxytocin Facilitates Adaptive Communication by Upregulating Prefrontal Aperiodic Activity

Oxytocin plays a key role in recipient design, the process by which communicators adapt their utterances based on their knowledge of an addressee. This form of adaptive communication requires cognitive exploration and flexibility, as individuals must integrate prior expectations with newly gathered interactional evidence to dynamically adjust their communicative behavior. Here, we investigate the electrophysiological mechanisms supporting recipient design and how oxytocin modulates this process. Fifty-one male participants received a double-blind intranasal administration of either oxytocin or placebo before undergoing magnetoencephalography (MEG) while engaging in a real-time communicative game. They interacted with two presumed addressees—a child and an adult—both portrayed by a role-blind confederate who exhibited consistent communicative behavior across roles. Initially, participants relied on prior expectations, communicating more emphatically with the presumably less competent child. Over time, however, individuals in the oxytocin group adapted more rapidly to interaction-based evidence of matched communicative ability across both addressees. This dynamic adjustment was associated with sustained increases in broadband aperiodic power, a macroscopic correlate of postsynaptic activity, in the right ventral prefrontal cortex. These findings suggest that oxytocin facilitates adaptive communication by upregulating broadband aperiodic activity in a brain region critical for integrating prior beliefs with real-time social cues.