Lateralised neural mechanisms facilitate auditory self-other distinction and coordination in human dyads.

Coordinating actions with others is essential for successful social interaction. Such coordination, as in sports and musical performances, often relies on sound, requiring the brain to process and integrate acoustic information related to the actions of 'self' and 'other' while maintaining sufficient distinction between them. However, such self-other differentiation can be challenged during real-world auditory interactions due to self and other signals being mixed when arriving at the eardrum, creating the potential for agency confusion and impaired coordination. Here we combined dual-EEG and frequency tagging techniques to investigate the behavioural and brain mechanisms supporting the self-other distinction during a joint auditory-motor synchronisation task. Twenty-five dyads synchronised self-paced, finger pressure-controlled continuous sound modulations. The results revealed better synchronisation when participants were associated with distinct sounds (different frequency and brightness) and designated leadership roles, facilitating the processing of self and other information and their separation at both peripheral and central levels. The results also indicated that this neural facilitation was stronger in the right hemisphere than the left, as well as for self than other, suggesting critical roles of spectral information and control over one's own actions for auditory self-other distinction and coordination. These findings highlight complementary behavioural and brain mechanisms compensating for self-other masking inherent to auditory interactions, opening new avenues to understanding interpersonal coordination and its disorders.