| The transition to online education during the COVID-19 pandemic altered the timing and
flow of group interactions, disrupting both temporal precision and social alignment. We
investigated the impact of various Modes of Communication (MoC), face-to-face, live-online, and
prerecorded conditions, on brain activity and stress responses while participants had to engage in
synchronized drumming with a virtual partner (VP) while we recorded electroencephalography
(EEG) and salivary cortisol levels during coordinated joint-rhythmic tasks. Grounded in Ideomotor
Theory, we posited that face-to-face interactions would enhance sensorimotor coupling through
increased mu-Event Related Desynchronization (mu-ERD) and amplified theta activity,
particularly in conditions of elevated asynchrony. Additionally, we anticipated elevated cortisol
levels in the face-to-face condition attributable to augmented social presence and evaluative stress.
Contrary to our hypotheses, mu-ERD and theta activity did not reveal significant differences across
all MoC conditions. Behavioral performance showed greater asynchrony in the live-online
condition at the slower tempo (120 BPM), suggesting reduced timing accuracy in virtual settings.
Interestingly, mu-ERD increased at the faster tempo (132 BPM), reflecting stronger motor
engagement with no associated improvement in timing accuracy. Cortisol levels did not differ for
MoC and declined from pre- to post-test across all groups, suggesting habituation, fatigue, or
recovery from stress. These results imply that while neural engagement remains consistent across
all MoCs, virtual interactions may impede temporal coordination during collaborative tasks. Future
studies should combine near-infrared spectroscopy (fNIRS) with EEG to better investigate the role
of the anterior cingulate cortex (ACC) in real-time error monitoring.
Keywords: EEG, Cortisol, Rhythmic Synchronization, Ideomotor Theory, Social Coordination |