Inter-brain synchronization in naturalistic EEG hyperscanning: a case study in educational settings

Despite the increasing use of EEG hyperscanning in social neuroscience, its application to educational settings faces critical challenges, particularly the need to distinguish true inter-brain synchronization from coincidental synchrony driven by shared stimuli. This study shows the use of the circular correlation coefficient (CCor) as a robust metric for quantifying inter-brain synchronization while minimizing these spurious effects. CCor is a bivariate undirected estimator which quantifies the circular covariance of deviations from the expected phase of each oscillator. By analyzing alpha-band synchronization between high school students during biology classes, we demonstrate the ability of this index to uncover the neural correlates of cognitive processes in a naturalistic educational scenario. Our results reveal that interactive teaching formats, such as class discussion (D), significantly enhance high-alpha synchronization (0.1051 ± 0.0025), reflecting heightened attention and cognitive engagement. In contrast, less interactive formats, such as teacher reading (TR), show reduced synchronization (0.0648 ± 0.0044), likely due to lower shared attention and engagement. These findings establish CCor as a valuable tool for studying learning dynamics and optimizing educational strategies, offering new insights into the neural mechanisms underpinning effective teaching and collaborative learning.