Becoming eager for belonging: enhanced interbrain synchrony during emotional interaction in social avoidance individuals after social rejection

Socially avoidant individuals, who are vulnerable to interpersonal conflict and social rejection, are characterized as low social approach motivation and high social avoidance motivation. However, the neural underpinnings of the influence of social rejection on socially avoidant individuals have not been fully studied. This study utilized EEG-based hyperscanning to examine the interbrain synchrony (IBS) of 18 socially avoidant dyads and 18 comparison dyads during a cooperative task. To examine the effects of social rejection on interpersonal interaction, satisfaction of belonging need and IBS during the cooperative task were compared between socially avoidant group and non-avoidant group before and after social rejection. Results showed that (i) satisfaction of belonging need of social avoidant group decreased significantly after rejection, with no significant difference between groups before rejection; (ii) alpha and theta IBS was higher in the socially avoidant group than in the non-avoidant group after social rejection, while no significant difference was observed between groups before rejection; (iii) in frontal and parietal-occipital regions, the causal directionality from the non-avoidant individual to socially avoidant individual was significantly increased after rejection. These findings advance the understanding of the paradox of social avoidance and the yearning for belonging in a neuroscience perspective.