EEG Correlates of Sustained Attention Variability during Discrete Multi-finger Force Control Tasks

Higher emotional synchronization is modulated by relationship quality in romantic relationships and not in close friendships

Emotions are fundamental to social interaction and deeply intertwined with interpersonal dynamics, especially in romantic relationships. Although the neural basis of interaction processes in romance has been widely explored, the underlying emotions and the connection between relationship quality and neural synchronization remain less understood. Our study employed EEG hyperscanning during a non-interactive video-watching paradigm to compare the emotional coordination between romantic couples and close friends. Couples showed significantly greater behavioral and prefrontal alpha synchronization than friends. Notably, couples with low relationship quality required heightened neural synchronization to maintain robust behavioral synchronization. Further support vector machine analysis underscores the crucial role of prefrontal activity in differentiating couples from friends. In summary, our research addresses gaps concerning how intrinsic emotions linked to relationship quality influence neural and behavioral synchronization by investigating a natural non-interactive context, thereby advancing our understanding of the neural mechanisms underlying emotional coordination in romantic relationships.

Interfinger Synchronization Capability of Paired Fingers in Discrete Fine-Force Control Tasks

This study examined whether within-a-hand and between-hands finger pairings would exhibit different interfinger synchronization capabilities in discrete fine-force control tasks. Participants were required to perform the designed force control tasks using finger pairings of index and middle fingers on one or two hands. Results demonstrated that the delayed reaction time and the timing difference of paired fingers showed a significant difference among finger pairings. In particular, paired fingers exhibited less delayed reaction time and timing difference in between-hands finger pairings than in within-a-hand finger pairings. Such bimanual advantage of the pairings with two symmetric fingers was evident only in the task types with relatively high amplitudes. However, for a given finger pairing, the asymmetric amplitude configuration, assigning a relatively higher amplitude to either left or right finger of paired fingers, has no significant effect on the interfinger synchronization. Therefore, paired fingers on both hands showed a bimanual advantage in the relatively high force, especially for the pairing of symmetrical fingers, whereas asymmetric amplitude configuration for a finger pairing was able to suppress the bimanual advantage. These findings would enrich the understanding of the interfinger synchronization capability of paired fingers and be referential for interactive engineering applications when leveraging the interfinger synchronization capability in discrete fine-force control tasks.