Social interactions play a role in synchronizing brain activity among individuals. A recent study looked at how the brain synchronization differs between pairs of people with strong social ties and pairs with weak social ties. Surprisingly, the study found that during a cooperative task, pairs of strangers showed more closely connected brain networks compared to pairs of acquaintances. This challenges the common belief that stronger social bonds lead to greater brain synchronization.
Social interactions play a significant role in affecting brain activity, both within an individual’s brain and between the brains of multiple individuals. Engaging in conversations, cooperative tasks, and intimate relationships can lead to coordinated neural activity. Researchers study brain synchronizations to better understand the neural processes behind social behaviors, which can be helpful in diagnosing and treating conditions such as social anxiety and communication-related disorders. However, most investigations on brain synchronization have primarily focused on specific groups.The study, published in the journal Scientific Reports on February 29, 2024, by a team of researchers from Waseda University in Japan, suggests that cooperative tasks between people with weaker social ties may lead to more synchronized brain activity compared to those with stronger ties, such as romantic partners or parents and children. Lead researcher Dr. Yuto Kurihara, a Research Associate at the Faculty of Human Sciences, believes that these findings challenge the traditional understanding of social ties and provide new insights into how the brain functions during social interactions.
A team of researchers from Waseda University, including Dr. Toru Takahashi from the Advanced Research Center for Human Sciences and Professor Rieko Osu from the Faculty of Human Sciences, conducted a study. They observed 14 pairs of strangers who met for the first time and 13 pairs of acquaintances, where one participant brought their partner. The analysis included 21 pairs due to artifacts (11 stranger pairs and 10 acquaintance pairs). The participants were tasked with tapping a mouse button in opposite rhythms, while wearing earphones to hear both their own taps and their partner’s taps.
synchronization in brain signals when tapping in coordination with each other compared to when tapping freely or with a metronome. The synchronized brain activity was most prominent in the alpha and beta frequency bands, indicating a strong connection between partners’ brain signals during coordinated tapping. This suggests that interpersonal brain synchronization is enhanced when individuals are engaged in a joint motor task, such as tapping in synchrony with a partner. These findings contribute to our understanding of how interpersonal coordination is reflected in brain activity and may have implications for fields such as social neuroscience and human-computer interaction.The study found that the synchronization of brain activity in the theta band was stronger in strangers compared to acquaintances. Additionally, the researchers used binary undirected graphs to show that the neural network was more interconnected in strangers than in acquaintances.
Dr. Kurihara remarked, “It is surprising that despite having weaker social ties, strangers demonstrated stronger intra- and inter-brain EEG networks than acquainted pairs.”
The researchers suggest that the lack of familiarity between strangers requires a more complex process for predicting each other’s actions or behaviors during a cooperative task. This finding suggests that the brains of strangers may work harder to understand and cooperate with each other.increased engagement results in a more effective exchange of information between closely connected nodes in the neural network.
This discovery emphasizes the significance of weak social connections in influencing social relationships and individual behavior. “By showing that strangers experience increased intra- and inter-brain synchronization, our study highlights the potential of weak connections in promoting new relationships and understanding the neural basis of social interactions,” Dr. Kurihara commented.
