A recent neuroimaging study revealed that after a group reaches consensus, the brain waves of its members become more synchronized. In this study, participants watched ambiguous movie clips and then discussed them to reach a common understanding. The researchers found that once agreement was reached, the brain wave patterns of the group members became more alike. The study was published in Nature Communications.
Communication is one of the most basic human necessities. Communication is necessary for babies and children to fully develop their cognitive capacities. The ability to communicate and coordinate actions through communication is what made humans the dominant species of the planet. It is very difficult for humans to maintain their mental health when they are deprived of an opportunity to communicate with others for prolonged periods.
Communication with others is also a way in which humans shape their beliefs, define their identity and achieve many things necessary for daily survival. The human society is highly specialized and humans generally obtain most of their necessities through communication and exchange with others. From all this, it is clear that communication shapes our neural processes, but it remains insufficiently clear how exactly.
Study author Beau Sievers and his colleagues wanted to explore how building consensus through conversation changes the brain activity of a group. They note that all human cultures have processes that involve groups reaching a consensus through conversation. These include juries, parliaments, group decisions in organizations, but also situations where groups of friends or family members talk about how to interpret events important to them.
The study involved 49 Master of Business Administration students from a private university in the U.S., who were previously part of a research study on social networks. The participants, aged 26 to 32, included 26 women. Prior to the study, participants completed a survey mapping their social network positions, revealing their connections and relationships with others.
The participants watched video clips from major movies while undergoing functional magnetic resonance imaging (fMRI) scans. The clips, focused on social interactions, were chosen for their ambiguity and shown without sound, removing dialogue and music cues.
Following this, participants gathered in groups of 3 to 6 to discuss the clips and reach a consensus on their interpretations. They then completed a survey reflecting this consensus. In a final session, they re-watched the clips while undergoing another fMRI scan.
The results showed that groups that reached consensus had greater similarity in their brain activities during the third session. This alignment was particularly evident in the visual and auditory sensory areas and in higher-order areas related to attention and the default mode network, such as the temporal parietal junction, angular gyrus, posterior cingulate, medial prefrontal cortex, and temporal pole.
The researchers also observed behavioral patterns during the discussions – participants perceived as having high social status spoke more and signaled disbelief in others. Their groups had unequal turn taking, but also lower levels of neural activity alignment. On the other hand, participants who held central positions in their social networks, encouraged others to speak, leading to more equal turn-taking. Such groups showed higher levels of neural alignment in the 3 session.
“These results suggest the possibility that thinking like one’s conversation partners facilitates social connection. Previous research on personality and social network centrality points in this direction: People with high self-monitoring personalities (i.e., those who adapt their behavior to the people around them) tend to be more socially central and they become so by making friends across disconnected cliques,” the study authors concluded.
“Although we do not know how our participants became central in their social networks, it is plausible that the ability to help groups reach consensus through a combination of influence and flexibility enabled them to grow large and diverse groups of friends. It is also possible that those in central network positions for independent reasons are motivated to develop consensus-building conversation behaviors.”
The study sheds light on the neural activity changes that happen as results of group discussions. However, the observed effects were relatively small. Also, the observed changes were the result of viewing and discussing specific movie clips. It is possible that with other movie clips or with other types of contents, affected brain areas would not be the same.
The study, “Consensus-building conversation leads to neural alignment,” was authored by Beau Sievers, Christopher Welker, Uri Hasson, Adam M. Kleinbaum, and Thalia Wheatley.