合意形成のための会話は神経の調整につながる

nature communications Article Consensus-building conversation leads to neural alignment Received: 4 September 2020 Accepted: 3 November 2023 Published online: 10 May 2024 https://doi.org/10.1038/s41467-023-43253-8 Beau Sievers 1,2*, Christopher Welker 1, Uri Hasson 3, Adam M. Kleinbaum 4* & Thalia Wheatley 1,5 Conversation is a primary means of social influence, but its effects on brain activity remain unknown. Previous work on conversation and social influence has emphasized public compliance, largely setting private beliefs aside. Here, we show that consensus-building conversation aligns future brain activity within groups, with alignment persisting through novel experiences partici- pants did not discuss. Participants watched ambiguous movie clips during fMRI scanning, then conversed in groups with the goal of coming to a con- sensus about each clip's narrative. After conversation, participants' brains were scanned while viewing the clips again, along with novel clips from the same movies. Groups that reached consensus showed greater similarity of brain activity after conversation. Participants perceived as having high social status spoke more and signaled disbelief in others, and their groups had unequal turn-taking and lower neural alignment. By contrast, participants with central positions in their real-world social networks encouraged others to speak, facilitating greater group neural alignment. Socially central participants were also more likely to become neurally aligned to others in their groups. We take for granted that conversation plays a profound role in shaping belief and coordinating behavior. We rely on consensus-building conversation when the stakes are high, as in jury trials, scientific funding decisions, corporate boardrooms, and elections. Conversa- tion is also pervasive in day-to-day life, from bars and coffee shops to workplace meetings1. Public conversation is the basis of deliberative democracy2, and disruption of public conversation is considered a 'serious political threat'3. Yet, we lack scientific understanding of how conversation shapes our beliefs and brain responses over time. How does talking change our thinking? Previous research has shown that conversation determines important attitudes and behaviors. Even brief conversations can have meaningful effects, such as creating support for antidiscrimination laws4 or influencing voting behavior5. Further, these effects can spread through social networks. Talking to a friend about may alter whom you vote for6,7. Remarkably, even brief social contact can influence the health outcomes of friends and friends of friends8,9, including depression10, and drug and alcohol use11-13. However, it remains unclear whether these conversations shape the way individuals fundamentally see the world, as behavior is not a perfect reflection of deeply held belief—private acceptance is distinct from public compliance14. Psychologists, economists, and others offering explanations of social