Finding Agreement: fMRI-hyperscanning reveals that dyads explore in mental state space to align opinions.

Many prize synchrony as the ingredient that turns a discordant conversation into a delightful duet. Although failure to align is sometimes associated with discord, exploring divergent opinions can also foster understanding and agreement, satisfy curiosity, and spur imagination. Using fMRI hyperscanning and natural language processing, we tested if dyadic alignment or exploration during decision-making conversations was a more effective route to agreement. Dyads (N = 60) discussed pressing societal problems while being instructed to either persuade or compromise with their partner. Our analysis uncovered four key insights: First, individuals instructed to compromise rather than persuade tended to agree more at the end of the conversation. Second, hyperscanning and linguistic analyses revealed that encouraging compromise resulted in increased exploration during conversations; dyads given compromise instructions traversed more diverse mental states and topics. Third, heightened exploration was linked to greater agreement at the end of the conversation. Fourth, the effect of the compromise instructions on agreement was entirely mediated by the degree of exploration. Together, these results suggest that finding agreement may be spurred by exploration, something that happens spontaneously when people are motivated to compromise. Significance StatementSuccessful conflict resolution is not just about syncing perfectly--it sometimes means leaning into differences. Our study employed fMRI hyperscanning to examine if exploratory conversation strategies promote consensus. We paired participants to discuss societal issues with either a persuasion or compromise mindset. We found that dyads aiming to compromise reached more agreement because they delved deeper into each others minds and covered more topics; in contrast, dyads aiming to persuade their partner covered a narrower scope of topics and mental states and ended up disagreeing more as a result. The finding that exploration rather than simple alignment facilitates agreement could sharpen communication strategies in fields from politics to education and economics.