Influence of interpersonal personality traits on cooperative and competitive behavior in transparent dyadic interactions

Social decision-making requires individuals to balance self-interest with mutual benefit,continuously adapting their behavior to the intentions and actions of others. Whileclassical economic games have provided important insights into cooperation andcompetition, they typically rely on discrete, turn-based decisions that fail to capture thefluid and reciprocal nature of real-world social interactions. The present study used anovel transparent Dyadic Interaction Platform and a novel Cooperation–CompetitionForaging task to examine how the interpersonal personality traits agency andcommunion shape dynamic, real-time social behavior. In this task, pairs of participants(dyads) jointly or individually collected targets with variable payoffs, allowingcooperative and competitive strategies to emerge naturally as both partnerscontinuously observed each other’s gaze, actions, and outcomes. Using a round-robindesign, we assessed how interpersonal traits and partner-specific adaptations jointlypredicted dyadic strategic outcomes. Within each session, dyads gradually convergedtoward stable interaction modes, with increasing cooperation across sessions. Highermean communion within dyads predicted enhanced cooperation, indicating that sharedaffiliative tendencies promote jointly oriented behavior. Additionally, behavior in eachsession was significantly influenced by prior dyadic history, indicatingexperience-dependent adaptation. These findings demonstrate that continuous,transparent interaction paradigms reveal how stable personality traits and dynamicpartner feedback jointly shape social strategies. By linking personality traits from theInterpersonal Circumplex to behavioral adaptations, this study contributes to bridgingthe gap between traditional game-theory approaches and ecologically valid models ofreal-world social decision-making.