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. While classical economic games have provided important insights into cooperation and competition, they typically rely on discrete, turn-based decisions that fail to capture the fluid and reciprocal nature of real-world social interactions. The present study used a novel transparent Dyadic Interaction Platform and a novel Cooperation–Competition Foraging task to examine how the interpersonal personality traits agency and communion shape dynamic, real-time social behavior. In this task, pairs of participants (dyads) jointly or individually collected targets with variable payoffs, allowing cooperative and competitive strategies to emerge naturally as both partners continuously observed each other’s gaze, actions, and outcomes. Using a round-robin design, we assessed how interpersonal traits and partner-specific adaptations jointly predicted dyadic strategic outcomes. Within each session, dyads gradually converged toward stable interaction modes, with increasing cooperation across sessions. Higher mean communion within dyads predicted enhanced cooperation, indicating that shared affiliative tendencies promote jointly oriented behavior. Additionally, behavior in each session was significantly influenced by prior dyadic history, indicating experience-dependent adaptation. These findings demonstrate that continuous, transparent interaction paradigms reveal how stable personality traits and dynamic partner feedback jointly shape social strategies. By linking personality traits from the Interpersonal Circumplex to behavioral adaptations, this study contributes to bridging the gap between traditional game-theory approaches and ecologically valid models of real-world social decision-making.