Neural signatures of context-dependent trust: How strategic interaction and social value orientation shape prosocial decisions

Trust is a cornerstone of human cooperation, yet it unfolds differently depending on who we interact with and under what circumstances. Understanding how the brain integrates social traits and contextual demands is key to explaining why we sometimes choose to trust-and sometimes refrain. Although prior studies have identified neural regions involved in trust, it remains unclear how dispositional factors, such as Social Value Orientation (SVO), interact with the strategic context of the decision. Few experiments have jointly manipulated both partner characteristics and game structure, limiting our understanding of how context-dependent trust is represented in the brain. This study examined how partner SVO and game context jointly shape trust behavior and its neural correlates. Thirty-one adults completed a multi-game fMRI paradigm, acting as trustors in the Trust Game (TG), which involves reciprocity, and the Tripled Dictator Game (TDG), assessing altruism. Partner SVOs ranged from aggressive to altruistic. Behaviorally, participants transferred more with prosocial partners, particularly in the TG, and this tendency was strongest among individuals who were themselves more prosocial, indicating that personal dispositions amplify sensitivity to cooperative partners in strategic contexts. Neurally, activity in the precuneus/posterior cingulate cortex increased with higher amount sent during the TG, and regions involved in social cognition, such as the right angular gyrus, reflected how the brain distinguishes cooperative from selfish partners depending on whether trust requires reciprocity. In conclusion, strategic context dynamically modulates both the behavioral expression and neural representation of trust, showing how social preferences and situational demands jointly guide prosocial decision-making.