Abstract
This study examined how cognitive load differently affects the neural mechanisms of self-concerned and prosocial decisions. Under low and high cognitive load, participants chose how many tokens (0-5) to spend to reduce unpleasant noise for themselves or others. Results showed that high cognitive load increased token spending for both self and others, with a stronger effect for others. Individuals with higher empathy showed greater prosocial behavior under high load, highlighting empathy's moderating role. Neuroimaging revealed that high load boosted left insula activation during self-concerned decisions, reflecting internal salience and self-protection. In prosocial decisions, cognitive load increased activation in the bilateral temporo-parietal junction (TPJ) and right dorsolateral superior frontal gyrus (dlSFG), areas linked to mentalizing and cognitive control. Functional connectivity within the TPJ-dlSFG-prefrontal network predicted the impact of cognitive load on prosocial choices. These findings reveal distinct neural pathways: cognitive load enhances self-concern via insula salience, while prosocial behavior relies on TPJ-dlSFG integration of empathy and control, deepening the understanding of social decision-making under cognitive constraints.