Reasoning and empathy are not competing but complementary features of altruism

Humans can care about distant strangers, an adaptive advantage that enables our species to cooperate in increasingly large-scale groups. Theoretical frameworks accounting for an expansive moral circle and altruistic behavior are often framed as a dichotomy between competing pathways of emotion-driven empathy versus logic-driven reasoning. Here, in a pre-registered investigation comparing variations in empathy and reasoning capacities across different exceptionally altruistic populations –– effective altruists (EAs) who aim to maximize welfare gains with their charitable contributions (N = 119) and extraordinary altruists (XAs) who have donated organs to strangers (N = 65) –– alongside a third sample of demographically-similar general population controls (N = 176), we assess how both capacities contribute to altruistic behaviors that transcend conventional parochial boundaries. We find that, while EAs generally manifest heightened reasoning ability and XAs heightened empathic ability, both empathy and reasoning independently predict greater engagement in equitable and effective altruism on laboratory measures and behavioral tasks. Interaction effects suggest combining empathy and reasoning often yields the strongest willingness to prioritize welfare impartially and maximize impact. These results highlight complementary roles for empathy and reasoning in overcoming biases that constrain altruism, supporting a unified framework for expansive altruism and challenging the empathy-reasoning dichotomy in existing theory.