Intergenerational Altruism and Sustainable Development: The Role of Descendants and Age Effects in Promoting Future Well‐Being

Sustainability challenges can be framed as problems of intergenerational altruism—how the current generation allocates resources to future generations. Institutional reforms such as Demeny voting assume that descendants act as intermediaries who enhance altruism toward the future. We test this “altruism premium” and evaluate two interventions, priming and proxy decision‐making, in an incentivized online donation experiment with 2735 Japanese participants (childless, Parents, and Grandparents groups). The child‐mediated altruism premium was confirmed, but the positive effect for grandparents was absorbed by a general age effect. Priming did not significantly increase donations, while proxy decision‐making significantly reduced them, especially among women. Notably, obligation toward intermediaries correlated negatively with future‐oriented altruism among male parents. These findings confirm that children strengthen future‐oriented altruism, but suggest that institutional strategies relying on intermediaries face challenges arising from psychological mechanisms and marked gender differences.