• Leor Hackel, Stanford Univ.
  • Jamil Zaki, Stanford Univ.
People tend to repay others’ generosity, and this tendency helps kindness spread. Yet, using economic games, we find that people reciprocate more towards wealthy, as opposed to less wealthy, individuals, exacerbating economic inequality. Computational modeling linked this tendency to reward-based reinforcement learning—people’s focus on material gains when forming impressions of others.