This study investigates how people decide whom to help—whether they target others within their own group or those outside it.

Researchers conducted an experiment where participants chose recipients for rewards, testing two main hypotheses: that altruism is driven by proximity (in-group preference) or by rational self-interest regarding long-term reputation benefits.

The findings suggest people are significantly more inclined to help members of their in-group. This pattern emerged despite potential reputational advantages from helping outsiders.

This result underscores the powerful pull of group identity over abstract notions like fairness across diverse global contexts.