original_query: What did Greenberg's studies reveal about people's perception of fairness?
query: What did Greenberg's studies reveal about people's perception of fairness?
answer: Greenberg's studies showed that people perceive overpayment to themselves as fairer than overpayment to others, and underpayment to themselves as less fair than underpayment to others.  This egocentrism disappeared when subjects were made self-aware (e.g., by placing a mirror in front of them), suggesting that self-awareness promotes a uniform standard of fairness.