Mechanisms underlying bidirectional norm enforcement: Examining the effects of fairness and kinship cues

Homo sapiens have a unique ability to establish and enforce social norms among Iarge and genetically diverse groups of individuals. The present study examined the effects of fairness and kinship cues on third-party social norm enforcement. To explore the mechanisms underlying social norm enforcement, participants (N = 80) evaluated and determined the appropriate punishment or reward for scenarios that varied in kinship cues and severity. There was no significant difference in mean ratings or reaction time measures following two-party interactions aimed at priming one's perception of fairness. By contrast, the presence of kinship cues resulted in significantly greater rewards for norm compliant scenarios and significantly less punishment for norm violation scenarios, suggesting an important role for kinship cues in third-party decision-making.