In this paper, we studied the enforcement mechanisms behind social norms, finding that a large percentage of subjects are willing to enforce distribution and cooperation norms even though they incur costs and reap no economic benefit from their sanctions and even though they have not been directly harmed by the norm violation. Thus, third-party sanctions provide a further important example for the notion of strong reciprocity (Fehr & Fischbacher 2003; Fehr et al., 2002; Gintis et al., 2003). Our questionnaire results are consistent with the view that third-party sanctions are driven by negative emotions and negative fairness judgments towards norm violators.

XREF: Connects to strong reciprocity literature — Fehr, Gintis. Links to known behavioral economics of altruistic punishment. QUESTION: Do third-party sanctions scale beyond lab settings, and what cultural variation exists in willingness to punish? Builds on: "Unaffected bystanders punish norm violators even without personal stakes"

Ernst Fehr, Third-Party Punishment and …, loc. 147