5 Some dictators seem to have anticipated this difference in punishment across treatments. While the modal transfer level is zero in the TP condition, the modal transfer level is 50 in the SP condition. A Wilcoxon signed rank test for matched pairs shows, however, that—despite the shift in the modal offer—the average offer is not different across conditions. This suggests that, to have an impact on the dictators’ behavior, dictators have to experience that low transfers do not pay in the SP condition.

Ernst Fehr, Third-Party Punishment and …, loc. 86