Fig. 1.

Contribution and prosocial punishment behaviour of DCC and DFR. a Contributions and beliefs in the without punishment treatment (N_DCC = 41; N_DFR = 27). Asterisks refer to Mann–Whitney/Wilcoxon signed-rank tests; n.s. P ≥ 0.10; **P < 0.05; ***P < 0.01. b Contributions and beliefs in the with punishment treatment (N_DCC = 49; N_DFR = 22). Asterisks refer to Mann–Whitney/Wilcoxon signed-rank tests; n.s. P ≥ 0.10; *P < 0.10; ***P < 0.01. c Average expenditure on prosocial punishment. n.s. P > 0.10; Mann–Whitney test. d Proportion of punishers engaged in prosocial punishment. n.s. P > 0.10; χ² test. The error bars indicate ± 1 SEM