Fig. 3
Third-party punishment test (TPPT) results. (a, b) Behaviors of two representative CNT rats in the TPPT. The CNT rats avoid approaching the mice. The two video captures show instants when ICR mice attacked BL6 mice. (c, d) Behaviors of an EAH rat. The rat suffered a retaliatory strike by an ICR mouse (c), at which point the rat nonviolently contacted the aggressive mouse (d). (e–g) Another EAH rat pressed down a violent ICR mouse with its forepaws but did not bite the mouse (e). The ICR mouse decreased its aggressive behaviors toward the BL6 mouse in the presence of the EAH rat (f). The rat approached the BL6 mouse but did not frequently touch it (g). (h) EAH rats showed more frequent contact with the aggressive ICR mice than with the BL6 mice compared to CNT rats. (i, j) When presented with a peaceful pair of mice, there were no fights at all in the absence (i) or presence (j) of an EAH rat. (k) When presented with peaceful pairs, the number of contacts did not significantly differ between the CNT and EAH rats. (l) Most EAH rats made contact more frequently with aggressive ICR mice than with BL6 mice; however, there was no significant difference regarding frequency of contact made by CNT rats. (m) The ICR mice reduced the number of attacks made in the presence of the EAH rats. (n) The number of ICR mice that attacked the BL6 mice within 1 min after rat removal; ‘yes’ and ‘no’ denote attacked and not-attacked in the TPPT, respectively. CNT, n = 16; EAH, n = 16; only the EAH group data in h, n = 15. (h, k) A two-way ANOVA and Tukey’s post hoc test; paired (l) or unpaired (m) two-tailed t-test; (n), χ2 and Fisher’s exact test.
