Fear Emotion Discrimination test for mice. (A) Schematic drawing of the test setting. (B) Timeline of pre-test and test procedures to evoke in one of the demonstrators a ‘‘fear’’ state by delivering the conditioned tone in the 2- to 4-min epoch. (C and D) Time (in seconds) spent sniffing demonstrators in neutral (gray bars) or tone-induced fear (red bars) state displayed by (C) male and (D) female observer mice during the 6-min test, divided into three consecutive 2-min epochs. *p < 0.05 versus the exploration of the neutral demonstrator. n = 8/15 observers per group. Modified from Ferretti et al Current Biology 2019.

Relief Emotion Discrimination test for mice. (A) Schematic drawing of the test setting. (B) Timeline of pre-test and test procedures to evoke in one of the two demonstrators a ‘‘relief’’ state during the testing phase. (C and D) Time (in seconds) spent sniffing demonstrators in neutral (gray bars) or water-induced relief (yellow bars) states displayed by (C) male and (D) female observer mice during the 6 min of the test, divided into three consecutive 2-min epochs. **p < 0.005 versus the exploration of the neutral demonstrator. n=15 observers per group. Modified from Ferretti et al Current Biology 2019.