Extended Data Figure 3. Mice change their responses to share food rewards with their conspecifics.

a, Experimental design of the SDM. Actor mice were trained on a two-choice decision paradigm where nose pokes resulted in food rewards. In the condition i.”with recipient” (orange) one nose poke resulted in food reward to actor (selfish choice) and the other nose poke in food reward both to the actor and to the recipient, in the adjacent compartment (altruistic choice). After an inter-trial interval of 5 seconds (ITI), a new trial started, and actor could make their choice. The location of the two responses were counterbalanced between left and right nose-pokes. In the condition ii. “no recipient” (grey) the structure of the task was identical, but the adjacent compartment was empty. iii. In the condition “with toy”, the recipient was replaced. b, Nose poke responses (in percentage) during baseline training in the right and left nose poke holes were not different at the group level (two-tailed paired t-test: t=0.47, d.f.=24, p=0.6423, n=13 mice). c, Change of preference (in percentage) to altruistic responses during the SDM with recipient compared to the baseline (one-sample t-test, t=2.36, d.f.=64, p=0.0211, n=13 mice). d, Number of tested mice grouped by preference. e, Change of preference (in percentage) to altruistic responses during the last session of SDM in males (n=7) compared to females (n=6) mice (two-tailed paired t-test: t=1.94, d.f.=11, p=0.0773). f, Change of preference when animals were tested one additional day with their recipient (R→R, n=7) or with an inanimate object (toy, R→T, n=6) (two-tailed unpaired t-test, t=2.49, d.f.=11, p=0.0296). *p<0.05. Values are expressed as mean ± s.e.m.