A study published in 2011 conducted by Inbal Ben-Ami,
Jean Decety, and
Peggy Mason working at the University of Chicago provided the first evidence of empathy-driven behavior in rodents. Appearing in the prestigious journal
Science, the results of this landmark study showed that untrained laboratory rats will free restrained companions and this helping is triggered by empathy (Ben-Ami Bartal, I., Decety, J., & Mason, P. 2011. Empathy and pro-social behavior in rats.
Science 334, 1427-1430). They'll even free other rats rather than selfishly feast on chocolate. Researcher Peggy Mason noted, "That was very compelling…It said to us that essentially helping their cagemate is on a par with chocolate. He can hog the entire chocolate stash if he wanted to, and he does not. We were shocked." In response to these studies I've received comments such as, "Oh really, I didn't know that" and "Wow, who would have thought chickens, mice, and rats would display empathy for others?"