Here's the abstract for the article:
Whereas human pro-social behavior is often driven by empathic concern for another, it is unclear whether nonprimate mammals experience a similar motivational state. To test for empathically motivated pro-social behavior in rodents, we placed a free rat in an arena with a cagemate trapped in a restrainer. After several sessions, the free rat learned to intentionally and quickly open the restrainer and free the cagemate. Rats did not open empty or abject-containing restrainers. They freed cagemates even when social contract was prevented. When liberating a cagemate was pitted against chocholate contained with a second restrainer, rats opened both restrainers and typically shared the chocolate. Thus, rats behave pro-socially in response to a conspecific's distress, providing strong evidence for biological roots of empathically motivated helping behavior.The authors report that the female rats were more empathic than the male rats. They also report that the levels of empathic behavior were associated with individual differences in boldness, so that those individual rats with personal propensities to bold behavior were more inclined to empathic behavior.
The authors also argue that this shows that the rats were engaging in deliberate action to free their cagemates.
This supports the claims of Aristotle and Darwin that some nonhuman animals--and particularly mammals--are capable of intentional action in caring for individuals for whom they feel some attachment. Moreover, as indicated by Jaak Panksepp's commentary on this article, research in "affective neuroscience" is uncovering the neural basis for social emotions, which allows us to see how the evolution of morality and politics could emerge from the evolution of the mammalian brain. Human morality and politics are unique insofar as they show the uniqueness of the human capacities for high-level mental processing in the neocortex, and yet even this can be explained by the natural evolution of the neocortical structures of the primate brain.
Many years ago, I was interviewed for a job in the Department of Political Science at the University of Rochester. At that time, the Department was famous for promoting "rational choice theory" in political science--explaining politics through economic models of human beings as rational maximizers of their self-interest. I gave a job talk that was entitled "Emotional Choice Theory," in which I criticized rational choice thinking for failing to see the importance of social emotions in human behavior, which are best explained through evolutionary psychology. As you might expect, my talk was not well received.
If I were giving that job talk today, I might be more persuasive by pointing out how research in evolutionary psychology--as, for example, in studies of empathy in mammalian psychology--has challenged rational choice theory by showing how the economic model of Homo economicus needs to be combined with a Darwinian model of Homo moralis
Inbal Ben-Ami Bartal, Jean Decety, and Peggy Mason, "Empathy and Pro-Social Behavior in Rats," Science, 334 (9 December, 2011): 1427-30.
Jaak Panksepp, "Empathy and the Laws of Affect," Science, 334 (9 December, 2011): 1358-59.
Jaak Panksepp, "The Basic Emotional Circuits of Mammalian Brains: Do Animals Have Affective Lives?" Neuroscience and Biobehavioral Reviews, 35 (2011): 1791-1804.
Some related posts can be found here, here, here, and here.