Empathy in rats - a great video

Bartal et al. show yet another example of how the kind of empathic concern humans can show for others is already developed in the rat, a much more simple mammal. I pass on the summary of the work in Science, and be sure to watch the really excellent instructional video the authors provide, showing how a free rat overcomes the fear (caused by emotional contagion from a distressed rat trapped in a small plastic box) to open a door to let the trapped rats escape:

Empathy, a well-known characteristic in humans, occurs when an individual is motivated to help another, while maintaining emotional separation. Thus, it is distinct from emotional contagion where an individual begins to experience the emotions of other individuals, and act similarly. Emotional contagion is known to occur in many mammalian species, but empathy has often been considered unique to primates. Through a controlled experiment in captive rats, Ben-Ami Bartal et al. (p. 1427; see the Perspective by Panksepp) show that the biological roots of empathy could be much deeper than recognized. Rats were highly motivated to release a restrained cagemate, even when they were not permitted any immediate contact with it after release. Furthermore, when presented with chocolate, a highly preferred food, the rats were still motivated to release their cagemate and even shared the food with them. Thus, empathically motivated prosocial behavior is not limited to primates, and—like many other behaviors previously thought to be limited to this group—may serve similarly important functions across species.