Mice are shown to be capable of empathy and envy
Shigeru Watanabe, Professor, Department of Psychology, Keio University, discovered that mice could distinguish between a condition in which they were subjected to stress together with others (empathy) and a condition in which they alone were subjected to stress while other mice were free from stress (envy). His research will be published on PlosOne: PONE-D-11-11013, DOI: 10.1371 on August 10, 14:00 Pacific Standard Time (PST).
Understanding the emotions of others is an important function for human beings or other social animals in order to live social lives. Professor Watanabe researched empathy and envy in mice in an experiment that took advantage of the fact that mice have a persistent unpleasant memory after they are subjected to stress.
In this experiment, mice were subjected to restraint stress. Then, they experienced an electric shock when they stepped down to the floor from a platform, in a condition in which they were each subjected to restraint stress alone without mates, another condition in which they were subjected to stress together with others, and a third condition in which they were each subjected to stress alone while the other mice were free. In the case in which the mice were each subjected to the restraint stress alone, they showed long hesitation to step down from the platform to the floor when the floor was no longer electrified; on the other hand, in the case in which they were subjected to the restraint stress together with other mice, they soon stepped down from the platform. In the case in which they were each subjected to the restraint stress individually while the others were free, the effect of the stress of the electric shock was more persistent, and so it took more time for them to step down from the platform. This suggests that the mice distinguished between the case in which they were each under stress together with others (empathy) and the case in which they were each under stress while others were free (envy).
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