Pavlov taught his dogs to slobber at the sound of a bell. Now, in a recent study, researchers have taught mice to flinch in pain at the sound of a buzzer. The difference is that the mice learned that behavior from watching each other—and their reaction suggests that there's a genetic basis to empathy.
In the study, published in the journal PloS ONE, researchers from the University of Wisconsin, Madison, and Oregon Health and Science University bred two different strains of mice, with two different genetic make-ups. One strain is known to be quite gregarious while the other is much less social.
With these genetically-engineered social and nonsocial mice, the researchers set up their experiment. They put one ordinary mouse in a cage and administered a mild electric shock to its foot while sounding a buzzer for 30 seconds. The mouse squeaked in distress.
In another cage, a mouse of either the social or antisocial strain looked on, within earshot of the buzzer.
Researchers then placed the voyeur mouse in the cage it had just been watching, and rang the buzzer.
The two genetic variations reacted differently. The social mice tended to freeze in place, as if—recalling the suffering they had sensed earlier in their neighboring mouse—they anticipated an experience of pain themselves. Antisocial mice were far less likely to behave this way; they showed just as little distress as did other mice whose neighbor-mouse had not been shocked.
The results suggest not just that mice can learn to feel another's pain, but that empathy may be encoded in animals' genes. After all, the two kinds of mouse differed only in their genes, yet one strain was far more likely to understand that a comrade was in pain—and to expect that same experience for themselves when placed in the same conditions.
Based on their finding, the authors conclude that "empathy may be widespread among mammalian species."