For their test of altruistic behavior, the team devised an experimental box with two compartments divided by a transparent partition. On one side of the box, a rat was forced to swim in a pool of water, which it strongly disliked. Although not at risk of drowning—the animal could cling to a ledge—it did have to tread water for up to 5 minutes. The only way the rodent could escape its watery predicament was if a second rat—sitting safe and dry on a platform—pushed open a small round door separating the two sides, letting it climb onto dry land.And then the true test of empathy:
Within a few days, the high-and-dry rats were regularly aiding their soaking companions by opening the door, the team reports online today in Animal Cognition. They did not open the door when the pool was dry, confirming that the rats were helping in response to others’ distress, rather than because they wanted company, neurobiologist Peggy Mason says. Rats that had previously been immersed learned how to save their cagemates much more quickly than those who had never been soaked, suggesting that empathy drove their behavior, she adds. “Not only does the rat recognize distress, but he is even more moved to act because he remembers being in that situation.”
In this experiment, rats on the dry platform had to choose between two doors, one that allowed their soaked companion to escape from the pool and another that provided access to a tasty chocolate treat. The rodents chose to help their companions before seeking the snack 50% to 80% of the time, showing that the urge to help a fellow rat was at least as strong as the desire for food.Perhaps human males should consider setting up a similar test for their mates; would she rescue you from five minutes of discomfort if it meant giving up chocolate?