In the argument about whether dogs are likely to leave some of their dinner for a stray cat who might come into the house later to eat it (let alone whether the dog knows the cat is pregnant and is feeding her because she’s pregnant…), someone linked to this interesting research that seems to show that rats can do altruism.
In the new study, Mason, Bartal and University of Chicago colleague Jean Decetyplaced pairs of rats in Plexiglass pens. One rat was trapped in a cage in the middle of the pen, whereas the other rat was free to run around. Most free rats circled their imprisoned peer, gnawing at the cage and sticking their paws, noses and whiskers through any openings. After a week of trial and error, 23 of the 30 rats in the experiment learned to open the cage and free their peers by head-butting the cage door or leaning their full weight against the door until it tipped over. (The door could only be opened from the outside.) At first the rats were startled by the noise of the toppling door. Eventually, however, they stopped showing surprise, which suggests that they fully intended to push the door aside. Further, the rodents showed no interest in opening empty cages or in those containing toy rats, indicating that a break out was their genuine goal.
In this first set of experiments, most rats seemed quite willing to help their peers, but Mason wanted to give them a tougher test. She placed rats in a Plexiglass pen with two cages: in one was another rat, in the other was a pile of five milk chocolate chips—a favorite snack of these particular rodents. The unrestricted rats could easily have eaten the chocolate themselves before freeing their peers or been so distracted by the sweets that they would neglect their imprisoned friends. Instead, most of the rats opened both cages and shared in the chocolate chip feast.
That’s pretty cool.
Mason’s new study is one of the most recent in a series of experiments changing how scientists think about empathy and altruism in the animal kingdom. At first, most people agreed that true altruism was a uniquely human characteristic requiring an awareness of one’s actions as selfless. Now it seems that many animals have evolved instincts to help others, even at a cost to themselves, and that we inherited these same instincts. “The bottom line is that helping an individual in distress is part of our biology,” Mason says. “It’s not something that develops or doesn’t develop because of culture.”
It’s a mammal thing. Oxytocin. Caring.
In earlier work, McGill University psychologist Jeffrey Mogil and his colleagues showed that mice recognize their peers’ pain—what researchers call “emotional contagion”—and spend more time with suffering cage mates. His team also developed a scale to measure pain expressed on the faces of mice.
Mogil was impressed with Mason’s study, but had some questions about the findings. “This is surprising because it’s not clear what the motivation for the prosocial behavior is, although the prosocial behavior is clearly there,” says Mogil. Both Mogil and Mason point out that because trapped rats squeak out alarm calls now and then, which stress out any fellows that hear them, the rats opening the doors might be trying to silence their peers. Mason thinks the alarm calls aren’t frequent enough to motivate the rats, but Mogil is not so sure.
So it could be just “stop making that noise.” Or it could be freedom, freedom, freedom.