January 2012

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Rats Show Empathy, Too

A new study shows that empathy may drive rats to help each other. The finding gives insight into the roots of our urge to assist others in need.

Empathy motivates us to take action when we see someone suffering. Apes and other primates also help each other when they perceive distress. Rats share the distress of other rats, too, but whether they would take the next step to help a fellow rat was unknown.

A team of NIH-funded researchers at the University of Chicago put pairs of rats together in cages. One rat roamed freely while the other was restrained in a clear tube. Each tube had a door that could be nudged open only from the outside by the free rat.

Most rats learned how to quickly release the door to set their companion free. But the rats paid little attention to tubes that were empty or contained only a toy rat. Even when the free rats couldn’t get to the liberated rats to play with them, they still released the trapped rats.

The scientists then tried giving rats 2 tubes—one with a rat inside and another with 5 chocolate chips, a favorite rat snack. The free rats opened both tubes in no consistent order and allowed their liberated cagemates an average of 1.5 chips.

“That was very compelling,” says researcher Dr. Peggy Mason. “It said to us that essentially helping their cagemate is on a par with chocolate. He could hog the entire chocolate stash if he wanted to, and he does not. We were shocked.”

The researchers say their experiments suggest we have a biological need to act on our empathic  feelings. “It’s in our brain,” Mason says.