Can mammals other than human beings demonstrate empathy for one another, engage in pro-social behavior, and help others in distress?

New Tel Aviv University (TAU) research based on an animal model using rats found that, just as with humans, rats are also split into various groups with different indicators to the point that they come to the aid of members of their group but do not help rats from other groups.

The study’s findings demonstrate that rats engage the brain’s reward system when trying to assist a trapped friend. On the other hand, when the trapped rat is from another, unfamiliar breed, the rats do not help it and the brain’s reward system does not activate. A sense of belonging seems to be the dominant factor that affects social solidarity, not empathy for the suffering and distress of others.

The study was led by Dr. Inbal Ben Ami Bartal of TAU’s School of Psychological Sciences and Sagol School of Neuroscience, in collaboration with Professor Daniela Kaufer of the University of California and Berkeley as well as additional researchers from Stanford University and the University of Toronto. The study was published in eLife.

According to Dr. Ben Ami Bartal, the new study relied on a previous discovery that found that rats show empathy for members of their own breed and even rescue them from trouble. Later research found that although rats help those in their peer group, they only help members of their own breed and not rats of other breeds. The research team decided to examine what change in the brain causes this behavioral difference that leads the rats to only help members of the same group.

Dr. Ben Ami Bartal explains that, during the course of the study, researchers used phosphoric markings to mark those neurons in the rats’ brains that were active when the rats were in the presence of trapped rats. Similarly, the researchers recorded their cerebral activity by means of a calcium signal that is released when neurons are active. When a free rat saw a trapped rat, a system in its brain, similar to that seen in humans when they report feeling empathy, was activated.

Nevertheless, only when the rats discerned that it was a rat of their own breed did the researchers observe “helpful behavior” and action by the brain’s “reward system,” the activation of a neural network that inspires motivation to perform acts that contribute to survival. 

“This research shows that the reward system has an important function in helping behavior. If we want to increase the likelihood of pro-social behavior, we must reinforce a sense of belonging more than a sense of empathy,” Dr. Ben Ami Bartal  says. “An additional study that we are currently conducting attempts to examine what happens in the brains of rats from different groups over the course of two weeks during which they live together and become friends, and how can we use artificial brain stimulation to cause the rats to show empathy for the plight of rats from another breed.”