A constant theme in the Torah, the Talmud and other Jewish texts is concern for one’s fellow man, helping the poor, widows, orphans and others in distress. Commenting on Leviticus 19:18 (“Love your fellow as yourself”) in the Jerusalem Talmud (Nedarim 30b), Rabbi Akiva taught: “This is the most important rule in the Torah.”

While the extent and complexity of human prosocial behavior is unique, basic empathic responses and prosocial behavior are common in social species across the phylogenetic spectrum and rely on evolutionarily conserved biological mechanisms. To care about your fellow man, one must have empathy. But what motivates people to show empathy and help a friend in distress?

Researchers at Tel Aviv University (TAU) who wanted to understand the biological basis for empathy used lab rats to investigate this. Are mammals at all able to demonstrate empathy for one another, engage in pro-social behavior and help others in distress? Their findings indicate that the brain activity that gives rise to one’s motivation to help only occurs when the “other” who is in distress is a member of one’s own group. Thus, their findings show that helping a friend in distress relates more to a sense of group belonging and identity and less to expressing empathy for another’s difficulty and suffering.

Humans, not so different from rodents, are an intensely social species, with complex social interactions and an ability to know and share others’ emotional states. “We often behave prosocially, acting with the intention of benefiting others or improving their well-being. Yet, prosocial behavior tends to be extended preferentially between group members and is less likely to be offered to others outside the group,” they wrote. 

The team 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 only 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. Thus, a sense of belonging is the dominant factor that affects social solidarity and 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 at the Tel Aviv University, in collaboration with Prof. Daniela Kaufer of the University of California at Berkeley as well as additional researchers from Stanford University and the University of Toronto. The study was published in the prestigious journal, eLife under the title “Neural correlates of ingroup bias for prosociality in rats.”

According to Ben Ami Bartal, her team’s new study relied on a previous discovery that was published in the journal Science, where it was found that rats show empathy for their peers and even rescue them from trouble and reaching out to help is as rewarding to them as eating chocolate. Later, additional research found that although rats love to help their peers, they only help members of their own group and not rats from other groups. As a result, in the current study, 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. 

Ben Ami Bartal explained 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 the trapped rats. Similarly, the researchers recorded their cerebral activity by means of a calcium signal that is released when neurons are active. 

Their findings are fascinating. Upon seeing the trapped rat, a system in the brain – which is 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” – meaning activation of a neural network that inspires motivation to perform acts that contribute to survival such as eating calorie rich foods.  

“This research shows that the reward system has an important function in helping behavior, and if we want to increase the likelihood of pro-social behavior, we must reinforce a sense of belonging more than a sense of empathy,” suggested Ben Ami Bartal. “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.”